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Non-weight bearing water exercise : changes in cardiorespiratory function in elderly men and women Jessop, Darrell James 1988

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Non-Weight Bearing Water Exercise: Changes in Cardiorespiratory Function i n Elderly Men and Women by Darrell James Jessop B.Sc, University of Bri t i s h Columbia, 1977 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF PHYSICAL EDUCATION in THE FACULTY OF GRADUATE STUDIES School of Physical Education and Recreation We accept this thesis as conforming to the required standards THE UNIVERSITY OF BRITISH COLUMBIA October, 1988 © Darrell James Jessop, 1988 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of P h y s i c a l E d u c a t i o n / R e c r e a t i o n The University of British Columbia Vancouver, Canada D a t e Octohftr l T f IQfifi DE-6 (2/88) ABSTRACT Non-Weight Bearing Water E x e r c i s e : Changes i n C a r d i o r e s p i r a t o r y Function i n E l d e r l y Men and Women The purpose of t h i s study was to evaluate the impact of a 5 week program of aquatic e x e r c i s e on s e l e c t e d c a r d i o r e s p i r a t o r y parameters i n the e l d e r l y p a r t i c i p a n t . F i f t e e n men and women (mean age 68.5 years, range 61-75 years) were r e c r u i t e d v o l u n t a r i l y from r e g i o n a l a d u l t day-care and community centre f a c i l i t i e s . P a r t i c i p a n t s underwent a s e r i e s of p h y s i o l o g i c a l t e s t s before the program s t a r t e d and 5 weeks l a t e r at the end of the program. 1 0 Measurements i n c l u d e d height, weight, spirometry measurements (FVC, FEV , V„ ), r e s t i n g blood pressure, r e s t i n g heart r a t e , e x e r c i s e heart r a t e and Emax o r o V0~ as determined by a continuous t r e a d m i l l t e s t (modified a f t e r Jones and 2max J Campbell, 1982). F o l l o w i n g the 5 week aquatic e x e r c i s e program, the experimental group (n = 8) showed a s i g n i f i c a n t decrease i n r e s t i n g s y s t o l i c blood pressure (SBPR) (EXPTL:131.5<CTRL:133.4 mmHg) and r e s t i n g h e a r t r a t e (HRn t ? c r i,) (EXPTL:71.0<CTRL:76.6 bts^min" 1) i n comparison to the c o n t r o l group (n = 7) which e x h i b i t e d no change. In a d d i t i o n , the experimental group y i e l d e d a s i g n i f i c a n t increase i n for c e d e x p i r a t o r y volume (FEV''"'^) (EXPTL:2.4>CTRL:2.2 l - s e c " 1 ) and maximal oxygen uptake (V0 o ) ° 2max - 1 - 1 (EXPTL:25.8>CTRL:23.5 ml*kg «min ) i n comparison to the c o n t r o l group. The f i n d i n g s i n t h i s study i n d i c a t e that the e x e r c i s e c a p a c i t y of the e l d e r l y p a r t i c i p a n t can increase w i t h aquatic e x e r c i s e : supervised aquatic e x e r c i s e at or above the recommended i n t e n s i t y of e x e r c i s e performed three times weekly can produce s i g n i f i c a n t changes i n the p h y s i c a l work c a p a c i t y of the e l d e r l y . i i TABLE OF CONTENTS Page A b s t r a c t . . . i i L i s t of Tables ' i v Acknowledgement v I I n t r o d u c t i o n 1 I I Review of L i t e r a t u r e 8 I I I Methods and Procedures 35 IV Experimental Design and Data A n a l y s i s 38 V R e s u l t s 40 VI D i s c u s s i o n 46 V I I Conclusions 59 V I I I Recommendations 61 IX References 83 Appendix A Time E f f e c t : Means at Ba s e l i n e (Tl) and 5 Weeks La t e r (T2) (Experimental Group, n = 8) 62 Appendix B Time E f f e c t : Means at B a s e l i n e (Tl) and 5 Weeks La t e r (T2) (Con t r o l Group, n = 7) 63 Appendix C Means of Experimental and C o n t r o l Groups at Ba s e l i n e ( T l ) and 5 Weeks Late r (T2) 64 Appendix D Model f o r Repeated Measures Design 65 Appendix E ANOVA Tables ' 66 Appendix F C o n t r a i n d i c a t i o n s f o r E x e r c i s e P a r t i c i p a t i o n and Te s t i n g ... 79 Appendix G Informed Consent Form 81 i i i List of Tables Table Page I Mean and Standard Deviations of P h y s i c a l and Metabolic C h a r a c t e r i s t i c s (Experimental and Co n t r o l Groups Combined) .... 41 I I Mean and Standard Deviations of P h y s i c a l and Metabolic C h a r a c t e r i s t i c s (Experimental vs. C o n t r o l Groups) 42 I I I Summary of V a r i a b l e A n a l y s i s 43 IV Comparison of Sele c t e d Parameters w i t h Other Studies 44 V Summary of Hypothesis T e s t i n g 45 i v ACKNOWLEDGEMENT This work i s dedicated to Karen, whose unwavering enthusiasm and encouragment spurred me on and to my parents and f a m i l y who always b e l i e v e d i n me. I would a l s o l i k e to thank a l l those who a s s i s t e d me i n the completion of t h i s work: Dr. Jack Taunton (committee chairman), committee members Dr. Richar d Ham, Dr. E. Rhodes and Dr. P. Grantham. A d d i t i o n a l thanks a l s o to Dr. Gary S i n c l a i r and Dr. R. Schutz. Thank you everyone f o r g i v i n g d i r e c t i o n to my ne u r o t i c i s m . v INTRODUCTION The aging process has been defined as a gradual d e c l i n e i n the a b i l i t y of the i n d i v i d u a l to adapt to changes i n the environment (Barry, 1986). As the p o p u l a t i o n ages, h e a l t h care p r o f e s s i o n a l s w i l l be pressed to meet the s p e c i a l needs of the e l d e r l y . A program of r e g u l a r e x e r c i s e may a i d i n meeting these goals. North Americans g e n e r a l l y engage i n l e s s p h y s i c a l a c t i v i t y as they age. According to the 1981 Canada F i t n e s s Survey, approximately 25% of those between the ages of 20 and 24 engage i n sport or other forms of vigorous a c t i v i t y at l e a s t 3 hours per week. With i n d i v i d u a l s between the ages of 65 and 69, only 6.5% are seen to engage i n r e g u l a r a c t i v i t i e s (Hogan, 1986). Less than 9% of Canadians over the age of 55 p a r t i c i p a t e i n any d e l i b e r a t e e x e r c i s e . I t i s p a r t i c u l a r l y the i n s t i t u t i o n a l i z e d e l d e r l y that are the l e a s t a c t i v e (Molloy and Watson, 1987). C u r r e n t l y , only 24% of Canadians can be considered adequately a c t i v e f o r m a i n t a i n i n g or improving c a r d i o v a s c u l a r f i t n e s s (Hogan, 1986). An understanding i s needed concerning the r e l a t i o n s h i p between the p h y s i o l o g i c a l d e c l i n e i n aging i n d i v i d u a l s and the e f f e c t s of e x e r c i s e and r e g u l a r a c t i v i t y , both i n the presence and absence of disease. Information concerning appropriate a c t i v i t y l e v e l s and p r e s c r i p t i o n g u i d e l i n e s f o r them are p r e s e n t l y inadequate (Holm and K i r c h h o f f , 1984). E x e r c i s e that i s i n i t i a t e d i n adulthood and continues throughout the l i f e t i m e i n t o o l d age i s d i f f e r e n t from e x e r c i s e that commences i n o l d age a f t e r years of i n a c t i v i t y , an acute i l l n e s s (such as a c a r d i o v a s c u l a r event) or c h r o n i c d e b i l i t a t i o n ( a r t h r i t i s ) . P h y s i o l o g i c a l changes that are seen to occur w i t h aging may be d i f f i c u l t to separate from those r e s u l t i n g from disease (Holm and K i r c h h o f f , - 2 -1984), but i n c r e a s i n g evidence suggests that much of the d i s a b i l i t y seen i n the e l d e r l y i s a r e s u l t of disuse or h y p o k i n e t i c disease (Hogan, 1986). The l i t e r a t u r e addresses aging and e x e r c i s e from many v a r i e d p e r s p e c t i v e s . In recent years, there have been re p o r t s of s i g n i f i c a n t improvements i n p h y s i o l o g i c f u n c t i o n and performance i n the e l d e r l y who have undergone extensive p h y s i c a l t r a i n i n g . Evidence i s accumulating that r e g u l a r , long-term e x e r c i s e slows the e f f e c t s of the aging process i n se v e r a l body systems and helps i n the prevention of c a r d i o v a s c u l a r disease (Kent, 1982). E x e r c i s e may prevent or reverse the e f f e c t s of premature aging and disease, but i t does not appear to a f f e c t the " n a t u r a l " r a t e of aging, as measured by the maximum l i f e span (Kent, 1982). There are few conc l u s i v e s t u d i e s examining the e f f e c t s of r e g u l a r a c t i v i t y on l o n g e v i t y i n humans (Molloy and Watson, 1987). In a d d i t i o n to the e f f e c t of e x e r c i s e i n the r e d u c t i o n of m o r t a l i t y from c a r d i o v a s c u l a r disease, e x e r c i s e has been shown to l e s s e n the age-related increases i n serum l i p i d and i n s u l i n l e v e l s and reduce the mineral l o s s i n bone (Molloy and Watson, 1987). The i n e v i t a b l e p h y s i o l o g i c a l changes that are seen to accompany aging i n c l u d e increased blood pressure l e v e l s , a decreased c a r d i a c reserve ( p r i m a r i l y secondary to a decrease i n maximal heart r a t e ) , and a decrease i n v i t a l c a p a c i t y and chest w a l l compliance, r e s u l t i n g i n a reduced maximum v o l u n t a r y v e n t i l a t i o n . These changes l i m i t the e l d e r l y i n d i v i d u a l ' s c a p a c i t y to maintain h i g h l e v e l s of aerobic f i t n e s s (Barry, 1986). Aging a l s o i n s t i g a t e s an o v e r a l l decrease i n muscular strength, although t h i s may be predominantly r e l a t e d to changes i n i n d i v i d u a l l i f e s t y l e s ( i . e . decreased l e v e l s of a c t i v i t y ) (Piscopo, 1985). Osteoporosis i s a s e r i o u s problem i n the e l d e r l y and i t s sequelae ( i . e . v e r t e b r a l compression and h i p f r a c t u r e s ) are major causes of m o r t a l i t y (Barry, 1986). Aging causes a decrease i n bone d e n s i t y of approximately 30% to 50% at the - 3 -ra t e of approximately 0.4% per year, beginning at about age 50 (Hogan, 1986). Men do not experience d i f f i c u l t i e s as a r e s u l t of the cumulative e f f e c t s of osteoporosis u n t i l approximately the e i g h t h decade of l i f e (Barry, 1986). In women, bone l o s s may begin at age 30-35 years and continues at a more r a p i d r a t e than t h a t observed i n man. The r a t e of bone l o s s i n woman may progress from approximately 1% per year to 2% - 3% per year at post-menopause (Mazess; 1979, Smith, 1982). I n d i v i d u a l s that are immobilized, bedridden (unweighted) or who have experienced a l o s s of muscular f u n c t i o n may experience an even greater r a t e of bone l o s s , as h i g h as 1% per week (Barry, 1986). The e f f e c t s of r e g u l a r e x e r c i s e on the s t r u c t u r a l i n t e g r i t y of bone have been demonstrated i n numerous s t u d i e s . I t has been shown th a t the bone mineral content i n the cor t e x i s t h i c k e r i n i n d i v i d u a l s who e x e r c i s e r e g u l a r l y when compared to those who do not (Dalen and Olsson, 1974; Jones et a l . , 1977; Montoye et a l . , 1980). From the f i f t h decade of l i f e , there i s a 3% - 5% l o s s of muscle t i s s u e per decade w i t h the gr e a t e s t l o s s seen i n the musculature of the legs and trunk (Barry, 1986). This l o s s of muscle t i s s u e i s enhanced by the r e s u l t i n g disuse from a sedentary l i f e s t y l e . Decreased f l e x i b i l i t y i s usually,, encountered w i t h the l o s s of musculature; a g e - r e l a t e d degenerative changes i n the e l a s t i n of connective t i s s u e and the e f f e c t s of osteoporosis and a r t h r i t i s i n a d d i t i o n to the a c t u a l shortening of the musculo-tendinous u n i t a l l c o n t r i b u t e to a decrease i n o v e r a l l f l e x i b i l i t y . E x e r c i s e programs have y i e l d e d s i g n i f i c a n t improvements i n j o i n t f l e x i b i l i t y and range of motion (Munns, 1981). A slowing i n r e a c t i o n time i s seen w i t h i n c r e a s i n g age, but t h i s also appears to be r e l a t e d to disuse from i n a c t i v i t y . Decreased p e r i p h e r a l nerve f u n c t i o n i n e l d e r l y i n d i v i d u a l s i s s u b s t a n t i a t e d by the increased incidence of absent deep tendon r e f l e x e s (Hogan, 1986). In a d d i t i o n to the o v e r a l l - 4 -r e d u c t i o n i n sensory f u n c t i o n , a slowing of mentation and impairment of motor responses are noted. C o o r d i n a t i o n and balance may d e c l i n e , c o n t r i b u t i n g to poor m o t i v a t i o n and i n a b i l i t y to perform everyday tasks (Barry, 1986). Regular e x e r c i s e has been shown to slow the d e t e r i o r a t i o n i n memory, c o g n i t i v e and psychomotor f u n c t i o n as w e l l as p r o v i n g to have b e n e f i c i a l e f f e c t s on depression, a n x i e t y and s t r e s s (Molloy and Watson, 1987). C i r c u l a t o r y diseases (heart disease, stroke and h y p e r t e n s i o n ) , d i g e s t i v e diseases and mental d i s o r d e r s head the l i s t of c u r r e n t h e a l t h care expenditures. Health expenses continue to r i s e and w i t h the increase i n the number of middle-aged and o l d e r a d u l t s , h e a l t h p r o f e s s i o n a l s f o r e c a s t higher c o s t s i n the years ahead (Piscopo, 1985). The prospect of continued e s c a l a t i o n i n h e a l t h care spending makes i t a major is s u e f o r both the p u b l i c and p r i v a t e s e c t o r s of our s o c i e t y . Our h e a l t h care system i s p r i m a r i l y designed to a s s i s t i n d i v i d u a l s a f t e r they have become i l l or f u n c t i o n a l l y i n c a p a c i t a t e d . Longevity i s d e s i r a b l e , but the i n d i v i d u a l ' s enjoyment of l i f e , sense of w e l l - b e i n g and c o n t r i b u t i o n s to s o c i e t y outweigh any q u a n t i t a t i v e dimension of aging. Medical technology has expanded the aging p o p u l a t i o n and w i l l continue to do so. Many s p e c i f i c diseases are now curable and the e f f e c t s of many others can now be c o n t r o l l e d but we have only r e c e n t l y begun to recognize the value of improving the aged population's h e a l t h and w e l l - b e i n g through p r e v e n t a t i v e and h e a l t h promotional measures. I t i s c l e a r that a c o n t i n u i n g emphasis on the development of acute care m o d a l i t i e s must be balanced w i t h an increased emphasis on f a c t o r s which w i l l improve the q u a l i t y of l i f e f o r the e l d e r l y i n d i v i d u a l and improve t h e i r a b i l i t y to maintain independence. The maintenance of h e a l t h and p r e v e n t a t i v e medicine have emerged as important aspects of h e a l t h care. The b e n e f i c i a l e f f e c t s of e x e r c i s e f o r the e l d e r l y have been documented and i t i s b e l i e v e d that the e l d e r l y should be - 5 -encouraged to engage i n r e g u l a r p h y s i c a l e x e r c i s e . With the i n c r e a s i n g number of such programs, i t has become necessary to evaluate them i n terms of t h e i r a b i l i t y to p o s i t i v e l y change the l e v e l of f i t n e s s i n the p a r t i c i p a n t . The f a c t o r s preventing the e l d e r l y from p a r t i c i p a t i n g i n a s t r u c t u r e d e x e r c i s e program are v a r i e d , numerous and not u n l i k e the reasons c i t e d by the younger p o p u l a t i o n f o r not implementing r e g u l a r e x e r c i s e i n t h e i r d a i l y a c t i v i t i e s (Piscopo, 1985). Factors unique to the e l d e r l y p o p u l a t i o n that may be seen as a c o n t r a i n d i c a t i o n to an e x e r c i s e program include o s t e o p o r o s i s , cardiopulmonary impairment by pathology, n e u r o l o g i c a l d e f i c i t (Alzheimer's, s t r o k e ) , metabolic d i s o r d e r s and decreased m o b i l i t y . Some areas of concern w i t h e x e r c i s e and i t s p r e s c r i p t i o n i n the e l d e r l y has been the m o t i v a t i o n to e x e r c i s e , the r i s k of i n j u r y and the requirement f o r proper medical assessment before p a r t i c i p a t i o n i n an e x e r c i s e program (Hogan, 1986). In supervised e x e r c i s e programs, musc u l o s k e l e t a l i n j u r y s e r i o u s enough to p r o h i b i t p a r t i c i p a t i o n has been seen to occur i n up to 50% of p a r t i c i p a n t s . In 20% of the p a r t i c i p a n t s , the i n j u r y w i l l be severe enough to warrant permanent c e s s a t i o n of the a c t i v i t y (Piscopo, 1985). Due to the high prevalence of disease s t a t e s i n the e l d e r l y , p r i o r medical assessment i s e s s e n t i a l before p r e s c r i b i n g any program of e x e r c i s e . The d e t e c t i o n of ischaemic heart disease should be the focus of t h i s assessment (Hogan, 1986). Un d e r l y i n g disease s t a t e s should not be considered as a c o n t r a i n d i c a t i o n to e x e r c i s e but as an i n d i c a t i o n of the requirement to modify the e x e r c i s e program to s u i t the i n d i v i d u a l . A q uatic or i n - p o o l e x e r c i s e programs have r e c e n t l y been c i t e d as an e f f e c t i v e means to maintain e x i s t i n g l e v e l s of f i t n e s s i n i n j u r e d runners (Koszuta, 1986). Water programs provide a means by which the major musculature can be e x e r c i s e d ; the f l u i d medium provides an accommodating type of r e s i s t a n c e and the buoyant forces decrease the impact fo r c e s imparted to - 6 -the p a r t i c i p a n t . Conventional "walk-jog" programs may not be p r a c t i c a l or even p o s s i b l e f o r the e l d e r l y i n d i v i d u a l who e x h i b i t s decreased m o b i l i t y or g a i t problems as a r e s u l t of orthopedic i n t e r v e n t i o n or chronic a r t h r i t i c c o n d i t i o n s . C l i n i c a l l y and f o r the purpose of p r o v i d i n g these i n d i v i d u a l s w i t h a means by which they can increase t h e i r l e v e l of f i t n e s s i n a safe and enjoyable manner, i n v e s t i g a t i o n i n t o the p o t e n t i a l of aquatic e x e r c i s e programs i s both warranted and necessary. Water e x e r c i s e has been shown to provide i t s b e n e f i t s to strength, f l e x i b i l i t y and c a r d i o v a s c u l a r c o n d i t i o n i n g independently of the p a r t i c i p a n t s ' s k i l l l e v e l and i t reduces the l i k e l i h o o d of i n j u r y from overuse syndromes and h e a t - s t r e s s problems (Koszuta, 1986). Water exe r c i s e u t i l i z e s the water's r e s i s t a n c e to achieve or maintain f i t n e s s : vigorous movements f o r a p r e s c r i b e d length of time account f o r the c a r d i o v a s c u l a r and r e s p i r a t o r y b e n e f i t s . The "aerobic" water e x e r c i s e sessions are s i m i l a r to the land-based c l a s s e s i n that choreographed movements are performed to music wh i l e an i n s t r u c t o r leads from the pool deck or i n the water. Classes u s u a l l y l a s t f o r one hour and are h e l d i n the shallow end of the p o o l . As the water i s only chest deep, the p a r t i c i p a n t s need not be swimmers. P a r t i c i p a n t s are encouraged to f o l l o w the i n s t r u c t o r and they can vary the i n t e n s i t y or pace of t h e i r own workout. In a d d i t i o n , water acts as an e q u a l i z i n g medium as i t provides p a t i e n t s who have a r t h r i t i s or back problems an o p p o r t u n i t y to engage i n a supervised e x e r c i s e program which may not be p o s s i b l e f o r them on dry land. In a d d i t i o n to the p o t e n t i a l c a r d i o v a s c u l a r b e n e f i t s , a r t h r i t i c s may b e n e f i t from t h i s e x e r c i s e as w e l l p a r t i c u l a r l y when range-of-motion e x e r c i s e s are i n c l u d e d (Koszuta, 1986). There have been few noteworthy s t u d i e s concerning water e x e r c i s e and the e l d e r l y . I t w i l l be the purpose of t h i s study to i n v e s t i g a t e the impact of a 5 week program of aquatic e x e r c i s e on s e l e c t e d c a r d i o r e s p i r a t o r y parameters - 7 -i n the e l d e r l y p a r t i c i p a n t . The subjects w i l l be c u l l e d from, and r e p r e s e n t a t i v e of, a d u l t day-care and community centre f a c i l i t i e s i n the Lower Mainland. These people are, f o r the most p a r t , u n f i t v olunteers who a l l e x h i b i t some degree of s o c i a l impairment and i s o l a t i o n . - 8 -LITERATURE REVIEW Numerous s t u d i e s have attempted to describe the r e l a t i o n s h i p between e x e r c i s e and h e a l t h ( B e l l o c and Breslow, 1972) and researchers have shown i n t e r e s t i n how the e l d e r l y f e e l about h e a l t h and p h y s i c a l a c t i v i t y . One study c h a r a c t e r i z e d the b e l i e f s that the e l d e r l y h e l d concerning e x e r c i s e and p h y s i c a l a c t i v i t y i n general (Sidney and Shephard, 1976). Some of the a t t i t u d e s i n c l u d e d (1) they per c e i v e d the requirement f o r p h y s i c a l a c t i v i t y decreases w i t h age; (2) e x e r c i s e i s dangerous; (3) l i g h t , sporadic e x e r c i s e i s b e n e f i c i a l to h e a l t h ; and (4) t h e i r own personal p h y s i c a l a b i l i t i e s were l i m i t e d . The author's con t e n t i o n was tha t such a t t i t u d e s may be the consequence of pre v a l e n t s o c i a l a t t i t u d e s which decree that an i n d i v i d u a l should "slow down" at retirement. With aging, the o l d e r i n d i v i d u a l i s faced w i t h adapting to a v a r i e t y of developmental changes ( R i f f l e , 1982). These in c l u d e an a l t e r e d s t a t e of p h y s i c a l h e a l t h , a p o s s i b l e increase i n dependency l e v e l , d e a l i n g w i t h the l o s s of a spouse and f a m i l y members ( s i b l i n g s ) and f r i e n d s through death, and a p o s s i b l e change i n l i v i n g s i t u a t i o n . Aging a l s o tends to predispose people to l e s s p h y s i c a l a c t i v i t y , p r e s e n t i n g a s i t u a t i o n that has numerous p o t e n t i a l l y negative e f f e c t s upon both p s y c h o l o g i c a l and p h y s i o l o g i c a l f u n c t i o n i n g . C l i n i c a l l y , t h i s could c o n s t i t u t e a h e a l t h t h r e a t ( R i f f l e , 1982). The e l d e r l y ' s p e r c e p t i o n of e x e r t i o n appears to be i m p l i c a t e d w i t h the i n c l i n a t i o n f o r e x e r c i s e . Studies (Sidney and Shephard, 1977; Sidney and Shephard, 1977b) have shown that when the Borg Psychophysical Scale was administered to volunte e r s (60-70 years of age) during a pre-retirement e x e r c i s e program, the pe r c e p t i o n of p h y s i c a l e x e r t i o n was 2-3 u n i t s higher than t h a t p e r c e i v e d by younger a d u l t s (age 30-50) i n previous s t u d i e s . This - 9 -d i f f e r e n c e was noted at a l l heart r a t e s . P h y s i c a l t r a i n i n g was not seen to s i g n i f i c a n t l y change t h i s p e r c e i v e d e x e r t i o n at any work l o a d even though the r e s u l t i n g h e a r t r a t e s were s u b s t a n t i a l l y lower (Sidney and Shephard, 1977). I t was a l s o r e p o r t e d that men and women (the sample contained subjects 60-80 years of age) tended to overestimate time devoted to e x e r c i s e , as c o n t i n u o u s l y monitored heart r a t e s d i d not c o i n c i d e w i t h the described a c t i v i t y (Sidney and Shephard, 1977). A s u b s t a n t i a l amount of time was a c t u a l l y devoted to a c t i v i t i e s which r e s u l t e d i n heart r a t e s below 120 beats per minute. The i s s u e s of whether poor h e a l t h or a f e a r of e x e r t i o n are important v a r i a b l e s i n the e l d e r l y ' s a t t i t u d e s concerning e x e r c i s e have not been addressed. The reason(s) f o r tendency to engage i n fewer p h y s i c a l a c t i v i t i e s w i t h i n c r e a s i n g age i s / a r e not c l e a r . Epidemiology These s t u d i e s are of importance to the f i e l d of aging as they suggest a b e n e f i c i a l requirement f o r p h y s i c a l a c t i v i t y and a need to encourage i t as p a r t of a normal, h e a l t h y l i f e s t y l e . O r i g i n a l l y , i n t e r e s t i n p h y s i c a l f i t n e s s by the p u b l i c was o u t l i n e d by Hedley (1939). This study and subsequent s t u d i e s i n d i c a t e d that the incidence of c a r d i o v a s c u l a r events, p a r t i c u l a r l y myocardial i n f a r c t i o n and sudden death, were lower i n subjects r o u t i n e l y i n v o l v e d i n p h y s i c a l l y a c t i v e and demanding occupations when compared w i t h i n d i v i d u a l s engaged i n sedentary occupations. The h i s t o r i c a l c o n c l u s i o n i s t h a t p h y s i c a l i n a c t i v i t y i s not as potent a r i s k f a c t o r as smoking, hypertension and/or hypercholesterolemia. M o r r i s et a l . (1958, 1973) s i m i l a r l y reported r a t e s of c a r d i a c m o r t a l i t y i n o c c u p a t i o n a l l y a c t i v e subjects even though i t was determined that "occupational s e l e c t i o n " may have i n f l u e n c e d the outcome. Regardless, M o r r i s ' observations were s u b s t a n t i a t e d at postmortem examination by the 10 -appearance of d i f f e r e n c e s i n the type of l e s i o n s i n the myocardium when comparing a c t i v e and sedentary people. He concluded that even i s o l a t e d "weekend" bouts of increased p h y s i c a l a c t i v i t y produced b e n e f i t s not c o n f e r r e d to t o t a l l y sedentary populations. A c t i v e populations may e x h i b i t higher incidences of v a r i e d symptoms of coronary heart disease even when the o v e r a l l incidence of i n f a r c t i o n and sudden death are lower (Naughton, 1982). Therefore, i t i s apparent that p h y s i c a l a c t i v i t y i s not s o l e l y p r e v e n t a t i v e of the development of coronary o b s t r u c t i o n . Kannel and S o r l i e (1979) (the Framingham Study) t y p i f i e d p h y s i c a l i n a c t i v i t y as a r i s k f a c t o r i n the development of ischaemic heart disease i n men of a l l ages. To t h i s end, The Framingham i n v e s t i g a t i o n provided the f i r s t emphatic h e a l t h statement concerning the need to promote reg u l a r p h y s i c a l a c t i v i t y . Paffenbarger's (1978) l o n g i t u d i n a l study allowed c o n t r o l l e d observations f o r the major coronary r i s k f a c t o r s . The f i n d i n g s suggest t h a t there i s a d i r e c t r e l a t i o n s h i p between occupational or l e i s u r e - t i m e a c t i v i t y and the incidence of c a r d i a c events. P h y s i o l o g i c a l Observations Various p o p u l a t i o n groups have been i n v e s t i g a t e d . Studies have examined p h y s i c a l l y a c t i v e subjects and determined the e f f e c t s of p h y s i c a l c o n d i t i o n i n g on p r e v i o u s l y sedentary s u b j e c t s . Regardless of the i n t e n t and design of the study, the f i n d i n g s have been c o n s i s t e n t : p h y s i c a l l y a c t i v e s u bjects are capable of a greater work c a p a c i t y , have lower r e s t i n g heart r a t e s , have lower heart r a t e s and s y s t o l i c blood pressures i n submaximal e x e r c i s e than sedentary subjects (Naughton, 1982). Regular p h y s i c a l a c t i v i t y a l s o promotes increased l e a n body mass ( i . e . increased muscle mass w i t h a - 11 -corresponding decrease i n percent body f a t . ) , improved glucose t o l e r a n c e and improved i n s u l i n t o l e r a n c e . The i n f l u e n c e of age on p h y s i c a l f i t n e s s i n he a l t h y subjects has been i n v e s t i g a t e d by Naughton (1982), Robinson (1938) and D i l l (1963). The f i n d i n g s have been c o n s i s t e n t i n that the l e v e l of p h y s i c a l f i t n e s s decreases w i t h age i n both men and women. At a l l ages, women e x h i b i t e d lower l e v e l s of f i t n e s s than men. These s t u d i e s were c r o s s - s e c t i o n a l and b i a s e d by subject s e l e c t i o n , p a r t i c u l a r l y i n the young s u b j e c t s . Taylor and Montoye (1974) attempted to c o r r e c t t h i s by studying f i t n e s s l e v e l s reported i n healthy p o p u l a t i o n i n r e l a t i o n to t h e i r a c t i v i t y p a t t e r n s (vigorous, moderate or sedentary a c t i v i t y ) . T h e i r f i n d i n g s i n d i c a t e d t h a t d i f f e r e n c e s i n f i t n e s s based on a c t i v i t y l e v e l s e x i s t e d across a l l ages, but th a t regardless of group assignment, the l e v e l of p h y s i c a l f i t n e s s decreased w i t h advancing age. Alexander (1974) examined the decrease of f i t n e s s w i t h age based on some of the r e p o r t e d observations. He found a decrease i n p h y s i c a l f i t n e s s ranging from 0.93 to 1.04 ml oxygen per kg body weight per min w i t h each successive year (when determined i n r e l a t i o n to body weight) . When the decrease was analyzed i n r e l a t i o n to h a b i t u a l p h y s i c a l a c t i v i t y s t a t u s , the d e c l i n e w i t h advancing age was steeper f o r the sedentary than f o r the p h y s i c a l l y a c t i v e s u b j e c t s . Naughton and Nagle (1965), studying a he a l t h y p o p u l a t i o n of middle-aged men, d i d not f i n d the usual h i g h l e v e l of f i t n e s s i n the younger subjects but a decrease w i t h men i n the p o p u l a t i o n group s t u d i e d . They found t h a t the f i t n e s s l e v e l s were n e a r l y i d e n t i c a l across the four decades. This i n d i c a t e s t h a t many young subjects i n the general p o p u l a t i o n may not develop a h i g h l e v e l of f i t n e s s and that f o r the nonactive p o p u l a t i o n the more normal l e v e l f i t n e s s i s 32 ml oxygen per kg body weight per min or about 8 to 9 mets ( 1 met = approx. 3.5 ml oxygen per kg body weight per min.), i n s t e a d of the s i g n i f i c a n t l y higher l e v e l s reported by other i n v e s t i g a t o r s . Eighteen - 12 -subjects were re-evaluated f o l l o w i n g c o n d i t i o n i n g and i t was found that f i t n e s s l e v e l s had increased s i g n i f i c a n t l y r e g a r d l e s s of age. Therefore, h e a l t h y i n d i v i d u a l s of a l l ages have a c a p a c i t y f o r c o n d i t i o n i n g and an expected range of change i s obtained. C u p e l l i et a l . (1984) demonstrated that r e g u l a r t r a i n i n g provided a decreased r e s t i n g heart r a t e (as an expres s i o n of decreased sympathetic s t i m u l a t i o n of the s i n o a t r i a l node) and a greater e f f i c i e n c y w h i l e those who t r a i n e d i r r e g u l a r l y showed a decreased p h y s i c a l work c a p a c i t y w i t h higher s y s t o l i c blood pressure values at r e s t . The authors a l s o s t a t e that t r a i n i n g induces a decrease i n myocardial oxygen consumption. Th e i r conclusions are tha t e l d e r l y s u b j e c t s , p a r t i c u l a r l y those w i t h a higher b a s i c blood pressure, should be encouraged to p a r t i c i p a t e i n aerobic a c t i v i t i e s . I n v e s t i g a t o r s have s t u d i e d the e f f e c t s of p h y s i c a l a c t i v i t y on serum l i p i d s , p a r t i c u l a r l y c h o l e s t e r o l , t r i g l y c e r i d e s and h i g h - d e n s i t y l i p o p r o t e i n c h o l e s t e r o l (HDL-C) (La Rosa et a l . , 1981). P h y s i c a l a c t i v i t y i t s e l f has not been found to i n f l u e n c e serum c h o l e s t e r o l , as weight l o s s corresponding to the a c t i v i t y program may cause the d e c l i n e i n c h o l e s t e r o l . As percent body f a t i s reduced (and l e a n body mass increased) , t r i g l y c e r i d e l e v e l s are seen to decrease. La Rosa (1981) concluded that HDL-C i s not a f f e c t e d s i g n i f i c a n t l y b y p h y s i c a l a c t i v i t y programs. I t i s suggested that p r i o r s t u d i e s that have shown a s i g n i f i c a n t r e l a t i o n s h i p between HDL-C and p h y s i c a l a c t i v i t y e x h i b i t b i a s i n subject s e l e c t i o n . In c o n t r a s t , Wood et a l . (1977) had shown e a r l i e r t h a t the average HDL l e v e l was 33% higher i n men runners than i n sedentary men and 25% higher i n women runners than sedentary women. Leon et a l . (1977) showed a s i g n i f i c a n t increase i n HDL l e v e l s among obese sedentary men on a walking program without d i e t a r y changes. Hartung et a l . (1980) summarily described a pro g r e s s i v e increase i n HDL l e v e l s d i r e c t l y r e l a t e d to the q u a n t i t y of e x e r c i s e . - 13 I CARDIOVASCULAR CHANGES WITH AGING - AN OVERVIEW A gradual d e c l i n e i n a l l body systems i s presumed w i t h aging (Holm and K i r c h h o f f , 1984). Although e x e r c i s e does help to r e t a r d c a r d i o v a s c u l a r d e c l i n e w i t h advancing age, i t cannot prevent i t . Studies have documented the d i m i n u t i o n w i t h age i n the b e n e f i c i a l e f f e c t s of e x e r c i s e on the ca r d i o v a s c u l a r system (Montoye, 1982). Blood pressure increases w i t h age, w i t h s y s t o l i c blood pressure i n c r e a s i n g to a greater extent than d i a s t o l i c pressure. A decreased cardiac output response to e x e r c i s e may be due to the i n t r i n s i c i n a b i l i t y of the aging myocardium to respond to an a d d i t i o n a l l o a d p l a c e d upon the v e n t r i c l e by decrements i n the v a s c u l a r network. Holm and K i r c h h o f f (1984) s t a t e that the decrease i n e x e r c i s e stroke volume i s p r i m a r i l y due to an increase i n a f t e r l o a d and i s not r e l a t e d to changes i n pr e l o a d a b i l i t y and myocardial c o n t r a c t i l i t y . I t i s f e l t that the combination of decreases i s maximal heart r a t e and e x e r c i s e stroke volume reduces c a r d i a c output (Yerg et a l . , 1985). Y i n e t a l . , (1981) i n an animal study, demonstrated a 20% increase i n impedance and a 28% decrease i n p e r i p h e r a l r e s i s t a n c e w i t h no increase i n stroke volume i n o l d animals (dogs) during graded t r e a d m i l l e x e r c i s e . In c o n t r a s t , the younger animals showed no increase i n impedance, a progressive decrease i n p e r i p h e r a l r e s i s t a n c e and a pro g r e s s i v e increase i n stroke volume at s i m i l a r e x e r c i s e l e v e l s . The marked d i f f e r e n c e i n the o l d e r animals c a r d i o v a s c u l a r response to e x e r c i s e r e s u l t e d i n a reduced c a r d i a c output, heart r a t e , maximal e x e r c i s e c a p a c i t y and oxygen consumption. Wenger (1981) o u t l i n e d four features that u l t i m a t e l y l i m i t the e l d e r l y i n d i v i d u a l ' s c a p a c i t y to work: 1) a decrease i n maximal oxygen consumption ( V 0 2 m a x ) ; 2) a decrease i n maximal heart r a t e , 3) a decrease i n the e x e r c i s e stroke volume, and 4) a r e s u l t a n t decrease i n c a r d i a c output. A d e c l i n e i n VO has been demonstrated i n many s t u d i e s , both cross - s e c t i o n a l l y (Hossack 14 -and Bruce, 1982; S t r a n d e l l , 1963) and l o n g i t u d i n a l l y (Astrand et a l . , 1973; Robinson et a l . , 1975). This d e c l i n e i n VO. i s l i n e a r throughout the 2max ad u l t years (McArdle et a l . , 1981) and i s estimated to amount to a t o t a l l o s s of 30-40% i n the 65 year o l d compared to the young a d u l t (Shephard, 1978). From age 20 years to 45 years, there i s l i t t l e age d i f f e r e n c e seen i n V O 2 during incremental graded t r e a d m i l l walking (Montoye, 1982). Beyond age 45 years, the increase i n V0£ i s s l i g h t , although s t a t i s t i c a l l y s i g n i f i c a n t and represents a small decrease i n walking e f f i c i e n c y . Hanson et a l . (1968) and Adams et a l (1969) reported no age d i f f e r e n c e s i n V0£ among adults walking at submaximal work loads. On a c y c l e ergometer, the oxygen uptake during submaximal e x e r c i s e was not r e l a t e d to age i n a d u l t s ( J u l i u s e t a l , 1967). This i s a l s o true f o r ergometry (Durnin and M i k u l i c i c , 1956) although N o r r i s e t a l . (1955) reporte d a higher oxygen requirement f o r o l d e r subjects i n arm work. Along w i t h a demonstrated d e c l i n e i n maximal heart r a t e , i t can be seen that the heart loses i t s e f f i c i e n c y as a pumping device w i t h age (Whitbourne, 1985). Both c e n t r a l and p e r i p h e r a l a g e - r e l a t e d changes are re s p o n s i b l e f o r the reported age l o s s e s i n maximum hea r t r a t e and oxygen consumption. A r e d u c t i o n i n the l e f t v e n t r i c u l a r e j e c t i o n volume i s seen w i t h age (Whitbourne, 1985). This p o t e n t i a t e s a decreased stroke volume and r e s u l t s i n a decreased c a r d i a c output (Hossack and Bruce, 1982; J u l i u s et a l , 1967; Port e t a l . , 1980; Robinson e t a l . , 1975). Maximum oxygen consumption (V0 o ) i s t h e r e f o r e reduced, as the r e s u l t i n g decrease i n blood flow 2max ° compromises a r t e r i a l flow and subsequent t i s s u e oxygen e x t r a c t i o n . V e n t r i c u l a r e f f i c i e n c y i s reduced due to increased w a l l thickness and an o v e r a l l increase i n v e n t r i c u l a r mass ( G e r s t e n b l i t h , 1980; Lakat t a , 1979). The e f f e c t of these anatomical changes i s seen w i t h an increase i n the time r e q u i r e d to complete the l e f t v e n t r i c u l a r c a r d i a c c y c l e (Granath e t a l . , - 15 -1970; McArdle et a l . , 1981; Port et a l , 1980). A r e d u c t i o n i n myocardial c o n t r a c t i l i t y i s observed (Whitbourne, 1985). E l e c t r o c a r d i o g r a p h i c changes and/or a b n o r m a l i t i e s may be noted during e x e r c i s e ; S-T segment depression being the most common (Bengsston et a l . , 1978; Montoye, 1975). Therefore, i t i s apparent t h a t a temporary, exercise-induced ischaemia may occur and the i n v o l v e d musculature may be inadequately s u p p l i e d w i t h oxygen. Several i n v e s t i g a t i o n s support the hypothesis t h a t p e r i p h e r a l f a c t o r s are r e s p o n s i b l e f o r a d e c l i n e i n c a r d i a c f u n c t i o n . One suggestion i s that the p e r i p h e r a l v a s c u l a r system increases systemic r e s i s t a n c e to blood flow, t h i s being due to an increased r i g i d i t y of the a r t e r i a l w a l l s . The r e s u l t i s a decreased a b i l i t y to accommodate s y s t o l i c flow surges and an o v e r a l l i ncrease i n blood flow during e x e r c i s e (Brooks and Fahey, 1984; Shephard and Sidney, 1978). This mechanism co u l d account f o r the higher r e s t i n g s y s t o l i c and d i a s t o l i c blood pressures seen i n o l d e r age populations (Sato et a l . , 1981) and during subrnaximal (Bengsston et a l . , 1978) and maximal exe r c i s e (Bengsston et a l . , 1978). A reduced o v e r a l l muscle mass may a l s o account f o r a decreased V0_ i n J 2max the e l d e r l y . Less oxygen i s e x t r a c t e d by the muscles as there are fewer s k e l e t a l muscles r e q u i r i n g oxygen during e x e r c i s e (Brooks and Fahey, 1984; McArdle et a l , 1981). With advancing age, a l t e r a t i o n s occur i n the c a r d i o v a s c u l a r system. What p r o p o r t i o n of these changes i s due to the process of aging alone and what i s due to environmental i n f l u e n c e s i s unknown. A. Maximal Exercise 1. Oxygen consumption (^ 2max^  The maximal c a p a c i t y of the c a r d i o v a s c u l a r system to d e l i v e r oxygen to the working muscles has been shown to decrease w i t h age. This has been found 16 -i n l o n g i t u d i n a l (Dawson and Hell e b r a n d t , 1945) and i n c r o s s - s e c t i o n a l studies (Astrand, 1960; Robinson, 1938); estimates of t h i s r e d u c t i o n range from 21 to 30% over a 30 to 40 year range. Conversely, has been increased 10% a f t e r 2 months ( M a z z a r e l l a et a l . , 1966) and 17% a f t e r 6 months (Robinson, 1938) of endurance t r a i n i n g . Naughton (1982), Robinson (1938) and D i l l (1963) examined the i n f l u e n c e of age on p h y s i c a l f i t n e s s (as measured by vO^max^ and i t was seen to decrease w i t h advancing age i n both men and Women. Women were a l s o seen to e x h i b i t a lower l e v e l of f i t n e s s than men at a l l ages. Montoye (1974) found that d i f f e r e n c e s i n f i t n e s s based on a c t i v i t y l e v e l s e x i s t e d across a l l ages and that the l e v e l s of p h y s i c a l f i t n e s s decreased w i t h advancing age. Alexander (1974) found a decrease i n V0„ 2max w i t h age ranging from 0.93 to 1.04 ml of oxygen per kg of body weight per minute w i t h each advancing year (when determined i n r e l a t i o n to body weight). Naughton and Nagle (1965), examining a health y p o p u l a t i o n of middle-aged men, found t h a t the younger subjects d i d not n e c e s s a r i l y e x h i b i t a higher l e v e l of f i t n e s s than t h e i r o l d e r counterparts. A decrease i n V0„ w i t h age was not 2max ° seen; f i t n e s s l e v e l s were n e a r l y i d e n t i c a l across the four r e p r e s e n t a t i v e decades. This i n d i c a t e d that many young subjects i n the general p o p u l a t i o n may not develop a h i g h l e v e l of f i t n e s s and that f o r the nonactive p o p u l a t i o n the more normal l e v e l of f i t n e s s i s 32 ml of oxygen per body weight per min, or about 8-9 mets (1 met = approximately 3.5 ml oxygen per kg body weight per min), i n s t e a d of the s i g n i f i c a n t l y higher l e v e l s r e p o r t e d by other i n v e s t i g a t o r s . The r a t e of d e c l i n e i n V0„ seems to be greater i n one time e l i t e 2max b a t h l e t e s who have become sedentary i n comparison w i t h t h e i r untrained counterparts who have remained sedentary and u n t r a i n e d (Robinson, 1964). Such i s not the case w i t h the a t h l e t e who remains a c t i v e i n t o o l d age; Clarence DeMar had a v 0 2 m a x o f 6 0 m l k S ~ 1 min" 1 at 49 years of age only - 17 -somewhat below a mean value of 17-20 year o l d males of 52.0 ml kg ^ min ^  ( D i l l , 1965). In a s e r i e s of a t h l e t e s ages 42 to 68 years, (Grimby and S a l t i n , 1966), VO- was 30% higher than i n non-athletes of comparable age 2max ° at a l l ages. V<^2max P e r u n ^ t °^ l e a n body mass (LBM) shows a s i m i l a r d e c l i n e . -1 -1 F i s c h e r e t a l . (1965) noted t h a t although V O g ^ ( i n ml kg min LBM) d e c l i n e s w i t h age, a c t i v e subjects i n t h e i r seventh decade had s i g n i f i c a n t l y h igher values than t h e i r sedentary counterparts. 2. HEART RATE Maximal heart r a t e (HR ) i s seen to decrease w i t h age i n both men and -max women (Astrand, 1960; Robinson 1938; Astrand, 1973; J u l i u s , 1967). For a given increase i n oxygen consumption over b a s a l l e v e l s , h eart r a t e remains constant or d e c l i n e s w i t h age (Cotes, 1974; Granath, 1964). The e f f e c t of t r a i n i n g has been found to be n e g l i g i b l e i n some cases whereas other i n v e s t i g a t o r s have found a decrease i n heart r a t e . M a z z a r e l l a et a l . (1966) reported l i t t l e or no change f o l l o w i n g a 2 month e x e r c i s e program. Skinner et a l . (1964) reported the same f i n d i n g s f o l l o w i n g a 6 month program (endurance t r a i n i n g w i t h middle-aged men). Older a t h l e t e s have shown a decreased HR which i s not u n l i k e that found i n u n t r a i n e d men of the same max age (Astrand, 1956). Seals et a l . (1984) found t h a t heart r a t e a f t e r t r a i n i n g was reduced at the same absolute work r a t e s and unchanged at the same r e l a t i v e work r a t e s . Although the heart r a t e of the o l d e r subject p h y s i o l o g i c a l l y decreases, the maximal heart r a t e and the heart r a t e at r e s t f o l l o w i n g t r a i n i n g provide i n d i c a t i o n s of vagotony (Granath et a l . , 1970; Zoneraich and Rhee, 1977). With age, there are noted changes i n the e f f e c t of e x e r c i s e on s y s t o l i c b lood pressure and heart r a t e . With i n c r e a s i n g age, s y s t o l i c blood pressure tends to be higher at a given i n t e n s i t y of e x e r c i s e (Bevegard, 1967; J u l i u s , - 18 -1967). Maximum heart r a t e f a l l s (Astrand, 1973; J u l i u s , 1967), but at a submaximal e x e r c i s e l e v e l , h eart r a t e i s greater i n the ol d e r subject (Astrand, 1973). For a given increase i n oxygen consumption over b a s a l l e v e l s , h e a r t r a t e remains constant or d e c l i n e s w i t h age (Cotes, 1974; Granath, 1964). Rowlands et a l . (1984) u s i n g a sample of 33 subjects ( i n c l u d i n g h y p e r t e n s i v e s ) , found t h a t during dynamic (walking) e x e r c i s e there was a s i g n i f i c a n t increase i n blood pressure and heart r a t e . 3. Stroke Volume There appears to be a s l i g h t decrease i n maximal stroke volume (SV ) r ° max w i t h i n c r e a s e d age (Astrand, 1967); Granath et a l . (1964) found a diminished SV i n very o l d , u n t r a i n e d men. An increased SV has been found i n some middle-aged and o l d e r a t h l e t e s (Grimby and S a l t i n , 1966). A decrease i n SV has been reporte d to occur i n o l d e r i n d i v i d u a l s at near maximal work rates (Port et a l . , 1980). 4. Cardiac Output Since maximal HR decreases and SV i s reduced to a commensurate degree w i t h aging, maximal c a r d i a c output decreases a l s o (Granath et a l . , 1960). A decrease i n CO has been reported by a s e r i e s of s t u d i e s i n which SV and/or HR are d i r e c t l y or i n d i r e c t l y measured (Brandfonbrener et a l . , 1955; Hossack and Bruce, 1982; J u l i u s et a l . , 1967; Port et a l . , 1980; Robinson et a l . , 1975). Grimby and S a l t i n (1966) found l i t t l e d i f f e r e n c e between the maximal CO of young and o l d a t h l e t e s , but both had higher values than d i d unt r a i n e d men of the same age. B. Submaximal Exercise 1. Heart Rate Although the maximal HR i s seen to decrease w i t h age, there i s l i t t l e d i f f e r e n c e i n the HR at a given submaximal workload (Asmussen and Mathiasen, 19 -1962; Robinson, 1938; S t r a n d e l l , 1964). At a subrnaximal e x e r c i s e l e v e l , h e a r t r a t e i s greater i n the o l d e r subject (Astrand, 1973). However, with t r a i n i n g , HR i s seen to be decreased at a given l e v e l of subrnaximal work (Barry et a l . , 1966; Skinner et a l . , 1964). An e l e v a t e d HR w h i l e performing a standard work task i s found i n sedentary i n d i v i d u a l s compared to a t h l e t e s or p h y s i c a l l y a c t i v e men (Taylor et a l . , 1963). I t takes longer f o r the c i r c u l a t o r y (and r e s p i r a t o r y ) systems of the o l d e r person to adapt to a workload (Robinson, 1938). More time i s r e q u i r e d f o r t h e i r HR to r e t u r n to the r e s t i n g l e v e l f o l l o w i n g e x e r c i s e (Astrand, 1967). F o l l o w i n g a six-month endurance t r a i n i n g program, s i g n i f i c a n t r e d uctions i n the recovery HR of middle-aged men were seen (Skinner et a l . , 1964). 2. Systolic Blood Pressure The s y s t o l i c BP at f i x e d subrnaximal workloads has been shown to be higher i n o l d e r persons ( N o r r i s et a l . , 1953; Robinson, 1938). Endurance t r a i n i n g has produced s i g n i f i c a n t reductions i n the s y s t o l i c BP of p r e v i o u s l y sedentary middle-aged subjects (Skinner et a l . , 1964) and e l d e r l y subjects (Barry et a l . , 1966). C. Aging of the Cardiovascular System: Effects of Exercise - A Summary The major dependent v a r i a b l e s of i n t e r e s t i n t r a i n i n g s t u d i e s are aerobic c a p a c i t y (maximum oxygen consumption) and heart r a t e under c o n d i t i o n s of maximum e x e r c i s e (Whitbourne, 1985). Various i n v e s t i g a t i o n s have examined the same parameters under subrnaximal e x e r c i s e c o n d i t i o n s . Subrnaximal studies have progressed from the premise that a more e f f i c i e n t c a r d i o v a s c u l a r system w i l l r e q u i r e l e s s e f f o r t (as i n d i c a t e d by a lower heart r a t e and increased stroke volume and c a r d i a c output) to perform s u c c e s s f u l l y at a given l e v e l of oxygen consumption. 20 -1. Effects of Physical Training on v°2m a x Naughton and Nagle (1965) found that f i t n e s s l e v e l s ( i . e . v ° 2 m a x ^ increase s i g n i f i c a n t l y r e g a r d l e s s of age w i t h t r a i n i n g . I t appears that h e a l t h y i n d i v i d u a l s of a l l ages have a c a p a c i t y f o r t r a i n i n g and increased f i t n e s s and an expected r a t e of change i s obtained. R e g u l a r l y performed endurance e x e r c i s e increases ^^2raax l n k °t n the young (Astrand, 1964; Hickson et a l . , 1981; Seals et a l , 1983) and middle-aged (Hanson et a l . , 1968; P o l l o c k e t a l . , 1971). Endurance t r a i n i n g could, t h e r e f o r e , reverse the age - r e l a t e d d e c l i n e i n aerobic c a p a c i t y i f o l d e r i n d i v i d u a l s undergo an adaptive increase i n VC>2max (Seals e t a l . , 1984). Previous i n v e s t i g a t i o n s have i n d i c a t e d l i t t l e or no change i n ^ C^max ^ n response to t r a i n i n g i n i n d i v i d u a l s over 60 years of age (Niinimaa and Shephard, 1978; P o l l o c k , 1973), y et increases i n v0 2max v a r y * - n 6 from 0.0 to 38.0 percent as a r e s u l t of t r a i n i n g have been reported i n the e l d e r l y (Barry et a l , 1966; Berestad, 1965) Thomas et a l . , 1985, examining 88 e l d e r l y men (mean age 63 y e a r s ) , found an average increase of 12 percent i n ^ ^max' Few s t u d i e s have i n v e s t i g a t e d the t r a i n i n g - i n d u c e d adaptations i n the determination of VO. ( i . e . , maximal stroke volume, maximal heart r a t e and zmax maximal arteriovenous oxygen d i f f e r e n c e ) i n middle-aged and o l d e r i n d i v i d u a l s (Seals, 1984). H a r t l e y et a l . (1969) reported that a 14 percent increase i n vC^MAX was due to an increased maximal stroke volume and c a r d i a c output i n the e l d e r l y , whereas the 15 percent increase i n V(->2max a ^ t ; e r t r a i n i n g observed i n the s t u d i e s concerning younger men was obtained as a r e s u l t of increases i n maximal c a r d i a c output and maximal arteriovenous oxygen d i f f e r e n c e . They a t t r i b u t e d the l a c k of marked change i n VO. subsequent J • 2max to t r a i n i n g i n middle-aged and ol d e r subjects to t h e i r a b i l i t y to e l i c i t s i g n i f i c a n t increases i n maximal arteriovenous oxygen d i f f e r e n c e . Seals et a l . (1984), i n c o n t r a s t to H a r t l e y e t a l . (1969), suggest t h a t the increase - 21 -i n the ^C^max of t h e i r subjects appears to have been p r i m a r i l y due to adaptations i n the s k e l e t a l muscle r e s u l t i n g i n an improved a b i l i t y to e x t r a c t oxygen, as r e f l e c t e d i n a higher maximal arteriovenous oxygen d i f f e r e n c e . The adaptations of s k e l e t a l muscle to endurance exe r c i s e i n c l u d e s both an increase i n mitochondria and an increase i n c a p i l l a r y d e n s i t y , both of which could account f o r the increase i n oxygen e x t r a c t i o n ( H o l l o s z y et a l . , 1977; S a l t i n et a l . , 1977). K i e s s l i n g et a l . , (1974), however, s t a t e t h a t m i t o c h o n d r i a l volume i s unaff e c t e d . I t appears that increased p e r i p h e r a l c i r c u l a t i o n i s p o t e n t i a t e d by changes i n the a r t e r i a l blood flow. 2. Intensity and Duration of Exercise Training C o n f l i c t i n g conclusions about the e f f e c t of t r a i n i n g i n t e n s i t y i n the e l d e r l y have been reported. Badenhop et a l . (1983) reported that both high or low i n t e n s i t y t r a i n i n g produced the same increase i n VO- , while others 2max (Seals e t a l . , 1984; Sidney and Shephard, 1978) found that h i g h i n t e n s i t y t r a i n i n g r e s u l t e d i n much l a r g e r gains than were seen w i t h a low i n t e n s i t y program. Seals et a l . (1984) a l s o determined that i n o l d e r men and women, s i x months of h i g h i n t e n s i t y t r a i n i n g (75-80% of maximum age-adjusted heart r a t e ) produced l a r g e r gains i n the d i r e c t l y measured VO„ than lower 2max i n t e n s i t y t r a i n i n g of the same d u r a t i o n . Sidney and Shephard (1978) reported that walking or jo g g i n g at a high i n t e n s i t y (heart r a t e s of 140 to 150 beats per minute) produced l a r g e r gains than at low i n t e n s i t y (heart r a t e of 120 to 130 beats per minute). Previous s t u d i e s on o l d e r subjects have u s u a l l y i n v o l v e d only m i l d to moderate i n t e n s i t y e x e r c i s e f o r r e l a t i v e l y b r i e f periods (6-12 weeks) (Berestad, 1965; Niimaa and Shephard, 1978). F a i l u r e to p r e v i o u s l y observe s i g n i f i c a n t improvements i n V^max ^ n ° ^ e r S U D J e c t s may have been the r e s u l t of an inadequate t r a i n i n g stimulus (Seals et a l . , 1984). Ernes (1979) found - 22 -that a l i g h t program of e x e r c i s e c o n s i s t i n g of three 45-minute sessions per week f o r 12 weeks r e s u l t e d i n noted d i f f e r e n c e s i n pre-post measures of s y s t o l i c and d i a s t o l i c blood pressures, weight and r e s t i n g r a t e . Seals et a l . (1984) determined that 12 months of endurance e x e r c i s e t r a i n i n g can e l i c i t i ncreases i n in h e a l t h y o l d e r men and women of equal of greater magnitude than have been p r e v i o u s l y reported f o r younger (Astrand, 1964; P o l l o c k et a l . , 1971; Seals et a l . , 1983) and middle-aged (Hanson et a l . , 1968; P o l l o c k et a l . , 1971) populations. T h e i r f i n d i n g s i n d i c a t e that a moderate increase i n d a i l y p h y s i c a l a c t i v i t y of a s i x month p e r i o d can r e s u l t i n a s mall but s i g n i f i c a n t increase i n V0„ . The 25-30 percent increase i n ° 2max d i r e c t l y measured a ^ t e r ^ months of the same program exceeds the responses p r e v i o u s l y reported f o r subjects 60 years of age and over (Berestad, 1965; Suominen et a l . , 1977). This suggests t h a t the t r a i n i n g s t i m u l i i n e a r l i e r s t u d i e s were of i n s u f f i c i e n t i n t e n s i t y and/or d u r a t i o n to e l i c i t the adaptions r e s u l t i n g i n an increased . Thomas et a l . (1985), examining 88 e l d e r l y men (mean age 63 y e a r s ) , found an average increase of 12 percent i n VG^max f o l l o w i n g 12 months of t r a i n i n g . The i n v e s t i g a t o r s s t a t e d that the best p r e d i c t o r of what an e l d e r l y s u b j e c t ' s would be a f t e r one year of t r a i n i n g i s the i n i t i a l V0„ . DeVries (1971) examined the r e l a t i o n of change i n V0„ estimated 2max ° 2max from a submaximal e x e r c i s e t e s t w i t h t r a i n i n g i n t e n s i t y and i n i t i a l f i t n e s s . M u l t i p l e r e g r e s s i o n a n a l y s i s i n d i c a t e d t h a t 41 percent of the v a r i a n c e i n the change score c o u l d be e x p l a i n e d by the i n i t i a l p r e d i c t e d VG^max a n c* t n e percentage of heart r a t e range at which the subject t r a i n e d . 3. Long-Term Training Effects P r i o r a t h l e t i c t r a i n i n g does not preclude an i n d i v i d u a l to the age r e l a t e d decrements i n aerobic c a p a c i t y (Robinson et a l . , 1973). I t appears that continued e x e r c i s e throughout the middle a d u l t years prevents age losses - 23 i n aerobic c a p a c i t y and perhaps even reverses them (Whitbourne, 1985). S i g n i f i c a n t increases i n ^ ^2max ^n t* i e ^ years between t e s t i n g i n one study by Robinson et a l . (1975) were seen only i n those subjects who continued to e x e r c i s e r e g u l a r l y throughout the d u r a t i o n of the study. Subjects who t r a i n e d and then stopped showed the same r a t e of l o s s of aerobic power as the others i n the l o n g i t u d i n a l sample. Endurance a t h l e t e s , such as o r i e n t e e r s , s k i e r s and other long-distance a t h l e t e s have been shown to have much l a r g e r aerobic c a p a c i t i e s than t h e i r sedentary counterparts, even those that are co n s i d e r a b l y younger (Suominen et a l . , 1980; Cumming, 1967; G o l l n i c k et a l . , 1972) . The l i t e r a t u r e supports the co n t e n t i o n that champion or master's a t h l e t e s who continue to compete have higher l e v e l s of ^ (~>2max t ^ i a n s e d e n t a r y a d u l t s of the same age and younger (Heath et a l . , 1981; Kavanagh and Shephard, 1978). Further s t u d i e s on o l d e r a d u l t s who have remained a c t i v e throughout t h e i r middle years have provided a d d i t i o n a l support f o r the advantage provided by continued e x e r c i s e i n that t h e i r s u bjects have the f u n c t i o n a l c a p a c i t y of sedentary i n d i v i d u a l s who are 10 to 20 years younger (Plowman et a l . , 1979; Wright et a l . , 1982). Seals et a l . (1984) found t h a t heart r a t e a f t e r t r a i n i n g was reduced at the same absolute work r a t e s and unchanged at the same r e l a t i v e work r a t e s . E q u i v a l e n t or l a r g e r reductions i n heart r a t e at the same absolute work rates occurred i n response to low i n t e n s i t y training.compared w i t h h i g h i n t e n s i t y t r a i n i n g . Low i n t e n s i t y t r a i n i n g was s i x months of unsupervised walking f o r 20-30 minutes a t a heart r a t e of 120 beats/min at l e a s t three times per week. High i n t e n s i t y t r a i n i n g was s i x months of supervised endurance e x e r c i s e , p r o g r e s s i n g from walking to c y c l i n g ergometer or graded t r e a d m i l l as t h e i r f i t n e s s improved. The choice of t r a i n i n g modality depended upon the subject's orthopedic s t a t u s . The d u r a t i o n and the i n t e n s i t y of the ex e r c i s e 24 -progressed from 30 minutes at 75 percent of the maximal heart r a t e to 45 minutes at 85 percent of the maximal heart r a t e (156 ± 6 beats/min) . Although the heart r a t e of the o l d e r subject p h y s i o l o g i c a l l y decreases, the maximal heart r a t e and the heart r a t e at r e s t f o l l o w i n g t r a i n i n g provide i n d i c a t i o n s of vagotony (Granath et a l . , 1970; Zoneraich and Rhee, 1977). In summary, the research i n d i c a t e s that there i s a s i g n i f i c a n t p o t e n t i a l b e n e f i t i n aerobic e x e r c i s e as i t increases the aging c a r d i o v a s c u l a r system's a b i l i t y to t r a n s p o r t blood to meet t i s s u e requirements. Continued and ongoing involvement i n endurance a c t i v i t i e s appear to compensate f o r the a g e - r e l a t e d f u n c t i o n a l l o s s e s normally seen. The h i g h l y t r a i n e d o l d e r person possesses a l e f t v e n t r i c l e t h a t i s capable of a h i g h l e v e l of c o n t r a c t i l i t y thereby ensuring a l a r g e stroke volume and c a r d i a c output, p a r t i c u l a r l y d u r i ng exhausting work (de V r i e s , 1980). 4. Short-Term Training Effects The negative e f f e c t of aging on the maximum oxygen consumption can be o f f s e t by aerobic e x e r c i s e t r a i n i n g . The normal l o s s of ^ u 2 m a x o v e r t n e a d u l t age span i s estimated to be 1% per year (Brandfonbrener et a l . , 1955), or 40% between 25 and 65 years of age, but t h i s l o s s can be reduced by a maximum 50% i n any 2 to 3 month t r a i n i n g study i n which the p a r t i c i p a n t s t r a i n 3 hours per week at 60% or more of t h e i r aerobic c a p a c i t y (Hodgson and Buskirk, 1977) . Most of the research i n which t h i s e f f e c t i s seen involv e s subjects not o l d e r than 65 years of age (Whitbourne, 1985). When the i n t e n s i t y of the e x e r c i s e i s s u f f i c i e n t l y strenuous, men and women i n t h e i r 70s have demonstrated an increase i n VO. (de V r i e s , 1980; Whitbourne, 2max 1985). Studies have'generally not shown a favorable t r a i n i n g e f f e c t on maximum heart r a t e i n middle-aged and o l d e r a d u l t s ( H a r t l e y et a l . , 1969), but a decreased heart r a t e during subrnaximal e x e r c i s e has been seen (Blumenthal et - 25 -a l . , 1982) . Cardiac output at submaximal work l e v e l s remains constant i n older a d u l t s d e s p i t e t r a i n i n g (Rost et a l . , 1979). Maximum c a r d i a c output i s incr e a s e d by t r a i n i n g i n middle-aged and o l d e r a d u l t s (Skinner, 1970). As the maximum hea r t r a t e i s not a l t e r e d by t r a i n i n g , an increased c a r d i a c output i n d i c a t e s an improved f u n c t i o n i n g of the l e f t v e n t r i c l e during maximal work, thereby ensuring a greater stroke volume. Submaximal e x e r c i s e i n the e l d e r l y produces a maximal stroke volume s i m i l a r to tha t a t t a i n e d during moderate submaximal e x e r c i s e i n young subjects (Astrand et a l . , 1964; H a r t l e y et a l . , 1969; Rodeheffer et a l . , 1984). A decrease i n stroke volume has been reported to occur i n older i n d i v i d u a l s at near maximal work ra t e s (Port et a l . , 1980). In general, the adaptions observed during submaximal e x e r c i s e a f t e r t r a i n i n g are q u a l i t a t i v e l y s i m i l a r to those report e d p r e v i o u s l y i n younger populations (Astrand and Rodahl, 1977; Ekblom et a l . , 1968; H a r t l e y et a l . , 1969) . II RESPIRATORY CHANGES WITH AGING - AN OVERVIEW The l i t e r a t u r e contends t h a t w i t h age there i s a r e d u c t i o n i n the amount of oxygen t h a t i s taken up by the t i s s u e s during e x e r c i s e . The s t r u c t u r e ( s ) of the r e s p i r a t o r y system are rendered l e s s e f f i c i e n t i n the ol d e r person, r e s u l t i n g i n an o v e r a l l decreased e f f i c i e n c y of gaseous exchange i n the lungs. The aging r e s p i r a t o r y system adds to the l i m i t a t i o n s of the aging c a r d i o v a s c u l a r and muscular systems (Whitbourne, 1985). A. Gaseous Exchange and Ventilation The f u n c t i o n a l measure r e p r e s e n t i n g the e f f i c i e n c y of d i f f u s i o n across the a l v e o l a r c a p i l l a r y i n t e r f a c e i s the d i f f e r e n c e between the a r t e r i a l oxygen pressure compared to the a l v e o l a r oxygen pressure. Studies have 26 -documented the drop i n a r t e r i a l oxygen pressure and/or the increase i n the a l v e o l a r - a r t e r i a l oxygen d i f f e r e n c e w i t h age (M a r s h a l l and Wycke, 1972; Melmgaard, 1966). The ex p l a n a t i o n f o r t h i s reduced oxygen t r a n s p o r t may be an i n c r e a s e d r e s i s t a n c e to oxygen d i f f u s i o n across a l v e o l a r and c a p i l l a r y membranes (Anderson and Shephard, 1969; Mauderly, 1978). Robinson (1938) reported that the r e s p i r a t o r y exchange r a t i o during moderate work on a t r e a d m i l l increased from ages 8 to 63 years. J u l i u s et a l . (1967) confirmed t h i s i n subjects aged 18 to 68 years. Wessel et a l . (1968) reporte d a s l i g h t increase i n r e s p i r a t o r y exchange r a t i o from ages 20 to 59 years and then a decrease i n the 60 to 69 year age group. These d i f f e r e n c e s were not s t a t i s t i c a l l y s i g n i f i c a n t and the e x e r c i s e values were thought to be low. R u l l i and Menotti (1969) a l s o reported no s t a t i s t i c a l l y s i g n i f i c a n t r e l a t i o n s h i p between r e s p i r a t o r y exchange r a t i o and age. Wessel e t a l . (1968) and R u l l i and Menotti (1969) reported no r e l a t i o n s h i p between age and v e n t i l a t i o n (V ) during submaximal e x e r c i s e . Robinson e t a l . (1973) and P a t r i c k et a l . (1983) showed an increase i n V w i t h age as a r e s u l t of an increased t i d a l volume whereas H a r r i s and Thomson (1958) a t t r i b u t e d the increase i n V to higher r e s p i r a t o r y r a t e s i n older subj e c t s . B. Dynamic and Static Ventilatory Volumes Lung f u n c t i o n may be q u a n t i f i e d by the e f f i c i e n c y by which the lungs and t h e i r a s s o c i a t e d s t r u c t u r e s can move a i r volume. Measurements of t h i s e f f i c i e n c y may describe the components of the t o t a l lung c a p a c i t y to h o l d a i r or describe the volumes of a i r that can be moved during a p e r i o d of time. Lower values during submaximal work i n d i c a t e a grea t e r r e s p i r a t o r y e f f i c i e n c y , i n terms of supplying oxygen, w i t h a minimum of energy cost. High l e v e l s of f u n c t i o n on these measures i n d i c a t e that the lungs can support the oxygen requirements f o r the working muscles. The f u n c t i o n a l measurements - 27 of the lung based on lung volumes are u s e f u l f o r d e s c r i b i n g age d i f f e r e n c e s i n the pulmonary response to e x e r c i s e (whitbourne, 1985). With age, there appears to be a r e d u c t i o n i n v i t a l c a p a c i t y accompanied by an increase i n r e s i d u a l volume (Asmussen et a l . , 1975). This process begins approximately at age 40 (Brady et a l . , 1974) and r e s u l t s i n a t o t a l of 40% l o s s of v i t a l c a p a c i t y between the ages of 20 and 70 (Lynne-Davies, 1977) . Age changes i n compliance are l a r g e l y r e s p o n s i b l e f o r an increased c l o s i n g volume, and i t has been suggested that the same process would account f o r the a g e - r e l a t e d increase i n the r e s i d u a l volume (and accompanying decrease i n v i t a l c a p a c i t y ) (Whitbourne, 1985). At subrnaximal work loads, a low v e n t i l a t o r y r a t e i s d e s i r a b l e . The l i t e r a t u r e i s confusing as to the age e f f e c t s on v e n t i l a t o r y r a t e . Some i n v e s t i g a t o r s show no change w i t h age (Denolin et a l . , 1970), a decrease (de V r i e s and Adams, 1972) or an increase (Robinson et a l . , 1975). Older i n d i v i d u a l s are l e s s able to maintain h i g h r a t e s of v e n t i l a t i o n at maximal l e v e l s of e x e r c i s e ( S a l t i n and Grimby, 1968). A decreased chest w a l l compliance w i t h age i s a c o n t r i b u t i n g f a c t o r (Baldwin et a l . , 1948). Since age has not been shown to a f f e c t t i d a l volume under c o n d i t i o n s of maximal e x e r c i s e , i t has been suggested that the decreased maximum frequency of b r e a t h i n g w i t h age i s r e s p o n s i b l e f o r the demonstrated age l o s s i n maximum v e n t i l a t o r y r a t e (Montoye, 1982). Forced e x p i r a t o r y volume (1 sec.) i s an index and measure of flow r a t e . The flow r a t e i s reduced w i t h age as i t i s dependent upon the e l a s t i c q u a l i t i e s of the lungs (Whitbourne, 1985). There appears to be a decrease i n flow r a t e (as expressed by f o r c e d e x p i r a t o r y volume) w i t h age (Kannel and Hubert, 1982; Shephard and Sidney, 1978). V e n t i l a t o r y e f f i c i e n c y ( r a t e of v e n t i l a t i o n / o x y g e n uptake) a l s o r e f l e c t s the e f f i c i e n c y of the oxygen t r a n s p o r t mechanisms of the body (de V r i e s , - 28 1980). At submaximal l e v e l s , the lungs of o l d e r a d u l t s are l e s s e f f e c t i v e i n oxygen t r a n s p o r t , t h i s being i n d i c a t e d by a higher v e n t i l a t o r y e f f i c i e n c y index (Robinson et a l . , 1975). Concurrently, the maximum l e v e l of v e n t i l a t o r y e f f i c i e n c y i s reduced w i t h age, suggesting t h a t the older i n d i v i d u a l i s l e s s able to provide adequate l e v e l s of oxygen at maximal l e v e l s of work, as v e n t i l a t i o n i s compromised. The r e s p o n s i v i t y of the r e s p i r a t o r y response to hypoxia i s reduced with age (Petersen et a l . , 1981). S t r u c t u r a l and/or f u n c t i o n a l changes i n the r e s p i r a t o r y system or the neuromuscular c o n t r o l over v e n t i l a t i o n may be r e s p o n s i b l e . I t has been suggested that a decreased n e u r a l output to the r e s p i r a t o r y muscles under c o n d i t i o n s of hypoxia i s the major reason f o r t h i s age e f f e c t (Petersen et a l . , 1981). There i s , however, evidence to show increased sympathetic a c t i v i t y i n the o l d e r i n d i v i d u a l . I t i s p o s s i b l e , then, t h a t the decreased response to hypoxia w i t h age i s a f u n c t i o n of the i n a b i l i t y of the lungs and chest w a l l to respond to sympathetic s t i m u l a t i o n (Whitbourne, 1985). The r e s p i r a t o r y c o n t r o l of b r e a t h i n g i n response to pressure v a r i a t i o n s i n carbon d i o x i d e has not been seen to change w i t h age (Rubin et a l . , 1982). C. Airway Closure and Compliance There appears to be an i n c r e a s i n g non-uniformity i n the d i s t r i b u t i o n of a i r i n the lungs w i t h age, r e s u l t i n g i n a reduced oxygen c o n c e n t r a t i o n i n the a r t e r i a l blood. This non-uniformity of a i r d i s t r i b u t i o n r e s u l t s i n a discrepancy between v e n t i l a t o r y and p e r f u s i o n r a t e s (Edelman et a l . , 1968). Such a discrepancy i s a l s o p r evalent i n young a d u l t s , but i t appears that i n t h i s age group, the e f f i c i e n c y of gaseous exchange i s not compromised. The lung of o l d e r i n d i v i d u a l s y i e l d s a greater t o t a l area of i n e q u a l i t y between v e n t i l a t i o n and p e r f u s i o n . The r e s u l t i s a decreased oxygenation of the blood l e a v i n g the lungs (West, 1977). At a l l ages, the t o t a l q u a l i t y of - 29 blood l e a v i n g the lungs contains a l a r g e volume of b l o o d from the lower lung. In the o l d e r person, t h i s blood i s not well-oxygenated. This i s due to a reduced v e n t i l a t i o n i n the lower aspect of the lung due to the decreased e l a s t i c i t y of the t i s s u e . A decreased e l a s t i c i t y promotes premature airway c l o s u r e i n e x p i r a t i o n , thereby a l l o w i n g unexpired a i r to be trapped i n s i d e . G r a v i t a t i o n a l f o r c e s a l s o cause a discrepancy i n the r e c o i l a c t i v i t y i n the upper and lower lung (the pressure over the lung surface i s more p o s i t i v e , by approximately 7.5 cm E^O i n comparison to the lower l u n g ) . As the lung t i s s u e l o s e s e l a s t i c i t y , i t i s the bottom regions t h a t are more a f f e c t e d . The r e s u l t i s t h a t the a l v e o l i i n the lower aspect of the aging person's lung are l i k e l y to be u n d e r v e n t i l a t e d , r e l a t i v e to the pulmonary c a p i l l a r y blood flow (Begin et a l . , 1975; Bode et a l . , 1976). A lower e l a s t i c r e c o i l w i t h age i s i n d i c a t e d by l e s s pressure across the lung surface at a given lung volume. I n a d d i t i o n , lung compliance (the volume increase f o r each pressure increase) i s seen to be greater i n o l d e r a d u l t s . An increased compliance w i t h age i s i n d i c a t i v e of the decreased r e s i s t a n c e to lung expansion i n i n s p i r a t i o n (Whitbourne, 1985). A l t e r a t i o n s i n a l v e o l a r s t r u c t u r e are seen w i t h age. E l a s t i c and collagenous i n t e g r i t y are compromised ( B r a n d s t e t t e r and Kazenni, 1983; Lynne-Davies, 1977) and a l v e o l a r ducts and a l v e o l i increase i n s i z e (Reid, 1967) . This r e s u l t s i n a decreased t o t a l number of a l v e o l i and f u n c t i o n a l surface area. Aging a l s o corresponds w i t h an increase i n the r i g i d i t y of the chest w a l l s t r u c t u r e s (Shephard and Sidney, 1978). T h i s , along w i t h the decreased e l a s t i c i t y of the lung, f u r t h e r compromises the a b i l i t y of the lung to compress i n e x p i r a t i o n and expand during i n s p i r a t i o n , and increases the amount of work r e q u i r e d by the r e s p i r a t o r y musculature i n the v e n t i l a t i o n c y c l e (Brooks and Fahey, 1984). 30 -D. Pulmonary Hemodynamics The normal range of pulmonary a r t e r i a l pressures g r a d u a l l y increases w i t h age. I t has been determined that the mean r e s t i n g a r t e r i a l pulmonary pressure increases 0.8 mm Hg per decade a f t e r the age of 40. D i a s t o l i c a r t e r i a l pulmonary pressure increases 0.7 mm Hg per decade w h i l e s y s t o l i c a r t e r i a l pulmonary pressure i s not seen to change s i g n i f i c a n t l y ( P e r r a u l t et a l . , 1969). T a r t f u l i e r et a l . , (1972) found that during supine e x e r c i s e , the observed r e l a t i o n s h i p between pulmonary a r t e r y pressures ( s y s t o l i c , d i a s t o l i c and mean) and c a r d i a c output were l i n e a r and were seen to increase w i t h age. I t was seen t h a t the pulmonary c a p i l l a r y wedge pressure increased w i t h age and i s r e s p o n s i b l e f o r the age - r e l a t e d increase In pulmonary a r t e r y pressures during supine e x e r c i s e . The pressure gradient across the pulmonary v a s c u l a r bed (PAP-PCW) remains constant, i n d i c a t i n g that pulmonary v a s c u l a r r e s i s t a n c e e x h i b i t s l i t t l e i ncrease w i t h age (Palevsky, 1986). E. Effects of Exercise Training on the Respiratory System The only muscular t i s s u e i n the r e s p i r a t o r y system t h a t can be strengthened by t r a i n i n g are the muscles that c o n t r o l v e n t i l a t i o n ( i n s p i r a t i o n and e x p i r a t i o n ) . The c a r d i o v a s c u l a r system, by c o n t r a s t , has a greater p o t e n t i a l f o r the r e v e r s a l of age e f f e c t s due to the t r a i n a b i l i t y of the myocardium (Whitbourne, 1985). The long term e f f e c t s of chronic i n a c t i v i t y have not been i n v e s t i g a t e d to t e s t the p o s s i b i l i t y that decreased l e v e l s of p a r t i c i p a t i o n i n ex e r c i s e c o n t r i b u t e to a g e - r e l a t e d decrements i n r e s p i r a t o r y f u n c t i o n (Whitbourne, 1985). A t h l e t e s and former a t h l e t e s show l e s s of a d e c l i n e i n v i t a l c a p a c i t y w i t h age than sedentary a d u l t s (Plowman et a l . , 1979; Robinson et a l . , 1973). This f i n d i n g has not always been c o n s i s t e n t w i t h a l l s t u d i e s (Astrand, 1973). - 31 -Short-term s t u d i e s have not shown a p o s i t i v e change i n v i t a l c a p a c i t y with aerobic t r a i n i n g (Niinimaa and Shephard, 1978; P o l l o c k et a l . , 1976), although an increase i n v i t a l c a p a c i t y at maximum l e v e l s of e x e r t i o n was seen i n an 8-week t r a i n i n g program i n which both young and middle-aged men and women p a r t i c i p a t e d (Heikkenen, 1978). I t i s , t h e r e f o r e , not c l e a r whether e x e r c i s e can enhance v i t a l c a p a c i t y or whether i t i s other v a r i a b l e s such as l i f e s t y l e t h a t may be more important. Whitbourne (1985) s t a t e s that e x e r c i s e may have the g r e a t e s t e f f e c t on v i t a l c a p a c i t y on those no o l d e r than 50-60 years of age. V e n t i l a t o r y r a t e ( t i d a l volume x r e s p i r a t o r y frequency), known to d e c l i n e w i t h age, i s modifi e d by both long and short-term e x e r c i s e programs. However, t h i s seems to be true only f o r v e n t i l a t o r y r a t e s measured at maximum (not subrnaximal) l e v e l s of e x e r t i o n . T r a i n i n g , then, increases the p o t e n t i a l maximum r a t e of v e n t i l a t i o n (Astrand, 1973; de V r i e s , 1970). This may be as a r e s u l t of an increased maximum br e a t h i n g frequency ( S a l t i n e t a l . , 1969) or an increased t i d a l volume (de V r i e s , 1970; Robinson et a l . , 1973). V e n t i l a t o r y flow i s seen to increase i n middle-aged and ol d e r adults w i t h t r a i n i n g (Whitbourne, 1985). I t has been e s t a b l i s h e d t h a t the t o t a l volume of a i r i n s p i r e d and e x p i r e d during a maximum v e n t i l a t o r y e f f o r t i s great e r i n a t h l e t e s and former a t h l e t e s than t h e i r sedentary counterparts at comparable ages ( S a l t i n and Grimby, 1968). The amount of a i r f o r c i b l y e x p i r e d during a maximum r e s p i r a t o r y attempt was found to be higher i n a t h l e t e s and former a t h l e t e s . Improvements w i t h t r a i n i n g have not been shown ( P o l l o c k et a l . , 1976). Since the maximum r a t e of v e n t i l a t i o n and v e n t i l a t o r y flow can be increased by e x e r c i s e t r a i n i n g , one may expect the index of v e n t i l a t o r y e f f i c i e n c y ( v e n t i l a t o r y r a t e s r e l a t i v e to oxygen consumption) to increase a l s o . T r a i n i n g has, however, no e f f e c t on the v e n t i l a t o r y e f f i c i e n c y index 32 -at e i t h e r maximal or submaximal l e v e l s of e x e r c i s e (Shephard and Sidney, 1978; Stanford, 1974). E x e r c i s e t r a i n i n g enables the middle-aged and o l d e r a d u l t to increase the r a t e of b r e a t h i n g to l e v e l s that meet the demands presented by maximal l e v e l s of work. T r a i n i n g has, however, no e f f e c t on lung s t r u c t u r e and volume: t i d a l volume, v i t a l c a p a c i t y and v e n t i l a t o r y r a t e (measurements dependent upon lung volume), do not show p o s i t i v e change(s) w i t h t r a i n i n g (Whitbourne, 1985). I l l THE PHYSIOLOGICAL RESPONSE TO AQUATIC EXERCISE There i s an i n c r e a s i n g amount of l i t e r a t u r e a v a i l a b l e that describes v a r i o u s water e x e r c i s e programs. Many have been evaluated as to t h e i r worth i n p r o v i d i n g adequate components of f i t n e s s . These components include p o t e n t i a l c a r d i o v a s c u l a r b e n e f i t s , f l e x i b i l i t y , s t r e n g t h , body composition, i n c l u s i o n of warm-up and cool-downs and s a f e t y precautions (Koszuta, 1986). Based on the adequacy t h a t these c r i t e r i a are met, 11 of the 15 programs evaluated were deemed s a t i s f a c t o r y . Whether the v a r i o u s books, videos and innovations are b e n e f i c i a l i n terms of s a t i s f y i n g the above c r i t e r i a may be i n c o n s e q u e n t i a l ; i t i s f e l t by some that any e x e r c i s e a i d or program that w i l l not cause i n j u r y may be h e l p f u l as a means of i n c r e a s i n g the m o t i v a t i o n to e x e r c i s e (Koszuta, 1986) . Attempts have been made to determine the d i f f e r e n c e i n metabolic demands between e x e r c i s e i n water and on land. C o s t i l l (1971) found t h a t subjects i n water c o u l d perform 66.7% to 71.4% of the t o t a l amount of work performed on land. The oxygen uptake during submaximal work was found to be s i g n i f i c a n t l y higher i n the water e x e r c i s e c o n d i t i o n s . When comparing the c a l o r i c cost of submaximal water work i n water to that of e x e r c i s i n g on land, water ex e r c i s e was found to increase the energy requirements by 33% to 42% f o r any given 33 -work l e v e l . In response to the Increased c a l o r i c demand i n water e x e r c i s e , heart r a t e s were a l s o higher at a l l l e v e l s of subrnaximal e x e r c i s e . Water r e s i s t a n c e appears to be r e s p o n s i b l e f o r a mean increase of approximately 34% i n the energy requirements during subrnaximal e x e r c i s e . V i c k e r y et a l . (1983) presented the f i r s t p h y s i o l o g i c a l response data concerning water "aerobic" e x e r c i s e ("aqua dynamics"). They proceeded from the premise t h a t i t was not known whether an e x e r c i s e program c o n s i s t i n g p r i m a r i l y of aquatic c a l i s t h e n i c s o f f e r e d s u f f i c i e n t i n t e n s i t y to e l i c i t acute t r a i n i n g e f f e c t s . The heart r a t e and energy expenditure of 3 c o l l e g e women were determined during three "Aqua Dynamics" workouts, ranging from 20 minutes to 60 minutes i n d u r a t i o n . Each workout c o n s i s t e d of a s e r i e s of water e x e r c i s e s performed c o n s e c u t i v e l y without stopping, f o l l o w e d by lap swimming. The e x e r c i s e i n c l u d e d warm-up s t r e t c h i n g , t w i s t i n g , simulated crawl swimming, running i n p l a c e , k i c k i n g and t r e a d i n g water. F l u c t u a t i o n s i n measured heart r a t e during the course of the workout suggest that i n d i v i d u a l e x e r c i s e v a r i e d i n i n t e n s i t y . K i c k i n g movements and bobbing movements produced the h i g h e s t heart r a t e s and l a p swimming produced the h i g h e s t h e a r t r a t e and oxygen uptake. A l l three workouts were found to be of moderate i n t e n s i t y , producing average heart r a t e s of 132 to 152 beats/minute (or 70% to 77% of the maximal age-adjusted heart r a t e ) , average oxygen uptakes of 1.2 to 1.3 l i t e r s / m i n u t e (or 51% to 57% of V-^max^ ' a n c * a v e r a S e r a t e s of energy expenditure of 5.9 to 65 kcals/minute. I t was found that the d i f f e r e n c e between the three workouts was t o t a l c a l o r i e expenditure and d u r a t i o n of e x e r c i s e and not the i n t e n s i t y of work. The authors concluded t h a t although some exercses i n the workout produced a lower than r e q u i r e d i n t e n s i t y of work, the o v e r a l l response to t h i s type of e x e r c i s e suggests that r e g u l a r and s u f f i c i e n t p a r t i c i p a t i o n would probably improve p h y s i c a l 34 -work c a p a c i t y , p a r t i c u l a r l y i n those i n d i v i d u a l s w i t h r e l a t i v e l y low p h y s i c a l work c a p a c i t i e s . Koszuta (1986) describes a study i n which s i x a e r o b i c a l l y f i t male subjects p a r t i c i p a t e d i n an aquatic e x e r c i s e program. The three r o u t i n e s (at 21, 36 and 46 minutes i n duration) were s i m i l a r to the conventional "aerobic" c l a s s e s on land. Heart r a t e s and mean oxygen uptakes were maintained at the lower end of the recommended ranges f o r f i t a t h l e t e s (American College of Sports Medicine, 1978). The i n v e s t i g a t o r s concluded that i n d i v i d u a l s with low to average aerobic c a p a c i t y would l i k e l y r e c e i v e c a r d i o v a s c u l a r and weight c o n t r o l b e n e f i t s from such a program. I t appears then, that d e s p i t e an inadequacy i n the number of i n v e s t i g a t i o n s examining t h i s type of e x e r c i s e , there i s a general consensus that water e x e r c i s e can be regarded as a v i a b l e and e f f e c t i v e form of e x e r c i s e and i t may be p a r t i c u l a r l y s u i t e d f o r those i n d i v i d u a l s w i t h low l e v e l s of f i t n e s s . - 35 -METHODS AND PROCEDURES F i f t e e n subjects (8 females and 7 males, mean age 68.5 years, range 61-75 years) were r e c r u i t e d v o l u n t a r i l y from r e g i o n a l community adult day-care f a c i l i t i e s . A l l subjects were f u l l y informed of the r i s k s and p o t e n t i a l discomfort a s s o c i a t e d w i t h the t e s t i n g procedures and p a r t i c i p a t i o n i n the program before g i v i n g t h e i r consent. A l l subjects were r e q u i r e d to undergo medical screening and clearance by t h e i r p h y s i c i a n s . The subjects were r e q u i r e d to demonstrate an absence of: 1. recent i l l n e s s r e q u i r i n g h o s p i t a l i z a t i o n , 2. c h r o n i c ( d e b i l i t a t i n g ) a r t h r i t i s or r e l a t e d j o i n t d i s o r d e r s , 3. u n c o n t r o l l e d diabetes, 4. u n c o n t r o l l e d hypertension, 5. symptomatic c a r d i o v a s c u l a r disease, 6. r e n a l / h e p a t i c disease, 7. n e u r o l o g i c a l disease (pronounced d e c l i n e i n motor a b i l i t i e s and/or m e n t i t i o n ) . (see. Appendix F f o r c o n t r a i n d i c a t i o n s f o r e x e r c i s e p a r t i c i p a t i o n and t e s t i n g ) . A l l subjects completed forms of informed consent p r i o r to entry i n t o the program (see Appendices G and H). P a r t i c i p a n t s i n the study underwent a s e r i e s of p h y s i o l o g i c a l t e s t s before the program s t a r t e d and 5 weeks l a t e r at the end of the program. The r e s u l t s of these p h y s i o l o g i c a l measurements and p h y s i c a l parameters at the s t a r t of the program are given i n Table I I . Measurements i n c l u d e d height, weight, a 5-lead e x e r c i s e electrocardiogram, spirometry measurements (forced v i t a l c a p a c i t y (FVC), f o r c e d e x p i r a t o r y volume i n 1 second (FEV^"^), maximum v e n t i l a t i o n )) • r e s t i n g blood pressure ( s y s t o l i c / d i a s t o l i c ) , r e s t i n g heart r a t e , e x e r c i s e heart r a t e and V0_ as determined by a continuous 36 -t r e a d m i l l t e s t (modified a f t e r Jones and Campbell, 1982). The p r o t o c o l c o n s i s t e d of a 3 minute warm-up walk at 2.0 mph (0% grade). T r e a d m i l l speed was then increased to 2.5 mph w i t h 2% increases i n e l e v a t i o n every 2 minutes. The r e l i a b i l i t y of ^C^max determinations i n e l d e r l y s ubjects has been desc r i b e d by Thomas et a l . (1985) w i t h the c o r r e l a t i o n c o e f f i c i e n t s between a f i r s t stage I (Jones and Campbell) t e s t and a second stage I t e s t one year l a t e r being 0.90. The c r i t e r i a f o r stopping the e x e r c i s e t e s t was mo d i f i e d from that suggested by Cunningham and Rechnitzer (1974). A l l subjects were encouraged to continue the t e s t u n t i l they i ) a t t a i n e d t h e i r maximal heart r a t e and/or, i i ) f a t i g u e (breathlessness, c l a u d i c a t i o n ) ensued. Subjects were acquainted w i t h a l l t e s t s and t r e a d m i l l p r o t o c o l during i n i t i a l o r i e n t a t i o n sessions a t the J.M. Buchannan Research and F i t n e s s Center at the U n i v e r s i t y of B r i t i s h Columbia. T e s t i n g was done on successive v i s i t s to the f a c i l i t y . Blood pressures were obtained by a u s c u l t a t i o n . R e s t i n g heart r a t e s were obtained by a r a d i a l pulse and e x e r c i s e ( t e s t i n g ) heart r a t e s were conti n u o u s l y monitored by d i r e c t ECG. Forced e x p i r a t o r y volume i n 1 second (FEV 1'^) and f o r c e d v i t a l c a p a c i t y (FVC) were recorded as the h i g h e s t of three t r i a l s ( a f t e r Thomas et a l . , 1985). Expired gases were co n t i n u o u s l y c o l l e c t e d and analyzed by a Beckman Metabolic Measurement Cart (BMMC) i n t e r f a c e d w i t h a Hewlett-Packard 3052A Data A c q u i s i t i o n System f o r 15 second determinations of r e s p i r a t o r y gas exchange v a r i a b l e s . The accuracy of t h i s means of data c o l l e c t i o n has been deemed h i g h l y s a t i s f a c t o r y by Montoye et a l . (1970). The a n a l y s i s of ex p i r e d gases f o r each subject was preceded by the c a l i b r a t i o n of the C O 2 and 0 ^ analyzers w i t h a c a l i b r a t i o n gas. Maximum oxygen consumption, maximum v e n t i l a t i o n and maximum r e s p i r a t o r y exchange r a t i o s were determined by averaging the h i g h e s t 2 consecutive f i f t e e n second values. 37 -E x e r c i s e Program Subjects were randomly assigned to e i t h e r c o n t r o l (n = 7) or experimental (n = 8) groups. Females were assigned to groups f i r s t and then males to ensure equal r e p r e s e n t a t i o n of sex i n each group. The e x e r c i s e sessions f o r the experimental group were h e l d on three (3) mornings per week, on non-consecutive days f o r a 5 week p e r i o d at the UBC Aquatic Center. A t o t a l of seventeen (17) sessions were attended by the experimental group. Each e x e r c i s e s e s s i o n began w i t h 25 minutes of s t r e n g t h and f l e x i b i l i t y movements on dry l a n d which i n c l u d e d t o r s o , arm and shoulder e x e r c i s e s while standing and mat work where each subject performed a d d i t i o n a l s t r e t c h i n g movements f o r the musculature i n the back and l e g s , ending w i t h a cool-down p e r i o d . The subjects then entered the pool and proceeded to a shoulder or chest depth of water. The pool work began w i t h a warm-up f o r the arms and t o r s o , proceeding to a c t i v e running/jogging movements which i n v o l v e d the e n t i r e body and was f o l l o w e d by a slower paced cool-down w i t h s t r e t c h and s t r e n g t h movements i n c o r p o r a t i n g the sides of the pool ( i s o m e t r i c s and s t r e t c h i n g ) A l l pool work was performed to s e l e c t e d pre-recorded music i n an attempt to d i c t a t e a cadence f o r the p a r t i c i p a n t s . T o t a l pool time f o r each s e s s i o n was 30 minutes, w i t h the e n t i r e s e s s i o n l a s t i n g 55 minutes. Pool temperatures ranged from (and were c o n t r o l l e d at) 28.3°C (83°F) to 30°C (86°F). The i n t e n s i t y of e x e r c i s e was recorded as a r a d i a l pulse obtained during each e x e r c i s e s e s s i o n (recorded as number of beats i n 15 seconds, m u l t i p l i e d by 4 to give beats per minute). Two heart r a t e determinations were obtained from each sub j e c t per s e s s i o n . Those subjects assigned to the c o n t r o l group proceeded w i t h t h e i r normal d a i l y a c t i v i t i e s during the course of the study. - 38 EXPERIMENTAL DESIGN AND DATA ANALYSIS Data a n a l y s i s was of a repeated measures design; one grouping f a c t o r (treatment and c o n t r o l ) and one w i t h i n f a c t o r (time). A n a l y s i s of variance was performed u s i n g the program BMDP2V (BMDP: S t a t i s t i c a l Software Inc., C a l i f o r n i a ; r e v i s e d 1982). The model f o r t h i s repeated measures design i s d e t a i l e d i n Appendix D. A n a l y s i s of vari a n c e was performed on each dependent v a r i a b l e to determine group, time and group x time e f f e c t s . A l l hypothesis t e s t i n g was c o n t r o l l e d at a predetermined alpha l e v e l of 0.01 (a = 0.01). For each v a r i a b l e , the hypothesis was that the (T1-T2) change i n the experimental group would be d i f f e r e n t from the (T1-T2) change i n the c o n t r o l group, with the n u l l hypothesis being M Q ^ Q U P I = ^GR0UP2 a t a = u-01- F o r A H v a r i a b l e s , when P > 0.01, the n u l l hypothesis was accepted, when P < 0.01, the n u l l hypothesis was r e j e c t e d . The dependent v a r i a b l e s are: 1. SBPR: s y s t o l i c blood pressure 2. V EMAX : maximum v e n t i l a t i o n 3. FEV 1' 0: fo r c e d e x p i r a t o r y volume ( i n 1 second) 4. FVC: f o r c e d v i t a l c a p a c i t y 5. HRO: ex e t c i s e heart r a t e at 0% t r e a d m i l l grade 6. HR2: ex e r c i s e heart r a t e at 2% t r e a d m i l l grade 7. HR4: ex e r c i s e heart r a t e at 4% t r e a d m i l l grade 8. HR6: e x e r c i s e heart r a t e at 6% t r e a d m i l l grade 9. HR8: ex e r c i s e heart r a t e at 8% t r e a d m i l l grade 10. HR10: e x e r c i s e heart r a t e a t 10% t r e a d m i l l grade 11. HR12: e x e r c i s e heart r a t e at 12% t r e a d m i l l grade - 39 -12. V 02MAX' m a x i m u m oxygen uptake 13. H R j ^ x : maximum heart r a t e 14. HR^ : r e s t i n g heart r a t e - 40 -RESULTS The p h y s i c a l c h a r a c t e r i s t i c s and metabolic parameters of the subjects are summarized i n Tables I and I I . ANOVA ta b l e s are reproduced i n Appendix E. A summary of v a r i a b l e a n a l y s i s i s given i n Table I I I . A n a l y s i s of va r i a n c e y i e l d e d main (Time) e f f e c t s f o r HR^,^ (P = 0.001) and FEV^'^ (P = 0.002) demonstrating t h a t , when averaged over groups, a s i g n i f i c a n t change from T ( l ) to T(2) i s seen i n these v a r i a b l e s . S i g n i f i c a n t 1 0 i n t e r a c t i o n s between Group and Time were seen w i t h , FEV ' (P = 0.001), H RREST ^ P = °- 0 0 3) a n d V 02MAX ^ P = ° - 0 0 7 ) ' demonstrating t h a t the change i n these v a r i a b l e s from T ( l ) to T(2) are not the same f o r both groups (experimental and c o n t r o l ) . No s i g n i f i c a n t main (Group) e f f e c t s were noted at T ( l ) . Therefore, the two groups d i d not show any s i g n i f i c a n t d i f f e r e n c e s at T ( l ) f o r p h y s i c a l or metabolic c h a r a c t e r i s t i c s . - 41 -TABLE I Mean and Standard D e v i a t i o n s o f P h y s i c a l and M e t a b o l i c C h a r a c t e r i s t i c s (Experimental and C o n t r o l Groups) V a r i a b l e AGE (yrs) 68. .5 + 4.68 WEIGHT (kg) 77. .57 + 18.70 HEIGHT (cms) 166. .65 + 7.33 SYSTOLIC BP (REST) (mmHg) 136. .00 + 10.57 V EMAX a-^n"1) 35. .57 + 10.32 F E V 1 - 0 ( l - s e c " 1 ) 2. .20 + 0.52 FVC ( l ^ s e c " 1 ) 3. .49 + 0.96 H RMAX t ^ 8 * 1 1 1 1 1 1 " 1 ) 143. .80 + 13.87 H RREST ( b ^ - 1 " ^ " 1 ) 76. .40 + 5.97 HR 0% (bts'min" 1) 119, .40 + 13.88 HR 2% (bts'min" 1) 124 .13 + 13.79 HR 4% (bts.min" 1) 131 .33 + 13.51 HR 6% (bts'min" 1) 137 .00 + 12.74 HR 8% (bts^min" 1) 137 .77 + 11.89' HR 10% (bts«min _ 1) 141 .14 + 16.69' HR 12% (bts-min" 1) 167 .00 + 0.00 V 02MAX ( m l * k S 1 , m l n 1 ) 24 .44 + 1.99 a l l v alues are means ± SD a l l v a l u e s n = 15 except where * (number i n brackets i s n) - 42 -TABLE II Mean and Standard Deviations of Physical and Metabolic Characteristics Variable Control AGE (yrs) WEIGHT (kg) HEIGHT (cms) SYSTOLIC BP (REST) (mmHg) V EMAX a-**'1) F E V 1 - 0 ( l . s e c " 1 ) FVC (1-sec" 1) H R M A X (hts'mi^'1y H RREST ( b t s ' 1 ^ " 1 ) HR 0% (bts-min" 1) HR 2% (bts-min" 1) HR 4% (bts-min" 1) HR 6% (bts-min" 1) HR 8% (bts-min" 1) HR 10% (bts-min" 1) HR 12% (bts-min" 1) -1 -1 V 02MAX ( m l ' k S * m l n > 67.71 ± 5.38 75.41 ± 18.76 167.10 ±7.82 132.43 ± 9.34 34.70 ± 11.64 2.31 ± 0.68 3.35 ± 0.82 141.43 ± 17.93 77.00 ± 2.77 116.57 ± 11.12 119.42 ± 12.16 127.14 ± 12.06 134.43 ± 13.26 138.14 ± 16.12 142.50 ± 22.55* (4) 167.00 ± 0.00* (1) 23.84 ± 1.99 Exp e r imenta1 69.12 ± 4.26 79.46 ± 19.72 116.25 ± 7.38 139.12 ± 11.17 36.32 ± 9.77 2.11 ± 0.37 3.61 ± 1.10 145.87 ± 9.92 75.78 ± 8.01 121.87 ± 16.25 128.25 ± 14.57 135.00 ± 14.40 139.25 ± 12.70 137.33 ± 5.24* (6) 139.33 ± 8.02* (3) (0) 24.98 ± 1.97 No. i n each group a l l values are means ± SD a l l values n = 15 except where * (number i n brackets is n) - 43 -TABLE III Summary of Variable Analysis EXPERIMENTAL CONTROL P V a r i a b l e T ( l ) T(2) T ( l ) T(2) TIME GROUPxTIME AGE (YRS.) 69. ,1 69. ,1 67. ,7 67.7 NS NS WEIGHT (Kg) 79. .4 79. ,4 75. ,4 75.4 NS NS HEIGHT (cm) 116, .2 116. ,2 167. .1 167.1 NS NS SBPR (mmHG) 139. .1 131. ,5 132. .4 133.4 NS NS V E M A X ( 1 * m i n " 1 ) 36. .3 36. ,9 34. .7 35.0 NS NS F E V 1 - 0 (1-sec" 1) 2, .1 2, .4 2, .3 2.2 0.002 0.001 FVC (1-sec' 1) 3, .6 3. .9 3, .3 3.3 NS NS H RMAX ( b t s , m i n l ) 145. .8 144. .6 141, .4 141.5 NS NS H RREST ( b t s * m i n 1 ) 75 .8 71, .0 77, .0 76.6 0.001 .0.003 HR 0% (bts-min" 1) 121, .8 116, .2 116, .5 115.8 NS NS HR 2% (bts-min" 1) 128, .2 123. .3 119, .9 118.1 NS NS HR 4% (bts-min" 1) 135 .0 128, . 5 127 .1 127.0 NS NS HR 6% ( b t s - m i n - 1 ) 139, .2 132. .3 134, .4 133.8 NS NS HR 8% (bts-min" 1) 137, .3 132. .8 138. .1 138.1 NS NS (13) HR 10% (bts-min" 1) _ (7) HR 12% (bts-min" 1) _ (1) -1 -1 V 02MAX ( m l , k S , m i n ) 24, .9 25. .8 23, .8 23.5 NS 0.007 a l l values n = 15 except where * (number i n brackets i s n) significance at P < 0.01 NS denotes non-significance (-) denotes insufficient data - 44 -TABLE IV Comparison of Selected Parameters VARIABLE Thomas Seals et a l . , 1985 et a l . , 1984 Larson et a l . , 1984 Jessop 1988 AGE (YRS.) 62.6 ± 3.1 63.3 ± 3.0 67.0 ± 0.00 68.5 ± 4 . i WEIGHT (kg) 79.8 ± 1.1 77.1 ± 10.7 77.57 ± 18.70 VO 2MAX (ml«kg «min ) 29.6 ± 0.6 25.4 ± 4.6 24.44 ± 1.99 VE MAX (l«min ) 83.4 ± 2.2 67.2 ± 16.4 35.57 ± 10.32 HR, MAX (bts.min ) 155.3 ± 2.4 174 ± 10 143.80 ± 13.87 1.0 FEV (l'sec ) 2.86 ± 0.05 2.80 ± 0.6 2.20 ± 0.52 100 24 644 15 a l l values are means ± SD (-) denotes data not available - 45 -TABLE V Summary of Hypothesis Testing (ml»kg «min ) V°2MAX E X P T L ( T 2 ) > V°2MAX C T R L ( T 2 ) SUPPORTED BP SYSTOLIC (RESTING) - " I N (bts-min ) BPSR E X P T L ( T 2 ) < BPSR C T R L ( T 2 ) NOT SUPPORTED V EMAX _ x. (l«min ) V EMAX E X P T L ( T 2 ) > V EMAX C T R L ( T 2 ) NOT SUPPORTED F E V 1 - 0 (1-sec" 1) FEV 1- 0 E X P T L ( T 2 ) > FEV 1" 0 C T R L ( T 2 ) SUPPORTED FVC ( l ^ s e c ) FVC E X P T L ( T 2 ) > FVC CTRL 2 NOT SUPPORTED H RREST ^ b t s * m i n ) H RREST E X P T L ( T 2 ) < H RREST C T R L ( T 2 ) SUPPORTED T l : b a s e l i n e measurement T2: measurements taken at end of study EXPTL: experimental (GROUP 1) CTRL: c o n t r o l (GROUP 2) R e l a t i o n s h i p s supported on b a s i s of s i g n i f i c a n c e P < 0.01 - 46 -DISCUSSION Tables I and I I summarize the v a r i a b l e s f o r the subjects i n the study. The s u b j e c t s were found to represent a homogeneous sample as i n d i c a t e d by the r e l a t i v e l y s m a l l standard d e v i a t i o n s f o r most of the v a r i a b l e s . When some s e l e c t p h y s i c a l and metabolic parameters are compared w i t h values obtained by previous i n v e s t i g a t o r s (Table IV) , i t can be seen that there are some parameters, p a r t i c u l a r l y body.weight, i n which a l a r g e standard d e v i a t i o n i s found. Standard d e v i a t i o n s f o r v a r i a b l e s such as weight, age, VO. , ° ° 2max maximum heart r a t e and FEV 1'^ are comparable to v a r i a b i l i t y found i n other i n v e s t i g a t i o n s ( i . e . Seals e t a l . , 1984; Thomas et a l . , 1985). D i f f e r e n c e s are noted i n VE : a lower mean value obtained i n t h i s study may be due to max J J the o l d e r mean age of the su b j e c t s . G e n e r a l l y , i n comparison to other s i m i l a r t r a i n i n g s t u d i e s i n v o l v i n g e l d e r l y s u b j e c t s , the subject i n t h i s study appears to be both o l d e r and e x h i b i t s a greater v a r i a t i o n i n body weight. I CARDIOVASCULAR PARAMETERS A. Resting Systolic Blood Pressure The experimental group d i d not show a s i g n i f i c a n t d e c l i n e i n r e s t i n g s y s t o l i c blood pressure (Table I I I ) . This i s not i n accordance w i t h the f i n d i n g s by Skinner et a l . , (1964) who found s i g n i f i c a n t reductions i n the s y s t o l i c b l o o d pressure of p r e v i o u s l y sedentary middle-aged subjects and by Barry e t a l . , (1966) who found s i m i l a r reductions i n e l d e r l y s u b j e c t s . Ernes' (1979) 12-week study a l s o demonstrated a r e d u c t i o n i n r e s t i n g s y s t o l i c blood pressure. I t i s known th a t the body adjusts a r t e r i a l pressure by a l t e r i n g heart r a t e , s t r o k e volume and p e r i p h e r a l v a s c u l a r r e s i s t a n c e . The major f a c t o r - 47 -tha t seems to be a l t e r e d i n the aging process i s the increased r i g i d i t y of the a r t e r i a l w a l l s , r e s u l t i n g i n an o v e r a l l i n creased systemic r e s i s t a n c e to blood flow (Sebban et a l . , 1981). This i s seen by the higher r e s t i n g s y s t o l i c and d i a s t o l i c blood pressures seen i n the e l d e r l y (Sato et a l . , 1981). I t i s u n l i k e l y t h a t t r a i n i n g c o u l d reverse the gradual age-related increase i n the e l a s t i c constant of the a r t e r i a l w a l l s and yet reductions i n r e s t i n g s y s t o l i c pressures are seen. Both s y s t o l i c and d i a s t o l i c blood pressures can be lowered s i g n i f i c a n t l y by a r e g u l a r program of exer c i s e (MCardle et a l . , 1981). This has been seen w i t h normotensive (Kasch and Boyer, 1969) and hypertensive (Boyer and Kasch, 1970; Choquette and Ferguson, 1973) subjects at r e s t . The Tecumseh Michigan study (Scheuer and Tipton, 1977) showed th a t r e g a r d l e s s of age, a c t i v e men had s i g n i f i c a n t l y lower s y s t o l i c and d i a s t o l i c pressures than l e s s a c t i v e men. For mean a r t e r i a l pressure to decrease, both c e n t r a l and p e r i p h e r a l mechanisms th a t c o n t r o l c a r d i a c output and t o t a l p e r i p h e r a l r e s i s t a n c e must be considered. T r a i n i n g has been reported to be a s s o c i a t e d w i t h increased, unchanged or reduced r e s t i n g c a r d i a c output but the decrease i n cardiac output has not been a s s o c i a t e d w i t h a f a l l i n blood pressure (Scheuer and Tip t o n , 1977) . T o t a l p e r i p h e r a l r e s i s t a n c e a f t e r t r a i n i n g was seen to increase i n some s t u d i e s ( M i t c h e l l and W i l d e n t h a l , 1974) and decrease i n others when compared to c o n t r o l v a l u e s , although an increase i n cardiac output obtained during maximal e x e r c i s e w i t h t r a i n e d muscle groups g e n e r a l l y has been r e l a t e d to a reduced p e r i p h e r a l r e s i s t a n c e and an increased systemic v a s c u l a r conductance (Clausen, 1977). Since the l i t e r a t u r e g e n e r a l l y agrees w i t h the f i n d i n g of a decreased r e s t i n g s y s t o l i c blood pressure w i t h t r a i n i n g , t h i s c u r r e n t study was i n c o n c l u s i v e as i t may have been too short i n d u r a t i o n to f a c i l i t a t e such a d e c l i n e i n blood pressure (Robinson, 1938). - 48 B. R e s t i n g Heart Rate R e s t i n g heart r a t e was seen to decrease s i g n i f i c a n t l y over the 5-week study (P = 0.003) i n the experimental group whereas the c o n t r o l group d i d not e x h i b i t a change (Table I I I ) . This 6.43% d e c l i n e i n r e s t i n g heart rate agrees w i t h C u p e l l i et a l . (1984), Ernes (1979), Granath e t ' a l . (1970) and Zoneraich and Rhee (1977). I t has been suggested that t r a i n i n g caused an increased centrogenic vagal c h o l i n e r g i c d r i v e combined w i t h a sympathoinhibitory mechanism, r e s u l t i n g i n a decreased r e s t i n g heart r a t e (Astrand, 1977). In younger p o p u l a t i o n s , the l i t e r a t u r e s t a t e s that t r a i n i n g creates an imbalance between the t o n i c a c t i v i t y of the sympathetic ( a c c e l e r a t o r ) and parasympathetic (depressor) neurons i n favor of a greater vagal dominance. I t i s b e l i e v e d t h a t t h i s i s mediated by increased parasympathetic a c t i v i t y and a decreased sympathetic discharge. I t has a l s o been suggested t h a t the i n t r i n i s c f i r i n g r a t e of the s i n o - a t r i a l (SA) node i s decreased by t r a i n i n g . Myocardial c h o l i n e s t e r a s e concentrations are not a f f e c t e d by t r a i n i n g (Scheuer and T i p t o n , 1977); these f i n d i n g s l e n d credence to the theory t h a t t r a i n i n g increases parasympathetic a c t i v i t y . Although animal s t u d i e s have i n d i c a t e d increased l e v e l s of a t r i a l c h o l i n e a c e t y l t r a n s f e r a s e a c t i v i t y and more myocardial a c e t y l c h o l i n e per gram of t i s s u e w i t h c h r o n i c e x e r c i s e (Williams et a l . , 1984; Wyatt et a l . , 1978), the l i t e r a t u r e holds t h a t parasympathetic a c t i v i t y to the myocardium increases and r e s t i n g sympathetic a c t i v i t y decreases w i t h t r a i n i n g . C. Maximal Heart Rate Ne i t h e r experimental or c o n t r o l groups showed any s i g n i f i c a n t change i n maximal he a r t r a t e over the course of the study (Table I I I ) . T r a i n i n g e f f e c t s have been described as being n e g l i g i b l e i n some i n v e s t i g a t i o n s and have been seen to cause a d e c l i n e i n maximal heart r a t e i n others. - 49 -M a z z a r e l l a e t a l . (1966) reporte d no s i g n i f i c a n t change f o l l o w i n g a 2 month e x e r c i s e program and Skinner e t a l . (1964) reported s i m i l a r f i n d i n g s as a r e s u l t of a 6 month program w i t h middle-aged men. Granath e t a l . (1970) and Zoneraich and Rhee (1977) described i n d i c a t i o n s of a decreased maximal heart r a t e f o l l o w i n g t r a i n i n g . I t i s p o s s i b l e t h a t the d u r a t i o n of t h i s study was too short to produce s i g n i f i c a n t changes i n maximal heart r a t e ( i . e . 5 weeks vs. 6-12 mos. i n other i n v e s t i g a t i o n s ) or the age of the subjects was too advanced to produce such a change, re g a r d l e s s of the d u r a t i o n of the study. The l i t e r a t u r e has not shown any changes i n maximum heart r a t e i n older subjects (65 years of age and o l d e r ) , and the m a j o r i t y of previous i n v e s t i g a t i o n s i m p l i c a t e an age - r e l a t e d d e c l i n e i n maximum heart r a t e as being u n a l t e r a b l e by e x e r c i s e . E a r l y papers d e s c r i b i n g younger subjects s t a t e t h a t t r a i n i n g caused an incr e a s e d stroke volume at a given submaximal VG^ and a p r o p o r t i o n a l decrease i n heart r a t e . I t became common knowledge that the decreased heart r a t e was secondary to the increase i n stoke volume although l a t e r s t u d i e s i n d i c a t e d that an increased stroke volume i s not e s s e n t i a l to a decreased heart rate (Clausen, 1977) . The p o t e n t i a l importance of p e r i p h e r a l c a r d i o v a s c u l a r adjustments was suggested. I n c o n t r a s t to st u d i e s i n v o l v i n g e l d e r l y s u b j e c t s , t r a i n i n g studies d e s c r i b i n g younger subjects have i n d i c a t e d a decrease i n maximal heart r a t e , r e g a r d l e s s of the mode of e x e r c i s e (Schaible and Scheuer, 1985). Autonomic c o n t r o l , endogenous catecholamines, CNS adaptations or an increased stroke volume have been suggested as caus a t i v e f a c t o r s . T r a i n i n g may a l t e r the p e r i p h e r a l or c e n t r a l components of the baroreceptor r e f l e x , thus a f f e c t i n g the p e r i p h e r a l v a s c u l a r r e s i s t a n c e and heart r a t e . A l s o , t r a i n i n g probably increases the c o n t r a c t i l i t y of the myocardium. Increased c o n t r a c t i l e forces may be met w i t h i n t r a c a r d i a l or ba r o r e c e p t i v e r e f l e x e s which cause a d e c l i n e - 50 -i n h e a r t r a t e , but no experimental evidence supports t h i s . There i s l i t t l e evidence to account f o r the p o s s i b i l i t y of no change i n the maximal heart r a t e f o l l o w i n g c h r o n i c e x e r c i s e , but some s t u d i e s suggest that i n subjects who are 60 years of age and o l d e r , the changes of c a r d i a c output, stroke volume and l e f t v e n t r i c u l a r e j e c t i o n f r a c t i o n are c o n s i d e r a b l y l e s s than i n younger su b j e c t s f o l l o w i n g acute bouts of e x e r c i s e (Kuikka and Lansimies, 1982). P o r t e t a l . , (1980) suggest that the l e f t v e n t r i c u l a r response to e x e r c i s e i s changed i n the seventh decade of l i f e and by the e i g t h decade there i s p r a c t i c a l l y no increase i n e j e c t i o n f r a c t i o n . I t i s p o s s i b l e , then, that c h r o n i c e x e r c i s e may not r e s u l t i n an enhanced stroke volume i n the e l d e r l y s u b j e c t as the myocardium cannot respond to the e f f e c t s of t r a i n i n g . This c o u l d e x p l a i n why maximal heart r a t e does not change i n the e l d e r l y s u b j e c t and may r e - e s t a b l i s h the r e l a t i o n s h i p between stroke volume and heart r a t e , p a r t i c u l a r l y i n the e l d e r l y . D. Heart Rate at Changing Treadmill Elevations During the t r e a d m i l l t e s t , heart r a t e was conti n u o u s l y monitored as the e l e v a t i o n was increased. The experimental and c o n t r o l groups d i d not show s i g n i f i c a n t decreases i n e x e r c i s e heart r a t e a t t r e a d m i l l e l e v a t i o n s corresponding to 0, 2, 4, 6, 8, 10 and 12 percent grades (Table I I I ) . I t has been shown with- t r a i n i n g t h a t heart r a t e decreases at a given subrnaximal workload (Barry et a l . , 1966; Skinner e t a l . , 1963), but the r e s u l t s of t h i s c u r r e n t study appear to be i n c o n c l u s i v e as appropriate d e c l i n e s i n heart r a t e were not seen at any of the workloads. whether a d e c l i n e i n e x e r c i s e heart r a t e occurs by c e n t r a l or p h e r i p h e r a l adaptations, the degree of change seems to be a s s o c i a t e d w i t h an increase i n VO. . Since a s i g n i f i c a n t increase i n the VO. of the 2max ° 2max experimental group was seen i n t h i s study, one would expect a d e c l i n e i n the e x e r c i s e h e a r t r a t e at a l l workloads as a r e s u l t of c e n t r a l and/or p e r i p h e r a l - 51 -adaptations. I t i s p o s s i b l e t h a t p e r i p h e r a l adaptations may account f o r the change i n VO. ; t r a i n i n g has been shown to a f f e c t the arteriovenous (a-v) 2max oxygen d i f f e r e n c e . L o n g i t u d i n a l s t u d i e s w i t h younger subjects show an increase i n the (a-v)C-2 d i f f e r e n c e a t maximal e x e r c i s e and t h i s d i f f e r e n c e increases w i t h t r a i n i n g (Scheuer and Tipton, 1977). Factors t h a t can cause the increase i n (a-v)G-2 d i f f e r e n c e i n c l u d e : changes i n the f u n c t i o n and number of mitochondria, increased o x i d a t i v e (aerobic) enzymes, changes i n f i b e r type recruitment and increased c a p i l l a r y d e n s i t y . The working muscle can increase i t s a b i l i t y to e x t r a c t oxygen by: (1) a decrease i n the a f f i n i t y of hemoglobin f o r oxygen at low PC^ te n s i o n s , (2) increased c a p i l l a r y d e n s i t y , (3) el e v a t e d myoglobin con c e n t r a t i o n s , or (4) changes i n the number and/or f u n c t i o n of mitochondria i n a c t i v e c e l l s (Astrand, 1977). These l o c a l muscular adaptations c o u l d e x p l a i n the increased VC^max i - n t n e absence of unchanged e x e r c i s e heart r a t e s . I t remains to be seen whether a longer study would e l i c i t decreases i n the e x e r c i s e h e a r t r a t e s . E. Maximum Oxygen Uptake The s u b j e c t s i n t h i s study e x h i b i t e d b a s e l i n e values that were comparable to other i n v e s t i g a t o r s (Table IV) . ^2max s n o w e < i a strong s i g n i f i c a n t increase i n the experimental group (P = 0.007) whereas the c o n t r o l group showed no change (Table I I I ) . A 3.4% increase was seen i n VO. over 5 weeks of t r a i n i n g . M a z z a r e l l a et a l . (1966) demonstrated a 10% 2max ° increase i n V^max a ^ t e r ^ months of endurance t r a i n i n g and Robinson (1938) showed a 17% increase i n VO. a f t e r 6 months. I t i s p o s s i b l e that an 2max aquatic program of greater d u r a t i o n ( i . e . 6-12 months) co u l d produce even greater increases i n VC^max' During the e x e r c i s e s e s s i o n s , the mean heart r a t e s obtained (117 ± 3.0 beats per min.) represented 77.5 % of the age-adjusted maximum heart r a t e . Since heart r a t e was not continuously monitored during the e x e r c i s e s e s s i o n s , i t i s assumed th a t the heart rates - 52 d i d not drop s i g n i f i c a n t l y below t h i s l e v e l throughout the 30 minutes of a c t i v e pool a c t i v i t i e s . When the experimental group's a c t u a l mean b a s e l i n e maximal heart r a t e i s considered (145.8 ± 9.9), the mean e x e r c i s e heart rates a c t u a l l y represented 80% of the mean maximum heart r a t e . There have been few stu d i e s to i n v e s t i g a t e the adaptations i n the determination of VC^max ^ n o l d e r i n d i v i d u a l s (Seals, 1984). H a r t l e y et a l . (1969) reporte d t h a t a 14 percent increase i n f o l l o w i n g t r a i n i n g i n e l d e r l y s u b j e c t s was due p r i m a r i l y to an increase i n maximal stroke volume and r e s u l t i n g c a r d i a c output. These same i n v e s t i g a t o r s , r e p o r t i n g on a 15 percent increase i n VC^max f o l l o w i n g t r a i n i n g i n younger men, s t a t e d that an incr e a s e d maximal (a-v)02 d i f f e r e n c e and r e s u l t i n g i n creased c a r d i a c output were r e s p o n s i b l e f o r the enhanced ^2max' H a r t l ' e y et a l . (1969) b e l i e v e d , then, t h a t e l d e r l y subjects could not e l i c i t s i g n i f i c a n t increases i n t h e i r maximal (a-v)02 d i f f e r e n c e . Seals et a l . (1984) suggested that the increased v°2max i n t h e i r e l d e r l y subjects was i n f a c t due to adaptations i n muscle, r e s u l t i n g i n an improved a b i l i t y to e x t r a c t oxygen, as r e f l e c t e d i n a higher maximal (a-v)02 d i f f e r e n c e . C l e a r l y , t h i s i s l i t t l e agreement as to the mechanism(s) r e s p o n s i b l e f o r , or c o n t r i b u t i n g t o , increases i n VO. i n the zmax e l d e r l y s u b j e c t . Since n e i t h e r experimental or c o n t r o l group e x h i b i t e d weight l o s s over the course of t h i s study, i t i s p o s s i b l e that the experimental group increased i t s muscle mass and decreased i t s body f a t , thereby i n c r e a s i n g the t o t a l l e a n body mass. This r e l a t i v e increase i n muscle mass cou l d account f o r the increase i n VO. (Brooks and Fahey, 1984; zmax McArdle et a l . , 1981). - 53 -II RESPIRATORY PARAMETERS Both the experimental and c o n t r o l groups showed no change i n F V C (Table I I I ) . This agrees w i t h the f i n d i n g s of Niinimaa and Shephard (1978) and P o l l o c k et a l . (1976) who a l s o could not demonstrate p o s i t i v e change i n v i t a l c a p a c i t y i n a short-term aerobic program. Heikkenen (1978), however, d i d show an increase i n the v i t a l c a p a c i t y of young and middle-aged men and women during an 8 week program. At t h i s p o i n t i n time, i t i s not known how decreased l e v e l s of a c t i v i t y c o n t r i b u t e to the known ag e - r e l a t e d d e c l i n e i n r e s p i r a t o r y f u n c t i o n . Presumably, e x e r c i s e p r i m a r i l y a f f e c t s the muscles of v e n t i l a t i o n , so increases i n the s t r e n g t h of these and accessory muscles w i l l augment measures of flow r a t e . I t i s d o u b t f u l that t h i s form or any form of ex e r c i s e w i l l do much to s i g n i f i c a n t l y a l t e r pulmonary hemodynamics ( v e n t i l a t i o n : p e r f u s i o n i n e q u a l i t i e s ) and i t i s r e a l i z e d t h a t much of the b e n e f i t from e x e r c i s e w i l l be i n the way of improved r e s p i r a t o r y mechanics. S a l t i n and Grimby (1968) demonstrated t h a t the t o t a l volume of a i r i n s p i r e d and ex p i r e d during a maximum v e n t i l a t o r y e f f o r t i s greater i n a t h l e t e s and former a t h l e t e s than t h e i r sedentary counterparts at s i m i l a r ages. P o l l o c k et a l . (1976) showed that the amount of a i r f o r c i b l y expired during a maximum attempt was found to be higher i n a t h l e t e s and former a t h l e t e s , and tha t t r a i n i n g e f f e c t s had not been shown. S i m i l a r l y , Thomas et a l . (1985) c o u l d not demonstrate changes i n FEV 1' 0. The subjects i n the experimental group i n t h i s present study i n c o n t r a s t to Thomas's study demonstrated a s i g n i f i c a n t increase i n F E V 1 - 0 (P = 0.001). Again, since FEV 1' 0 i s dependent upon the e l a s t i c components of the lung parenchyma (Whitbourne, 1985), any increase i n t h i s measurement must be due to the augmentation of the r e s p i r a t o r y musculature. V e n t i l a t o r y flow has been seen to i n c r e a s e i n middle-aged and o l d e r a d u l t s w i t h t r a i n i n g (Whitbourne, 1985). I t i s p o s s i b l e t h a t the st r e n g t h components of the program increased the - 54 -s t r e n g t h of the i n v o l v e d musculature thereby f a c i l i t a t i n g an increase i n FEV 1'^, although s p e c i f i c t e s t s to detect changes i n muscular s t r e n g t h were not i n c o r p o r a t e d i n t h i s present study. Maximum v e n t i l a t i o n has been seen to increase w i t h t r a i n i n g (Astrand, 1973; de V r i e s , 1970) This may be as a r e s u l t of an increased breathing frequency ( S a l t a n et a l . , 1969) or an increased t i d a l volume (de V r i e s , 1970; Robinson et a l . , 1973). Neither the c o n t r o l or experimental group were seen to demonstrate any change i n VE over the 5 week p e r i o d . Thomas et a l . J b max (1985), however showed a 15% increase i n VE over a 12 month p e r i o d . One max reason f o r t h i s discrepancy may be due to the d u r a t i o n of the study; t h i s study being too short i n d u r a t i o n to produce any changes i n VE a . Another p o s s i b i l i t y i s t h a t the low average b a s e l i n e VE ( f o r combined c o n t r o l and r J ° max experimental groups) (Table I) i s a r e f l e c t i o n of the c o n d i t i o n of the s u b j e c t s . I t had been noted p r e v i o u s l y t h a t subjects i n t h i s experiment d i f f e r e d from comparably aged subjects i n other s t u d i e s w i t h respect to the great v a r i a t i o n seen i n body weight. A d d i t i o n a l weight, i n the form of f a t . can hinder chest w a l l m o b i l i t y and compliance and may be a c o n t r i b u t i n g f a c t o r . Since age has not been shown to a f f e c t t i d a l volume under c o n d i t i o n s of maximal e x e r c i s e , i t i s p o s s i b l e t h a t the r e s u l t i n g decreased maximum frequency of r e s p i r a t i o n due to a decreased chest w a l l compliance may augment the known a g e - r e l a t e d l o s s i n maximum v e n t i l a t o r y r a t e . Another p o t e n t i a l f a c t o r i n the low v e n t i l a t i o n values obtained i n t h i s study c o u l d be the general d e c l i n e of the r e s p i r a t o r y response to hypoxia w i t h age (Petersen et a l . , 1981). An increased sympathetic a c t i v i t y has been shown to e x i s t i n the o l d e r i n d i v i d u a l , yet the lungs and chest w a l l do not/cannot respond to t h i s increase i n sympathetic s t i m u l a t i o n . This f a c t o r may e x e r t more of an e f f e c t on v e n t i l a t i o n i n o l d e r s u b j e c t s . - 55 -In any event, the b a s e l i n e values f o r VE obtained i n t h i s J ' - max -1 i n v e s t i g a t i o n (mean 35.57 ± 10.32 l«min ) are lower than the values repo r t e d by Thomas et a l . (1985) or Seals et a l . (1984). This, study reported VE values t h a t were only 42.6% of those reported by Thomas et a l . and max 52.9% of those reported by Seals et a l . (Table I V ) . The question that remains at t h i s time i s whether the o l d e r age of the subjects i n t h i s study (mean 68.5 ± 4.7 y r s . ) accounts f o r some of the discrepancy i n V £ values seen i n Thomas et a l . (mean 62.6 ± 3.1 y r s . ) or Seals et a l . (mean 63.3 ± 3.0 y r s . ) . None of the subjects demonstrated a h i s t o r y of c h r o n i c o b s t r u c t i v e pulmonary disease. The r a t i o FEV^'^/FVC ( p r o v i d i n g a f r a c t i o n of the t o t a l e x p i r e d volume d e l i v e r e d i n 1 second) can give an i n d i c a t i o n of pulmonary f u n c t i o n (West, 1985). An FEV^'^/FVC of 80% i s considered to denote normal pulmonary f u n c t i o n . Less than 80% i s considered as being i n d i c a t i v e of o b s t r u c t i v e changes and values greater than 80% i s considered as r e p r e s e n t i n g r e s t r i c t i v e ( f i b r o t i c ) lung disease. The subjects i n t h i s study y i e l d e d a mean FEV 1 -°/FVC of 63% which, by d e f i n i t i o n , denotes them as being o b s t r u c t i v e ( e x h i b i t i n g increased airway r e s i s t a n c e and l i m i t e d e x p i r a t i o n due to a l v e o l a r c o l l a p s e ) . Indeed, i n the e l d e r l y , a general decrease i n lung e l a s t i c i t y promotes premature airway c l o s u r e i n e x p i r a t i o n . The r e s u l t i s a t r a p p i n g of a i r w i t h i n the lung and a s l i g h t h y p e r i n f l a t i o n . B r a n d s t e t t e r and Kazenni (1983), Lynne-Davies (1977) and Reid (1967) a l l describe changes i n a l v e o l a r s t r u c t u r e w i t h age which cause a decrease i n the a l v e o l a r surface area. These age- r e l a t e d changes are continuous w i t h an o b s t r u c t i v e process. The r e s u l t s of the hypothesis t e s t i n g are given i n Table V. I t i s apparent t h a t the m a j o r i t y of e x e r c i s e s t u d i e s concerning e x e r c i s e and the e l d e r l y i n v o l v e a c t i v i t i e s other than a q u a t i c , i n - p o o l e x e r c i s e 56 -programs. I t i s d i f f i c u l t to meaningfully compare data when the modes of e x e r c i s e are d i f f e r e n t . Some meaningful comparisons can be made i n general terms as some s t u d i e s have been done to show some acute e f f e c t s of aquatic e x e r c i s e . V i c k e r y et a l . (1983) demonstrated that 30 minute sessions of "Aqua Dynamics" produced e x e r c i s e heart r a t e s of 145 ± 3.0 beats per minute i n 21-year o l d c o l l e g e women. This heart r a t e represented 77% of the maximum heart r a t e of these s u b j e c t s . A s i m i l a r l e v e l of i n t e n s i t y was a t t a i n e d by the c o n s i d e r a b l y o l d e r subjects i n t h i s study. Johannessen et a l . (1986) examined ten women (mean age 54.7 ± 1.0 y r s . ) during moderate-intensity e x e r c i s e programs f i v e days a week f o r . t e n weeks. A c t u a l aerobic a c t i v i t y comprised 20 to 35 minutes of each s e s s i o n and d i f f e r e n t modes of aerobic e x e r c i s e were used each week throughout the ten weeks ( b r i s k walking/slow j o g g i n g , ergometry, swimming and water c a l i s t h e n i c s and aerobic dancing). A 20% increase i n VO- was found a f t e r the ten weeks. Whether the subjects 2max i n t h i s study c o u l d have a t t a i n e d s i m i l a r increases i n v ° 2 m a x a f t e r a s i m i l a r p e r i o d of time or w i t h d a i l y e x e r c i s e i s open to conte n t i o n . One aspect of aquatic e x e r c i s e that has not been addressed i n t h i s or r e l a t e d s t u d i e s i s the e f f e c t of water on the metabolism and c a r d i o v a s c u l a r adjustment. C r a i g and Dvorak (1969) reported heart r a t e s averaging 10 beats per minute lower i n 23°C water than i n warmer water or i n a i r at s i m i l a r l e v e l s of VO^. These same i n v e s t i g a t o r s a l s o reported observations of br a d y c a r d i a during water immersion at both e x e r c i s e and r e s t . Holmer and Bergh (1974) found that at s i m i l a r swimming speeds, VO^ was s i g n i f i c a n t l y h igher i n c o l d e r water compared to warmer water. In a d d i t i o n ; the heart rate was s i g n i f i c a n t l y lower i n c o l d e r water at the same VO^. McArdle et a l . (1976) s t a t e t h a t w i t h immersion i n c o l d water a sm a l l e r f r a c t i o n of the c a r d i a c output i s shunted to the s k i n f o r heat d i s s i p a t i o n . Increased p e r i p h e r a l v a s o c o n s t r i c t i o n and h y d r o s t a t i c pressure on the body surface - 57 -causes an increase i n both c e n t r a l volume and venous r e t u r n , therefore r e s u l t i n g i n a l a r g e r stroke volume. I t i s p o s s i b l e t h a t a decreased heart r a t e observed i n c o l d water would be balanced by the increase i n stroke volume. Therefore, the c a r d i a c output would be the same at s i m i l a r l e v e l s of VC>2 i n water of d i f f e r e n t temperatures. McArdle et a l . (1976), using successive increments of discontinuous work w i t h arm-leg ergometry found that during work i n 25 and 18°C water, the VC>2 averaged 9.0% (150 ml) and 25.3% (400 ml) hig h e r , r e s p e c t i v e l y , than values observed i n 33°C water. VO^ averaged 250-700 ml higher i n c o l d water compared to a i r and 33°C water at a mean heart r a t e . At s i m i l a r l e v e l s of V0 2, stroke volume was s i g n i f i c a n t l y g r e a t e r i n 25 and 18°C water than i n a i r or 33°C water. I t i s apparent, then, t h a t a r e d u c t i o n i n heart r a t e during work i n c o l d water i s compensated f o r by a pr o p o r t i o n a t e increase i n stroke volume. The i n v e s t i g a t o r s concluded t h a t c a r d i a c output i s maintained at s i m i l a r l e v e l s of energy expenditure i n a i r , 18, 25 and 30°C water. Pool temperatures recorded during t h i s study ranged from 28.3°C (83°F) to 30°C (86°F). Therefore, recorded e x e r c i s e heart r a t e s were l i k e l y true i n d i c a t i o n s of the i n t e n s i t y of e x e r c i s e and were not i n f l a t e d values due to c o l d water temperatures and there was l i k e l y no d i s c r e p a n c i e s between the heart r a t e s and V0 2 during e x e r c i s e . Energy expenditure i s another area t h a t r e q u i r e s e x p l o r a t i o n i n t h i s type of e x e r c i s e . V i c k e r y et a l . (1983) reported average energy expenditures of 5.9 to 6.5 Kcal s per minute during "Aqua Dynamics" ses s i o n s . This energy expenditure i s greater than the q u a n t i t y of energy expended i n a b r i s k l e v e l walk and i s s i m i l a r to the r a t e of energy expenditure f o r slow joggin g at a 12 minute m i l e pace and c y c l i n g a t approximately 10 mph f o r college-aged women at t h i s bodyweight. C o s t i l l (1971) , u s i n g l e g ergometry i n water ranging i n temperature from 24.6 to 25.0°C discovered that when comparing the - 58 -c a l o r i c requirements of subrnaximal work i n the water to those of e x e r c i s i n g on land, water e x e r c i s e was found to increase the energy requirements by 33 to 42 percent f o r any given work l e v e l . In response to the increased energy requirements at each of the e x e r c i s e l e v e l s , the s u b j e c t s ' heart r a t e s were a l s o higher i n the water than on land. More study i s r e q u i r e d i n the area of energy expenditure and aquatic e x e r c i s e . The t r e a d m i l l was chosen as a t e s t i n g device f o r t h i s study because of the f a m i l i a r i t y of the subjects w i t h walking (as opposed to c y c l i n g ) and because many previous i n v e s t i g a t i o n s have a l s o u t i l i z e d t r e a d m i l l t e s t i n g f o r ol d e r s u b j e c t s (Drinkwater et a l . , 1975; McDonough et a l . , 1970; P o l l o c k et a l . , 1974; Sidney and Shephard, 1977). The use of the t r e a d m i l l data also f a c i l i t a t e d the comparison of data. I t was subsequently found, however, that some subjects had d i f f i c u l t i e s w i t h the t r e a d m i l l , o f t e n adopting exaggerated or unna t u r a l g a i t s during the t e s t i n g . This was due i n some cases to a per c e i v e d f e a r of the t r e a d m i l l or due to genuine g a i t problems. Some su b j e c t s , due to o b e s i t y , had d i f f i c u l t y a t t a i n i n g a "steady-state"; they appeared to be c o n t i n u a l l y a d j u s t i n g s t r i d e l e n g t h and/or frequency. Some su b j e c t s , c l e a r l y not used to walking any d i s t a n c e , a l s o had d i f f i c u l t y a d j u s t i n g to the t r e a d m i l l . I t i s d i f f i c u l t to a s c e r t a i n how much of a bea r i n g these problems had on the t e s t r e s u l t s . D e c i s i o n s concerning the choice of t e s t i n g apparatus should consider the c o n d i t i o n s o f t e n seen i n the e l d e r l y : o b e s i t y , o s t e o a r t h r i t i s and rheumatoid a r t h r i t i s i n a d d i t i o n to any other g a i t problems. - 59 CONCLUSIONS I t was the purpose of t h i s study to determine the e f f i c a c y of aquatic e x e r c i s e f o r the e l d e r l y p a r t i c i p a n t . Water e x e r c i s e provides i t s b e n e f i t s independently of p a r t i c i p a n t s ' s k i l l l e v e l s and i t reduces the l i k e l i h o o d of i n j u r y from overuse syndromes and heat r e l a t e d problems (Koszuta, 1986). This study has i n d i c a t e d that a supervised and c o n t r o l l e d aquatic e x e r c i s e program i s capable of p r o v i d i n g a p o s i t i v e source of aerobic c o n d i t i o n i n g f o r the e l d e r l y as can be evidenced by the outcome of hypothesis t e s t i n g . This mode of e x e r c i s e may be p r e s c r i b e d by the primary care p h y s i c i a n f o r the aging i n d i v i d u a l knowing t h a t the c r i t e r i a f o r aerobic b e n e f i t s can be met. Research, u s i n g other modes of e x e r c i s e , i n d i c a t e s that the minimum i n t e n s i t y r e q u i r e d f o r the development of p h y s i c a l work c a p a c i t y i n unconditioned a d u l t s i s approximately 50 to 60% of maximum oxygen uptake or approximately 70% of the maximum heart r a t e . The heart r a t e responses i n t h i s study were w e l l above t h i s minimum value and, l i k e V i c k e r y et a l . (1983), suggest that aquatic e x e r c i s e has s u f f i c i e n t i n t e n s i t y to p o s i t i v e l y change the p h y s i c a l work c a p a c i t y of e l d e r l y p a r t i c i p a n t s who are t y p i c a l l y p o o r l y conditioned and/or have low l e v e l s of p h y s i c a l work c a p a c i t y . Another important concern i n the p r e s c r i p t i o n of e x e r c i s e i s compliance. The i n v e s t i g a t o r found i n i t i a l recruitment of subjects d i f f i c u l t , no doubt due to the pe r c e p t i o n that many e l d e r l y i n d i v i d u a l s m a i n t a i n concerning a c t i v i t y ( p a r t i c u l a r l y when g a i t problems are apparent). Compliance f o r t h i s study was 100%; f u l l t u r n out f o r every s e s s i o n . P a r t i c i p a n t s g e n e r a l l y found these e x e r c i s e sessions b e n e f i c i a l and rewarding, r e p o r t i n g that they " f e l t b e t t e r " as a r e s u l t of p a r t i c i p a t i o n . The "fun f a c t o r " should not be discounted; although p a r t i c i p a n t s were c o n t i n u a l l y urged to work as hard as - 60 -i they c o u l d w i t h each s e s s i o n , i t i s the impression of t h i s i n v e s t i g a t o r that p a r t i c i p a n t s d i d not regard t h i s as e x e r c i s e as such. The e l d e r l y i n d i v i d u a l a l s o tends to show marked decreases i n s o c i a l i n t e r a c t i o n and i t i s f e l t t hat t h i s mode of e x e r c i s e w i l l do much to improve t h i s s i t u a t i o n through the non-threatening nature of the e x e r c i s e i t s e l f and the encouraging compliance. P s y c h o l o g i c a l and s o c i a l i n t e r a c t i o n f a c t o r s are d i f f i c u l t to measure and were beyond the scope of t h i s study, but they should be regarded as being no l e s s important than the c a r d i o r e s p i r a t o r y c o n s i d e r a t i o n s . In a general scope, the ongoing debate concerning d u r a t i o n and i n t e n s i t y i n a erobic types of e x e r c i s e must be re-evaluated; t h i s study i n d i c a t e d that supervised aquatic e x e r c i s e at or above the recommended i n t e n s i t y of e x e r c i s e performed three times weekly can show s i g n i f i c a n t changes i n p h y s i c a l work c a p a c i t y i n the e l d e r l y . The e l d e r l y p a r t i c i p a n t s need not r e s i g n themselves to d a i l y e x e r c i s e f o r extended periods of time i n order f o r measurable b e n e f i t s to occur; although continued p a r t i c i p a t i o n should be encouraged, i t i s important f o r the e l d e r l y and t h e i r p h y s i c i a n s to recognize the r e s i l i e n c e and adaptive c a p a c i t y of the e l d e r l y i n d i v i d u a l so they themselves can be the source of encouragement f o r p a r t i c i p a t i o n and p r e s c r i p t i o n . - 61 -RECOMMENDATIONS I t i s the s i n c e r e hope that t h i s study w i l l serve to s t i m u l a t e continued i n t e r e s t i n the f i e l d of e x e r c i s e and the e l d e r l y . S p e c i f i c a l l y , there are some areas t h a t merit f u r t h e r i n v e s t i g a t i o n : 1. There are other components of t h i s type of e x e r c i s e that should be evaluated, such as changes i n range of motion, muscular strength, body composition and p s y c h o l o g i c a l / s o c i a l f a c t o r s . 2. A d d i t i o n a l s t u d i e s a s s e s s i n g changes i n c a r d i a c output as a r e s u l t of t h i s type of e x e r c i s e ( i . e . CO^ r e b r e a t h i n g ) . 3. A d d i t i o n a l i n v e s t i g a t i o n s concerning aquatic e x e r c i s e should be undertaken to evaluate the f i n d i n g s i n t h i s study and to b u i l d a data base upon which meaningful comparisons can be made between st u d i e s of t h i s type. 4. Longer term (duration) s t u d i e s are recommended to determine i f a longer e x e r c i s e p r o t o c o l w i l l produce b e t t e r r e s u l t s . 5. Continued e f f o r t s are r e q u i r e d to determine which s p e c i f i c components of the e x e r c i s e program provide the • most c a r d i o r e s p i r a t o r y b e n e f i t . 6. A l a r g e r s c a l e study (more subjects) i s necessary to determine whether the r e s u l t s of t h i s study have l a r g e r , general i m p l i c a t i o n s f o r the e l d e r l y p o p u l a t i o n . 7. When d e a l i n g w i t h an e l d e r l y group of s u b j e c t s , one must c a r e f u l l y decide on the t e s t i n g apparatus to be used: a d e c i s i o n that must take g a i t , bodyweight and m o t i v a t i o n a l f a c t o r s among others i n t o account. 62 -APPENDIX A Time Effect: Comparison of Means at Baseline (Tl) and 5 Weeks Later (T2) (Experimental Group, n = 8) Variable T(D T(2) SBPR (mmHg) V E M A V (1-min ) MAX F E V 1 - 0 (1-sec" 1) FVC (1-sec ) H RMAX (bts-min" 1) H RREST (bts-min" 1) HR 0% (bts-min" 1) HR 2% (bts-min ) HR 4% (bts-min ) HR 6% (bts-min" 1) HR 8% (bts-min" 1) V°2MAX ( n i l* kg~ 1' n l i n~ 1) 139.12 36.32 2.11 3.61 145.87 75.87 121.87 128.25 135.00 139.25 137.33 24.98 ± 11.17 ± 9.77 ± 0.37 ±1.10 ± 9.92 ±8.01 ± 16.25 ± 14.57 ± 14.40 ± 12.70 ±5.24 ± 1.97 131.50 ± 7.44 36.91 ± 1.54 2.42 ± 0.18 3.94 ± 0.37 144.62 ±2.19 71.00 ± 2.75 116.25 ± 16.19 123.37 ± 10.83 128.50 ± 8.73 132.37 ± 7.77 132.83 ± 2.74 (6) 25.83 ± 0.213 a l l values are means ± SD - 63 -APPENDIX B Time Effect: Comparison of Means at Baseline (Tl) and 5 Weeks Later (T2) (Control Group, n = 7) Variable nil T ( 2 ) SBPR (mmHg) VE„. V ( l . m i n ) MAX F E V 1 - 0 (1-sec" 1) FVC ( l - s e c " 1 ) HR„.„ (bts«min ) MAX H RREST (bts.min" 1) HR 0% (bts.min" 1) HR 2% (bts«min" ) HR 4% (bts.min" 1) HR 6% (bts.min" 1) HR 8% (bts.min" 1) V 02MAX ( m l * k S 1 , m i n 1 ) 132. ,43 + 9.34 133. ,43 + 2. 31 34. ,70 + 11.64 35. ,04 + 0. 56 2. .31 + 0.68 2. .29 + 0. 09 3, .35 + 0.82 3. .35 + 0. 09 141. ,43 ± 17.93 141. ,57 + 1. 57 77. .00 + 2.77 76. .57 + 1. 72 116, .57 + 11.12 115, .86 + 4. 23 119. .42 + 12.16 118, .14 + 11 ..18 127. .14 + 12.06 127, .00 + 2. 54 134, .43 + 13.26 133, .86 + 2. 51 138, .14 + 16.12 138 .14 + 3. 32 23 .84 + 1.99 23 .52 + 0. 82 a l l values are means ± SD 64 APPENDIX C Means of Experimental and C o n t r o l Groups a t B a s e l i n e ( T l ) and 5 Weeks L a t e r (T2) T ( l ) T(2) VARIABLE EXPTL (n=8) CONTROL (n=7) EXPTL (n=8) CONTROL (n=7) SBPR (mmHg) 139.12-± 11.17 132.43 ± 9.34 131.50 ± 7.44 13-3.43 ± 2.31 FEV 1" 0 (1-sec" 1) 2.11 ± 0.37 2.31 ± 0.68 2.42 ± 0.18 2.29 ± 0.09 FVC (1-sec" 1) 3.61 ± 1.10 3.35 ± 0.82 3.94 ± 0.37 3.35 ± 0.09 HR 6% (bts-min" 1) 139.25 ± 12.70 134.43 ± 13.26 132.37 ± 7.77 133.86 ± 2.51 HR 8% (bts-min' 1) 137.33 ±5.24 138.14 ± 16.12 132.83 ±2.74 138.14 ± 3.32 V 0 2 M A X . (ml-kg -min ) 24.98 ± 1.97 23.84 ± 1.99 - 25.83 ± 0.60 23.52 ± 0.82 H RREST ( b t s - m i n " ) 75.87 ± 8.01 77.00 ± 2.77 71.00 ± 2.75 76.57 ± 1.72 a l l v a l u e s are means ± SD u n d e r l i n e d P va l u e s are s i g n i f i c a n t (P < 0.05) - 65 -APPENDIX D l j k p 1 k ( i ) ' j ^ j k ( i ) Where: represents the grouping f a c t o r ( i . e . : treatment and c o n t r o l ) represents subjects w i t h i n the grouping f a c t o r (used to o b t a i n the e r r o r term f o r the grouping f a c t o r ) represents the w i t h i n f a c t o r ( i . e . the time e f f e c t ) represents the i n t e r a c t i o n between the grouping f a c t o r and the w i t h i n f a c t o r represents the i n t e r a c t i o n of the w i t h i n f a c t o r and the subjects w i t h i n the grouping f a c t o r (used to o b t a i n the e r r o r term f o r the w i t h i n f a c t o r and f o r the i n t e r a c t i o n o f the grouping f a c t o r and w i t h i n f a c t o r ) . Program i s BMDP2V (BMDP: S t a t i s t i c a l Software Inc., C a l i f o r n i a ; USA, Revised 1982) . * k ( i ) ^ > j k ( i ) - 66 APPENDIX E ANOVA TABLES R e s t i n g S y s t o l i c Blood Pressure SOURCE df Ms Prob Mean 537251.10060 3714.31 0.0000 Group ( C o n t r o l / E x p t l ) 42.4339 0.29 0.5972 E r r o r 13 144.64354 Time (Pre/Post) 81.92917 5.07 0.0422 Time By Group 138.86250 8.60 0.0117 E r r o r 13 16.14904 - 67 -Maximum V e n t i l a t i o n SOURCE df Ms Prob Mean 38161.17135 175.94 0.0000 Group ( C o n t r o l / E x p t l ) 1 22.72688 0.10 0.7513 E r r o r 13 216.90425 Time (Pre/Post) 1.60829 2.27 0.1555 Time By Group 0.10466 0.15 0.7067 E r r o r 13 0.70735 - 68 Forced Expiratory Volume (in 1 second) SOURCE df Ms F Prob Mean 1 155.87357 266.97 0.0000 Group ( C o n t r o l / E x p t l ) 1 0.00929 0.02 0.9016 E r r o r 13 0.58385 Time (Pre/Post) 1 0.15990 14.36 0.0023 Time By Group 1 0.20306 18.23 0.0009 E r r o r 13 0.01114 underlined P values are significant (P < 0 . 0 1 ) - 69 -Forced V i t a l Capacity SOURCE df Ms Prob Mean 379.63923 158.72 0.0000 Group ( C o n t r o l / E x p t l ) 1.32947 0.56 0.4692 E r r o r 13 2.39186 Time (Pre/Post) 0.20328 5.19 0.0403 Time By Group 0.20328 5.19 0.0403 E r r o r 13 0.03919 - 70 Maximum Heart Rate SOURCE df Ms Prob Mean 613950.86667 1635.52. 0.0000 Group ( C o n t r o l / E x p t l ) 1 105.00000 0.28 0.6058 E r r o r 13 375.38462 Time (Pre/Post) 2.28810 1.23 0.2875 Time By Group 3.62143 1.95 0.1863 E r r o r 13 1.85989 - 71 R e s t i n g Heart Rate SOURCE df Ms F Prob Mean 1 168500. .37202 2832. .69 0. 0000 Group ( C o n t r o l / E x p t l ) 1 83. .70536 1. .41 0. ,2568 E r r o r 13 59. .48420 Time (Pre/Post) 1 52. .50536 19. . 34 0. .0007 Time By Group 1 36. .90536 13 .59 0, .0027 E r r o r 13 2. .71497 u n d e r l i n e d P values are s i g n i f i c a n t (P < 0.01) - 72 (E x e r c i s e ) Heart Rate a t 0% Grade SOURCE df Ms Prob Mean 413318.57202 1794.46 0.0000 Group ( C o n t r o l / E x p t l ) 1 60.57202 0.26 0.6167 E r r o r 13 230.33036 Time (Pre/Post) 75.01488 1.00 0.3345 Time By Group 45.01488 0.60 0.4514 E r r o r 13 74.6652 - 73 -( E x e r c i s e ) Heart Rate a t 2% Grade SOURCE df Ms Prob Mean 446717.87202 1777.14 0.000 Group ( C o n t r o l / E x p t l ) 368.67202 1.47 0.2474 E r r o r 13 251.36882 Time (Pre/Post) 70.84821 1.35 0.2655 Time By Group 24.04821 0.46 0.5097 E r r o r 13 52.31937 - 74 -( E X E R C I S E ) HEART RATE AT 4% GRADE SOURCE df Ms F Prob Mean 1 500181.03810 1780.28 0.0000 Group ( C o n t r o l / E x p t l ) 1 163.43810 0.58 0.4593 E r r o r 13 280.95604 Time (Pre/Post) 1 82.37143 3.74 0.0752 Time By Group 1 75.43810 3.42 " 0.0871 E r r o r 13 22.03297 - 75 -( E x e r c i s e ) Heart Rate a t 6% Grade SOURCE d f Ms Prob Mean 544140.01488 2045.85 0.0000 Group ( C o n t r o l / E x p t l ) 20.81488 0.08 0.7841 E r r o r 13 265.97321 Time (Pre/Post) 103.50536 5.84 0.0311 Time By Group 74.17202 4.19 0.0615 E r r o r 13 17.71497 - 76 -( E x e r c i s e ) Heart Rate a t 8% Grade SOURCE df Ms F Prob Mean 1 482370.33059 1747.64 0.0000 Group ( C o n t r o l / E x p t l ) 1 60.48443 0.22 0.6488 E r r o r 11 276.01190 Time (Pre/Post) 1 32.71154 6.95 0.0231 Time By Group 1 32.71154 6.95 0.0231 E r r o r 11 4.70455 a l l v a lues n = 13 - 77 -(Exercise) Heart Rate at 10% Grade SOURCE df Ms F Prob Mean 1 270001.33929 427.17 s 0.0000 Group ( C o n t r o l / E x p t l ) 1 73.33929 0.12 0.7472 E r r o r 5 632.07500 Time (Pre/Post) 1 5.00595 3.73 0.1113 Time By Group 1 7.29167 5.43 0.0671 E r r o r 5 1.34167 a l l values n = 8 - 78 Maximum Oxygen Uptake SOURCE ' df Ms F Prob Mean 1 17988.21272 2011.46 0.0000 Group ( C o n t r o l / E x p t l ) 1 22.23870 2.49 0.1388 E r r o r 13 8.94287 Time (Pre/Post) 1 0.54324 2.15 0.1665 Time By Group 1 2.54671 10.07 0.0073 E r r o r 13 0.25289 underlined P value is significant (P < 0.05) - 79 -APPENDIX F Contraindications for Exercise and Exercise Testing (Out-of-Hospital Setting) A. Contraindications 1. Acute myocardial i n f a r c t i o n 2. Unstable or a t - r e s t angina p e c t o r i s 3. Dangerous arrhythmias ( v e n t r i c u l a r t a c h y c a r d i a or any rhythm s i g n i f i c a n t l y compromising c a r d i a c f u n c t i o n ) 4. H i s t o r y suggesting excessive medication e f f e c t s ( d i g i t a l i s , d i u r e t i c s , psychotropic agents) 5. Manifest c i r c u l a t o r y i n s u f f i c i e n c y (congestive h e a r t f a i l u r e ) 6. Severe a o r t i c s t e n o s i s 7. Severe l e f t v e n t r i c u l a r outflow t r a c t o b s t r u c t i v e disease (IHSS) 8. Suspected or known d i s s e c t i n g aneurysm 9. A c t i v e or suspected m y o c a r d i t i s or cardiomyopathy ( w i t h i n the past year) 10. Thrombophlebitis--known or suspected 11. Recent embolism, systemic or pulmonary 12. Recent or a c t i v e i n f e c t i o u s episodes ( i n c l u d i n g upper r e s p i r a t o r y i n f e c t i o n s ) 13. High dose of phenothiazine agents B. Relative Contraindications 1 1. U n c o n t r o l l e d or h i g h - r a t e s u p r a v e n t r i c u l a r arrhythmias 2. R e p e t i t i v e or frequent v e n t r i c u l a r e c t o p i c a c t i v i t y 3. Untreated severe systemic or pulmonary hypertension 4. V e n t r i c u l a r aneurysm 5. Moderate a o r t i c s t e n o s i s 6. Severe myocardial o b s t r u c t i v e syndromes ( s u b v a l v u l a r , muscular, or membranous o b s t r u c t i o n s ) 7. Marked c a r d i a c enlargement 8. U n c o n t r o l l e d metabolic disease (diabetes, t h y r o t o x i c o s i s , myxedema) 9. Toxemia C. Condition Requiring Consideration and/or Precautions 1. Conduction disturbances a. Complete a t r i o v e n t r i c u l a r b l o c k b. L e f t bundle branch b l o c k c. Wolff-Parkinson-White anomaly or syndrome d. Lown-Ganong-Levine syndrome e. B i f a s c i c u l a r b l o c k (with or without 1st block) 2. C o n t r o l l e d arrhythmias 3. F i x e d - r a t e pacemaker 4. M i t r a l v a l v e prolapse (click-murmur) syndrome In the p r a c t i c e of medicine, the b e n e f i t s of e v a l u a t i o n o f t e n exceed the r i s k s f o r p a t i e n t s w i t h these r e l a t i v e c o n t r a i n d i c a t i o n s . - 80 -5. Angina p e c t o r i s and other m a n i f e s t a t i o n s of coronary i n s u f f i c i e n c y 6. C e r t a i n medications a. D i g i t a l i s , d i u r e t i c s , p sychotropic drugs b. Beta-blocking and drugs of r e l a t e d a c t i o n 7. E l e c t r o l y t e disturbance 8. C l i n i c a l l y severe hypertension ( d i a s t o l i c above 110, grade I I I r e t i n o p a t h y ) 9. Cyanotic heart disease 10. I n t e r m i t t e n t or f i x e d r i g h t - t o - l e f t shunt 11. Severe anemia (hemoglobin below 10 gm/d.) 12. Marked o b e s i t y (20% above optimal body weight) 13. Renal, h e p a t i c , and other metabolic i n s u f f i c i e n y 14. Overt psychoneurotic disturbances r e q u i r i n g therapy 15. Neuromuscular m u s c u l o s k e l e t a l , orthopedic, or a r t h r i t i c d i s o r d e r s which would prevent a c t i v i t y 16. Moderate to severe pulmonary disease 17. I n t e r m i t t e n t c l a u d i c a t i o n 18. Diabetes A f t e r American College of Sports Medicine, Guidelines for Graded T e s t i n g and E x e r c i s e - 81 -APPENDIX G Non-Weight Bearing Water E x e r c i s e : Changes i n Cardiopulmonary F u n c t i o n i n E l d e r l y Men and Women J.E. Taunton, M.D., E.C. Rhodes, Ph.D., R.J. Ham, M.D., P.R. Grantham, M.D., D.J. Jessop, B.Sc. The purpose of t h i s i n v e s t i g a t i o n i s to examine the c a r d i o v a s c u l a r and pulmonary responses to non-weight bea r i n g i n - p o o l e x e r c i s e ( t r a i n i n g ) i n the e l d e r l y . The p r o j e c t e d aims of the study are to determine: 1) the e f f i c a c y of a r e p r e s e n t a t i v e , e s t a b l i s h e d program of e x e r c i s e f o r the e l d e r l y , 2) the adaptations of the e l d e r l y c a r d i o v a s c u l a r system f o l l o w i n g 1 month of e x e r c i s e , 3) the adaptations i n pulmonary f u n c t i o n i n the e l d e r l y f o l l o w i n g 1 month of e x e r c i s e , 4) whether such a program of e x e r c i s e c o u l d be c l i n i c a l l y a p p l i c a b l e and p r e s c r i p t i v e . You w i l l perform a graded e x e r c i s e t e s t on a b i c y c l e ergometer and/or a motor-driven t r e a d m i l l . The purpose of t h i s t e s t i s to examine the response of your heart and lungs to e x e r c i s e . The t e s t c o n s i s t s of running, or r i d i n g the ergometer at one or more l e v e l s of d i f f i c u l t l y . Your electrocardiogram w i l l be monitored throughout the e x e r c i s e and recovery p e r i o d s . I t i s expected t h a t you w i l l complete t h i s e x e r c i s e t e s t w i t h no complications. Because of the very uncommon, unpr e d i c t a b l e response of some i n d i v i d u a l s to e x e r c i s e , unforeseen d i f f i c u l t i e s may a r i s e which would n e c e s s i t a t e treatment. Complications have been few during e x e r c i s e t e s t s and these u s u a l l y c l e a r q u i c k l y w i t h l i t t l e or no treatment. You are asked to report any unusual symptoms during the t e s t . We may stop the t e s t at any time because of signs of f a t i g u e or you may stop when you wish to because of personal f e e l i n g s of f a t i g u e or discomfort. Every e f f o r t w i l l be made to conduct the t e s t i n such a way as to minimize discomfort and r i s k . However, there e x i s t s the p o s s i b i l i t y of p o t e n t i a l r i s k s such as; abnormal blood pressure, f a i n t i n g , d i s o r d e r s of heart beat, and very r a r e instances of heart a t t a c k . You w i l l a l s o perform a t e s t of lung c a p a c i t y . The e x e r c i s e program w i l l be performed three (3) times per week f o r a maximum of 1 month. You are reminded to take a l l necessary precautions when i n the p o o l , p a r t i c u l a r l y when e n t e r i n g and l e a v i n g the pool and surrounding area. In s i g n i n g t h i s consent form you s t a t e that you have read and understand the d e s c r i p t i o n of the t e s t s , the experiment and t h e i r c o m p l i c a t i o n s . You enter - 82 -the battery of tests and the experiment willingly and may withdraw at any time. Additionally, your identity and test results will be kept in confidence and will become the property of the above investigators. 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