THE ACUTE EFFECTS OF AEROBIC EXERCISE ON CIGARETTE SMOKING by CARMEN MIKHAIL B . S c , The U n i v e r s i t y of L e t h b r i d g e , 1979 A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS i n THE FACULTY OF GRADUATE STUDIES Psychology Department We accept t h i s t h e s i s as conforming ' to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA August 19 8 3 © Carmen M i k h a i l , 1983 e 6 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t o f the requirements f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and study. I f u r t h e r agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the head o f my department o r by h i s or her r e p r e s e n t a t i v e s . I t i s understood t h a t copying o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be allowed without my w r i t t e n p e r m i s s i o n . Department o f 7^S -V c^...c /o JAJ The U n i v e r s i t y o f B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date DE-6 (3/81) i ABSTRACT The e f f e c t s of two i n t e n s i t i e s of e x e r c i s e and a no-e x e r c i s e c o n t r o l c o n d i t i o n on c i g a r e t t e smoking were i n v e s -t i g a t e d i n 18 men, aged 20 to 30 y e a r s . Each s u b j e c t , who was b l i n d to the purpose of the study, came to the l a b o r a t o r y a t the same time on three c o n s e c u t i v e days t o pedal a s t a -t i o n a r y b i c y c l e a t a work-load s u f f i c i e n t t o maintain a he a r t r a t e between 130-135 b.p.m. or 160-165 b.p.m. or to be monitored w h i l e seated i n a c h a i r , f o r 10 minutes. Each s u b j e c t was then ushered i n t o a w a i t i n g room where he r e -mained f o r one hour while i n d i c e s of smoking behavior i n -c l u d i n g number and weight of c i g a r e t t e s consumed, c i g a r e t t e d u r a t i o n (time e l a p s e d from the i n s t a n c e the c i g a r e t t e was l i t t o the i n s t a n c e i t was extingui s h e d ) and number of p u f f s taken f o r the f i r s t cigar.ette p o s t - e x e r c i s e were s u r r e p t i t i o u s l y observed by a conf e d e r a t e . Subjects a l s o s e l f - m o n i t o r e d c i g a r e t t e i n t a k e d u r i n g the three days of the study. Urine samples were c o l l e c t e d p r e - and 15 and 64 minutes f o l l o w i n g e x e r c i s e . The only smoking measure found t o be s i g n i f i c a n t l y a f f e c t e d by e x e r c i s e was c i g a r e t t e d u r a t i o n , which was i n -v e r s e l y r e l a t e d t o e x e r c i s e i n t e n s i t y . A d d i t i o n a l analyses r e v e a l e d t h a t h i g h - i n t e n s i t y e x e r c i s e s i g n i f i c a n t l y a c i d i f i e d t h e u r i n e , and t h a t a s i g n i f i c a n t i n v e r s e c o r r e l a t i o n e x i s t e d i i between u r i n a r y pH change and c i g a r e t t e d u r a t i o n f o r t h i s c o n d i t i o n . The i m p l i c a t i o n s of t h i s f i n d i n g are d i s c u s s e d i n regard to Schachter's hypothesis of n i c o t i n e a d d i c t i o n . i i i TABLE OF CONTENTS Page ABSTRACT i LIST OF TABLES i v LIST OF APPENDICES v INTRODUCTION 1 L i t e r a t u r e Review on A e r o b i c E x e r c i s e and Smoking 5 A n e c d o t a l Reports and C o r r e l a t i o n a l S t u d i e s 5 E xperimental S t u d i e s on E x e r c i s e and Smoking 7 P h y s i o l o g i c a l I n c o m p a t i b i l i t y between A e r o b i c E x e r c i s e and Smoking 11 P s y c h o l o g i c a l F a c t o r s R e l a t e d to E x e r c i s e and Smoking 15 Summary of Research on E x e r c i s e and Smoking 19 Schachter's Model of Smoking: I m p l i c a t i o n s f o r E x e r c i s e 20 Statement of Purpose and Experimental' Hypotheses 24 METHOD 25 Subj e c t s 25 Apparatus . . . . 26 Procedure 26 Dependent V a r i a b l e s 33 RESULTS 34 Data Analyses . . . . . 34 M a n i p u l a t i o n Checks 35 R e l i a b i l i t y Checks 38 Dependent V a r i a b l e s 39 C o r r e l a t i o n a l S t a t i s t i c s 40 DISCUSSION 47 REFERENCES 54 i v LIST OF TABLES Page Table 1. Summary ANOVA Table f o r U r i n a r y pH measures 36 Table 2. Means and Standard D e v i a t i o n s of Smoking Measures 41 Table 3. C o r r e l a t i o n M a t r i x f o r Smoking Measures f o l l o w i n g No-Exercise C o n d i t i o n 43 Table 4. C o r r e l a t i o n M a t r i x f o r Smoking Measures f o l l o w i n g Low-Intensity E x e r c i s e 44 Table 5. C o r r e l a t i o n M a t r i x f o r Smoking Measures f o l l o w i n g H i g h - I n t e n s i t y E x e r c i s e 45 LIST OF APPENDICES Page Appendix A. Information f o r Phone Contact 66 Appendix B. P h y s i c a l A c t i v i t y Readiness Q u e s t i o n n a i r e (PAR-Q) 6 7 Appendix C. P h y s i o l o g i c a l Responses t o E x e r c i s e Among Smokers: O u t l i n e of Study 69 Appendix D. Consent Form 70 Appendix E. S u b j e c t i v e Ratings of B r e a t h l e s s n e s s Form 72 Appendix F. Experimental S c r i p t : Waiting Room 73 Appendix G. E x e r c i s e and Smoking Q u e s t i o n n a i r e 75 Appendix H. Post-Study Q u e s t i o n n a i r e 7 8 v i AC KNOWLEDGEMENT S The a u t h o r w i s h e s t o a c k n o w l e d g e t h e h e l p o f h e r t h e s i s a d v i s o r , D r . D a v i d L a w s o n a n d members o f h e r t h e s i s c o m m i t t e e , D r . R o b e r t McMahon a n d D r . J i m J o h n s o n . S p e c i a l t h a n k s a r e a l s o due t o D r . T e d Rhodes f o r a s s i s t a n c e w i t h t h e s t u d y a n d t o D r . K e n n e t h C r a i g f o r l o a n o f e q u i p m e n t . Sam C h i w a , P a u l L a r o c h e l l e a n d Ken R e e s o r s e r v e d a s a s s i s t a n t s i n t h e s t u d y , f o r w h i c h t h e i r h e l p i s a l s o a p p r e c i a t e d . 1 INTRODUCTION C i g a r e t t e smoking i s an a d d i c t i v e behavior with s t a g -g e r i n g medical and economic consequences. I t has been l i n k e d to lung cancer, cancer of the mouth and t h r o a t , c a r d i o v a s -c u l a r d i s e a s e , and pulmonary d i s e a s e i n c l u d i n g b r o n c h i t i s and emphysema ( S h i l l i n g t o n , 1977). The U.S. Surgeon General (1979) estimated t h a t approximately $27 b i l l i o n i s spent each year i n m e d i c a l expenses, decreased work p r o d u c t i v i t y and work absenteeism, and a c c i d e n t s a t t r i b u t e d to smoking. In view of the adverse e f f e c t s of t h i s behavior i t i s not s u r -p r i s i n g t h a t the m a j o r i t y of smokers not o n l y express a d e s i r e t o q u i t but a l s o have i n i t i a t e d a t l e a s t one s e r i o u s attempt to do so (USPHS, 1976). Given the magnitude of the problems caused by smoking a number of techniques have been developed i n an attempt to d i s c o v e r an e f f e c t i v e treatment f o r smoking. Yet d e s p i t e the v a s t amount of r e s e a r c h i n t h i s area, the e f f e c t i v e n e s s of smoking c e s s a t i o n methods i s unimpressive. Reviews of the l i t e r a t u r e on smoking i n d i c a t e t h a t although i n i t i a l success r a t e s are h i g h , abstinence r a t e s are much lower. M c F a l l and Hammen (1971) summarized the r e s u l t s of e i g h t prominent s t u d i e s on smoking c e s s a t i o n . They found a post-treatment r e d u c t i o n i n c i g a r e t t e consumption to 30-40% of b a s e l i n e 2 frequency, returning to 75% of baseline frequency at a 4 to 6 month follow-up. Hunt and Bespalec (1974) summarized data from 8 0 studies on smoking cessation and found that less than one-third of subjects who are able to quit smoking at the end of treatment maintain nonsmoking over the following six to twelve months. I t seems, therefore, that one problem with present smoking cessation techniques l i e s i n th e i r r e l a t i v e l y poor long-term e f f e c t s (Bernstein and Glasgow, 1979) . Another concern with methods for eliminating smoking stems from the fact that although nonaversive strategies are available, aversive techniques are more popular (Lichtenstein and Brown, 1980). Rapid smoking i s the most common aversion technique, wherein subjects are required to puff rapidly on a cigarette every f i v e to six seconds, inhaling normally, u n t i l they can tolerate no more. While t h i s method y i e l d s favorable r e s u l t s (Lando, 1976; Best, Owen, and Trentadue, 1978) i t i s rather unpleasant to the smoker. Furthermore, i t induces i n subjects a number of p o t e n t i a l l y harmful physi-o l o g i c a l changes which have been of concern to several re-searchers (tLichtenste'ih a n d Glasgow, 1977; M i l l e r , S c h i l l i n g , Logan, and Johnson, 1977). The use of rapid smoking, there-fore, seems to be limited by a car e f u l preselection of c l i e n t s i n view of i t s physiological e f f e c t s and unpleasant nature. From the above discussion i t can be concluded that two current issues pertaining to smoking cessation techniques are 3 t h a t : 1) although i n i t i a l smoking r e d u c t i o n r a t e s are im-p r e s s i v e , r a t e s f o r maintenance of nonsmoking are r e l a t i v e l y d i s a p p o i n t i n g , and 2) most s t r a t e g i e s have implemented a v e r s i v e techniques which are unpleasant and not without p o t e n t i a l u n d e s i r a b l e consequences. These two concerns have l e d numerous r e s e a r c h e r s to suggest t h a t smoking c e s s a t i o n programs i n c o r p o r a t e techniques which f a c i l i t a t e maintenance of nonsmoking and which are nonaversive ( B e r n s t e i n , 1969; Hunt and Matarazzo, 1973; L i c h t e n s t e i n and Brown, 1980). I t i s p a r t l y i n response t o these suggestions t h a t p s y c h o l o g i s t s have recommended the use of e x e r c i s e i n t r e a t -ment f o r smoking. L i c h t e n s t e i n and Brown (1980) and Engs and M u l h a l l (1982) d i s c u s s " l i f e s t y l e b a l a n c i n g " i n smoking r e l a p s e p r e v e n t i o n , wherein a " p o s i t i v e l y a d d i c t i n g " a c t i v i t y such as p h y s i c a l e x e r c i s e r e p l a c e s smoking. Hunt and Matarazzo (1973) suggest the use of e x e r c i s e i n an approach where s u p p o r t i v e techniques are i n c o r p o r a t e d i n t o i n d i v i d u a l l y - t a i l o r e d programs f o r non-smoking. These sug-g e s t i o n s have r e s t e d on the assumption t h a t an i n v e r s e r e l a -t i o n s h i p e x i s t s between smoking and e x e r c i s e . However, r e s e a r c h on the e f f e c t s of e x e r c i s e on c i g a r e t t e smoking has been l i m i t e d t o date, w i t h no s i n g l e adequately c o n t r o l l e d study demonstrating t h a t the former i n h i b i t s the l a t t e r . The purpose of t h i s t h e s i s , t h e r e f o r e , i s to i n v e s t i g a t e the e f f e c t s of e x e r c i s e on c i g a r e t t e smoking. A review of the r e s e a r c h s u g g e s t i n g an i n v e r s e r e l a t i o n -4 s h i p between a e r o b i c e x e r c i s e and c i g a r e t t e smoking i s pre-sented below. I t i s f o l l o w e d by an examination of a c u r r e n t theory of smoking which c o u l d p r e d i c t an i n c r e a s e r a t h e r than decrease i n smoking f o l l o w i n g e x e r c i s e . F i n a l l y , a statement of purpose f o r the prese n t study and experimental hypotheses are presented. L i t e r a t u r e Review on E x e r c i s e and Smoking 5 Evidence suggesting an i n v e r s e r e l a t i o n s h i p between e x e r c i s e and smoking stems from a n e c d o t a l r e p o r t s as w e l l as c o r r e l a t i o n a l and experimental r e s e a r c h . V a r i o u s s t u d i e s a l s o suggest a p h y s i o l o g i c a l i n c o m p a t i b i l i t y between these two b e h a v i o r s . F i n a l l y , r e s e a r c h e x i s t s which suggests t h a t smoking and e x e r c i s e are both l i n k e d t o p s y c h o l o g i c a l v a r i -a b l e s which may mediate an e f f e c t of the former on the l a t -t e r . These s t u d i e s are presented below. Anecdotal Reports and C o r r e l a t i o n a l S t u d i e s Morgan, G i l d i n e r and Wright (1976) conducted a m a i l survey to determine the e x e r c i s e performance and smoking be-h a v i o r of members of a running c l u b , who averaged 35 m i l e s per week. Of the 141 members, 35 had been smokers, of whom a l l but t h r e e abandoned smoking a f t e r j o i n i n g the c l u b . In a s i m i l a r a n e c d o t a l r e p o r t on e x e r c i s e and smoking, Hickey, Mulcahy, Bourke, Graham and Wilson-Davis (1975) que s t i o n e d men about t h e i r work and l e i s u r e a c t i v i t y over the p r e v i o u s s i x months. They found a s i g n i f i c a n t i n v e r s e c o r r e l a t i o n between heavy l e i s u r e a c t i v i t y , i n c l u d i n g running, squash, t e n n i s and swimming, and smoking i n men 25 to 60 years o l d . Although t h i s f i n d i n g was based e x c l u s i v e l y on r e t r o s p e c t i v e s e l f - r e p o r t of change i n smoking, i t suggests t h a t e x e r c i s e reduces smoking. 6 In an a e r o b i c e x e r c i s e program f o r 237 NASA employees (Durbeck, Heinzelmann, Schacter, H a s k e l l , Payne, Moxley, Nemiroff, L i m o n c e l l i , A r n o l d i , and Fox, 1972) 35 to 55 year o l d men e x e r c i s e d f o r 30 minutes, three times per week. At the c o n c l u s i o n of the 12-month program approximately 15 per-cent of "good adherers" r e p o r t e d a decrease i n smoking, com-pared t o 10 and 5 pe r c e n t f o r e q u a l l y l a r g e groups of " f a i r " and "poor" e x e r c i s e adherers, r e s p e c t i v e l y . Two c o r r e l a t i o n a l s t u d i e s f a i l e d to f i n d an e f f e c t of e x e r c i s e on smoking. Bonanno and L i e s (1974) engaged 19 middle-aged coronary-prone male smokers i n a 12-week super-v i s e d a e r o b i c e x e r c i s e program of walking and j o g g i n g . N e i t h e r s u b j e c t s i n the experimental group nor those i n a matched n o - e x e r c i s e c o n t r o l group d i s c o n t i n u e d or substan-t i a l l y decreased smoking d u r i n g the program. Engs and M u l h a l l (1982) i n v e s t i g a t e d the smoking h a b i t s of u n i v e r s i t y undergraduates b e f o r e and a f t e r 15-week courses r e q u i r i n g e i t h e r strenuous a c t i v i t y such as jog g i n g and c o n d i t i o n i n g e x e r c i s e s , or l e i s u r e a c t i v i t y such as b i l l i a r d s and r i f l e r y . No p r e - to post-program changes i n smoking behavior were found f o r s u b j e c t s i n e i t h e r group. I n t e r p r e t a t i o n of data i n the above s t u d i e s i s d i f f i c u l t f o r a number of reasons. The r e s e a r c h e r s , with the e x c e p t i o n of Engs and M u l h a l l , d i d not d e s i g n t h e i r s t u d i e s to examine s p e c i f i c a l l y the r e l a t i o n s h i p between these two v a r i a b l e s and t h e r e f o r e they l a c k e d c o n t r o l procedures. The smokers were not r e p r e s e n t a t i v e of the g e n e r a l p o p u l a t i o n as three of 7 these programs were designed f o r those a t r i s k f o r coronary h e a r t d i s e a s e . Consequently, most s u b j e c t s were middle-aged coronary-prone men who may have been changing other l i f e s t y l e b e h a v i o r s i n a d d i t i o n t o p h y s i c a l a c t i v i t y . Another d i f -f i c u l t y w i t h i n t e r p r e t a t i o n i s t h a t although the frequency, i n t e n s i t y and d u r a t i o n of e x e r c i s e were r e p o r t e d i n most s t u d i e s e x e r c i s e adherence was not always monitored. F i n a l -l y , the assessment of smoking behavior was r e t r o s p e c t i v e f o r the most p a r t and based s o l e l y on s e l f - r e p o r t . One aspect of the Engs and M u l h a l l (1982) study which may mask an e f f e c t of smoking i s the f a c t t h a t most students i n the group (85 of 100 i n the strenuous a c t i v i t y group and 72 of 100 i n the l e i s u r e a c t i v i t y group) d i d not smoke, and o n l y a very s m a l l percentage of s u b j e c t s (2 percent i n the former and 12 per-cent i n the l a t t e r group) i n i t i a l l y smoked at l e a s t one package of c i g a r e t t e s d a i l y . Experimental S t u d i e s on E x e r c i s e and Smoking The r e l a t i o n s h i p between e x e r c i s e and smoking has been i n v e s t i g a t e d i n c i d e n t a l l y i n s t u d i e s on the r e l a t i o n s h i p between p h y s i c a l a c t i v i t y and coronary r i s k f a c t o r s . Mann, G a r r e t t , F a r h i , Murray, B i l l i n g s , Shute, and Schwarten (1969) t r a i n e d 106 men, aged 25 to 60 y e a r s , i n a strenuous program of s u p e r v i s e d e x e r c i s e , i n c l u d i n g c a l i s t h e n i c s , walking, j o g g i n g and running i n an attempt to reduce the r i s k of coronary h e a r t d i s e a s e . Each s u b j e c t was e x e r c i s e d a t one of 8 three i n t e n s i t i e s a c c o r d i n g t o h i s f i t n e s s l e v e l , f o r f i v e days per week f o r s i x months. At the end of the program, 22% r e p o r t e d a decrease i n smoking, versus 7% f o r a n o - e x e r c i s e c o n t r o l group. One d i f f i c u l t y w i t h data i n t e r p r e t a t i o n i n t h i s study a r i s e s from the f a c t t h a t no mention i s made of the p r o p o r t i o n of s u b j e c t s who i n i t i a l l y smoked. I f i t i s assumed t h a t smokers were p r o p o r t i o n a l l y r e p r e s e n t e d i n both groups, as s u b j e c t s were randomly assi g n e d to the groups, then the data suggest t h a t e x e r c i s e i s i n v e r s e l y r e l a t e d to smoking. Heinzelmann and Bagley (1970) e x e r c i s e d 239 i n i t i a l l y sedentary men, 45 to 59 years o l d , f o r one hour, three times per week f o r 18 months. The study does not mention the nature of e x e r c i s e performed; however, i t was most l i k e l y a e r o b i c as i t was designed t o improve cardio-pulmonary f u n c t i o n of men at r i s k f o r coronary h e a r t d i s e a s e . A randomly assi g n e d c o n t r o l group of 142 men d i d not e x e r c i s e , b u t : f i l l e d out q u e s t i o n n a i r e s on h e a l t h a t t i t u d e s and b e l i e f s , and r e c e i v e d m e d i c a l e v a l u a t i o n s a t standard t h r e e - t o four-month, i n t e r -v a l s . Twenty percent of men i n both the experimental and c o n t r o l groups r e p o r t e d smoking l e s s a t the end of 18 months. I t may be t h a t f i l l i n g out the h e a l t h q u e s t i o n n a i r e s and p o s s i b l e exposure to the experimental s u b j e c t s , who were r e c r u i t e d from the same u n i v e r s i t y s e t t i n g , may have spurred the c o n t r o l s u b j e c t s to i n i t i a t e t h e i r own e x e r c i s e program d u r i n g the course of the study. The experimenters would have 9 been uninformed of t h i s as change i n e x e r c i s e h a b i t s of con-t r o l s u b j e c t s was not assessed a t the. end of the study. Two unpublished s t u d i e s were designed s p e c i f i c a l l y to assess the e f f e c t s of e x e r c i s e i n treatment f o r smoking. Johnson, Rosenbaum, Framer and Wildman (1979) assessed the i n f l u e n c e of an 8-week e x e r c i s e program on c i g a r e t t e consump-t i o n and p h y s i c a l f i t n e s s . The study compared the e f f e c t s on smoking of two e x e r c i s e programs the f i r s t i n v o l v i n g 30 minutes of walking per day, the second c o n s i s t i n g of an i n -cremental program of walking and a weekly e x e r c i s e s e s s i o n which began a t the same l e v e l as the f i r s t . S ubjects i n both groups r e c e i v e d , i n a d d i t i o n to e x e r c i s e , i n s t r u c t i o n i n s e l f - m o n i t o r i n g , r e l a x a t i o n t r a i n i n g , c i g a r e t t e r e f u s a l t r a i n i n g and b e h a v i o r a l a n a l y s i s of smoking. R e s u l t s i n d i -c ate no d i f f e r e n c e i n smoking behavior between the groups e i t h e r post-treatment or a t a one year f o l l o w - u p . Subjects i n both programs s i g n i f i c a n t l y decreased smoking, r e t u r n i n g to 67% of b a s e l i n e frequency a t a one-year follow-up. The l a c k of a n o - e x e r c i s e c o n t r o l group and the use of a m u l t i -component treatment package f o r smoking c e s s a t i o n p r e c l u d e s any assessment of the e f f e c t s of e x e r c i s e on smoking. An important f i n d i n g , however, i s t h a t post-treatment c i g a r e t t e smoking was s i g n i f i c a n t l y i n v e r s e l y r e l a t e d t o p r e - and p o s t -treatment a e r o b i c c a p a c i t y (r = and r = -0.86, respec-t i v e l y ) as determined by a step t e s t , s u g g e s t i n g t h a t smoking i s r e l a t e d t o i n i t i a l l e v e l of p h y s i c a l f i t n e s s and p h y s i c a l 10 improvement f o l l o w i n g e x e r c i s e . In a study by Howley, C a l l a h a n and Yaeter (1980), a 2 X 2 f a c t o r i a l d e sign was implemented to determine the separate and combined e f f e c t s of e x e r c i s e and self-management s t r a t e g i e s on smoking. Subjec t s i n an e x e r c i s e group f o l l o w e d an i n d i v i d u a l i z e d e x e r c i s e p l a n i n c l u d i n g walking and running, which was g r a d u a l l y i n c r e a s e d d u r i n g the study. Smokers i n a self-management group l e a r n e d s e l f - c o n t r o l procedures f o r d e a l i n g w i t h smoking s i t u a t i o n s . In both groups s e l f -m o n i t o r i n g , c o n t r a c t i n g , and s o c i a l f a c i l i t a t i o n were used f o r treatment adherence. A t h i r d group r e c e i v e d both exer-c i s e and self-management t r a i n i n g components, w h i l e a f i n a l group served as a delayed treatment c o n t r o l . R e s u l t s i n d i c a t e t h a t a l l three treatment groups s i g n i f i c a n t l y reduced t h e i r smoking r a t e and t h a t there was no d i f f e r e n c e among these groups post-treatment nor a t six-week and six-month f o l l o w -ups . In both the Howley e t a l . and Johnson e t a l . s t u d i e s , p h y s i o l o g i c a l i n d i c e s of r e c o v e r y were used to assess exer-c i s e adherence. However, changes i n these measures cannot be a t t r i b u t e d s o l e l y to e x e r c i s e p a r t i c i p a t i o n , as smoking c e s s a t i o n alone i s s u f f i c i e n t t o improve a e r o b i c c a p a c i t y (Rode, Ross and Shepard, 1972). I t may be, t h e r e f o r e , t h a t i n these s t u d i e s p h y s i o l o g i c a l i n d i c e s of r e c o v e r y d i d not r e f l e c t e x e r c i s e adherence a c c u r a t e l y . Another d i f f i c u l t y w i t h data i n t e r p r e t a t i o n i n these s t u d i e s stems from the f a c t 11 t h a t no c o n t r o l s were made f o r s u b j e c t e x p e c t a n c i e s and be-l i e f s t h a t the treatment would reduce smoking. As programs i n both s t u d i e s were presented as anti-smoking treatments, s u b j e c t s v o l u n t e e r i n g f o r the s t u d i e s may have reduced smoking p a r t l y or wholly as a r e s u l t of these n o n s p e c i f i c treatment f a c t o r s (McFall and Hammen, 1971). F i n a l l y , con-c l u s i v e i n t e r p r e t a t i o n of an e f f e c t of e x e r c i s e i n the Howley e t a l . study i s hampered by the f a c t t h a t seven of the 36 s u b j e c t s i n the three treatment groups dropped out of the study (no drop-out data are presented f o r the e x e r c i s e group a l o n e ) , w h i l e f o u r of the nine s u b j e c t s i n the e x e r c i s e group f a i l e d t o adhere to the e x e r c i s e regimen. P h y s i o l o g i c a l I n c o m p a t i b i l i t y between A e r o b i c E x e r c i s e and Smoking There e x i s t s evidence s u g g e s t i n g t h a t a e r o b i c e x e r c i s e i s i n c o m p a t i b l e w i t h smoking. While a e r o b i c e x e r c i s e i n -creases cardio-pulmonary f u n c t i o n , c i g a r e t t e smoking produces p h y s i o l o g i c a l changes i n an o p p o s i t e d i r e c t i o n '(Cooper, Gey, and Bottenberg,1969). S t u d i e s c o n f i r m i n g t h i s f i n d i n g i n d i -c a t e t h a t : 1) smokers perform worse than nonsmokers on c a r -d i o v a s c u l a r and pulmonary t e s t s , 2) smokers' e x e r c i s e per-formance decreases f o l l o w i n g c i g a r e t t e consumption, and 3) nonsmokers respond more f a v o r a b l y than smokers to p h y s i c a l t r a i n i n g programs. A review of these s t u d i e s i s presented below. 12 In a comparison of smokers' and nonsmokers' c a r d i o -pulmonary performance, Cunningham, Montoye, H i g g i n s , and K e l l e r (1972) engaged male and female smokers i n a bench s t e p p i n g t e s t and found they had s i g n i f i c a n t l y higher h e a r t r a t e s than nonsmokers p r e - and three minutes p o s t - e x e r c i s e . Shaver (1973) found d i f f e r e n c e s i n e x e r c i s e performance between female smokers and nonsmokers on three measures of c a r d i o v a s c u l a r and pulmonary e f f i c i e n c y : a bench step t e s t , a 60 yar'd run-walk t e s t and a r e p e t i t i v e t r e a d m i l l t e s t . Furthermore, Franks (1970) noted t h a t when smokers a b s t a i n from t h e i r u s u a l p a t t e r n of smoking f o r one day, they expe-r i e n c e an improvement i n three c a r d i a c measures: d i a s t o l i c b lood p r e s s u r e , s t r o k e volume and c a r d i a c sympatho-adrenergic a c t i v i t y , i n response to e x e r c i s e . Krone, Goldbarg, Balkoura, S c h u e s s l e r and Resnekov (1972) determined smokers' e x e r c i s e performance both b e f o r e and a f t e r c i g a r e t t e smoking. In the f i r s t s e s s i o n nine male smokers aged 21 to 27 years pedaled a b i c y c l e ergometer f o r 18 minutes a t a h e a r t r a t e e l e v a t i o n of up to 150 beats per minute, r e s t e d f o r 30 minutes, and repeated the e x e r c i s e . T h i s sequence was l a t e r repeated f o r a second s e s s i o n , except t h a t the s u b j e c t smoked a s i n g l e c i g a r e t t e d u r i n g the 30-minute r e s t p e r i o d . The authors found an i n c r e a s e i n h e a r t r a t e and a decrease i n s t r o k e volume d u r i n g e x e r c i s e a f t e r smoking a c i g a r e t t e . The same r e s u l t s were found by Goldbarg, Krone and Resnekov (1971) u s i n g a s i m i l a r methodology with 13 nine male h a b i t u a l smokers, aged 22 to 26 y e a r s . F u r t h e r support f o r the p h y s i o l o g i c a l i n c o m p a t i b i l i t y between a e r o b i c e x e r c i s e and smoking i s p r o v i d e d by s t u d i e s comparing the response of smokers and nonsmokers to p h y s i c a l t r a i n i n g programs. Cooper, Gey, and Bottenberg (1969) t e s t e d endurance performance u s i n g a running t e s t i n 419 young a i r -men (mean age 19.1 years) b e f o r e and a f t e r s i x weeks of b a s i c t r a i n i n g . They found t h a t smokers had lower r e s p i r a -t o r y minute volume and oxygen consumption a t e q u i v a l e n t h e a r t r a t e s compared to nonsmokers both before and a f t e r t r a i n i n g . T h i s impairment was s i g n i f i c a n t i n s u b j e c t s who had smoked f o r over s i x months, and performance was i n v e r s e l y r e l a t e d t o d a i l y c i g a r e t t e consumption. S i m i l a r l y , Peterson and K e l l y (1969) c o n d i t i o n e d 60 men i n an eight-week running program and found t h a t smokers i n c r e a s e d t h e i r maximal oxygen uptake (MV02) l e v e l s a t a lower r a t e than nonsmokers. The above f i n d i n g s of an i n c o m p a t i b i l i t y between exer-c i s e and smoking are c o n s i s t e n t w i t h the f a c t t h a t two com-pounds i n c i g a r e t t e s , carbon monoxide (CO) and n i c o t i n e , have been l i n k e d t o decreased cardio-pulmonary e f f i c i e n c y . Carbon monoxide i n c i g a r e t t e smoke binds t o hemoglobin thus l e a v i n g l e s s a v a i l a b l e f o r oxygen t r a n s p o r t i n the blood (Montoye, Gayle and H i g g i n s , 19 80). A smoker may have approximately 5 per c e n t or more of h i s blo o d c e l l s b l o c k e d by CO, making oxy-gen t r a n s p o r t more d i f f i c u l t (Astrand and Rodahl, 1970). Body t i s s u e s a l s o r e c e i v e l e s s oxygen because CO reduces 14 p e r i p h e r a l blood flow, pulmonary d i f f u s i o n c a p a c i t y and v i t a l c a p a c i t y (Montoye e t a l . , 19 80). Furthermore, CO i n c r e a s e s airway r e s i s t a n c e , which i n t e r f e r e s with oxygen-carrying c a p a c i t y and causes v a s t c o n s t r i c t i o n of blood v e s s e l s , r e s u l t i n g i n i n c r e a s e d h e a r t r a t e (Rode and Shepard, 1971) . Carbon monoxide, t h e r e f o r e , i s a t l e a s t p a r t i a l l y respon-s i b l e f o r smokers' reduced cardiopulmonary f u n c t i o n . A second harmful agent i n tobacco, n i c o t i n e , decreases c a r d i a c output and s t r o k e volume ;(Astrand and Rodahl, 1970). I t a l s o s t i m u l a t e s the r e l e a s e of catecholamines, which r a i s e h e a r t r a t e and t h e r e f o r e i n c r e a s e the h e a r t ' s work-load (Astrand and Rodahl, 1970). C o l l e c t i v e l y , the above f i n d i n g s i n d i c a t e t h a t smoking induces numerous p h y s i o l o g i c a l changes op p o s i t e to those produced by a e r o b i c e x e r c i s e . I t i s p o s s i b l e , t h e r e f o r e , t h a t smokers exposed to a e r o b i c e x e r c i s e may be encouraged to decrease t h e i r smoking i n order to p a r t i c i p a t e more e f f e c -t i v e l y i n p h y s i c a l a c t i v i t y . C o n v e r s e l y , i f they were to smoke l e s s they would become aware of the improved q u a l i t y of t h e i r e x e r c i s e performance. T h i s p o s i t i v e feedback r e g a r d i n g p h y s i c a l f i t n e s s may, i n t u r n , p r o v i d e f u r t h e r m o t i v a t i o n f o r smoking a b s t i n e n c e . C o n s i s t e n t with t h i s h y p o t h e s i s , Paxton and S c o t t (1981) found t h a t improvement i n lung f u n c t i o n f o l l o w i n g smoking c e s s a t i o n was i n v e r s e l y c o r r e l a t e d w i t h r e l a p s e , and suggested t h a t p o s i t i v e feedback r e g a r d i n g p h y s i o l o g i c a l change r e s u l t e d i n g r e a t e r maintenance of treatment suc c e s s . 15 P s y c h o l o g i c a l F a c t o r s R e l a t e d t o E x e r c i s e and Smoking A number of p s y c h o l o g i c a l f a c t o r s have been l i n k e d to e i t h e r an i n c r e a s e or decrease i n c i g a r e t t e smoking ( L i c h t e n s t e i n and Brown, 19 80). Research suggests t h a t these same v a r i a b l e s may be a f f e c t e d by p h y s i c a l a c t i v i t y (Martin and Dubbert, 1982). To the extent t h a t e x e r c i s e may reduce p s y c h o l o g i c a l s t a t e s r e l a t e d to i n c r e a s e d smoking or i n c r e a s e mental s t a t e s known to reduce smoking, i t may modify smoking through these mediating v a r i a b l e s . One v a r i a b l e which i s n e g a t i v e l y r e l a t e d to smoking i s h e a l t h awareness. Research suggests t h a t smokers are l e s s l i k e l y t o guard t h e i r h e a l t h than are nonsmokers. E i s e r , Sutton, and Wober (1979) found t h a t smokers were l e s s l i k e l y to b e l i e v e t h a t smoking was ' r e a l l y dangerous', were l e s s prone to wearing seat b e l t s , and were more l i k e l y to b e l i e v e t h a t i n d i v i d u a l s have a r i g h t to r i s k t h e i r own h e a l t h r a t h e r than a moral r e s p o n s i b i l i t y t o p r o t e c t themselves from h e a l t h r i s k s . To the extent t h a t e x e r c i s e improves one's a t t i t u d e towards h e a l t h and w e l l - b e i n g , i t may mediate a r e d u c t i o n i n smoking. Two s t u d i e s a t t e s t to the improvement i n h e a l t h a t t i t u d e f o l l o w i n g p a r t i c i p a t i o n i n e x e r c i s e programs. Heinzelmann and Bagley (1970) found more p o s i t i v e f e e l i n g s r e g a r d i n g h e a l t h h a b i t s and behavior, w h i l e Durbeck et a l . (1972) r e p o r t e d i n c r e a s e d p o s i t i v e f e e l i n g s about h e a l t h s t a t u s . Smoking presumably would be a n t i t h e t i c a l to an i n c r e a s e d concern over one's h e a l t h p a t t e r n s and a smoker might, 16 t h e r e f o r e , abandon h i s smoking to mai n t a i n c o n s i s t e n c y w i t h h i s newly a c q u i r e d b e l i e f s r e g a r d i n g h i s h e a l t h l i f e s t y l e . G o t t l i e b , Freidman, Cooney, Gordon and M a r l a t t (1981) d i d , i n f a c t , f i n d t h a t h e a l t h was by f a r the most common reason c i t e d by smokers to attempt smoking c e s s a t i o n . F u r t h e r support f o r h e a l t h as a mediat i n g v a r i a b l e i n smoking ce s s a -t i o n i s p r o v i d e d by S h i p l e y (19 81) who found t h a t ex-smokers with an i n t e r n a l h e a l t h l o c u s of c o n t r o l (HLC - the b e l i e f t h a t one c o n t r o l s h i s / h e r health) remained a b s t i n e n t longer than those w i t h an e x t e r n a l HLC. Va r i o u s s t u d i e s have i n d i c a t e d t h a t e x e r c i s e decreases f e e l i n g s of s t r e s s , t e n s i o n and a n x i e t y (McCrae, Costa and Bosse, 1978; L i c h t e n s t e i n and Brown, 1980). Moreover, these f a c t o r s are known to be a s s o c i a t e d w i t h smoking. S u b j e c t s p a r t i c i p a t i n g i n a NASA-US P u b l i c H e a l t h S e r v i c e Health E d u c a t i o n and Enhancement program (Durbeck et a l . 1972) reported decreased f e e l i n g s of s t r e s s and t e n s i o n a f t e r e x e r c i s i n g , as d i d those i n e x e r c i s e programs f o r men a t r i s k f o r coronary h e a r t d i s e a s e (Heinzelmann and Bagley, 1970; F o l k i n s , 1976). Cooper (1977) r e p o r t e d a " g r e a t e r a b i l i t y to r e s i s t a l l types of s t r e s s " f o l l o w i n g p h y s i c a l f i t n e s s t r a i n i n g , and Cureton (1963) r e p o r t e d t e n s i o n r e d u c t i o n i n a d u l t s p a r t i c i p a t i n g i n a p h y s i c a l c o n d i t i o n i n g program. Morgan (1979) reviewed seven s t u d i e s i n which the e f f e c t s of acute a e r o b i c a c t i v i t y are i n v e s t i g a t e d . Of these, two f a i l e d to demonstrate a decrement i n p e r c e i v e d a n x i e t y f o l l o w i n g e x e r c i s e . In both 17 s t u d i e s , however, the e x e r c i s e c o n s i s t e d simply of walking, s u g g e s t i n g t h a t p h y s i c a l a c t i v i t y may need to be more vi g o r o u s to achieve a s i g n i f i c a n t r e d u c t i o n i n a n x i e t y . Of the f i v e remaining s t u d i e s , f o u r c o n s i s t e d of i n v e s t i g a t i o n s where s u b j e c t s ran and one e n t a i l e d p a r t i c i p a t i o n i n r a c q u e t b a l l . A l l f i v e s t u d i e s demonstrated a r e d u c t i o n i n a n x i e t y through s e l f - r e p o r t . F o l k i n s and Sime (1981) reviewed s i x s t u d i e s i n v e s t i g a t i n g the e f f e c t of p h y s i c a l f i t n e s s t r a i n i n g on a n x i e t y , t e n s i o n and/or w e l l - b e i n g , of which a l l show an improvement i n a f f e c t (obtained by s e l f - r e p o r t ) i n response to e x e r c i s e . They note t h a t the decrement i n n e g a t i v e emo-t i o n s i s p a r t i c u l a r l y e v i d e n t w i t h s u b j e c t s who are e i t h e r i n i t i a l l y l e s s p h y s i c a l l y f i t or more p s y c h o l o g i c a l l y d i s -t r e s s e d . Ikard and Tompkins (19 73) p r o v i d e evidence t h a t people smoke f o r two major reasons: to i n c r e a s e p o s i t i v e a f f e c t and to decrease negative a f f e c t . Furthermore, smokers main-t a i n smoking when they r e a l i z e t h a t i t i s a source of reward and/or a means of c o n t r o l l i n g n e g a t i v e a f f e c t . I f e x e r c i s e has a s i m i l a r e f f e c t on mental s t a t e , i t may decrease the need f o r smoking. Numerous s t u d i e s r e p o r t t h a t s u b j e c t s " f e e l b e t t e r " a f t e r e x e r c i s e (Morgan, Roberts, Brand and Feinerman, 1970). F o l k i n s and Sime (1981) reviewed seven s t u d i e s a s s e s s i n g the e f f e c t of e x e r c i s e on d e p r e s s i o n , mood and w e l l - b e i n g . Of these, s i x demonstrated a s i g n i f i c a n t p o s t - e x e r c i s e improvement i n a f f e c t , as determined by 18 q u e s t i o n n a i r e , w h i l e the seventh found t h i s i n depressed, but not i n normal s u b j e c t s . F u r t h e r support f o r i n c r e a s e d p o s i t i v e a f f e c t f o l l o w i n g e x e r c i s e stems from r e s e a r c h i n d i c a t i n g t h a t p h y s i c a l a c t i v i t y r e l e a s e s beta-endorphins, substances i n the b r a i n known to a c t as o p i a t e s , i n h i b i t i n g p a i n and improving mood s t a t e s ( A p p e n z e l l e r , 1981; A p p e n z e l l e r , Standefer, A p p e n z e l l e r and A t k i n s o n , 1980). P h y s i c a l e x e r c i s e a l s o a c t i v a t e s the sym-pathetic!; nervous system, r e s u l t i n g i n p o s i t i v e emotional s t a t e s (Dimsdale and Moss, 1980). Furthermore, e x e r c i s e reduces f e e l i n g s of c h r o n i c f a t i g u e , known to be a s s o c i a t e d w i t h d e p r e s s i o n (Dimsdale and Moss, 1980). In a d d i t i o n to h e a l t h awareness and n e g a t i v e a f f e c t , o t h e r v a r i a b l e s may a l s o mediate an e f f e c t of e x e r c i s e on smoking. Some people smoke f o r s o c i a l approval ( L i c h t e n s t e i n and Brown, 1980). A smoker might a l s o c u l t i v a t e s o c i a l a pproval by engaging i n r e g u l a r e x e r c i s e and becoming more p h y s i c a l l y f i t . E x e r c i s e enhances se l f - i m a g e and c o n f i d e n c e (Heinzelmann and Bagley, 1970; Collingwood and W i l l e t t , 1971; Cooper, 1977) and t h e r e f o r e might a c t u a l l y decrease one's i n i t i a l need f o r s o c i a l a p p r o v a l . Other f a c t o r s l i n k e d to c i g a r e t t e smoking i n c l u d e boredom ( L i c h t e n s t e i n and Brown, 1980) and a need f o r sensorimotor s t i m u l a t i o n (Flaxman, 1979), both of which may be combatted u s i n g e x e r c i s e . In c o n c l u s i o n , the above s t u d i e s c o n f i r m t h a t a number of p s y c h o l o g i c a l f a c t o r s may be r e s p o n s i b l e f o r smoking. 19 Furthermore, e x e r c i s e has been demonstrated t o be r e l a t e d to many of these v a r i a b l e s . I f smoking and e x e r c i s e are r e l a t e d to p s y c h o l o g i c a l s t a t e s i n an o p p o s i t e d i r e c t i o n , e x e r c i s e p a r t i c i p a t i o n may induce a decrement i n smoking. Summary of Research on E x e r c i s e and Smoking Although the above s t u d i e s i n d i c a t e t h a t e x e r c i s e and smoking may be i n v e r s e l y r e l a t e d , f i r m c o n c l u s i o n s r e g a r d i n g the e f f e c t s of e x e r c i s e on smoking cannot be made on the b a s i s of evidence p r o v i d e d . Of the s t u d i e s reviewed, on l y f o u r were concerned s p e c i f i c a l l y w i t h an examination of the r e l a -t i o n s h i p between these two v a r i a b l e s . Of these f o u r , the r e s u l t s of two (Johnson e t a l . , 1979; Howley e t a l . , 1980) suggest t h a t e x e r c i s e may l e a d t o a decrement i n smoking, but e x e r c i s e i s not manipulated to the e x c l u s i o n o f other t r e a t -ment f a c t o r s . While Morgan e t a l . (1976) found a r e d u c t i o n i n smoking f o l l o w i n g 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, the study was r e t r o s p e c t i v e , and i n f o r m a t i o n on smoking was pr o v i d e d s o l e l y by s e l f - r e p o r t . F i n a l l y , the c o r r e l a t i o n a l study by Engs and M u l h a l l (1982) f a i l e d t o f i n d a decrease i n smoking f o l l o w i n g enrolment i n p h y s i c a l e d u c a t i o n courses, but o n l y a s m a l l percentage o f s u b j e c t s were r e g u l a r smokers who consumed at l e a s t one package of c i g a r e t t e s per day. The remaining r e s e a r c h on the e f f e c t s o f a e r o b i c exer-c i s e on smoking i s o f t e n r e t r o s p e c t i v e and a n e c d o t a l , with s t u d i e s a s s e s s i n g the r e l a t i o n s h i p between these two v a r i a b l e s 20 o n l y as p a r t of a l a r g e r p r o j e c t . In c o n c l u s i o n , there i s a need f o r w e l l - c o n t r o l l e d e m p i r i c a l r e s e a r c h e x p l o r i n g the e f f e c t s of a e r o b i c e x e r c i s e on smoking before a d e c i s i o n r e g a r d i n g i t s c l i n i c a l u t i l i t y can be made. Schachter's Model of Smoking: I m p l i c a t i o n s f o r E x e r c i s e Schachter (1977) proposed a model of smoking which would p r e d i c t a change i n smoking f o l l o w i n g e x e r c i s e i n a d i r e c t i o n o p p o s i t e t o t h a t suggested by r e s e a r c h on e x e r c i s e and smoking reviewed above; i . e . , i t would p r e d i c t a pos t -e x e r c i s e i n c r e a s e r a t h e r than decrease i n smoking. He sug-gested t h a t people smoke to r e g u l a t e n i c o t i n e , and t h a t an i n t e r n a l homeostatic mechanism i s r e s p o n s i b l e f o r mo n i t o r i n g n i c o t i n e l e v e l s i n the body. A c c o r d i n g t o Schachter, when a smoker's n i c o t i n e r e s e r v e s are d e p l e t e d he w i l l compensate f o r t h i s l o s s by i n c r e a s i n g h i s c i g a r e t t e consumption. Furthermore, Schachter e x p l a i n s t h a t when u r i n a r y pH decreases, i . e . , when u r i n e becomes more a c i d i c , as i t does when sub-j e c t s are s t r e s s e d , the r a t e o f n i c o t i n e e x c r e t i o n i n c r e a s e s (Wesson, 1969)'. T h i s would r e s u l t i n i n c r e a s e d r a t e s of smoking i n order to compensate f o r n i c o t i n e l o s s . Schachter (1977) presented a s e r i e s of f i v e s t u d i e s to v e r i f y t h a t smokers r e g u l a t e n i c o t i n e . In the f i r s t (Schachter, 1977) he demonstrated t h a t heavy smokers c o n s i s t e n t l y consume more low- than h i g h - n i c o t i n e c i g a r e t t e s when these are a l t e r -nated on a weekly b a s i s . In a second study, an i n c r e a s e i n 21 smoking was found f o l l o w i n g u r i n e a c i d i f i c a t i o n by v i t a m i n C i n t a k e , but smoking d i d not i n c r e a s e when u r i n e was a l k a l i z e d u s i n g sodium b i c a r b o n a t e or was unchanged u s i n g a placebo (Schachter, Kozlowski and S i l v e r s t e i n , 1977). Next, S i l v e r -s t e i n , Kozlowski and Schachter (1977) determined the e f f e c t s of p a r t y going on u r i n a r y pH and smoking, and found t h a t smokers have lower bedtime u r i n a r y pH and r e p o r t smoking more c i g a r e t t e s on days i n which they a t t e n d p a r t i e s than on 'nonparty' days. In a p a r a l l e l manner, Schachter, S i l v e r s t e i n , Kozlowski, Herman, and L i e b l i n g (197 7) found lower u r i n a r y pH l e v e l s and a g r e a t e r i n c r e a s e i n smoking r a t e and number of p u f f s taken per c i g a r e t t e f o l l o w i n g e l e c t r i c shock. F i n a l l y , Schachter, S i l v e r s t e i n and P e r l i c k (1977) separated the e f f e c t s of p s y c h o l o g i c a l s t r e s s from those of u r i n a r y a c i d i f i c a t i o n on c i g a r e t t e smoking. In a 2 X 2 f a c t o r i a l d e s i g n , s u b j e c t s were giv e n e i t h e r sodium b i c a r b o n a t e or a placebo and were p l a c e d i n a high or low s t r e s s c o n d i t i o n . S u b j e c t s were then e s c o r t e d to a w a i t i n g room where smoking r a t e and number of p u f f s taken f o r each c i g a r e t t e were un-o b t r u s i v e l y observed. In the h i g h - s t r e s s placebo c o n d i t i o n u r i n e was s i g n i f i c a n t l y a c i d i f i e d , whereas the h i g h - s t r e s s b i c a r b o n a t e c o n d i t i o n d i d not a c i d i f y the u r i n e . R e s u l t s i n d i c a t e t h a t the m anipulations i n c r e a s e d smoking only when pH was decreased, sugge s t i n g t h a t smoking was i n f l u e n c e d by p h a r m a c o l o g i c a l r a t h e r than p s y c h o l o g i c a l m a n i p u l a t i o n s . The r e l a t i o n s h i p between u r i n a r y pH and smoking as 22 p r e d i c t e d by Schachter was a l s o v e r i f i e d by Dobbs, S t r i c k l e r and Maxwell (1981). These i n v e s t i g a t o r s p l a c e d .undergraduates under s t r e s s by l e a d i n g them to b e l i e v e they would be asked to speak i n f r o n t of graduate students and f a c u l t y . Subjects were then exposed to e i t h e r a r e l a x a t i o n tape (S-R), a s t r e s s -provoking tape (S-S), or a n e u t r a l tape (S-N). Subjects i n a c o n t r o l group (N-N) d i d not a n t i c i p a t e having to g i v e a speech and l i s t e n e d to a n e u t r a l tape. U r i n a r y pH measures were ob t a i n e d d u r i n g b a s e l i n e , and 10 and 35 minutes pos t -treatment. In a d d i t i o n , measures of p u f f r a t e and centimeters of c i g a r e t t e smoked were obt a i n e d b e f o r e , and f o r 35 minutes f o l l o w i n g treatment. Analyses r e v e a l e d s i g n i f i c a n t l y g r e a t e r u r i n e a c i d i f i c a t i o n d u r i n g treatment f o r the S-S group than f o r the N-N and S-R groups and a s i g n i f i c a n t decrease i n p u f f r a t e and amount smoked f o r the S-R group than f o r the other two s t r e s s groups. In a d d i t i o n , changes i n amount of c i g a -r e t t e smoked d u r i n g a 35-minute post-treatment s e s s i o n were n e g a t i v e l y c o r r e l a t e d w i t h treatment pH l e v e l s , s u g g e s t i n g t h a t the i n c r e a s e i n smoking under s t r e s s f u l c o n d i t i o n s was r e l a t e d t o u r i n e a c i d i f i c a t i o n . In c o n t r a s t to the above f i n d i n g s , Schachter's sugges-t i o n t h a t u r i n a r y pH may mediate changes i n smoking behavior was not borne out by M a r s h a l l , Green, E p s t e i n , Rogers and McCoy (1980) who examined the e f f e c t of c o f f e e d r i n k i n g and u r i n a r y pH on c i g a r e t t e smoking. In a w i t h i n - s u b j e c t s design smokers were giv e n water, c o f f e e , c o f f e e and sodium 23 b i c a r b o n a t e or c o f f e e and a s c o r b i c a c i d , and were subsequent-l y asked to remain i n a w a i t i n g room f o r one hour. Pre- to p o s t - s e s s i o n u r i n e analyses i n d i c a t e d t h a t c o f f e e d i d not a c i d i f y the u r i n e ; y e t s u b j e c t s smoked more c i g a r e t t e s i n s e s s i o n s f o l l o w i n g c o f f e e consumption, su g g e s t i n g t h a t smoking behavior was a l t e r e d i n response to c o f f e e d r i n k i n g r a t h e r than to u r i n a r y pH changes. One d i f f i c u l t y with i n t e r p r e t a t i o n of these r e s u l t s , however, i s t h a t the manip-u l a t i o n s f a i l e d t o a c i d i f y the u r i n e . T h i s i s important, as i n c r e a s i n g the a l k a l i n i t y of the u r i n e does not a l t e r appre-c i a b l y n i c o t i n e e x c r e t i o n (Schachter, 1980), and t h e r e f o r e no consequent change i n smoking should have o c c u r r e d . The above s t u d i e s i n d i c a t e t h a t Schachter's theory of n i c o t i n e a d d i c t i o n has some e m p i r i c a l support. The theory p o i n t s to the importance of u r i n a r y pH as a mediating v a r i -a ble i n the d e t e r m i n a t i o n of smoking. T h i s has important i m p l i c a t i o n s f o r the p r e s e n t study, s i n c e one f a c t o r known to decrease u r i n a r y pH i s e x e r c i s e , which a c i d i f i e s u r i n e f o r approximately one hour a f t e r acute strenuous a c t i v i t y (Wesson, 1969). As u r i n e a c i d i f i c a t i o n s t i m u l a t e s n i c o t i n e e x c r e t i o n , smokers would be expected to i n c r e a s e t h e i r c i g a r e t t e con-sumption f o l l o w i n g e x e r c i s e . 24 Statement of Purpose and Hypotheses The p r e s e n t study was designed to examine the acute e f f e c t s of two i n t e n s i t i e s of e x e r c i s e and a n o - e x e r c i s e c o n t r o l on smoking r a t e and topography. I t was p r e d i c t e d t h a t c i g a r e t t e smoking would be i n v e r s e l y r e l a t e d to e x e r c i s e i n t e n s i t y , being lowest f o l -lowing h i g h - i n t e n s i t y e x e r c i s e , i n t e r m e d i a t e f o l l o w i n g low-i n t e n s i t y e x e r c i s e , and g r e a t e s t f o l l o w i n g no e x e r c i s e . T h i s would apply f o r a l l the smoking i n d i c e s assessed, i n -c l u d i n g the number and weight of c i g a r e t t e s smoked, p u f f frequency per c i g a r e t t e and c i g a r e t t e d u r a t i o n . Furthermore, l a t e n c y to smoke was expected to be d i r e c t l y r e l a t e d to e x e r c i s e i n t e n s i t y . A second purpose of the study was to examine the r e l a -t i o n s h i p between u r i n a r y pH, e x e r c i s e and c i g a r e t t e smoking a c c o r d i n g to Schachter's h y p o t h e s i s . I f Schachter's hypoth-e s i s holds then, c o n t r a r y to the above p r e d i c t i o n , strenuous e x e r c i s e would be expected to l e a d to a decrease i n u r i n a r y pH and t h e r e f o r e to a subsequent i n c r e a s e i n smoking. 25 METHOD Subjects E i g h t e e n male s u b j e c t s between the ages df 20 and 30 (mean age = 25.5), who had smoked f o r an average of 10.3 years (range = 3 to 17 years) were r e c r u i t e d through adver-tisements posted a t the U n i v e r s i t y of B r i t i s h Columbia campus and a t v a r i o u s p u b l i c l o c a t i o n s i n West P o i n t Grey and K i t s i l a n o . C r i t e r i a f o r i n c l u s i o n i n the experiment were: 1. The s u b j e c t had to be 20 to 30 years o l d . I t was necessary to s e l e c t a homogeneous group of s u b j e c t s w i t h r e s p e c t to age i n order to minimize extraneous f a c t o r s which may have i n f l u e n c e d e x e r c i s e . 2. The s u b j e c t had to be screened by a PARQ ( P h y s i c a l A c t i v i t y Readiness Q u e s t i o n n a i r e ) , which was completed to determine t h a t he had no medical c o n d i t i o n which p r e c l u d e d h i s p a r t i c i p a t i o n i n the study. 3. S u b j e c t s c o u l d not be on any m e d i c a t i o n which a l t e r e d t h e i r cardiopulmonary f u n c t i o n or smoking r a t e d u r i n g , or f o r one day b e f o r e the study. 4. The s u b j e c t had to be i n poor to average p h y s i c a l c o n d i -t i o n as determined by h i s r e p o r t of weekly p h y s i c a l a c t i v i t y on a s c r e e n i n g q u e s t i o n n a i r e . Weekly a c t i v i t i e s were t r a n s -formed i n t o a e r o b i c p o i n t s (Cooper, 1977), and o n l y s u b j e c t s w i t h accumulated p o i n t s p l a c i n g them i n a below-average f i t n e s s 26 category were s e l e c t e d f o r the study. 5. The s u b j e c t s had to have smoked at l e a s t one package of c i g a r e t t e s d a i l y f o r the l a s t t hree y e a r s . I f there had been a gap i n the s u b j e c t ' s smoking h i s t o r y , the t h r e e - y e a r p e r i o d was lengthened by t h a t amount. V o l u n t e e r s p a r t i c i p a t i n g i n smoking c e s s a t i o n programs or implementing smoking r e d u c t i o n s t r a t e g i e s , as w e l l as those who attempted to q u i t smoking w i t h i n 30 days of the study were screened out. Apparatus Urine samples were c o l l e c t e d i n 150ml p l a s t i c specimen c o n t a i n e r s and analyzed u s i n g an O r i o n Research Model 701A D i g i t a l I o n a l y z e r pH meter. Subjects were e x e r c i s e d on a Monark s t a t i o n a r y b i c y c l e . Heart r a t e was recorded u s i n g a Grass polygraph D.C. d r i v e r a m p l i f i e r , model 7DAB and a Grass p r e a m p l i f i e r , model 7P4 A, and Beckman one centimeter s i l v e r s i l v e r - c h l o r i d e e l e c t r o d e s . Blood p r e s s u r e was measured w i t h an Accoson sphygmomanometer and b l o o d p r e s s u r e c u f f , and a Dittman stethoscope. C i g a r e t t e b u t t s were weighed on a Canlab S a r t o r i u s model 2603 a n a l y t i c balance. Other equipment i n c l u d e d a W i t t n e r Super M i n i T a k t e l l metronome, a s c a l e f o r measuring s u b j e c t s ' body weight, and two stopwatches. Procedure The study was conducted i n two classrooms, one designated 27 the e x e r c i s e l a b o r a t o r y and the other a w a i t i n g room, i n the Chemical E n g i n e e r i n g B u i l d i n g a t The U n i v e r s i t y of B r i t i s h Columbia. Each s u b j e c t p a r t i c i p a t e d i n f o u r s e s s i o n s , three e xperimental s e s s i o n s and a d e b r i e f i n g s e s s i o n , on f o u r con-s e c u t i v e days at the same time each day. E x e r c i s e m o n i t o r i n g and f i t n e s s t e s t i n g were performed by an experimenter t r a i n e d i n cardio-pulmonary r e s u s c i t a t i o n . As a s a f e t y p r e c a u t i o n an a s s i s t a n t was present a t a l l s e s s i o n s . During i n i t i a l telephone c o n t a c t , the experimenter e x p l a i n e d the study to i n t e r e s t e d p o t e n t i a l s u b j e c t s and screened them to ensure they f i t the s p e c i f i e d c r i t e r i a . At the f i r s t s e s s i o n s u b j e c t s were r e q u i r e d to s i g n a consent form which s t a t e d t h a t the purpose of the study was to examine the p h y s i o l o g i c a l e f f e c t s of three d i f f e r e n t i n t e n s i t i e s of e x e r c i s e on c i g a r e t t e smokers. I t i n c l u d e d i n f o r m a t i o n on the procedure of the study, i . e . , e x e r c i s e s e s s i o n s and s e l f -m o n i t o r i n g of c i g a r e t t e i n t a k e . M i s i n f o r m i n g s u b j e c t s of the purpose of the study was intended to minimize demand charac-t e r i s t i c s and e x p e c t a n c i e s of change i n smoking behavior. P r i o r to p a r t i c i p a t i o n i n the study s u b j e c t s a l s o com-p l e t e d the PAR-Q and a q u e s t i o n n a i r e about t h e i r smoking and e x e r c i s e h i s t o r i e s . Questions assessed pa s t and c u r r e n t attempts at r e d u c i n g or q u i t t i n g smoking and the p r e s e n t r a t e of smoking as w e l l as the frequency and i n t e n s i t y of e x e r c i s e i n which the s u b j e c t s had p r e v i o u s l y engaged and i n which they were p r e s e n t l y engaged. 28 Subjects were asked to a b s t a i n from smoking f o r one-h a l f hour, from e a t i n g , and from d r i n k i n g beverages c o n t a i n -i n g c a f f e i n e and a l c o h o l f o r two hours b e f o r e each s e s s i o n , as these would a f f e c t t h e i r h e a r t r a t e . Subjects were asked i f they had a b s t a i n e d from these upon t h e i r a r r i v a l a t the l a b o r a t o r y , and those not having done so were to have been resche d u l e d . Subjects p r o v i d e d u r i n e samples b e f o r e and a t 15 and 64 minutes f o l l o w i n g e x e r c i s e and a t e q u i v a l e n t i n t e r v a l s i n the n o - e x e r c i s e c o n d i t i o n . These were c o l l e c t e d i n sampling c o n t a i n e r s and analyzed w i t h i n f o u r hours on a D i g i t a l I o n a l y z e r pH meter. Sampling c o n t a i n e r s were reused a f t e r b e i n g washed and r i n s e d with d i s t i l l e d water. The design of the study c o n s i s t e d of a repeated measures de s i g n i n which each s u b j e c t p a r t i c i p a t e d i n three s e s s i o n s , each one a t a d i f f e r e n t e x e r c i s e i n t e n s i t y . P r i o r to each s e s s i o n measures of body weight and b l o o d p r e s s u r e were taken. During two of the f i r s t t h r e e s e s s i o n s of t h e study each s u b j e c t was r e q u i r e d to e x e r c i s e f o r 10 minutes on a s t a t i o n a r y b i c y c l e a t one of two d i f f e r e n t i n t e n s i t i e s , one r e s u l t i n g i n a h e a r t r a t e of 130-135 bpm (66% t o 69% of maximal h e a r t rate) and the other a h e a r t r a t e of 160-165 bpm (82% to 85% of maximal h e a r t r a t e ) . S u b j e c t s ' h e a r t r a t e s were monitored v i a a Grass Polygraph ECG machine. A metro-nome was s e t a t 100 beats per minute, pacing s u b j e c t s ' p e d a l -i n g a t 50 rpms. Subjects s t a r t e d p e d a l i n g and w i t h i n 5 29 s e c o n d s a w o r k - l o a d o f two o r t h r e e k i l o p o n d s f o r a l o w o r h i g h i n t e n s i t y w o r k o u t , r e s p e c t i v e l y , was a d d e d . A f t e r 55 s e c o n d s t o one m i n u t e a r e c o r d i n g was made o f t h e h e a r t r a t e and i f n e c e s s a r y , t h e w o r k - l o a d was i n c r e a s e d u n t i l t h e t a r g e t h e a r t r a t e was a c h i e v e d . A f t e r t e n m i n u t e s o f e x e r c i s e , t h e w o r k l o a d was r e d u c e d t o n e a r z e r o r e s i s t a n c e a n d s u b j e c t s c o n t i n u e d t o p e d a l f o r an a d d i t i o n a l t w o - m i n u t e r e c o v e r y p e r i o d . I m m e d i a t e l y a f t e r w a r d a n d a t 3 0 - s e c o n d i n t e r v a l s t h e r e a f t e r s u b j e c t s r a t e d t h e i r r e s p i r a t i o n r a t e s on a s e v e n p o i n t s c a l e u n t i l t h e y i n d i c a t e d t h a t t h e y w e r e b r e a t h i n g n o r m a l l y . B l o o d p r e s s u r e was t a k e n 3 1/2 m i n u t e s f o l l o w i n g e x e r c i s e . M a x i m a l o x y g e n u p t a k e (MV02) was p r e d i c t e d f o r e a c h s u b j e c t on t h e b a s i s o f h i s h e a r t r a t e a n d t h e c o r r e s p o n d i n g w o r k - l o a d d u r i n g t h e f o u r t h t o s i x t h m i n u t e o f l o w e x e r c i s e i n t e n s i t y a n d t h e s u b j e c t ' s w e i g h t u s i n g a nomograph ( A s t r a n d . and R o d a h l , 1970) . I n t h e n o - e x e r c i s e c o n d i t i o n s u b j e c t s ' h e a r t r a t e s w e r e m o n i t o r e d f o r 10 m i n u t e s w h i l e t h e y r e m a i n e d s e a t e d i n a c h a i r . A l l o t h e r p r o c e d u r e s w e r e t h e same a s t h o s e o f t h e e x e r c i s e c o n d i t i o n s , w i t h t h e e x c e p t i o n o f t h e s e l f - r a t i n g o f r e s p i r a t i o n r a t e w h i c h was d e l e t e d i n t h i s c o n d i t i o n f o r t h e l a s t e i g h t s u b j e c t s , a s t h e f i r s t t e n v o l u n t e e r s h a d c o n s i s -t e n t l y r a t e d t h e i r b r e a t h i n g as b e i n g ' c o m p l e t e l y n o r m a l ' f o l l o w i n g h e a r t r a t e m o n i t o r i n g . When h e a r t r a t e m o n i t o r i n g was c o m p l e t e d a n d b l o o d 30 p r e s s u r e measurements were repeated, s u b j e c t s were ushered i n t o the w a i t i n g room where they remained f o r one hour. They were ad v i s e d t h a t smoking was pe r m i t t e d d u r i n g t h i s p e r i o d . To s t a n d a r d i z e a c t i v i t y d u r i n g the w a i t i n g p e r i o d , r e a d i n g m a t e r i a l , i n c l u d i n g a d a i l y newspaper, Time, Macleans, and People was p r o v i d e d . Subjects were a l s o asked t o remain i n t h e i r gym c l o t h i n g u n t i l the l a s t u r i n e sample of each s e s s i o n was ob t a i n e d . They were p r o v i d e d w i t h a schedule so t h a t they would know i n advance of a l l s e s s i o n s e x a c t l y when they would be asked t o g i v e u r i n e samples. In order to s t a n d a r d i z e c i g a r e t t e smoking i n t h e w a i t i n g room, i f a s u b j e c t was smoking when i t was time to p r o v i d e a u r i n e specimen, e i t h e r at 15 or 64 minutes f o l l o w i n g e x e r c i s e , the observer was i n s t r u c t e d to wait u n t i l the s u b j e c t had f i n i s h e d h i s c i g a r e t t e b e f o r e ask-i n g him to p r o v i d e a u r i n e sample. The number and weight of c i g a r e t t e s were p r o r a t e d i f the s u b j e c t extended h i s time i n the w a i t i n g room beyond 6 4 minutes. Subjects were u n o b t r u s i v e l y observed by a male a s s i s t a n t whose presence i n the w a i t i n g room was o s t e n s i b l y f o r the purpose of prompting the s u b j e c t s a t times when u r i n e s p e c i -mens were to be c o l l e c t e d . In order t o s t a n d a r d i z e and m i n i -mize any i n t e r a c t i o n between the s u b j e c t and the observer, s u b j e c t s were b r i e f l y i n t r o d u c e d by f i r s t name and were t o l d t h a t the observer would be working i n the w a i t i n g room. The observer was a l s o i n s t r u c t e d to be r e a d i n g o r w r i t i n g , t o look up f o r a moment and to say " H i " when i n t r o d u c e d . In 31 a d d i t i o n , he was coached on p o l i t e l y t e r m i n a t i n g any conver-s a t i o n i n i t i a t e d by the s u b j e c t w i t h , "I would l i k e t o chat with you now, but I've got to get t h i s f i n i s h e d f o r my next c l a s s " . The observer d i d not smoke, but had on h i s desk i n c l e a r view of the s u b j e c t a package of c i g a r e t t e s , matches and an empty a s h t r a y . Measurement of smoking l a t e n c y began f o u r minutes a f t e r the s u b j e c t dismounted from the b i c y c l e ergometer when he en-t e r e d the w a i t i n g room. At t h a t time the observer a c t i v a t e d a stopwatch and when the s u b j e c t took h i s f i r s t i n h a l a t i o n while l i g h t i n g h i s f i r s t c i g a r e t t e , the observer recorded the time. The observer a l s o recorded the number of p u f f s taken from the f i r s t c i g a r e t t e (a p u f f d e f i n e d as an i n s t a n c e where the c i g a r e t t e i s i n c o n t a c t w i t h a smoker's l i p s and f l a r i n g ) and the time a t which i t was e x t i n g u i s h e d (defined as the time when the c i g a r e t t e came i n t o i n i t i a l c o n t a c t w i t h the a s h t r a y w h i l e being e x t i n g u i s h e d ) . As an a d d i t i o n a l measure of smoking r a t e , one hour a f t e r e x e r c i s e , c i g a r e t t e b u t t s d i s c a r d e d i n an a s h t r a y a f t e r the s u b j e c t s ' stay i n the w a i t i n g room were counted. Furthermore, the weight of c i g a r e t t e smoked i n the w a i t i n g room was c a l c u -l a t e d . T h i s was done by deducting the combined weight i n grams (to f o u r decimal p l a c e s ) of the a s h t r a y and i t s con-t e n t s a f t e r the s e s s i o n from the combined weight of the ash-t r a y and as many unused c i g a r e t t e s of the s u b j e c t ' s brand smoked d u r i n g the w a i t i n g p e r i o d . 32 A p i t c h e r of water and g l a s s e s were a v a i l a b l e f o r sub-j e c t s i n the w a i t i n g room to e l i m i n a t e the p o s s i b i l i t y t h a t they would decrease t h e i r smoking i n response to d e h y d r a t i o n induced by e x e r c i s e . Records were kept of the amount of water drunk a t each s e s s i o n f o r each s u b j e c t . The amount of water consumed was taken as the d i f f e r e n c e i n m i l l i l i t e r s between the water p i t c h e r contents a t the b e g i n n i n g and a t the end of the s e s s i o n , with any water remaining i n the sub-j e c t ' s g l a s s r e t u r n e d to the p i t c h e r b e f o r e the f i n a l measure-ment was made. Subjects monitored t h e i r d a i l y c i g a r e t t e consumption u s i n g s m a l l t a l l y cards and a p e n c i l which f i t c o n v e n i e n t l y i n t o t h e i r c i g a r e t t e packages. The t a l l y cards were d i v i d e d i n t o s e c t i o n s corresponding to an h o u r l y sequence beg i n n i n g w i t h the o b s e r v a t i o n p e r i o d . Subjects were asked to p l a c e a t a l l y mark i n the a p p r o p r i a t e time segment each time they had a c i g a r e t t e to permit a c a l c u l a t i o n of d a i l y smoking r a t e . S u b j e c t s were a l s o asked to r e c o r d to the n e a r e s t hour the time a t which they r e t i r e d and awoke each day. The r a t i o n a l e p r o v i d e d f o r t h i s was t h a t i t was necessary to know how long they s l e p t i n order to e v a l u a t e a c c u r a t e l y t h e i r e x e r c i s e per-formance. Subje c t s handed i n a t a l l y c a r d a t the beginning of each experimental s e s s i o n and were p r o v i d e d w i t h a new c a r d f o r the f o l l o w i n g day. During the .fourth s e s s i o n s u b j e c t s handed i n t h e i r l a s t t a l l y c a r d and completed a post-study q u e s t i o n n a i r e which 33 assessed t h e i r b e l i e f s and e x p e c t a t i o n s r e g a r d i n g the study. The q u e s t i o n n a i r e asked f o r t h e i r p e r c e p t i o n s of the .purpose of the study i n order to assess the c r e d i b i l i t y of the r a t i o n a l e p r o v i d e d d u r i n g i n i t i a l c o n t a c t . In a d d i t i o n , s u b j e c t s were questioned as to whether they b e l i e v e d exer-c i s e would a f f e c t t h e i r smoking behavior. S u b j e c t s were de-b r i e f e d as to the a c t u a l purpose of the study, and were gi v e n time to ask q u e s t i o n s . They were p a i d $25 and were o f f e r e d i n f o r m a t i o n r e g a r d i n g t h e i r p h y s i c a l f i t n e s s (aerobic c a p a c i t y ) which was d e r i v e d from t h e i r e x e r c i s e performance. Dependent V a r i a b l e s Smoking behavior was assessed u s i n g measures of smoking r a t e and d i r e c t and i n d i r e c t measures of smoking topography f o r each s u b j e c t . Smoking r a t e was determined by s u b j e c t s ' s e l f - m o n i t o r i n g of c i g a r e t t e s consumed f o r one hour and 23 hours p o s t - e x e r c i s e , and by a count of c i g a r e t t e b u t t s d i s -carded i n an a s h t r a y d u r i n g t h e i r s tay i n the w a i t i n g room. Top o g r a p h i c a l measures of smoking i n c l u d e d l a t e n c y to smoke and p u f f frequency f o r the f i r s t c i g a r e t t e consumed f o l l o w i n g e x e r c i s e , and weight of c i g a r e t t e ( s ) smoked one hour p o s t - e x e r c i s e . In a d d i t i o n , c i g a r e t t e d u r a t i o n was c a l -c u l a t e d by s u b t r a c t i n g e x t i n c t i o n time from the time the c i g a r e t t e was l i t , f o r the f i r s t c i g a r e t t e f o l l o w i n g e x e r c i s e . 34 RESULTS Eighte e n v o l u n t e e r s p a r t i c i p a t e d i n the e n t i r e study. One a d d i t i o n a l s u b j e c t dropped out a f t e r the f i r s t s e s s i o n , and h i s data are not i n c l u d e d i n the a n a l y s e s . Post study q u e s t i o n n a i r e s a d m i n i s t e r e d to s u b j e c t s d u r i n g the d e b r i e f i n g s e s s i o n r e v e a l e d t h a t they were unaware of the a c t u a l purpose of the study. Furthermore, s u b j e c t s d i d not r e a l i z e t h a t t h e i r c i g a r e t t e or water consumption was being monitored i n the w a i t i n g room. Sub j e c t s ' r e p o r t s of weekly p h y s i c a l a c t i v i t y on a s c r e e n i n g q u e s t i o n n a i r e were analyzed and i t was found t h a t s u b j e c t s accumulated a weekly average of 19.2 a e r o b i c p o i n t s (range = 5 to 30), which, a c c o r d i n g to Cooper (1977) i s i n -s u f f i c i e n t f o r m a i n t a i n i n g one's a e r o b i c f i t n e s s l e v e l . Con-s i s t e n t w i t h these s e l f - r e p o r t data, maximal oxygen uptake (MV02) l e v e l s , p r e d i c t e d f o r each s u b j e c t on the b a s i s of e x e r c i s e performance d u r i n g l o w - i n t e n s i t y e x e r c i s e , ranged from 36 to 55 ml/kg/min (mean of 45.3 ml/kg/min), p l a c i n g most v o l u n t e e r s i n the low-average range f o r a e r o b i c f i t n e s s . Data Analyses H a r t l e y F-max t e s t s conducted on a l l the data b e f o r e analyses of v a r i a n c e (ANOVAs) were conducted i n d i c a t e d t h a t 35 i n every case the v a r i a n c e s across the c o n d i t i o n s were homo-geneous. For measures of u r i n a r y pH, the v a r i a n c e s were homogeneous across both c o n d i t i o n s and time p e r i o d s i n which the samples were taken. M a n i p u l a t i o n Checks Measures of u r i n a r y pH, taken be f o r e and a t 15 and 64 minutes f o l l o w i n g e x e r c i s e , averaged 6.28 (SD = .81), 5.94 (SD = .80) and 6.34 (SD = .80) f o r the h i g h - i n t e n s i t y exer-c i s e c o n d i t i o n , 6.23 (SD = .70), 5.98 (SD = .84) and 6.60 (SD = .80) f o r the l o w - i n t e n s i t y e x e r c i s e c o n d i t i o n , and 5.95 (SD = .81), 5.94 (SD = .88) and 6.20 (SD = .87) f o r the no - e x e r c i s e c o n d i t i o n , r e s p e c t i v e l y . A two-way ( c o n d i t i o n X time i n which the u r i n e sample was obtained) repeated measures ANOVA was c a l c u l a t e d on measures of u r i n a r y pH, and the r e s u l t s are t a b u l a t e d i n Table 1. There was a s i g -n i f i c a n t main e f f e c t f o r time (F(2,34) = 17.15, p < .01) and a s i g n i f i c a n t e f f e c t f o r samples ob t a i n e d 15 minutes f o l l o w -i n g e x e r c i s e versus those obtained 6 4 minutes f o l l o w i n g exer-c i s e (F(l,17) = 59.04, p < .01). A s i g n i f i c a n t i n t e r a c t i o n e f f e c t was found f o r c o n d i t i o n by time i n which the u r i n e sample was obt a i n e d (F(4,68) = 2.87, p < .05) wit h a s i g n i f i c a n t e f f e c t i n the i n t e r a c t i o n between the n o - e x e r c i s e c o n d i t i o n versus e x e r c i s e c o n d i t i o n s and both o v e r a l l time as w e l l as 15 minutes versus 64 minutes f o l l o w i n g e x e r c i s e ( i . e . , C 3 - C±C2 X T, F(2,34) = 4.14, p < .05; C 3 ~ C 1 C 2 X T 2 " T 3 ' ^(1,17) = 4.63, p < .05). A Table 1 Summary ANOVA Table f o r U r i n a r y pH Measures e r r o r term SS df MS c C x S C 3 " " C 1 C 2 ( C 3 — C.^) x S C l * ' C 2 < C 1 — C 2) x S T T x S T l • - T T 2 3 < Ti T 2 T 3 ) x S T 2 • " T 3 ( T 2 — T 3) x S C x T C x T x S ( c 3 - C 1 C 2 ) X (T x - T 2 T 3 ) ( C 3 - C 1 C 2 ) x ( T 1 ( C 3 - C 1 C 2 ) X (T 2 - T 3) < C 3 — C l C 2 ) x ( T 2 ( C 1 " C 2 ) X ( T 1 - T T ) 2 3 ' ( C 1 — C 2 ) x ( T l -( C 1 " C 2 ) x ( T 2 3 ; ( C 1 — C ^ x ^ -(c 3 - C 1 C 2 ) X T