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The relationship between physical activity and fitness level, and physiological and psychological stress in individuals with spinal cord injury

University of British Columbia

Introduction: Although research involving able-bodied individuals has explored the relationships between cardiorespiratory (CR) fitness, cortisol, perceived stress, and leisure time physical activity (LTPA), limited research has investigated these relationships in people with a SCI. This study examined the relationships between LTPA, CR fitness and psychological (i.e., perceived) and physiological (i.e., circulating cortisol) stress in adults with chronic SCI. It was hypothesized that LTPA and CR fitness would negatively correlate with 1) perceived stress, and 2) circulating cortisol. Methods: Nine men with chronic (>1-year post injury) traumatic SCI (M=18.4 years post-injury; 4 tetraplegia; 5 AIS-A) participated in this cross-sectional study. Participants arrived at the lab fasted (≥ 12 hours) and completed the Perceived Stress Scale and a self-report measure of LTPALTPAQ-SCI prior to performing a graded V̇O₂peak test. Blood samples were taken in the fasted state prior to the V̇O₂peak test. Cortisol concentration was assessed using a cortisol ELISA. Results: Hypothesis 1 received partial support as V̇O₂peak (i.e., CR fitness) was only trivially negatively correlated with perceived stress (r=-.076) whereas a small negative correlation was observed between total LTPA and perceived stress (r=-.187). Hypothesis 2 was supported as both V̇O₂peak (r=-.306) and total LTPA (r =-.475) demonstrated a medium-large negative correlation with levels of cortisol. Forced regression analysis indicated V̇O₂peak and LTPA together explained 23.2% of the variance in cortisol (R²adj=.232, F[2,5] = 0.755, p=.517) and 3.5% of the variance in perceived stress (R²adj=.035, F[2,5]=0.091, p=.914). Conclusions: Both LTPA and CR fitness showed a medium-large negative correlation with cortisol, suggesting that as physical activity and fitness increase, cortisol levels decrease. More variance in cortisol is explained by a combination of LTPA and fitness than by either variable alone, suggesting that a combination of physiological adaptation (i.e., fitness) and behaviour (i.e., LTPA) may play a role in cortisol secretion. Interestingly, LTPA and CR fitness explained less variance in perceived stress than cortisol, suggesting that additional factors not examined in the present study likely contribute to variations in perceived stress.

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2021-04-16

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/77812

Health and Exercise Sciences

University of British Columbia

UBCO

http://creativecommons.org/licenses/by-nc-nd/4.0/