Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Phillip J. Brantley


This study examined exercise as a moderator of the stress-illness relation by exploring leisure physical activity and aerobic fitness as "buffers" of the effects stress has on physical and psychological symptoms in a sample of 135 college students. Specifically, the goal was to provide information regarding the mechanisms by which exercise exhibits its "buffering effects" against minor stress. It was questioned as to whether both increased aerobic fitness associated with exercise and actual participation in the activity itself were necessary for the apparent buffering effects exercise has on stress or is one factor more important than the other. Existing data support the utility of minor life events over major life events in predicting illness. Results of this study were consistent with previous research indicating minor life events provided significant incremental variance above that accounted for by major life events on psychological symptoms including depression and anxiety and physical symptoms report. Major life events no longer predicted physical symptoms once the minor life event variable was entered into the regression equation. Results supported the rationale for examining the moderating effects of exercise on minor life events as opposed to major life events. Findings suggested a "buffering effect" for leisure physical activity indicating that participants experiencing higher levels of minor stress and engaging in lower levels of physical activity experienced more physical symptoms and anxiety than those with higher stress and higher levels of physical activity. This association was not found with depression. Additionally, there was no apparent moderating effect for aerobic fitness on physical or psychological symptoms. Collectively, the data suggested that participating in leisure physical activity as opposed to improving aerobic fitness is the key component to the "buffering effect" of exercise. Results indicated that just as health benefits increase with increased physical activity so do the protective effects against stress. The prescription of increasing physical activity for physical health benefits also may be applied to mental health, and the implications for both are that more individuals can and should participate in regular physical activity.