Exercise and Psychological Stress: How Does Exercise Promote the Alleviation of Stress?

Abstract

Stress is an inevitable aspect of life, so how does one handle it on a daily basis? Exercise is an excellent coping mechanism for many. But how does exercise reduce stress? Previous research indicates a difference in cortisol levels, reactivity to, and recovery from stress (Jackson & Dishman, 2006).The purpose of this study was to examine cortisol levels between high and low fit groups as well as differences in reactivity to and recovery from stress. First, a fitness questionnaire was given to participants to assess total number of hours per week of exercise. Saliva samples were used to analyze cortisol levels and were obtained using a Salivette collection device. A saliva sample was first taken to establish baseline cortisol levels. Then, the participant completed a series of tasks in the following order: public speaking, mental arithmetic, and a cold pressor task followed by another saliva sample. Lastly, saliva samples were taken following a recovery period. An immunosorbent assay kit was used to measure cortisol levels in the saliva (IBL America, Minneapolis, MN). Following cortisol analysis, the fitness questionnaire was evaluated. Participants were divided into two groups based on a five hour per week median. Five or less hours was considered low fit (N=21) and more than five hours was considered high fit (N=24). A 2x7 ANOVA was used to analyze the differences in cortisol levels, reactivity, and recovery between high and low fit. A significant difference was found in cortisol levels between high and low fit participants (F4.1, 174=2.595, p= 0.036). High fit participants were also found to have greater reactivity to a stressor (F1, 42=3.780, p=0.059) as well as faster recovery from a stressor (F1, 42=7.656, p=0.008). These results imply that high fit individuals have lower overall cortisol levels and greater reactivity to and recovery from a stressor.