Exercise and stress responses: The influence of time of stressor administration and the autonomic nervous system.

摘要

Despite the anecdotal claims that exercise is effective in alleviating stress, the scientific community has been much more reluctant to make such claims due to issues regarding the nature of the relationship between exercise and stress, including the time course of stress-induced cardiovascular changes following exercise as well as plausible mechanisms underlying the effects. In light of these considerations, the purpose of this study was to assess the time course of cardiovascular reactivity and recovery from mental arithmetic following acute aerobic exercise. A related purpose was to examine the role of the autonomic nervous system (ANS), using low and high frequency components of HR C variability, as a contributing mechanism underlying cardiovascular responses to stress following acute exercise. The effects of 30 min of high- and low-intensity (i.e., 75--80% & 50--55% VO2 max, respectively) aerobic exercise were compared to the effects of a 30 min sedentary control condition. As predicted, both low- and high-intensity exercise resulted in significantly reduced stress reactivity and recovery following exercise. Furthermore, high-intensity exercise was more effective at reducing cardiovascular reactivity and recovery at 5, 30, and 60 min post-exercise. The results indicate that attenuated stress responses following acute exercise depend both on exercise intensity and time of exposure to psychological stress. The results also demonstrated greater cardiac vagal tone following exercise that persisted during exposure to the laboratory stressor suggesting that the ANS is a viable mechanism underlying exercise-induced reductions in cardiovascular responses to stress.