Physical activity plays a key role in the control of neuroendocrine, autonomic, and behavioral responses to physical and psychosocial stress. However, little is known about how the level of physical activity modulates stress responsiveness. Here, we test whether different levels of physical activity are associated with different adrenal, cardiovascular, and psychological responses to psychosocial stress. In addition, competitiveness is assessed as a personality trait that possibly modulates the relationship between physical activity and stress reactivity. Eighteen elite sportsmen, 50 amateur sportsmen, and 24 untrained men were exposed to a standardized psychosocial laboratory stressor (Trier Social Stress Test). Repeated measures of salivary free cortisol, heart rate, and psychological responses to psychosocial stress were compared among the 3 study groups. Elite sportsmen exhibited significantly lower cortisol, heart rate, and state anxiety responses compared with untrained subjects. Amateur sportsmen showed a dissociation between sympathetic and hypothalamic-pituitary-adrenal responsiveness to stress, with significantly reduced heart rate responses but no difference in cortisol responses compared with untrained men. Different levels of competitiveness among groups did not mediate stress reactivity. Our results are in line with previous studies indicating reduced reactivity of the autonomic nervous system to psychosocial stress in trained individuals. More importantly, these findings imply a differential effect of the level of physical activity on different stress-related neurophysiological systems in response to psychosocial stress.

Physical activity has proven benefits for physical and psychological well-being and is associated with reduced responsiveness to physical stress. However, it is not clear to what extent physical activity also modulates the responsiveness to psychosocial stress. The purpose of this study was to evaluate whether the reduced responsiveness to physical stressors that has been observed in trained men can be generalized to the modulation of physiological and psychological responses to a psychosocial stressor. Twenty-two trained men (elite sportsmen) and 22 healthy untrained men were exposed to a standardized psychosocial laboratory stressor (Trier Social Stress Test). Adrenocortical (salivary free cortisol levels), autonomic (heart rate), and psychological responses (mood, calmness, anxiety) were repeatedly measured before and after stress exposure. In response to the stressor, cortisol levels and heart rate were significantly increased in both groups, without any baseline differences between groups. However, trained men exhibited significantly lower cortisol and heart rate responses to the stressor compared with untrained men. In addition, trained men showed significantly higher calmness and better mood, and a trend toward lower state anxiety during the stress protocol. On the whole, elite sportsmen showed reduced reactivity to the psychosocial stressor, characterized by lower adrenocortical, autonomic, and psychological stress responses. These results suggest that physical activity may provide a protective effect against stress-related disorders.