Cortisol and affective responses to exercise

It has been reported that physically active individuals demonstrate attenuated cortisol responses to acute exercise compared to inactive individuals. Furthermore, a number of studies have demonstrated that increased cortisol levels are associated with negative affective states. Conversely, low cortisol levels have been demonstrated to be related to positive psychological constructs such as self-efficacy. However, the roles of activity history and adrenocortical activity in affective responses to acute exercise have not been examined. We therefore compared salivary cortisol, perceived exertion and affective responses to acute exercise in 13 male cross-country runners and 13 non-runners. The experimental trial consisted of a 30 min treadmill run at 60% (V)over dot O-2 max. Cortisol and affective responses were assessed before, during and after exercise; ratings of perceived exertion (RPEs) were recorded during exercise. Analyses of variance indicated no significant group differences in cortisol responses. However, there was a main effect for time (P<0.05), with cortisol increasing from baseline to the 29th minute of exercise and then decreasing to 30 min post-exercise. Non-runners possessed greater perceptions of effort and negative affect during exercise compared to cross-country runners. Furthermore, the RPEs were positively related to post-exercise cortisol levels (P<0.05), and affect and cortisol responses were inversely related 30 min post-exercise (P<0.05). These results provide partial support for the hypothesis that cortisol levels are related to exercise-induced affective states.