Dose-response and mechanistic issues in the resistance training and affect relationship

The purpose of this study was to examine the dose-response gradient of exercise-induced affective change and the role of the stress response as a contributing mechanism. Male and female participants (N = 31) completed three different resistance training protocols (40%, 70%, and 100% of 10-repetition maximum [RM]) and a no-treatment control condition. Affective responses were assessed immediately before and at 0-5, 15, 30,45, and 60 minutes postexercise. Salivary cortisol and heart rate (HR) responses were also assessed during each condition. As predicted, moderate intensity resistance training generally produced the greatest improvements in affect (p < .05). HR and cortisol accounted for as much as 27.3% and 5.4% of the affective variance, respectively. Findings support a curvilinear dose-response relationship between intensity and affective responses, with moderate intensity training resulting in immediate, large, and enduring affective benefits. Results also suggest that moderate activation of the stress response positively influences exercise-induced affective change.