Affective responses to exercise are dependent on intensity rather than total work.

PURPOSE The purpose of the study was to compare affective responses for two bouts of cycle ergometry with differing duration and intensity, but equal total work in kilocalories. METHODS Thirty-seven participants (20 male, 17 female, mean age 23.9 yr) completed a multistage cycle ergometer protocol to determine ventilatory threshold (VT) and peak oxygen consumption (mean = 34.9 mL.kg(-1).min(-1)). Two cycling trials were prescribed: 30 min at 85% of VT (50.1% VO2 reserve) and an average of 24 min at 105% of VT (64.7% VO2 reserve). The length of the 105% of VT bout was adjusted to yield equal total work in each exercise trial. RESULTS Using repeated-measures ANOVA, heart rate and exertion were significantly higher, and affective valence was significantly less positive (P < 0.01) for the higher-intensity, shorter-duration bout, with no differences in felt arousal (P > 0.05). Additionally, affective valence became less positive during the higher-intensity bout (P < 0.01) but not the lower-intensity bout (P > 0.05). CONCLUSION These data extend previous findings by showing that the decline in ratings of pleasure during higher-intensity exercise is not dependent on differences in total caloric expenditure. Additionally, results from this study support continued promotion of prescriptions that focus on exercise intensity that does not exceed the VT.