The effect of acute exercise on the cortisol awakening response

The effects of acute exercise on the cortisol awakening response (CAR), characterized by the rapid increase in cortisol concentrations within the 30–45 min following sleep offset has yet to be fully elucidated. Thus, our study investigated the effects of late-evening acute exercise on the CAR the following morning. We hypothesized that exercise would have a significant effect on the CAR the following morning. Twelve participants (mean (SD): age = 23 (4) years; mass = 76.8 (8.7) kg; height = 175.6 (5.0) cm; V̇ O2max = 48.9 (7.5) ml.kg −1 .min −1 ) reported to the laboratory in the evening (1800 h) on two occasions and were randomly assigned to either exercise for one hour (70–75