Effects of Exhaustive Exercise on the Sleep of Men and Women

The effects of exhaustive exercise on sleep were examined in 5 women and 4 men who performed an acute bout of submaximal exercise (50–70% Vo_2max) to the point of volitional exhaustion. Significant changes were observed in the quantity and temporal distribution of slow-wave sleep (SWS) on the exercise night. The duration of SWS prior to rapid eye movement (REM) sleep onset increased markedly, along with a moderate increase in stage 4 and total SWS. REM sleep variables were affected in the early portion of the night, with an increased latency to first REM onset and a decrease in the duration of the first REM period. Initial REM cycle length (from first to second REM period onset) decreased as well. The magnitude of the SWS increase prior to REM onset was sex-related, averaging 24 min for women and 5.7 min for men. A correlation of .85 was observed between this increase and total caloric expenditure during exercise for the women. Cardiovascular measures indicated significant elevations of heart rate and cardiac output during sleep on the exercise night. Analysis of urine samples revealed a significant drop in nocturnal cortisol excretion rates after exercise. The results suggest that exhaustive exercise affects sleep primarily in the early portion of the night, inducing an increase in SWS pressure at the expense of REM sleep.