PROLONGED ENDURANCE EXERCISE AND SLEEP DISRUPTION

To determine whether exercise duration effects the recovery sleep foll owing exercise, eight fit male endurance athletes, ages 23-42 yr, had their sleep electrophysiologically studied. This was done on four sepa rate occasions: after a day on which no specific exercise was performe d; after a day of a 15-km run; after a 42.2-km run day; after a day in which the athletes participated in a strenuous ultra-triathlon. Sleep patterns following the no exercise day and the 15-km and the 42.2-km run days were similar. The sleep pattern of the ultra-triathlon day wh en compared with the other three days showed significantly increased w akefulness and delayed and decreased rapid eye movement (REM) sleep. T he duration of slow wave sleep (SWS) in the first 6 h after lights out , however, was no different. The increased wakefulness and decreased R EM clearly indicate increased stress after the ultra-triathlon. REM sl eep appears to be a more sensitive index of exercise induced stress th an SWS.