Sleep disturbances after an ultra-trail endurance race: a field study

Endurance running has a substantial influence on sleep, while insufficient or disturbed sleep prior to exercise may impair endurance performance. However, these interactions remain poorly characterized under real-life conditions. The aim of this field study was to examine sleep patterns in athletes before and after an ultra-trail race.

Eighteen athletes (mean age 34.6 ± 8.13, 3 women) underwent an ultra-trail race at 03:30 a.m. (Ultra Marathon des Cirques, La Réunion, France, 64 km, 5000 m of elevation gain, June 2024). After completing various questionnaires to assess their sleep, all participants filled out a sleep diary and all wore an actimeter for six nights before and after the event.

The athletes reported modest subjective sleep alterations, mainly a later wake-up time and reduced sleep quality on the night following the race (p < 0.05). However, actigraphy-based sleep measurements revealed objective sleep changes, including reduced sleep efficiency (p < 0.05), longer nocturnal wake time (p < 0.05), an increased number of awakenings (p < 0.05), and wake after sleep onset (p < 0.05), lasting up to four nights after the race.

Participants reported minor sleep complaints following the ultra-trail, whereas more pronounced sleep disruptions can persist for up to four nights postrace. These disruptions are characterized by sleep fragmentation and reduced sleep efficiency. The mechanisms underlying these alterations remain to be elucidated and may involve factors such as sleep deprivation, cumulative fatigue, hypoxia, and hyperthermia.