Impact of extreme physical exercise (28 consecutive marathons) on sleep time and structure.

Objective: It is known that physical exercise influences sleep, however, the effect in extreme sporting conditions has been less studied. We analyzed the sleep quality and duration of an athlete who ran 28 consecutive marathons (one per day). Methods: We evaluated with three polysomnography recordings to explore the sleep-dependent recovery process: Post-marathons, partial recovery, and baseline. Results: The participant reported a low sleep quality during the challenge, along with short sleep time, several awakenings, and daytime sleepiness. We observed differences in sleep duration, quality, and distribution in all variables evaluated through polysomnography. From baseline to the final condition after the physical test, we observed a progressive decrease in sleep time and sleep efficiency. In addition, we observed an increase in sleep onset and REM sleep latencies, a 45.8 % increase in slow wave sleep, which affects the complete sleep structure after physical exertion. REM decreased by up to 14.4 % because of intense and continuous physical exercise, and with respect to SWS (38.5 %) this represents an increase in SWS of 267 % with respect to REM. Conclusion: sleep is affected by high-intensity physical exercise and is modulated by the recovery process. The results of this study highlight the importance of SWS in the recovery from physical fatigue due to the effect of extreme physical exercise, which is demonstrated by the enormous increase in SWS that accounts for almost 40 % of the Total Sleep Time, surpassing even the stage 2 percentage. It is also shown that REM sleep has no role in the recovery from physical fatigue, as it is in fact considerably decreased by the effect of extreme physical exercise. Previous studies had not reported results with these magnitudes.