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Measuring Neural Mechanisms Underlying Sleep-Dependent Memory Consolidation During Naps in Early Childhood
Published on: October 2, 2019
Do power naps save sleepiness? Cognitive benefits of brief sleep during a 100 miles ultramarathon
Valentin Bourlois1, Antoine Boulagnon2, Charlotte Elsworth-Edelsten1
1Univ. Littoral Côte d'Opale, Univ. Artois, Univ. Lille, ULR 7369 - URePSSS - Unité de Recherche Pluridisciplinaire Sport Santé Société, Dunkerque, F-59140, France.
Objectives:
This study aimed to investigate the effects of short naps on perceived sleepiness and cognitive vigilance during extreme sleep deprivation in ultra-endurance racing. It tested whether baseline cognitive performance predicts nap decisions and if 20-min naps enhance objective cognitive function while reducing subjective sleepiness.
Design:
An observational field study was conducted during the 2022, 2023, and 2024 editions of the Ultra-Trail du Mont-Blanc® (170 km; ∼10 000 m elevation gain).
Methods:
Sleep was recorded via wrist accelerometery for 52 completing runners (43.9 ± 8.3 years). Subjective sleepiness (Karolinska Sleepiness Scale, KSS) and reaction time (Psychomotor Vigilance Test, PVT) were assessed at five checkpoints (CP0-CP4). At CP1-CP3, participants chose between a 20-min sleep opportunity (nap group, NG) or remaining awake (awake group, AG). Measurements occurred at checkpoint entry (ENT) and 1 km post-checkpoint.
Results:
Finishers slept an average of 28.4 ± 21.9 min. Linear mixed-effects models confirmed robust circadian modulation of both sleepiness and reaction times. Nap decisions were primarily driven by subjective sleepiness rather than objective vigilance deficits. While 20-min naps produced immediate reductions in KSS 1 km post-checkpoint, cognitive benefits (PVT) manifested more gradually, with significantly faster reaction times observed only at subsequent checkpoints.
Conclusions:
Brief naps serve as an effective reactive strategy to reduce perceived drowsiness and provide partial protection against late-race performance decline without compromising overall race completion times.
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