20-minute naps reduce subjective sleepiness and improve cognitive vigilance during extreme sleep deprivation in ultramarathon runners
In an observational field study of 52 finishers of the Ultra-Trail du Mont-Blanc (170 km, ~10,000 m elevation gain), 20-minute naps produced immediate reductions in subjective sleepiness (Karolinska Sleepiness Scale) 1 km post-checkpoint, while cognitive benefits (Psychomotor Vigilance Test reaction times) appeared more gradually, with significantly faster reaction times at subsequent checkpoints. Naps served as an effective reactive strategy to reduce perceived drowsiness and partially protect against late-race performance decline without compromising overall race completion times.
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20-minute naps reduce subjective sleepiness and improve cognitive vigilance during extreme sleep deprivation in ultramarathon runners The current body of evidence comprises 1 study. EvidenceHub rates the overall confidence at 32/100 (low).
The Claim
20-minute naps reduce subjective sleepiness and improve cognitive vigilance during extreme sleep deprivation in ultramarathon runners
This conclusion is most relevant to: 52 completing runners (mean age 43.9 ± 8.3 years) in the 2022, 2023, and 2024 Ultra-Trail du Mont-Blanc.
What the Research Shows
The conclusion draws on 1 linked study. Highlights from the cited literature:
- ▸Do power naps save sleepiness? Cognitive benefits of brief sleep during a 100 miles ultramarathon. (Sleep medicine, 2026) — In an observational field study of 52 finishers of the Ultra-Trail du Mont-Blanc (170 km, ~10,000 m elevation gain), 20-minute naps produced immediate reductions in subjective sleepiness (Karolinska Sleepiness Scale) 1 km post-checkpoint, while cognitive benefits (Psychomotor Vigilance Test reaction times) appeared more gradually, with significantly faster reaction times at subsequent checkpoints. Naps served as an effective reactive strategy to reduce perceived drowsiness and partially protect against late-race performance decline without compromising overall race completion times.
How It Works
The proposed biological pathway:
- ▸Nap reduces subjective sleepiness immediately post-nap (1 km checkpoint)
- ▸Cognitive vigilance improvement (faster reaction times) emerges gradually
- ▸Benefits persist to subsequent checkpoints
- ▸Result: Partial protection against late-race performance decline without affecting overall race time
Who Might Benefit
Evidence fit by population:
- ▸52 completing runners (mean age 43.9 ± 8.3 years) in the 2022, 2023, and 2024 Ultra-Trail du Mont-Blanc
Recommended Dose
20-minute nap opportunity
Limitations & Caveats
Important context when interpreting this evidence:
- ▸Observational design; participants self-selected nap or awake groups, introducing potential selection bias
- ▸Nap duration was an opportunity (20 min) rather than controlled actual sleep time; average total sleep across race was 28.4 ± 21.9 min
Frequently Asked Questions
Did the 20-minute naps improve reaction times immediately?▼
No, cognitive benefits (faster reaction times) were not immediate but manifested more gradually, observed only at subsequent checkpoints.
What drove the decision to nap?▼
Nap decisions were primarily driven by subjective sleepiness rather than objective vigilance deficits.
Did napping affect overall race completion times?▼
No, brief naps did not compromise overall race completion times.
How much sleep did runners get on average during the race?▼
Finishers slept an average of 28.4 ± 21.9 minutes total during the race.
References
- 1.Bourlois V, Boulagnon A, Elsworth-Edelsten C, Ceugniez M, Claeyssen C, Smith M, Comont L, Clergue J, Baron P, Bonduelle C, Pezé T, Hurdiel R. “Do power naps save sleepiness? Cognitive benefits of brief sleep during a 100 miles ultramarathon..” Sleep medicine, 2026. PMID: 42497815 DOI: 10.1016/j.sleep.2026.109159