Do power naps save sleepiness and improve performance in ultra marathons? 💤
Is the snooze worth the squeeze?
Do power naps save sleepiness? Cognitive benefits of brief sleep during a 100 miles ultramarathon
Study Details
This new study followed 52 finishers across the 2022–2024 Ultra-Trail du Mont-Blanc, a 170 km race with ~10,000 m of elevation gain 🏔️
To establish the effects of short naps on sleepiness, cognition and race performance 🔍
Here is what they found ⬇️
Key Findings
⏱️ Runners completed the race in an average of 41 hours 50 minutes
😴 Nearly 79% of the runners recorded at least one period of sleep during the race
🛌 Total sleep averaged only 28.4 minutes across the entire event
💤 Runners were offered 20-minute nap opportunities at three checkpoints and independently decided whether to sleep or remain awake
🥱 The decision to nap was primarily driven by greater perceived sleepiness rather than objectively slower reaction times
🔄 This suggests runners generally used naps reactively once they felt very sleepy, rather than proactively before cognitive performance declined
📉 A 20-minute nap produced an immediate reduction in perceived sleepiness within 1 km of leaving the checkpoint
🧠 Objective cognitive improvements developed more gradually and were not immediately apparent after waking
⚡ Runners who napped at the third checkpoint had reaction times ~ 53 ms faster at the following checkpoint than those who remained awake
⚠️ Feeling more alert immediately after a nap did not necessarily mean cognitive function had fully recovered
🕒 Sleepiness was greatest at ~03:18, highlighting the strong influence of the overnight circadian low
📈 Perceived sleepiness increased progressively with every additional hour spent racing
🐢 Reaction time also became ~1.3 ms slower for every additional hour of racing
🌙 Circadian patterns remained evident despite more than 40 hours of exertion and sleep deprivation
✅ Brief naps appeared to provide partial protection against the decline in attention and vigilance late in the race
🏁 Napping did not meaningfully compromise finishing time, with nappers finishing in 42:04 compared with 41:33 for non-nappers
Conclusion
Preserving vigilance may be particularly important for reducing late-race risks such as falls, poor coordination and navigation errors ‼️
20-min naps may be long enough to obtain cognitive benefits while limiting the sleep inertia associated with deeper sleep ✅
Brief, strategically timed naps appear to be a useful late-race safety and fatigue-management strategy during multi-day ultramarathons 💤
Naps are essentially a risk management strategy in ultra endurance events.
Reference
https://pubmed.ncbi.nlm.nih.gov/42497815/
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