REF-608 · Lastella, Halson, Vitale, Memon & Vincent, 2021 · Nature and Science of Sleep, · Paper · PubMed
Daytime napping in athletes — systematic review of 37 studies: naps may benefit physical and cognitive performance, perception, psychological state and night sleep; 20-90 min between 13:00 and 16:00, with 30 min to clear sleep inertia before training
Key Findings
37 studies (observational and experimental, able-bodied athletes, searched to 11 August 2020), of moderate quality on the Downs and Black checklist; most did not report nap frequency, duration and timing consistently.
Napping may be beneficial for physical and cognitive performance, perceptual measures (fatigue, muscle soreness, sleepiness, alertness), psychological state and night-time sleep.
Naps let athletes supplement night-time sleep without compromising night sleep quality.
Authors' recommendation: nap 20 to 90 min, between 13:00 and 16:00, and allow 30 min after waking to reduce sleep inertia before training or competition.
Not from the abstract: that the benefit is largest after a short night — the abstract does not stratify by prior sleep (plausible, and stated in individual studies, but not this review's finding).
Practical Application
Systematic review of 37 moderate-quality studies in athletes: naps may improve physical and cognitive performance, perceived fatigue and soreness, mood and even night-time sleep, and the authors recommend a nap of 20-90 min between 13:00 and 16:00 with 30 min awake before training or competition to shed sleep inertia — so an early-afternoon nap is a legitimate recovery tool on double days or after early sessions; keep it shorter (~20-30 min) when a session follows soon, since the longer the nap the more inertia to clear.
Use the long end (~60-90 min) only with a free afternoon or a long gap before the next session.
Keep naps before ~16:00 to protect night sleep — the review found naps did not compromise night sleep quality when placed in that window; a short nap also bridges a fatigued arrival afternoon after travel (avoid long naps entrenching the wrong time zone — house advice, not from this review).
Limitations
SR without meta-analysis of 37 mostly small, heterogeneous studies of moderate quality; most did not report nap frequency, duration or timing consistently.
The abstract says naps "may be beneficial" — the direction is consistent but the effect sizes are not pooled.
Whether benefit depends on prior night sleep is not reported in the abstract.
How this entry was checked and changed
Content correction 2026-09-27
First bullet "20-30 min nap" -> the review's recommendation 20-90 min, 13:00-16:00, 30 min to reduce sleep inertia before training; shorter naps for less inertia kept as the practical reading.
"Especially when night sleep is short / clearest benefit when prior sleep inadequate" -> not in the abstract; marked as not from this review.
Type clarified as systematic review without meta-analysis (37 studies, moderate quality).
Full text (checked 2026-10-12)
The 37 studies (published 2009 to 2020) included 3489 participants with a mean age of 23±4 years; 18 studies were males only, 3 females only, 13 mixed and 3 did not report sex, across 11 sports (full text).
The review states that the physical performance benefits of napping are greater in sleep restricted athletes compared to well-rested athletes, and that the physical, cognitive and mood state benefits were greater in sleep restricted athletes (full text).
In sleep-restricted athletes (3.0–4.5 h), naps of 20 to 90 min consistently improved physical performance, and in two studies the 90 min nap had greater effects on sprint-test performance than the 20 min nap (full text).
In one treadmill study, the 90 min afternoon nap had a greater influence on time to exhaustion when runners slept less than 7 h the previous night (full text).
Nap durations were similar on training (43±28 min) and competition (44±24 min) days and much shorter on rest days (6±10 min) (full text).
Only two studies examined night-time sleep: a 20 min nap between 13:00 and 14:00 h increased sleep onset latency from 13±6 min to 24±12 min without altering other sleep variables, and the authors conclude that daytime naps of up to 45 min may increase the time taken to fall asleep at night (full text).
Sleepiness rose immediately after a 20 min nap and returned to baseline after 90 min; the authors note sleep inertia usually takes 15–30 min to dissipate and that no countermeasure reliably clears it within the first 15 min (full text).
Only two studies reported a negative effect on physical performance: slower 20 m sprint times after a nap in well-rested youth athletes, and slower finish times when napping during a ~24 hour ultra-cycling race (full text).