Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of randomized controlled trials
PubMed 36690376 · doi:10.1136/bjsports-2022-106355
What was done
Authors searched six databases (PubMed, Scopus, Web of Science, Cochrane Central, SportDiscus, PsycINFO) through December 2, 2022, for randomized controlled trials evaluating the effects of daytime napping on sport performance and fatigue. Analyses were conducted for outcomes following normal sleep and partial sleep deprivation. Standardized mean differences (SMD) and 95% compatibility intervals (CI) were calculated using DerSimonian-Laird random-effects models.
What was found
Twenty-two trials comprising 291 male participants (164 trained athletes, 127 physically active adults; aged 18-35 years) were analyzed. After normal sleep, napping between 12:30 and 16:50 improved cognitive performance (SMD = 0.69, 95% CI: 0.37 to 1.00; I² = 71.5%) and physical performance (SMD = 0.99, 95% CI: 0.67 to 1.31; I² = 89.1%) and reduced fatigue perception (SMD = -0.76, 95% CI: -1.24 to -0.28; I² = 89.5%). Benefits were also confirmed after partial sleep deprivation. Optimal benefits occurred with nap durations between 30 and <60 min and when awakening-to-testing intervals exceeded 1 hour.
Why it matters
This review establishes that moderate-duration afternoon naps reliably enhance physical and cognitive performance in active young males, even when night sleep was not restricted.
Limits
All 291 participants across the 22 trials were male and aged 18-35 years, precluding direct generalizability to female athletes or other age groups. Individual trial sample sizes were very small, and statistical heterogeneity across all pooled analyses was high (I² between 71.5% and 89.5%).
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- partial In sleep-deprived individuals, a daytime nap significantly improves metabolism and muscle strength.