Research
Mixed
Following nocturnal sleep restriction, a 10-minute afternoon nap provides immediate and sustained improvements in subjective alertness and cognitive performance, whereas a 30-minute nap causes immediate performance decline due to sleep inertia.
If you are sleep-deprived, take a 10-minute nap in the afternoon. It will boost your alertness and cognitive performance immediately and keep it up for an hour. Avoid 30-minute naps if you need to function right away, as they will likely make you feel worse due to sleep inertia until you recover after ~35 minutes.
GoodQualifiesHIGH confidence
Following the 10-minute nap there was an immediate improvement in subjective alertness and cognitive performance which was sustained for the hour of post nap testing. Immediately following the 30 minute nap most measures of alertness and performance declined but showed some recovery by the end of testing.
Why this rating
Randomized, repeated-measures design with objective and subjective measures, though sample size is small (n=12).
Source
The Short-Term Benefits of Brief and Long Naps Following Nocturnal Sleep Restriction
Amber J. Tietzel et al. · SLEEP · 2001
DOI 10.1093/sleep/24.3.293
crossover · n=12Cited 175×
Read the paper DOI resolved against Crossref · corpus check 2026-06-10
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