Naps

A short nap of 10 to 20 minutes in the early afternoon can boost alertness without hurting your night. Long or late naps cost you deep sleep and make it harder to fall asleep.

• Evidence: Some
• Low effort
• Free
• Works: today

Why it matters

A nap spends some of the sleep pressure you’ve built up since waking. That’s why it makes you more alert, and also why it can cost you at night. Naps during the day, and especially in the late afternoon or early evening, reduce deep sleep at the start of the following night [4]. In a lab study of young men, an early-evening nap made them take longer to fall asleep and weakened the build-up of deep sleep that night [5].

Naps do work for alertness. A meta-analysis of 11 lab studies with 381 working-age adults found that a daytime nap improved overall mental performance, mostly alertness. The benefit lasted up to about 2 hours, and results during the groggy period right after waking were mixed [3].

How to do it

1. Keep it short. In 24 young adults who had slept about 5 hours, a 10-minute nap at 3 p.m. improved alertness and performance straight away, with some benefits lasting about 2.5 hours. A 20-minute nap helped too, but only from about 35 minutes after waking. A 30-minute nap caused a spell of grogginess first. A 5-minute nap did little [1].
2. Set an alarm for 20 to 30 minutes total. That allows a few minutes to fall asleep plus 10 to 20 minutes of sleep.
3. Nap early in the afternoon. Late naps hit the next night hardest [4][5]. Oura also says early afternoon is usually the best time [9]. No study we found sets an exact cutoff. As a rule of thumb, finish napping at least 7 to 8 hours before bed.
4. Give yourself time to wake up. Grogginess after a nap, called sleep inertia, can follow even short naps, depending on how much sleep you’ve lost and the time of day [2]. Don’t nap right before driving or anything that needs you sharp.
5. Skip naps if you have trouble sleeping at night. Avoiding daytime naps is part of the AASM’s stimulus control advice for insomnia [8].

Who benefits most

• People short on sleep: the strongest short-nap results were after a restricted night [1].
• Older adults: in 32 healthy people aged 55 to 85, an afternoon nap barely affected that night’s sleep, added to total sleep across 24 hours, and improved performance the next day [6].
• Not people with insomnia, for the reasons above.

Common mistakes

• The 90-minute nap. Long naps leave you groggy [2] and spend more sleep pressure.
• The early-evening doze on the sofa. This is a nap at the worst time [4][5].
• Napping every day to cover short nights. In a meta-analysis of 44 cohort studies with over 1.8 million people, habitual naps of 30 minutes or longer were linked to higher risk of death, heart disease and metabolic disease; shorter naps weren’t [7]. These studies show links, not cause; long naps may be a sign of poor health or poor night sleep rather than a cause. Either way, fixing the night is better than relying on daily long naps.

Effect on your sleep score

• Deep sleep: a late or long nap reduces deep sleep early that night [4][5].
• Time to fall asleep: longer after an evening nap [5].
• Total sleep: in older adults, a nap added to 24-hour sleep without cutting the night much [6]. Many wearables can detect naps; Oura includes them in several of its metrics [9].
• HRV and resting heart rate: we found no study measuring them after naps in healthy adults with wearables.

How confident: moderate. The direction is clear; the size depends on nap length, timing and how much sleep you lost.

Evidence

Rated Some. Lab trials and a meta-analysis agree that short naps improve alertness [1][3], and sleep research shows clearly that naps reduce the next night’s deep sleep, more so when late [4][5].

Limits: most trials were small and in young adults, and the 10-minute nap trial was after a night of restricted sleep [1]. A review found mixed results on whether naps of 30 minutes or less always avoid grogginess and deep sleep [2]. The health risks of long naps come from observational studies [7].

General information for healthy adults, not medical advice. If you have a sleep problem that lasts, read when to see a doctor. Sources checked 4 October 2026. Spot a mistake? Tell us.