How Long Should a Nap Be? Short Naps vs Longer Rest

The short answer

If you want to feel more alert soon after waking, a short nap is a good place to start. Several studies from Flinders University in Australia found that about 10 minutes of actual sleep produced the quickest improvement in alertness and performance after a shortened night. [1] [2]

The US National Heart, Lung, and Blood Institute (NHLBI) recommends that adults keep naps short, at no more than 20 minutes. [8] Longer naps are not “wrong”, but they come with more grogginess at first and can make it harder to fall asleep at night.

What the experiments compared

In the study by Brooks and Lack, 24 healthy young adults restricted their night sleep to about five hours and came to the lab for an afternoon nap at 3 PM. They slept for exactly 5, 10, 20 or 30 minutes, or not at all, and were tested for up to three hours afterwards. [1]

• 5 minutes: few benefits compared with no nap.
• 10 minutes: immediate improvements in sleepiness, fatigue, vigour and cognitive performance, some lasting up to 155 minutes.
• 20 minutes: improvements appeared about 35 minutes after waking and lasted up to 125 minutes.
• 30 minutes: a short period of impaired alertness right after waking, followed by improvements lasting up to 155 minutes.

An earlier study by the same group compared 10 and 30 minutes after a night of 4.7 hours of sleep and found a similar pattern. [2]

Is a 30-second nap enough?

Probably not. Tietzel and Lack also tested ultra-short naps of 30 and 90 seconds of sleep. Neither produced measurable improvements compared with no nap, whereas the 10-minute nap did. [3]

So simply nodding off for a moment does not seem to deliver the effect. Somewhere between a couple of minutes and ten minutes of sleep, something happens that makes the brief nap worthwhile. Researchers are still debating what that process is. [4]

What about 30, 60 or 90 minutes?

A review by Lovato and Lack summarises the trade-off: brief naps of 5–15 minutes bring benefits almost immediately that last one to three hours. Naps longer than about 30 minutes can cause a short period of impairment after waking, but may then improve performance for longer. [4]

Longer naps are more likely to include deep sleep. NHLBI describes sleep cycles that repeat roughly every 80 to 100 minutes, which is why 90-minute naps are popular. [7] But cycle lengths vary between people and from nap to nap. A 90-minute alarm cannot guarantee that you will wake at the end of a cycle.

Why “under 30 minutes” is not a guarantee

Many workplace guides say that naps of 30 minutes or less avoid deep sleep and grogginess. A 2017 review checked the evidence and found mixed results. Whether deep sleep appears and how groggy you feel depends heavily on how much sleep you had before and on the time of day. At night and after sleep loss, even short naps can be followed by noticeable sleep inertia. [5]

In practice, that means a short timer is a sensible default, not a promise. If you are very sleep-deprived, expect more grogginess, and plan more time before demanding tasks.

Time in bed versus time asleep

Most nap studies count minutes of actual sleep, measured with EEG. Your timer counts minutes from the moment you start it. If it takes you seven minutes to fall asleep, a 20-minute timer gives you about 13 minutes of sleep.

That is why it helps to plan three parts: time to settle in, the nap itself and a few minutes to return to your day. In Nap & Recharge, the Sleep Buffer adds the settling-in time before the countdown starts. It is a fixed delay you choose, not a measurement of when you fall asleep.

A simple guide for choosing

Scroll the table sideways on small screens.

Research also shows that people differ. Milner and Cote point out that age, time of day and how used you are to napping all influence the benefit. [6] Try one setting for a week and note how you feel.

Common questions about nap length

Is a 20-minute nap a power nap?

“Power nap” is not a scientific term, but it usually means a short nap of about 10 to 20 minutes aimed at feeling more alert.

Why do I feel worse after a long nap?

Waking from deeper sleep often causes temporary grogginess, called sleep inertia. It usually wears off, but plan time for it.

Should I nap every day?

People who nap regularly seem to benefit more from naps than people who rarely nap. [4] If naps make it harder to sleep at night, shorten them or move them earlier.