Naps: how long, when, and who benefits

For most adults, the best nap is short and early: about 10 to 20 minutes, taken in the early afternoon. That's long enough to feel sharper and short enough to wake up without grogginess. People with insomnia are the main exception, and the NHS advises them to skip daytime naps.

What does the research say about naps?

Short naps have good support. A 2015 review in Sleep Medicine Reviews says the evidence clearly shows that naps under 30 minutes benefit alertness, mood and performance on mental tasks.

The most useful study on nap length came from Flinders University in Australia. Twenty-four healthy young adults slept only about 5 hours at home, then came into a lab for a 3 p.m. nap. On different days they had no nap, or a nap of exactly 5, 10, 20 or 30 minutes of sleep, followed by 3 hours of testing.

The 5-minute nap did little. The 10-minute nap gave immediate improvements across every measure, including sleepiness, fatigue, vigor and mental performance, and some of those lasted up to 155 minutes. The 20-minute nap helped too, but the gains only showed up about 35 minutes after waking. The 30-minute nap was followed by a spell of impaired alertness before the benefits arrived. The authors concluded that 10 minutes was the most effective length overall.

How long should a nap be?

A nap should last about 10 to 20 minutes. The Sleep Foundation suggests about 20 minutes and no longer than 30, because that gives you some light sleep without slipping into deep sleep. Waking from deep sleep is what leaves you groggy, a state called sleep inertia.

The Sleep Foundation explains that longer naps of more than 30 minutes can take you into deep sleep, and that deep sleep may start even sooner if you're sleep deprived. That matches what happened after the 30-minute nap in the Flinders study.

There's one other length that can work. The Sleep Foundation says a nap of around 90 minutes lets the body go through a full sleep cycle, which avoids waking in the middle of deep sleep. It suggests this may help emergency and shift workers fight fatigue, but warns that a nap that long can interfere with night sleep if it's taken too late.

When is the best time to nap?

The best time to nap is early afternoon. The Sleep Foundation says experts typically recommend napping 8 or more hours before bedtime, which for most people means before 3 p.m.

There's a reason so many people feel drowsy after lunch. The Sleep Foundation explains that the body clock has two peaks of sleepiness a day, the biggest at night and a smaller one in the early afternoon. A short nap just before or during that post-lunch dip can ease afternoon sleepiness without getting in the way of sleep at night.

Late naps are where trouble starts. The 2015 review notes that evening naps in particular may be a problem because they can use up the sleep pressure you need to fall asleep at bedtime.

Do naps ruin your night sleep?

Naps ruin night sleep less often than people think. The 2015 review found that most research, mostly in older adults, showed no significant link between daytime napping and night sleep. A study of young and middle-aged adults found no link either, and one that compared no nap, naps under 20 minutes and naps over 20 minutes for a week found no difference in self-reported night sleep.

There are exceptions. In one study, older adults who took a 90-minute afternoon nap every day for two weeks slept less and less efficiently at night, measured in a sleep lab, than when they skipped naps. The review's authors called the overall evidence inconclusive.

Who benefits most from napping?

People who are short on sleep are the clearest winners, since the Flinders study was done after a night restricted to about 5 hours. The Sleep Foundation adds that naps can be particularly useful for shift workers who need to be alert at irregular hours, and that some studies have found athletes' endurance, reaction times and mental performance improve after a daytime nap.

If you nap well and sleep well at night, there's no need to change anything. The Sleep Foundation says you only need to change your napping habits if you're having problems with your night sleep or your daily energy.

Who should skip naps?

If you have insomnia, the NHS advises not napping during the day, alongside its other advice to keep regular sleep hours and not sleep in after a bad night. The 2015 review explains the thinking behind that advice: naps are thought to use up some of the sleep drive that builds during the day.

Older adults may want to keep naps short too. The Sleep Foundation notes that in older adults, napping is linked to sleep problems such as waking often during the night. It also cites observational studies linking long naps with health problems, including an analysis that tied naps of more than 60 minutes a day to a higher risk of type 2 diabetes. These are associations, and the Sleep Foundation says it isn't clear how naps affect health.

How do you take a better nap?

To take a better nap, the Sleep Foundation's practical advice is simple. Find a cool, quiet, dark spot, and use an eye mask or earplugs if you're napping somewhere bright or noisy. Set an alarm for about 20 minutes and get up when it goes off instead of hitting snooze. A second alarm a few minutes later can stop you oversleeping.

Some people try a coffee nap. The Sleep Foundation says caffeine takes about 30 minutes to take effect, so drinking some right before a short nap may help you feel more alert when you wake. Keep it early, since afternoon caffeine can cut into your night sleep, as we explain in how late is too late for caffeine?.

What if you snore or wake with a dry mouth after a nap?

Naps often happen on a sofa or in a chair rather than in bed. If you wake from them with a dry mouth, or someone tells you that you snore when you doze off, how you breathe is worth a look. The Sleep Foundation notes that nasal breathing filters allergens and warms and humidifies the air.

If your nose feels stuffy, a nasal strip is an easy thing to try for a nap as well as at night. If your nose is clear but your mouth falls open when you doze, some adults use a small piece of mouth tape to keep their lips closed and stay on nasal breathing. We cover how to do this in mouth tape for naps and mouth tape for dry mouth. Take the nose test first.

If you want to try mouth tape and nasal strips together, our pick is the Titan Sleep System, which pairs TitanAir Nasal Strips with Titan Mouth Tape.

Snoring that comes with other signs needs a doctor rather than tape. The American Academy of Sleep Medicine lists choking or gasping during sleep, silent breathing pauses and daytime sleepiness as warning signs of sleep apnea. If you need a nap every day despite a full night in bed, see snoring vs. sleep apnea and talk to your doctor.

Read next

• How much sleep do adults need?
• Why do I wake up tired?
• How to fall asleep faster: what the evidence supports

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.