How long is the ideal nap?

Key takeaways

• For most adults, the ideal nap is 10 to 20 minutes. That’s long enough to feel more alert and short enough to wake up without grogginess.

• Thirty minutes is about where naps start to backfire. Sleep gets deeper the longer you’re down, and waking from deep sleep leaves you foggy for a while.

• A 90-minute nap is the other option. It covers about one full sleep cycle, so you’re more likely to wake from lighter sleep, but it uses up more of the sleep pressure that helps you fall asleep at night.

• Nap in the early afternoon. The Sleep Foundation suggests napping at least eight hours before bed, which for most people means before 3pm.

• If you have insomnia, skip the nap. Daytime sleep makes it harder to fall asleep at night, which is why insomnia treatment asks people to stop napping.

The short answer

Set an alarm for 20 minutes, lie down, and get up when it goes off, even if you only dozed. A nap of 10 to 20 minutes gives most adults a lift in alertness that lasts an hour or two, without the heavy, drugged feeling a longer nap can leave behind. If you have the time and want to wake up rested rather than just alert, a nap of about 90 minutes is the other length that tends to work.

Anything in between, and especially the 30 to 60 minute range, is where people most often wake up feeling worse than before they lay down.

What the research says about short naps

The best-known test of nap length comes from Flinders University in Australia. In a 2006 study, 24 young adults slept only about five hours, then took an afternoon nap of exactly 5, 10, 20, or 30 minutes, or no nap at all.

• Five minutes did little more than no nap.

• Ten minutes cut sleepiness and improved mood and mental performance right away, and some of the gains lasted about two and a half hours.

• Twenty minutes helped too, but the benefits took about 35 minutes after waking to show up.

• Thirty minutes left people groggier and slower right after waking, before they recovered and improved.

The researchers concluded the 10-minute nap was the most effective. A 2021 review of 11 lab studies found the same general pattern: short daytime naps gave a small boost to mental performance and a larger one to alertness.

The NASA nap

You may have heard of the “NASA nap” of 26 minutes. It comes from a study of long-haul airline pilots published in 1994 by NASA and the Federal Aviation Administration. Pilots on transpacific flights were given a 40-minute window to rest in the cockpit, while a second group flew without one. The pilots who rested fell asleep in about six minutes and slept for an average of 26 minutes.

The nap paid off later in the flight. In the last 90 minutes, through descent and landing, the pilots who’d napped had fewer than half as many brief bursts of drowsiness (measured by brain and eye sensors) as those who hadn’t. Nobody chose 26 minutes as a target; it’s simply how long the pilots slept in the time they were given.

Why longer naps can leave you groggy

That foggy, heavy feeling after a nap has a name: sleep inertia. It’s the drop in alertness and coordination you get on waking, and it’s worse when you wake from deep (slow-wave) sleep. According to a 2019 review of the research, it usually wears off within 15 to 30 minutes, though it can take an hour or more.

Deep sleep tends to start about 30 minutes after you fall asleep, which is why the review suggests keeping naps under half an hour. It isn’t a hard rule. Even a short nap can leave you groggy if you’ve been awake a very long time or you nap at night.

When a 90-minute nap makes sense

A full sleep cycle, from light sleep through deep sleep and into REM (the stage linked with vivid dreams), takes about 90 minutes on average. Sleep for about that long and you’re more likely to wake from lighter sleep than from the depths of the cycle.

Longer naps may do something short ones don’t. In a 2003 Harvard study, naps of 60 to 90 minutes that included both deep sleep and REM improved people’s performance on a visual learning task about as much as a full night’s sleep did. That was one specific task, though, so it says little about memory in general.

Two caveats. Cycle length varies from person to person and from cycle to cycle, so treat 90 minutes as a rough guide. And a long nap late in the day is more likely to cut into your sleep that night.

The best time to nap

Most people have a natural dip in alertness in the early afternoon. It’s part of the body’s daily rhythm and happens whether or not you’ve eaten lunch, which makes it a good window for a nap.

The Sleep Foundation suggests napping at least eight hours before bedtime, and says that for most people that means before 3pm. Napping much later than that eats into the sleep pressure you’ve built up through the day, so you may lie awake at bedtime.

What about a coffee nap?

A coffee nap means drinking a cup of coffee and then lying down right away. Caffeine takes a while to kick in, so the idea is that it starts working just as you wake up.

There’s a little research behind it. In a 1997 driving-simulator study of 12 sleepy people, those who had 200 mg of caffeine (about two cups of coffee) and then napped for 15 minutes or less made far fewer driving errors over the next two hours than those who had a placebo. Caffeine plus a nap worked better than caffeine alone, and the nap helped even when people only dozed. A 2003 Japanese study with 10 young adults found caffeine before a 20-minute nap gave the biggest boost of the methods it tried.

Both studies were small. If you try it, keep the coffee early in the afternoon; caffeine lasts long enough to affect sleep that night, as we explain in how late you can drink coffee and still sleep.

Is napping good or bad for you?

The research on napping and long-term health is mostly observational. It shows which habits tend to go together, not what causes what, and it’s mixed.

• Long naps. A 2020 analysis of 20 studies covering more than 313,000 people found that naps longer than an hour were linked to a 30% higher risk of dying during the study period and a 34% higher risk of cardiovascular disease. Naps shorter than an hour weren’t linked to higher heart risk.

• Occasional naps. A Swiss study of about 3,400 adults found that people who napped once or twice a week had fewer cardiovascular events, such as heart attacks, strokes, and heart failure, over about five years than those who never napped. Napping more often showed no such link.

• Napping and the brain. A 2023 UK Biobank study found that people genetically inclined to nap had slightly larger brain volume. It didn’t find a difference in reaction time or memory.

One explanation for the long-nap findings is that illness causes the napping, not the other way around. People with heart disease, sleep apnea, depression, or early dementia often feel sleepy during the day. If you’ve started needing long naps and you don’t know why, mention it to your doctor.

Who should skip the nap

People with insomnia. If you struggle to fall or stay asleep at night, a nap takes the edge off the sleep pressure you need at bedtime. Avoiding daytime naps is one of the standard instructions in cognitive behavioral therapy for insomnia (CBT-I), the treatment the American Academy of Sleep Medicine strongly recommends.

Shift workers are the exception. For people working nights, a planned nap is useful. NIOSH, the federal workplace safety agency, describes a longer nap before a night shift (studies have used 1.5 to 3 hours) to improve alertness at work, and a brief nap of about 30 minutes during a work break.

Naps for children

Young children need naps; for them, daytime sleep counts toward their daily total. The American Academy of Sleep Medicine’s guidance, which the American Academy of Pediatrics endorses, gives these totals per 24 hours, naps included:

Most children drop their last nap somewhere between about ages three and five. Our post on whether everyone needs 8 hours of sleep has the full range by age.

How to take a good nap

• Set an alarm. Twenty minutes for a quick lift, or about 90 if you want a full cycle. Add five minutes or so to fall asleep.

• Aim for early afternoon. Somewhere between lunch and 3pm suits most schedules.

• Make it dark and quiet. A sleep mask, earplugs, or a dim room helps you drop off faster.

• Don’t worry if you don’t sleep. In the driving study, even dozing helped.

• Give yourself a few minutes after waking. Bright light and moving around clear grogginess faster than lying in bed.

Frequently asked questions

Is a 20-minute nap enough?

For most adults, yes. Naps of 10 to 20 minutes improve alertness for an hour or two, and they’re short enough that you’re unlikely to wake from deep sleep. In one study, a 10-minute nap worked best of the lengths tested.

Is a 30-minute nap too long?

It’s on the edge. In the Flinders University study, people who napped 30 minutes were groggier right after waking than those who napped 10 or 20, before they improved. Deep sleep tends to begin about 30 minutes in, so stopping at 20 is safer.

Why do I feel worse after a nap?

That’s sleep inertia, the grogginess that comes from waking during deep sleep. It’s most likely after naps longer than about 30 minutes and usually fades within 15 to 30 minutes. A shorter nap, or a full 90-minute one, makes it less likely.

Is a 2-hour nap bad?

An occasional long nap after a short night is fine. Regular naps of more than an hour have been linked with higher risks of cardiovascular disease and early death in observational studies, though illness may explain part of that. A long nap late in the day can also make it harder to sleep at night.

What time should you stop napping?

Most people should nap before about 3pm. The Sleep Foundation suggests leaving at least eight hours between a nap and bedtime, so if you go to bed late, your cutoff moves later too.

Is it bad to nap every day?

Not for most people, if the naps are short and early in the afternoon and you still sleep well at night. If you need a nap every day because you’re exhausted despite sleeping seven or more hours, talk to a doctor, since daytime sleepiness can be a sign of a sleep disorder or another health problem.