Is napping good for you? How to nap without wrecking your night

Is napping good for you?

For most healthy adults, yes, on two conditions: keep it short and keep it early. A brief nap can restore alertness for a couple of hours; taken too late or stretched too long, it leaves you groggy and makes the coming night harder. A nap you need every day despite a full night in bed is another matter.

How long should a nap be?

Aim for 20 to 30 minutes: long enough to help, short enough to stop you before deep sleep. If you do not drift off, resting with your eyes closed still helps; in one driving-simulator study, people who only dozed still benefited.

The reason for the limit is sleep inertia, the heavy, foggy feeling of being woken out of deep sleep. Deep sleep usually starts 20 to 30 minutes after you fall asleep, sooner if you are short on sleep, and is deepest around the hour mark. Wake then and you can function worse than before you lay down. The fog usually clears within about 30 minutes but can last an hour or more, especially if you were already sleep-deprived.

If you truly need longer, a full 90-minute cycle leaves you less groggy than waking at 45 or 60 minutes.

When to nap, and when to stop

Early afternoon is the natural window: most people feel a dip in alertness between about 2 and 4 p.m., and a short nap at the start of it works with your body clock. Be up again by mid-afternoon; later naps spend sleep pressure that should be building towards bedtime, which is why an evening doze on the sofa so often wrecks the night.

• Nap somewhere quiet, dim and cool, phone out of reach.
• Set an alarm for 20 to 30 minutes and get up when it goes off.
• Allow at least 15 to 30 minutes of light and movement before driving or any other safety-critical task.
• If naps are becoming a daily necessity, look at your nights first.

The caffeine nap

A caffeine nap means drinking a coffee, then lying straight down for a short nap. Caffeine takes about 30 minutes to reach full effect, so it kicks in as you wake and the two effects stack. In a small study of sleepy drivers, about 200 mg of caffeine (roughly two small, 8 oz cups of coffee; one large take-out coffee can exceed this alone) plus a nap of under 15 minutes cut driving incidents in a simulator far more than caffeine alone did.

It is a stop-gap for a long drive or a night shift, not a daily habit: the benefit lasts a couple of hours at most, and if you are still sleepy afterwards, do not drive. The only real cure for sleepiness is sleep. Caffeine lingers, so avoid the coffee version after early afternoon. If you are pregnant or a teenager, have a heart-rhythm problem or an anxiety disorder, or have been told to limit caffeine, skip the coffee and just nap. If you have insomnia, see the next section: napping itself is usually the problem.

Naps and insomnia

If you struggle to fall or stay asleep at night, naps are usually part of the problem: they use up sleep pressure that a person with insomnia cannot spare. The US National Heart, Lung, and Blood Institute's advice is blunt: avoid naps, especially in the afternoon.

This matters most during cognitive behavioural therapy for insomnia (CBT-I). Its core technique, sleep restriction, sets a fixed time in bed, sleep or no sleep, so that pressure builds and nights become more solid. A nap releases exactly the pressure the treatment is trying to build, so the advice while you work through it is not to nap at all. It feels counter-intuitive when you are exhausted, but that tiredness is what makes it work.

Shift workers

Night workers have two naps to know about. The first is a longer, planned nap of about 90 minutes to 2 hours in the afternoon or evening before your first night: it reaches deep sleep, takes some pressure off the coming night, and in studies of nurses improved alertness late in the shift. Leave time for the grogginess to clear before work. The second is a 20 to 30 minute nap on a break, if your workplace allows it, which can lift alertness for a couple of hours; allow a few minutes for sleep inertia to pass before returning to tasks.

Be careful with long naps in the early hours: sleep inertia lasts longer after an hour's sleep at around 4 to 5 a.m., when the drive for sleep is so strong that the brain drops quickly into deep sleep. Keep those naps short, and never rely on one to make a drowsy drive home safe. See our guide to shift work and sleep.

Older adults

Sleep often becomes lighter and more broken with age, and a short early-afternoon nap is a reasonable top-up. What deserves attention is change: needing more naps, or waking unrefreshed after a full night, can mean medicines, low mood or an undiagnosed sleep disorder are interfering.

When napping is a red flag

The nap itself is rarely the problem; the need for it can be. Excessive daytime sleepiness means regularly feeling sleepy, or dozing off, during the day despite enough time in bed. Dozing off in meetings or in front of the television every evening means your nights are not working. Nodding off at the wheel is more serious: if you have fallen asleep while driving, or feel you might, stop driving and get assessed promptly. In the UK, for example, a hypersomnia diagnosis must be reported to the driver licensing agency.

Common causes include obstructive sleep apnea (breathing repeatedly stopping during sleep), restless legs syndrome, some medicines, depression and, more rarely, narcolepsy. Loud snoring or gasping in your sleep makes sleep apnea more likely, and a quick STOP-Bang self-check helps gauge the risk. Talk with a doctor if you need to nap more than you used to, wake still feeling sleepy, or find daytime sleepiness affecting your driving, work or relationships.

In summary

A short nap is good for most people: 20 to 30 minutes, over by mid-afternoon, with time to wake up properly before anything demanding. A coffee first can help ahead of a long drive or night shift, but it is a stop-gap, never a reason to drive while still sleepy. With insomnia, or during CBT-I, naps do more harm than good. If you need to nap more and more, treat that as a message about your nights.