Last updated: October 2026
A power nap works best at 10 to 20 minutes, taken in the early afternoon, ideally between about 1pm and 3pm. In a sleep-lab study, a 10-minute nap improved alertness straight away, with benefits lasting over 2 hours. Naps of 30 minutes or more often leave you groggy at first and can make it harder to sleep at night.
Below: the right nap length, the best time, the “coffee nap”, napping when driving, on shifts or at work, when naps backfire, and a step-by-step method.
How long should a power nap be?
The best-known study on nap length comes from Flinders University in Australia. Twenty-four healthy young adults slept about 5 hours at night, then took a 3pm nap of exactly 5, 10, 20 or 30 minutes, or no nap at all:
| Nap length | What happened |
|---|---|
| 5 minutes | Few benefits compared with no nap |
| 10 minutes | Immediate improvements in sleepiness, fatigue, vigour and thinking, some lasting up to 155 minutes |
| 20 minutes | Benefits started about 35 minutes after waking and lasted up to 125 minutes |
| 30 minutes | Grogginess first (“sleep inertia”), then improvements lasting up to 155 minutes |
So 10 to 20 minutes of actual sleep is the sweet spot for most people. Set your alarm for about 20 to 25 minutes to allow a few minutes to drop off.
Which nap length suits you?
| Nap | What to expect | Best for |
|---|---|---|
| 10 to 20 minutes | Quick lift in alertness, little or no grogginess | The afternoon slump, a work break, a stop on a long drive |
| 30 to 60 minutes | More likely to wake from deeper sleep and feel groggy for a while | Only when you have time to come round before you need to be sharp |
| About 90 minutes | Roughly one full sleep cycle, so you often wake from lighter sleep | Recovering from a very short night, or before a night shift |
| 2 hours or more | Likely to eat into night-time sleep | Rarely a good idea; if you need this often, see “When naps backfire” below |
20-minute nap vs 90-minute nap
A 20-minute nap is the everyday option: it fits into a lunch break and is unlikely to spoil your night. A 90-minute nap can help when you are badly short of sleep, but it is more likely to push back your bedtime. Our sleep calculator works out bedtimes around sleep cycles.
Why you feel groggy after a nap (sleep inertia)
That heavy, foggy feeling after a nap is sleep inertia: a short spell of grogginess and slower thinking after waking. It tends to be worse when you wake from deep sleep, which is more likely the longer you nap.
Short naps help, but aren’t a guarantee. A 2017 review of naps of 30 minutes or less found mixed results, depending on how much sleep you’d had beforehand and the time of day. In practice:
- Give yourself 10 to 15 minutes after a nap before anything that needs full concentration, such as driving or an important meeting.
- Get into daylight and move around to shake it off faster.
- If you always wake groggy, try a shorter nap or skip it.
Best time for a power nap
Most people have a natural dip in alertness in the early afternoon (see the afternoon slump), which is the easiest time to nap. The DVLA describes two daily low points in alertness caused by changes in body rhythm: midnight to 6am, and 2pm to 4pm. A big lunch can add to it; see why you feel tired after eating.
For a day starting around 7am, aim for about 1pm to 3pm. Napping late in the afternoon or evening uses up the “sleep pressure” that helps you drop off at night. Early risers may find their window is earlier, night owls later; see the best time to sleep and wake up.
Can you power nap at night or after an all-nighter?
Yes, as damage limitation. On night shifts, a planned nap can help you stay alert (see below). After an all-nighter, a 20-minute nap can take the edge off, but it won’t replace proper sleep, and don’t drive if you’re still sleepy.
Is napping good for you? Power nap benefits
For most healthy adults, a short nap is a good thing. Studies of brief naps have found:
- Less sleepiness and more alertness in the afternoon
- Better concentration and reaction time
- Improved mood and energy
- Safer driving in simulator studies, when sleepy drivers napped during a break (see below)
A review of napping research found brief naps improve alertness and performance in healthy adults, with the gain depending on nap length, timing, age and how used you are to napping. Regular nappers tend to get more out of them.
The catch: a nap is a top-up, not a fix. If you rely on naps every day, look at your nights first. Our guide to sleep debt explains what you can catch up on.
The coffee nap: does it work?
A coffee nap (or “nappuccino”) means drinking a coffee, then napping straight away for 15 to 20 minutes. Caffeine takes a while to kick in, so you wake as it starts to work. The research is small but encouraging:
- Loughborough University, 1996: in a driving simulator, a nap of under 15 minutes and 150mg of caffeine each reduced driving errors and sleepiness in 10 sleepy volunteers. A break on its own didn’t help.
- Loughborough University, 1997: 12 sleepy people had 200mg of caffeine plus a short nap before a 2-hour afternoon drive. Driving incidents fell to 9% of the placebo level, compared with 34% for caffeine alone. Even naps that were mostly light dozing still worked.
- Hiroshima University, 2003: in 10 young adults, 200mg of caffeine before a 20-minute lunchtime nap beat a nap alone, a nap plus bright light, and a nap plus face washing for sleepiness and performance over the next hour.
These were small lab studies in young, healthy people: promising rather than proven.
How to do a coffee nap safely
- Keep it early. The NHS says caffeine’s effects can last up to 7 hours, and advises no tea or coffee within 6 hours of bedtime if you struggle to sleep. See how long caffeine lasts.
- Mind the dose. The European Food Safety Authority says single doses up to 200mg, and up to 400mg a day, are fine for healthy adults (200mg a day in pregnancy), but 100mg close to bedtime can affect sleep in some people.
- Skip it if caffeine makes you jittery or anxious, or if your doctor has told you to limit it.
Power naps and driving
The DVLA says up to one fifth of accidents on motorways and other monotonous roads may be caused by drivers falling asleep at the wheel, and that it is “not an excuse in law”. Drivers always get some warning, so heavy eyelids, yawning or drifting in your lane are your cue to stop.
The Highway Code (Rule 91) says:
- don’t begin a journey if you are tired, and get enough sleep before a long drive
- avoid long journeys between midnight and 6am
- take a break of at least 15 minutes after every two hours of driving
- if you feel sleepy, stop in a safe place, not on the hard shoulder or in an emergency area of a motorway
Once you’ve stopped safely, the Loughborough research suggests a coffee followed by a short nap is the most effective quick fix, but it only buys limited time. If you still feel sleepy, or have a long way to go, stop for the night. The only real cure for sleepiness is sleep.
If you often feel sleepy at the wheel despite enough sleep, see your GP. The DVLA calls sleep apnoea the most common sleep-related medical disorder, and you may need to tell the DVLA about a condition that causes excessive sleepiness. See sleep apnoea symptoms and tests.
Who benefits most from a power nap?
- Shift workers. A systematic review of 13 studies found that planned naps during night shifts reduced sleepiness and improved performance, despite a short spell of grogginess on waking. The studies were small, and none measured workplace safety directly. See our guide to shift work and sleep.
- New parents. The NHS suggests resting when your baby sleeps rather than doing chores, with an alarm if you’re worried about sleeping too long. If you can’t sleep even when your baby does, or you feel low, speak to your GP or health visitor.
- Anyone after a short night. The Flinders study tested naps after only 5 hours’ sleep. For longer runs of short nights, see sleep deprivation and how to recover.
- Pilots and other safety-critical jobs. NASA research found planned in-flight rest helped long-haul pilots stay alert during descent and landing.
How to nap at work
In the UK, if you work more than 6 hours a day you have the right to one uninterrupted 20-minute rest break, which could be your lunch break. That is just enough for a power nap:
- Check it’s OK. Some workplaces have a quiet room; otherwise a parked car or a quiet corner can work.
- Set a 20-minute alarm on your phone and put it on vibrate.
- Block out light and noise with an eye mask and earplugs.
- Plan 10 minutes to come round before a meeting or anything that needs a clear head.
- Can’t sleep at your desk? Even resting with your eyes closed, or a short yoga nidra (NSDR) session, can help you feel more refreshed.
For night or long shifts, NASA’s work on “strategic naps” supports planned naps on the job, but warns that grogginess on waking and effects on later sleep need planning for.
When naps backfire: insomnia and poor night-time sleep
- People with insomnia. Daytime naps reduce the sleep pressure you need at night. The NHS advice for insomnia is not to nap during the day, and CBT for insomnia usually asks you to avoid naps too. See our full guide to insomnia.
- Anyone needing long naps every day despite a full night’s sleep. That can be a sign of poor sleep quality, sleep apnoea or another health condition. See why am I always tired?
- People who wake groggy even after short naps; try a shorter nap or skip it.
If you’re napping because your nights are poor, the bigger win is fixing the night: regular wake times, a wind-down routine and a dark, cool bedroom. Start with our 12 sleep hygiene habits, or try how to fall asleep fast.
Some people add our Magnesium Glycinate Sleep Complex to their evening wind-down (it is for the evening, not for naps): magnesium bisglycinate and citrate with glycine, L-theanine, chamomile, passionflower, hops and oat straw. Magnesium contributes to normal functioning of the nervous system. Magnesium contributes to normal psychological function. Magnesium contributes to a reduction of tiredness and fatigue. For adults only. We don’t recommend our products during pregnancy or breastfeeding. Check with your GP or pharmacist first if you take any medication.
The FSA’s 10mg a day figure for CBD is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.
Long daily naps and your health: what the research says
Large studies have looked at napping habits and long-term health. Most are observational, so they show links, not cause and effect: long naps may simply be a sign of poor night-time sleep or an existing health problem.
| Study | Who | What it found |
|---|---|---|
| Meta-analysis, 2016 | 288,883 adults in Asia and the West | Naps of 60 minutes or more a day were linked with a higher risk of type 2 diabetes. Naps under 60 minutes were not, with no link up to about 40 minutes a day. |
| Swiss cohort, 2019 | 3,462 adults followed for about 5 years | Napping once or twice a week was linked with a lower risk of cardiovascular events such as heart attack and stroke. The higher risk seen in daily nappers disappeared once other health factors were taken into account. |
| UK Biobank, 2023 | Up to 378,932 adults, average age 57 | A genetic tendency to nap was linked with slightly larger total brain volume, but not with reaction time or memory. |
The takeaway: short naps look fine, possibly helpful, for most people. Regularly needing naps of an hour or more is worth raising with your GP, especially if you also snore loudly or wake unrefreshed.
How to take a power nap: step by step
- Pick your time: early afternoon, ideally between about 1pm and 3pm.
- Optional coffee: for a coffee nap, drink it just before you lie down, and only if it is at least 6 hours before bed.
- Set an alarm for 20 to 25 minutes (allowing a few minutes to drop off).
- Find somewhere quiet and dim, or use an eye mask and earplugs.
- Lie down or recline; sitting slightly upright makes it easier to wake.
- Don’t worry if you don’t fully sleep. Light dozing or resting with your eyes closed still helps.
- Get up when the alarm goes, into daylight, and have a glass of water.
- Give yourself 10 to 15 minutes before driving or anything that needs your full attention.
Planning a nap after an overnight game? See our guide to watching late-night sport and still functioning.
FAQs
How long should a power nap be?
10 to 20 minutes. In a sleep-lab study, a 10-minute nap gave immediate benefits, while 30 minutes caused grogginess first.
What is the best time for a power nap?
Early afternoon, between about 1pm and 3pm. Napping later can make it harder to sleep at night.
Is a 20-minute nap better than coffee?
In one study, combining the two (coffee then a short nap) worked best for the afternoon slump.
Why do I feel worse after a nap?
Longer naps can take you into deep sleep, and waking from it causes grogginess called sleep inertia. Keep naps under 20 to 30 minutes.
Are daily naps healthy?
Short naps are fine for most people. Needing long naps every day despite enough sleep is worth discussing with your GP.
Is a 90-minute nap better than a 20-minute nap?
Not usually. A 90-minute nap covers roughly one full sleep cycle and can help after a very short night, but it is more likely to affect your night-time sleep. For an everyday boost, 10 to 20 minutes is better.
Do coffee naps really work?
Small lab studies suggest they do. Caffeine followed by a short nap reduced sleepiness more than either on its own. Have it by early afternoon so the caffeine doesn’t disturb your night.
Can a nap make up for a bad night’s sleep?
Partly. A short nap can restore alertness for a couple of hours, but it doesn’t replace a full night. If you rely on naps most days, focus on improving your night-time sleep.
Sources
- Brooks A, Lack L (2006). A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? Sleep.
- Milner CE, Cote KA (2009). Benefits of napping in healthy adults: impact of nap length, time of day, age, and experience with napping. Journal of Sleep Research.
- Hilditch CJ, Dorrian J, Banks S (2017). A review of short naps and sleep inertia: do naps of 30 min or less really avoid sleep inertia and slow-wave sleep? Sleep Medicine.
- Horne JA, Reyner LA (1996). Counteracting driver sleepiness: effects of napping, caffeine, and placebo. Psychophysiology.
- Reyner LA, Horne JA (1997). Suppression of sleepiness in drivers: combination of caffeine with a short nap. Psychophysiology.
- Hayashi M et al (2003). The alerting effects of caffeine, bright light and face washing after a short daytime nap. Clinical Neurophysiology.
- Ruggiero JS, Redeker NS (2014). Effects of napping on sleepiness and sleep-related performance deficits in night-shift workers: a systematic review. Biological Research for Nursing.
- Rosekind MR et al (1995). Alertness management: strategic naps in operational settings. Journal of Sleep Research.
- Yamada T et al (2016). J-curve relation between daytime nap duration and type 2 diabetes or metabolic syndrome: a dose-response meta-analysis. Scientific Reports.
- Häusler N et al (2019). Association of napping with incident cardiovascular events in a prospective cohort study. Heart.
- Paz V, Dashti HS, Garfield V (2023). Is there an association between daytime napping, cognitive function, and brain volume? A Mendelian randomization study in the UK Biobank. Sleep Health.
- GOV.UK. The Highway Code: rules for drivers and motorcyclists (Rule 91).
- DVLA. Tiredness can kill: advice for drivers (INF159).
- GOV.UK. Rest breaks at work.
- NHS. Insomnia.
- NHS. Self-help tips to fight tiredness.
- NHS. Sleep and tiredness after having a baby.
- European Food Safety Authority. Caffeine.
This guide is general information, not medical advice.
