In 30 seconds
- In 22 trials with young, active men, a nap after lunch improved physical and mental performance and reduced fatigue. Naps of 30 to 60 minutes worked best.
- After a night of about 5 hours, a nap of just 10 minutes immediately improved alertness and performance, with an effect lasting up to 155 minutes.
- On waking there are about 20 minutes of grogginess: before training, leave at least an hour between the nap and the effort.
- In 3,275 adults in a University of Murcia study, naps of more than 30 minutes were associated with higher weight, waist size, glucose and blood pressure. Short ones were not.
Napping works. After lunch, a 30 to 60 minute nap improved physical and mental performance and reduced fatigue in 22 trials with athletes and active people. If you are short of time, 10 minutes already clears your head. What makes the difference is the length, the time of day and the gap you leave before training.
Level of evidence by outcome
| Outcome | Evidence | What the data show |
|---|---|---|
| Physical performance after a normal night | Moderate | Moderate to large improvement in trials with young, active men; better with naps of 30-60 minutes. |
| Alertness and mental performance | Moderate | Improvements in 11 studies, especially in alertness, for about 2 hours. |
| Perceived fatigue | Moderate | Less feeling of fatigue after the nap in trials with athletes. |
| Making up for a bad night | Preliminary | Benefits in small studies; the authors do not yet make a firm recommendation. |
| Metabolic and cardiovascular health | Preliminary | Observational studies: short or occasional naps are associated with better figures; long ones, with worse. |
The rating is our own, based on the number of studies, their quality and the consistency of the results.
The key studies
| Study | Type | Sample | Outcome |
|---|---|---|---|
| Mesas et al., 2023 | Meta-analysis | 22 trials, 291 men aged 18 to 35 | A nap after lunch improved physical and cognitive performance and reduced fatigue. Better with 30 to 60 minutes and at least an hour's gap before the test. 1 |
| Souabni et al., 2021 | Systematic review | 18 studies, 158 active people and 168 athletes | 15 studies found benefits, especially in short efforts, reaction time and attention. 90-minute naps gave the largest improvements. 2 |
| Waterhouse et al., 2007 | Crossover trial | 10 men who slept 4 hours | 30-minute nap at 13:00: more alertness, better short-term memory and a 20 m sprint from 3.97 to 3.88 seconds. 3 |
| Brooks and Lack, 2006 | Trial | 24 young adults who slept about 5 hours | The 10-minute nap was the most effective: immediate improvements that lasted up to 155 minutes. 4 |
| Dutheil et al., 2021 | Meta-analysis | 11 studies, 381 people | Afternoon naps of 15 to 90 minutes improved mental performance, especially alertness, for up to about 2 hours. 5 |
| Vizmanos et al., 2023 | Cross-sectional study | 3,275 adults | Naps of more than 30 minutes: higher body mass index, waist size, glucose, blood pressure and metabolic syndrome. Short ones, no. 7 |
| Häusler et al., 2019 | Cohort study | 3,462 Swiss adults, about 5 years | One or two naps a week were associated with 48% fewer cardiovascular events than taking none. 8 |
Nap length
How long a nap should last
Napping and sports performance
The most comprehensive meta-analysis brought together 22 trials with 291 men aged 18 to 35: 164 athletes and 127 active people. The naps lasted between 10 and 120 minutes and were taken after lunch, between 12:30 and 16:50; the most common time was 14:00 1.
After a normal night, napping improved physical and cognitive performance and reduced perceived fatigue, with a moderate to large effect. Naps of 30 to under 60 minutes worked best 1.
A review of 18 studies, with 158 active people and 168 athletes, reached a similar conclusion. 15 studies found benefits, especially in short efforts, reaction time and attention 2. 90-minute naps gave the largest improvements, although the authors urge caution because there are few studies 2.
After a bad night
In one trial, 10 men slept only 4 hours, from 23:00 to 3:00. The next day, a 30-minute nap at 13:00 improved their alertness and short-term memory. And they ran faster: over 20 metres they went from 3.97 to 3.88 seconds 3. Grip strength did not change 3.
With little sleep, the meta-analysis also found benefits, but these rest on fewer studies. That is why its authors do not yet venture to say that a nap makes up for a bad night 1.
Napping and the mind: alertness and concentration
In 11 studies with 381 people, an afternoon nap of 15 to 90 minutes improved mental performance. What rose most was alertness, and the effect lasted up to about 2 hours. Memory did not clearly improve 5.
And if you only have a few minutes? In one study, 24 young adults slept about 5 hours and the next day tried naps of different lengths at 15:00 4:
| Nap | On waking | How long the effect lasted |
|---|---|---|
| 5 minutes | Hardly any improvement compared with not sleeping | Little effect |
| 10 minutes | Immediate improvements in alertness, tiredness, vigour and performance | Up to 155 minutes |
| 20 minutes | Improvements from about 35 minutes onwards | Up to 125 minutes |
| 30 minutes | Worse at first, due to sleep inertia; then, improvements | Up to 155 minutes |
Source: Brooks and Lack, 2006. 24 young adults after sleeping about 5 hours, with the nap at 15:00.
The winner was the 10-minute nap: it immediately improved alertness, tiredness, vigour and performance, and part of the effect lasted more than two and a half hours 4.
After the nap
How long to wait after waking up
Groggy on waking: sleep inertia
It is that feeling of grogginess when you wake up. It usually passes in about 20 minutes, and it is stronger if you wake from deep sleep, if you have been awake for many hours or if you are carrying a sleep debt 6.
To reduce it, specialists advise naps of under 30 minutes or of about 90, which are less likely to wake you in the middle of deep sleep. And waiting at least 20 minutes after waking before a demanding task, such as driving 6.
For training, the gap is bigger. In the meta-analysis of 22 trials, the benefit grew the more time passed between waking up and the test, and the authors recommend at least 60 minutes 1.
A trick with evidence behind it: have a coffee just before a nap of about 20 minutes. Caffeine takes about 20 minutes to take effect, so it kicks in as you wake up. Bright light on waking also helps 6. That said, if you go to bed early, watch the clock: we tell you more in caffeine and sleep.
The siesta in Spain
The Mediterranean siesta, in figures
The Spanish siesta: better short
A University of Murcia study with 3,275 adults looked at the Mediterranean siesta. 35% usually took one, and 16% napped for more than 30 minutes 7.
Long naps were associated with a higher body mass index, a larger waist, higher fasting glucose, higher blood pressure and more metabolic syndrome. Short ones, of 30 minutes or less, were not: they were even associated with a lower likelihood of high systolic blood pressure 7.
Part of the explanation lies in the habits that go with long naps: going to bed and eating later, a larger lunch and smoking more 7.
In Switzerland, a follow-up of 3,462 adults over about 5 years found that those who napped once or twice a week had 48% fewer cardiovascular events than those who did not nap. With almost daily naps, the difference disappeared once other risk factors were taken into account 8.
These are observational studies: they show associations, not cause and effect.
How to take a good nap
- After lunch. Almost all the trials scheduled it between 12:30 and 16:50 1.
- Choose the length to suit your afternoon. 10-20 minutes if you need to perform straight away; 30-60 minutes if you train later and have time 1 4.
- Leave at least an hour before training 1.
- If you nap every day, keep it short. Naps of 30 minutes or less are the ones associated with better health figures 7.
- Coffee first, if you want it short and effective, always well away from bedtime 6.
A nap does not replace the night
It is a good trump card, not a substitute. If you need one every day to function, take a look at your nights: our sleep test helps you see your ideal number of hours, and you will find what happens when you sleep too little in sleep deprivation and performance.
If you sleep badly on an ongoing basis, see your doctor.
Frequently asked questions
How long should a nap be?
It depends on what you do afterwards. In one study, 10 minutes was enough to immediately improve alertness and performance. For sport, naps of 30 to 60 minutes after lunch worked best in 22 trials.
Is it good to nap before training?
Yes, if you leave enough time. In the trials, the benefit was greater the more time passed between waking up and the test, and the authors recommend at least an hour.
Why do I feel worse when I wake up from a nap?
It is sleep inertia, a grogginess that usually passes in about 20 minutes. It is stronger if you wake up from deep sleep; to avoid it, naps of under 30 minutes or of about 90 are advised.
Do long naps make you put on weight?
In a study with 3,275 adults, naps of more than 30 minutes were associated with a higher body mass index and a larger waist; short ones were not. Part of the link was explained by habits such as eating and going to bed later.
Sources
- Mesas AE, Núñez de Arenas-Arroyo S, Martinez-Vizcaino V, Garrido-Miguel M, Fernández-Rodríguez R, Bizzozero-Peroni B, Torres-Costoso AI. Is daytime napping an effective strategy to improve sport-related cognitive and physical performance and reduce fatigue? A systematic review and meta-analysis of randomised controlled trials. Br J Sports Med. 2023;57(7):417. View publication
- Souabni M, Hammouda O, Romdhani M, Trabelsi K, Ammar A, Driss T. Benefits of daytime napping opportunity on physical and cognitive performances in physically active participants: a systematic review. Sports Med. 2021;51(10):2115-2146. View publication
- Waterhouse J, Atkinson G, Edwards B, Reilly T. The role of a short post-lunch nap in improving cognitive, motor, and sprint performance in participants with partial sleep deprivation. J Sports Sci. 2007;25(14):1557-1566. View publication
- Brooks A, Lack L. A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? Sleep. 2006;29(6):831-840. View publication
- Dutheil F, Danini B, Bagheri R, Fantini ML, Pereira B, Moustafa F, Trousselard M, Navel V. Effects of a short daytime nap on the cognitive performance: a systematic review and meta-analysis. Int J Environ Res Public Health. 2021;18(19):10212. View publication
- Hilditch CJ, Vincent GE. Fighting grogginess after sleep. Sleep Research Society. View publication
- Vizmanos B, Cascales AI, Rodríguez-Martín M, Salmerón D, Morales E, Aragón-Alonso A, Scheer FAJL, Garaulet M. Lifestyle mediators of associations among siestas, obesity, and metabolic health. Obesity. 2023;31(5):1227-1239. View publication
- Häusler N, Haba-Rubio J, Heinzer R, Marques-Vidal P. Association of napping with incident cardiovascular events in a prospective cohort study. Heart. 2019;105(23):1793. View publication
Information based on published studies. It does not replace the advice of a doctor or registered dietitian. The results describe what was measured in each study, not the properties of any specific product. A varied and balanced diet and a healthy lifestyle are important.
