Take a 20-minute nap after a short night
After a short night, a 10 to 20 minute nap improved alertness and performance for the rest of the afternoon.
In a sleep lab in Adelaide, young adults were allowed only five hours in bed, then offered a nap at 2:30 the next afternoon. Some slept 5 minutes, some 10, 20 or 30, and some did not nap at all. This habit borrows what worked best: a short nap, early afternoon, alarm set, taking about 25 minutes from lying down to getting up.
What it helps with
Afternoon sleepiness
After a short night, a 10 to 20 minute nap improved alertness and performance for the rest of the afternoon.
Tired after poor sleep
Naps under about 30 minutes are linked to better alertness, while longer naps bring more grogginess.
Key facts
- 1In a sleep-lab study, a 10-minute nap after a five-hour night improved alertness right away, with benefits lasting up to about two and a half hours.
- 2In the same lab study, a 20-minute nap also improved alertness, though the benefit appeared about half an hour after waking.
- 3A 30-minute nap in that study was followed by a period of grogginess before any improvement appeared.
- 4In a separate study, naps of 30 or 90 seconds gave no clear benefit, while a 10-minute nap improved alertness and test performance.
- 5A research review found that naps under about 30 minutes were linked to better alertness and performance in adults.
Why a short night catches up with you
After a short night, the pressure to sleep keeps building through the day. In the early afternoon, your body clock also adds a natural dip in alertness. Together they make the hours after lunch the hardest part of the day. Sleepiness slows reaction times and makes small mistakes more likely, at a desk or behind the wheel. A brief nap clears some of that pressure without replacing a proper night of sleep.
The whole habit fits in a few words: short nap, early afternoon, alarm set. Each part does a specific job, explained below.
Why 20 minutes beats an hour
When you fall asleep, you pass through light sleep first. If you stay asleep much longer than about 20 to 30 minutes, you can slide into deep sleep. Waking from deep sleep often brings sleep inertia, the heavy, foggy feeling after a nap that can last a while. So more is not better here. A longer nap trades a better afternoon for a groggy one, and it can make it harder to fall asleep that night.
The timing matters for the same reason. A nap late in the day uses up some of the sleep pressure you need at bedtime. Napping in the early afternoon fits the natural dip and leaves the evening alone. Here is what the Adelaide study found for each nap length.
| Nap length | What happened afterwards |
|---|---|
| 5 minutes | Little change compared with no nap |
| 10 minutes | Alertness improved right away, for up to about 2.5 hours |
| 20 minutes | Alertness improved, starting about half an hour after waking |
| 30 minutes | Grogginess first, then improvement |
What the research found
The main study, by Amber Brooks and Leon Lack in 2006, compared these nap lengths after a five-hour night. The 10-minute nap gave the quickest benefit, and the 20-minute nap a similar one that arrived a little later. An earlier study from the same lab found that naps of 30 or 90 seconds made no clear difference. Ten minutes of real sleep did. A 2010 review of the wider research found that naps under about 30 minutes were linked to better alertness and performance in adults.
These were small studies, mostly of healthy young adults napping in a quiet, dark lab bedroom. How well the results carry over to a noisy office, a parked car or older adults is less certain. The effects were real but modest: a nap took the edge off a short night. It did not make up for it.
Making it stick
Plan the nap for after lunch, when the dip arrives anyway. If you lie down at 1:30 p.m., an alarm at 1:55 gives you about five minutes to drift off and 20 minutes of sleep. Find your spot in advance: a sofa, a quiet room, or a parked car with the seat tipped back. Expect to hear yourself say you will just rest your eyes for a moment. The alarm is there for exactly that moment.
On a bad day you may not fall asleep at all, and that is fine. Lying still with your eyes closed is still a break, so get up when the alarm sounds either way. Over time you become someone who handles a rough night calmly: short nap, early afternoon, alarm set. If you feel very sleepy most days even after enough time in bed, or you nod off without meaning to, see a doctor. And when you are drowsy, do not drive until you have rested. Where could you lie down for 25 minutes after lunch tomorrow?
Action steps
- 1Choose your nap spot today. Pick a quiet place you can use after lunch, like a sofa, a spare room or a parked car, and keep an eye mask or scarf there.
- 2Set an alarm for 20 minutes plus five minutes. After lunch on a day following a short night, lie down before 3 p.m. and set the alarm before you close your eyes.
- 3Get up when the alarm goes. Stand up, open the curtains or step outside, and drink some water, giving yourself 10 to 15 minutes before demanding tasks.
Suggested routines
- Irregular sleep schedule
Wake up at the same time every day
Going to bed and waking at regular times is linked to a lower risk of early death, more strongly than total hours slept.
- Trouble falling asleep
Get 10 minutes of outdoor light after waking
People who get more bright light in the morning tend to fall asleep faster at night.
- Poor sleep quality
Stop drinking coffee 9 hours before bed
Studies show mistimed caffeine use reduces total sleep by about 45 minutes and deep sleep by 11.4 minutes.
References
- Brooks, A., et al. (2006). A brief afternoon nap following nocturnal sleep restriction: which nap duration is most recuperative? Sleep, 29(6), 831–840. doi.org/10.1093/sleep/29.6.831
- Tietzel, A. J., et al. (2002). The recuperative value of brief and ultra-brief naps on alertness and cognitive performance. Journal of Sleep Research, 11(3), 213–218. doi.org/10.1046/j.1365-2869.2002.00299.x
- Lovato, N., et al. (2010). The effects of napping on cognitive functioning. Progress in Brain Research, 185, 155–166. doi.org/10.1016/B978-0-444-53702-7.00009-9