A power nap should last 10 to 20 minutes. That's long enough to leave you more alert, and short enough that you wake from light sleep rather than deep sleep, so you skip the grogginess. If you need more, go for a whole 90-minute cycle. Naps in between, of 30 to 60 minutes, are the ones most likely to leave you feeling worse.
What the research found
- Ten minutes was the sweet spot in a 2006 study by Amber Brooks and Leon Lack, who compared afternoon naps of 5, 10, 20 and 30 minutes. The 10-minute nap gave immediate improvements in alertness and performance that lasted a couple of hours. Five minutes did little; 20 and 30 minutes helped too, but only after a period of grogginess.
- The NASA nap. In NASA's study of long-haul pilots in the early 1990s, crews allowed a 40-minute rest in their seats slept about 26 minutes on average and were measurably more alert afterwards than crews who didn't rest.
- Longer naps for learning. Sara Mednick and colleagues found that a 60 to 90-minute nap, including deep and REM sleep, improved performance on a perceptual learning task about as much as a full night's sleep.
Nap lengths at a glance
| Nap | What you get |
|---|---|
| 10 minutes | Quick boost, almost no grogginess |
| 20 minutes | Stronger boost; you may feel slow for a few minutes |
| 30–60 minutes | Risk of waking from deep sleep: groggy for up to half an hour |
| 90 minutes | A full cycle; good after a short night, but can affect that night's sleep |
When to nap
Early afternoon, roughly 1 to 3 PM, is ideal for most people: the body clock dips anyway, and it's late enough not to replace morning alertness and early enough not to spoil the night. Avoid napping in the six or so hours before bed. Night owls can shift that window later; see the chronotype quiz.
The coffee nap
Drink a coffee, then immediately nap for 15 to 20 minutes. Caffeine takes about 20 minutes to start working, so it kicks in as you wake. Studies, including Jim Horne and Louise Reyner's work with sleepy drivers, found the combination worked better than either alone. Keep it to the early afternoon: caffeine's half-life is around five hours.
How to nap well
- Set an alarm. The power nap timer adds a few minutes for falling asleep.
- Dark and quiet: an eye mask, earplugs or some brown noise.
- Lie down if you can; sitting with your head supported works too.
- Don't worry if you don't fully fall asleep. Quiet rest still helps.
- Get up with the alarm, and find some daylight.
If you need a nap every day
Regular naps are fine if they help. But if you're sleepy every afternoon despite seven hours or more at night, or you fall asleep without meaning to, it's worth talking to a doctor.
After the nap
The half hour after a good nap is a great time to focus. Book it in Flight: pick a short hop, and work until you land.