Power Naps Bring Power

Sleep science is very curious about napping.  Some people do it, others avoid it, babies are multiple nappers, oldies need to avoid taking too many for too long. What and when and how is a nap?

Once upon a time when humans lived by the day-night cycle and seasons, with only fire to lighten the darkness, night sleep was longer (especially in winter) and was broken up into a “first” deep sleep followed by a long break awake, then a “second” sleep towards morning. A nap during the day helped avoid the tropical heat.  Like many animals, humans showed what we call polyphasic sleep (just look at your cat).  Of course, this is still visible in infants who sleep in small bouts throughout the day and night, and whose sleep only gradually coalesces into primarily nocturnal sleep with one or two naps during the day as they grow older. But in today’s society there is little time for adults to take a nap, nor is there widespread acceptance that they are useful, and not escapism.

In other words, naps are normal, and naps can restore alertness, energy and performance, even improving learning.

The key to a power nap is duration

The evidence from many careful studies of napping indicates that naps under 30 minutes are best. Shorter naps provided immediate benefit of feeling fitter and ready-to-go.  One of the problems of longer naps — indeed, a phenomenon we all know when waking up after a night’s sleep — is what we call “sleep inertia” or sleep drunkenness, that weird feeling of disorientation and slowed-down reactions that lasts about half an hour after waking.  So if you nap too long in the afternoon, you will wake up sleepy and fatigued and it will take some time until you are back in form.

Longer and frequent naps, especially for older people, are associated with poor health. These longer daytime naps are often associated with shorter and worse sleep at night, thus it is the total amount of sleep over 24 hours that counts in estimating healthy behavior.  One study followed elderly adults in the community for decades and found that naps of more than 30 minutes were associated with depressed mood, coronary heart disease, and cancer.

Don’t take your power nap too late

The classic post-prandial (post-lunch) early afternoon siesta is the right nap.  Timing is important – don’t nap in the late afternoon. If you do, the build-up of sleep pressure during waking will be reduced, so that when you try to go to sleep at night there’s not enough sleep pressure left!

Strategic Napping

Under some circumstances napping may be essential.

If you:

  • have to drive at night, a short nap beforehand can increase alertness and reduce the chances of a car accident.
  • take a midday nap of 20 to 30 minutes, mood improves.
  • suffer from narcolepsy — excessive daytime sleepiness, uncontrollable sleep attacks, and sudden loss of muscle tone — multiple brief daytime naps can help you manage this risk.