The Science Behind Power Naps - National Sleep Foundation

Few of us enjoy jobs that allow an afternoon siesta, but we’d probably all be better off if they did--including our employers. According to new research, all we’d really need is a solid 10-minute power nap to boost our focus and productivity.

Researchers tested four nap time spans: 5, 10, 20 and 30 minutes (and a control group that didn’t nap). They then tested participants across several benefits for three hours after the nap. Here’s a summary of the results:

The 5-minute nap produced few benefits in comparison with the no-nap control.  The 10-minute nap produced immediate improvements in all outcome measures (including sleep latency, subjective sleepiness, fatigue, vigor, and cognitive performance), with some of these benefits maintained for as long as 155 minutes.The 20-minute nap was associated with improvements emerging 35 minutes after napping and lasting up to 125 minutes after napping. The 30-minute nap produced a period of impaired alertness and performance immediately after napping, indicative of sleep inertia, followed by improvements lasting up to 155 minutes after the nap.

The problem is that naps are awfully hard to cut down to 10 minutes; once you get a little taste, it's tempting to just keep sleeping. But as this and other studies indicate, longer naps are not the best naps. Snooze for just 30 minutes and you fall into sleep inertia,  the feeling of grogginess and disorientation that comes with awakening from a deep sleep.

Another thing to remember about naps is that timing is everything. If you nap too late in the day, you'll interfere with your body's circadian rhythm and will probably sleep poorly at night. Best times to nap are mid to late morning or early afternoon.