By Tom Achebe
Twenty minutes helps. Ninety minutes can too. Anything in between is where naps go wrong.
A good nap is either short enough to stay in light sleep, or long enough to finish a full cycle. The groggy ones are the naps that wake you from deep sleep in the middle.
Twenty minutes, before three
For most people, a twenty-minute nap before mid-afternoon helps without costing anything at night. Set an alarm for twenty-five, to give yourself time to drift off.
The best nap ends before it gets interesting.
