The sleep experts in the article say a 10-to-20-minute power nap gives you the best "bang for your buck," but depending on what you want the nap to do for you, other durations might be ideal:
For a quick boost of alertness, experts say a 10-to-20-minute power nap is adequate for getting back to work in a pinch.
For cognitive memory processing, however, a 60-minute nap may do more good, Dr. Mednick said. Including slow-wave sleep helps with remembering facts, places and faces. The downside: some grogginess upon waking.
Finally, the 90-minute nap will likely involve a full cycle of sleep, which aids creativity and emotional and procedural memory, such as learning how to ride a bike. Waking up after REM sleep usually means a minimal amount of sleep inertia, Dr. Mednick said.
In addition to those recommendations, one surprising suggestion is to sit slightly upright during your nap, because it will help you avoid a deep sleep. And if you find yourself dreaming during your power naps, it may be a sign you're sleep deprived. While you're planning your nap, don't forget to time it during the right time of day as well.