Taking a nap, we've seen time and again, is like rebooting your brain. But napping may be as much of an art as it is a science. Scientists offer recommendations for planning your perfect nap, including how long to nap and when.
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.
For the rest of the story: http://www.altering-perspectives.com/2013/09/how-long-to-nap-for-biggest-brain.html