I've never been much of a napper—have you? I find that I usually
wake up panicked and bewildered, negating any of the beauty of
the actual nap. But you know what? It turns out that I've
probably just been doing it wrong. Lots of us have!   Sleep
scientist David Dinges tells the Wall Street Journal: "You have
to be deliberative about when you're going to nap, how long
you're going to nap, and if you're trying to use the nap
relative to work or what you have coming up."  So! When should
you nap? Anywhere between 1 and 4 P.M. Napping later than that
will most likely interfere with nighttime sleep patterns.  OK,
now how long should you nap? 10 to 20 minutes: If all you're
looking for is a quick hit of alertness, experts say a power nap
is all you need to get an energy boost. (Note: If you find
yourself dreaming during the nap, that's a sign that you're
sleep-deprived.)  30 minutes: Sleeping for a half hour can lead
to grogginess upon waking; a kind of "sleep hangover" than can
last for 30 minutes before you start