Wikipedia defines power nap as a short sleep which terminates before the occurrence of deep sleep or what they call slow-wave sleep (SWS) intended to quickly revitalize the subject from drowsiness.
Power nap can make you alert and productive but only if it is correctly done. So how do you do it? It takes good practice to take a 20-minute nap and wake up renewed and alert once more for another four or five hours work.
First thing of course is for you to find a good place to nap. Back when I was still working, some of my office mates and I were so used to taking a 20-30 minute nap during lunch break. An hour break is good enough to take a light 10-minute lunch, another 10-minute walk from the bank canteen to the 4th floor and around 20-25 minutes of power napping. Of course, it is kind of different from your afternoon siesta wherein you can sleep leisurely to your heart’s content. Lying your head down on your desk for a quick snooze usually brings relaxation. Less stress at work makes you more productive. Research says that it is better to have that all important 20-minute nap than going back to bed in the morning for another hour of sleep.
Contrary to popular opinion, napping is not for the lazy people who’ve got nothing to do. Napping gives you that shot of physical and mental energy in the middle of the day. It’s like giving yourself that all important adrenalin shot, keeping you rested and energized.