The average adult only gets about six hours of sleep a night—two hours less than the recommended amount. The key to staying alert and functioning is making up some of the deficit with a little midday shut-eye.

But in America's multi-tasking, double-caff, workaholic culture, sleeping during the day is often thought of as a sign of weakness. Even though a NASA study led by the University of Pennsylvania School of Medicine found that a 30 to 40 minute nap significantly increases alertness and memory by up to 100%. Other studies have found that a 20 minute nap is more effective than a grande-sized Starbucks coffee or a bout of exercise.

Break up your busy days with a nap and return to the second part of your day as rested, refreshed and energetic as you were in the first. Here's how to do it.