New study says it’s OK to take a nap, but not a long one. The sweet spot is 20 to 30 minutes. If you nap any longer than that, you start getting into deeper stages of sleep, and can wake up feeling groggy. Just 20 to 30 minutes is enough to give you a boost in energy, help you focus, and improve your mood.

Expert say we should set an alarm for 30 minutes.  That gives us five to ten minutes to fall asleep, and 20 minutes of actually sleep time.

Of course, you shouldn’t be napping at work, school, or driving.