Stan, sleep medicine center at the university of creator, m.d., Ph.D., William.Diamond in his new book, author wrote in the promise of sleep the night sleep focus is to consistently adhere to at least eight hours of sleep a day.Some people say: that's good, weekend I usually sleep 12 hours a day.However, if a night of the week, you only slept for 5 hours, average calculation, amount of sleep you still do not meet minimum standards.

Although most experts agree, sleep in the afternoon nap can help restore one morning nervous study and work and the consumption of energy, however, sporadic nap or nap cannot make up for the damage due to long-term lack of sleep.A warning: the nap for half an hour later, the human body into deep sleep state, when woke up, the body will feel dull laziness.So, the expert suggests to sleepy, take a nap and nap time reduced to half an hour.