Sleep is inherently a vital requirement for most animals because it takes up one third of their life. During sleep, the body will release important hormones to help metabolism and accumulate energy for activities during the day. Not to mention it also helps the brain to systematically organize information and remember longer.
According to neuroscientist Matthew Walker of the University of California Berkeley (USA), the less sleep, the shorter the life cycle should all adults have to sleep 7-9 hours / night to be good. But not every time to sleep, because there are some times if we sleep will be harmful to health