Optimal Duration of Sleep

Most of the people require five to seven hours of sleep at night.

clipped from news.bbc.co.uk Lack of sleep 'linked to early death' Getting less than six hours sleep a night can lead to an early grave, UK and Italian researchers have warned. They said people regularly having such little sleep were 12% more likely to die over a 25-year period than those who got an "ideal" six to eight hours. They also found an association between sleeping for more than nine hours and early death, although that much sleep may merely be a marker of ill health. "Sleep is just a litmus paper to physical and mental health. Sleep is affected by many diseases and conditions, including depression," he said. And getting improved sleep may not make someone better or live longer, he said. "But having less than five hours a night suggests something is probably not right. "Five hours is insufficient for most people and being drowsy in the day increases your risk of having an accident if driving or operating dangerous machinery."