Who Needs Sleep?

It is, apparently, dangerous to have eight hours of sleep a night.

Adults who sleep eight hours a night or more die younger than those who only sleep six to seven hours a night.

A six-year study involving 1.1 million people published by Professor Daniel Kripke at the University of California in 2004 showed that a significantly larger number of people who slept eight or more hours (or less than four) a night died during the six-year study.

The average Briton gets between six and seven hours of sleep a night, which is one and a half hours less every night than our grandparents did. In 1900 a normal night's sleep was nine hours.

There is evidence to suggest that sleep deprivation leads to short-term loss of IQ, memory, and the ability to reason.

Leonardo da Vinci spent almost half his life sleeping. Like Einstein, he took short naps during the day, in his case, fifteen minutes every four hours. The great lexicographer Dr. Johnson rarely got up before noon. The French philosopher Pascal also spent much of his day dozing in bed.

On the other hand, the famously long-lived elephant sleeps for only two hours a day. Koalas sleep for twenty two hours a day, but only live ten years. Ants sleep for only a few minutes a day.

The average person takes seven minutes to fall asleep. Normal healthy sleepers wake up between fifteen and thirty-five times every night.

Twenty percent of UK motorway accidents are caused by drivers falling asleep at the wheel.