Why do we need to sleep?

We sleep primarily to prevent sleepiness, but sleep seems to serve several useful functions. Although they are not sure why, researchers claim it is as necessary to life as eating and drinking.

• Marginal lack of sleep can cause headaches, daytime tiredness and irritability, and leave you functioning below par.
• Chronic lack of sleep can impair growth, reduce immunity to infection, and seriously affect concentration and decision-making abilities. It can also cause or worsen depression and other mental health problems, cause hallucinations and anti-social behaviour, and reduce sex drive. Laboratory animals deprived of sleep die very quickly, and some research suggests that chronic poor sleepers have a shorter life expectancy than those who sleep well.