Too much or too little sleep 'can cause premature death'

A major international study, published in the 'Sleep' journal, has found that sleeping less than six hours a night can increase the risk of an early death, while sleeping more than nine hours daily can also cut down life expectancy.

In fact, the scientists have based their findings on an analysis of data from 16 researches from Europe, the US and Asia, involving more than 1.5 million people worldwide for up to 25 years.

People who regularly had sleep less than six hours were 12 per cent more likely to die over a period of 25 years or less than those who got the recommended six to eight hours. A link was also seen between sleeping more than nine hours a night and early death, the 'Daily Mail' reported.

In total, more than 100,000 deaths were recorded during the observation periods, the scientists say.

"Consistently sleeping six to eight hours per night may be optimal for health. While short sleep may represent a cause of ill-health, long sleep is believed to represent more an indicator of ill-health.

"Modern society has seen a gradual reduction in the average amount of sleep people take, and this pattern is more common among fulltime workers, suggesting that it may be due to societal pressures for longer working hours.

"On the other hand, the deterioration of our health status is often accompanied by an extension of our sleeping time," Professor Francesco Cappucio of University of Warwick. who led the study, was quoted as saying.