People who sleep for less than six hours a night risk premature death, scientists have claimed.
“Unequivocal evidence” of a direct link between sleeping less than six hours a night and an early death was found by scientists analysing data from 16 studies involving more than 1.5 million participants.
Those who got less than six hours sleep a night were 12 per cent more likely to die over a period of 25 years compared to those who slept for the recommended six to eight hours a night.
Sleeping for more than nine hours a night was also linked to premature death, but this is thought to be because long-sleeping is a marker of serious underlying illness and not the effect of sleep itself.
Professor Francesco Cappucio, head of the sleep health and society programme at the University of Warwick, said: “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 full-time workers, suggesting that it may be due to societal pressures for longer working hours and more shift-work. On the other hand, the deterioration of our health status is often accompanied by an extension of our sleeping time.”
The research, reported in the journal Sleep, reviewed 16 prospective studies from the UK, US, Europe and Asia which together monitored more than 1.3 million people for up to 25 years.