Too little (and too much) sleep can increase risk of premature death, scientists reveal

By Daily Mail Reporter

Health risks: studies of more than one million people worldwide link irregular sleep and premature death

Getting just the right amount of sleep can quite literally be a matter of life and death, according to new research.
Scientists have revealed that sleeping less than six hours a night can increase the risk of an early death, while sleeping more than nine hours can also cut down life expectancy.
After analysing data from 16 studies, involving more than 1.5 million participants, researchers found 'unequivocal evidence' of a direct link between sleeping less than six hours a night and dying prematurely.
People who regularly had this little sleep 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.
An association was also seen between sleeping more than nine hours a night and early death.
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 people for up to 25 years.
In total, more than 100,000 deaths were recorded during the observation periods.
Pooling together data in this way, known as meta-analysis, can indicate patterns and trends that may not be obvious in individual studies.
Professor Cappucio, who worked with colleagues from the Federico II University Medical School in Naples, Italy, added: 'Consistently sleeping six to eight hours per night may be optimal for health.'