Perils of cutting down on your sleepNew research says it can increase risk of death

25 September 2007

Researchers are warning of the perils of cutting down on sleep to accommodate the 24/7 culture as a new study suggested it could almost double the risk of death.

Long-term research has shown those who reduced their sleep levels from seven hours to five hours or fewer faced a 1.7-fold increased risk in mortality and twice the increased risk of death from a cardiovascular problem.

Those who increased their sleep to eight hours or more a night were also more than twice as likely to die as those who had not changed their habits, but from predominantly non-cardiovascular disease.

However researchers said the increased risk for long sleepers might be a symptom of impending health problems.

Sleep patterns

The study by the University of Warwick and University College London, looked at how sleep patterns affected the mortality of 10,308 mainly white collar civil servants.

The data provided information on the same group at two points in their life - 1985-8 and those still alive in 1992-3.

Once adjustments were made for factors such as age, smoking status and illness, the study was able to isolate the effect that changes in sleep patterns over five years had on mortality rates 11 to 17 years later.

Currently around one third of the UK adult population regularly sleep five hours or fewer a night. The average night's sleep is seven hours.

Professor Francesco Cappuccio, of the University of Warwick medical school, told the British Sleep Society: 'Fewer hours sleep and greater levels of sleep disturbance have become widespread in industrialised societies.

'This change, largely the result of sleep curtailment to create more time for leisure and shift-work, has meant that reports of fatigue, tiredness and excessive daytime sleepiness are more common than a few decades ago.

'Sleep represents the daily process of physiological restitution and recovery, and lack of sleep has far-reaching effects.'

Hypertension

He added: 'Short sleep has been shown to be a risk factor for weight gain, hypertension and type 2 diabetes sometimes leading to mortality but in contrast to the short sleep-mortality association it appears that no potential mechanisms by which long sleep could be associated with increased mortality have yet been investigated.

'Some candidate causes for this include depression, low socio-economic status and cancer-related fatigue.

'In terms of prevention, our findings indicate that consistently sleeping around seven hours per night is optimal for health and a sustained reduction may predispose to ill-health.'

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