Thursday, September 27, 2007

Lack of sleep may be deadly, says study

26 Sep 2007, ST

People who sleep less than five hours are twice as likely to die of heart disease

LONDON - People who do not get enough sleep face more than double the risk of dying of heart disease, according to a British study released on Monday.

Although the reasons are unclear, researchers said lack of sleep appeared to be linked to increased blood pressure, which is known to raise the risk of heart attacks and stroke.

A 17-year analysis of 10,000 government workers showed those who cut their sleep from seven hours a night to five or less faced a 1.7-fold increased risk of death from all causes and more than double the risk of cardiovascular death.

The findings highlight a danger in busy modern lifestyles, according to professor of cardiovascular medicine at the University of Warwick's medical school Francesco Cappuccio.

Speaking to the annual conference of the British Sleep Society in Cambridge, he said: 'A third of the population of the United Kingdom and over 40 per cent in the United States regularly sleep less than five hours a night, so it is not a trivial problem.

'The current pressures in society to cut out sleep, in order to squeeze in more, may not be a good idea - particularly if you go below five hours.'

Previous research has highlighted the potential health risks of shift work and disrupted sleep.

But the study by Prof Cappuccio and colleagues, which was supported by British government and US funding, is the first to link duration of sleep and mortality rates.

The study looked at sleep patterns of participants aged 35 to 55 at two points in their lives - 1985 to 1988 and 1992 to 1993 - and then tracked their mortality rates until 2004.

The results were adjusted to take account of other possible risk factors such as initial age, sex, smoking and alcohol consumption, body mass index, blood pressure and cholesterol.

The correlation with cardiovascular risk in those who slept less in the 1990s than in the 1980s was clear but, curiously, there was also a higher mortality rate in people who increased their sleep to more than nine hours.

In this case, however, there was no cardiovascular link.

Prof Cappuccio said it was possible that longer sleeping could be related to other health problems such as depression or cancer-related fatigue.

'In terms of prevention, our findings indicate that consistently sleeping around seven hours per night is optimal for health,' he said.

Reuters


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