Why Sleepless Nights Can Mean Piling on the Pounds

Daily Mail

05-26-06

WOMEN who do not get enough sleep are more likely to pile on the pounds, research shows.

Scientists found women who sleep for five hours or less a night typically weigh more than those who get at least seven hours.

And over a 16-year period they are more likely to end up obese than those who get plenty of sleep.

Researchers said it was not entirely clear why a lack of sleep makes women put on weight, but it may disrupt the body's normal metabolism.

They also suggested that those who do not get enough sleep may move around less during the day and so burn off fewer calories.

The study, presented yesterday at the American Thoracic Society International Conference in San Diego, California, underlines the importance of getting a good night's sleep.

Experts have warned previously that middle-aged people who sleep for less than five hours a night are more likely to suffer high blood pressure.

Rest is also vital for boosting long-term memory by helping consolidate the day's events in the brain.

Many people struggle to get a good night's sleep, with only one in five achieving eight hours a night.

In some parts of the UK, half the population are regularly surviving on just five hours of sleep. In the American study, a team from the Case Western Reserve University in Cleveland, Ohio, followed almost 70,000 middle-aged women for 16 years.

By the end, women who slept less than five hours were 32 per cent more likely to have experienced major weight gain classed as increasing their weight by 33lb than those who slept for seven hours each night.

Women who slept for five hours or less were also 15 per cent more likely to be obese at the end of the research.

Women who slept for six hours were 12 per cent more likely to have had major weight gain and a 6 per cent greater risk of obesity than those who slept for seven hours.

At the beginning of the study, on average women who slept for five hours or less a night weighed 5.4lb more than those getting seven hours or more, and ten years later had added on average another 1.6lb to their weight.

Lead researcher Sanjay Patel said: 'That may not sound much but it is an average amount some women gained much more than that and even a small difference in weight can increase the risk of health problems such as diabetes and hypertension.' Dr Patel looked at what the women ate and their exercise levels to see if this could explain the trends. But she found that women who slept for five hours actually ate less than the others and both groups did similar amounts of exercise.

Dr Patel said: 'We don't have an answer from this study about why reduced sleep causes weight gain but there are some possibilities that deserve further study.

Sleeping less may affect changes in a person's basal metabolic rate the number of calories you burn when you rest.' She said scientists have also recently discovered that involuntary activity, such as fidgeting or standing up instead of sitting down, can also have an effect on weight loss.

'It may be that if you sleep less, you move around less too and therefore burn up fewer calories,' she suggested.