If you manage to get a good night's sleep on a regular basis your chances of staying slim or becoming slimmer are significantly higher, say researchers from Care Western University, Ohio, USA, after monitoring nearly 70,000 women for over a decade and-a-half. This is the largest study ever to examine the effects of sleep on weight over the long-term.

What constitutes a good night's sleep? For this study, the researchers observed the effect sleeping five or fewer hours regularly has on a woman's weight over the medium and long term. They compared them to women who managed to regularly get 7 hours' sleep each night.

The findings were presented at the American Thoracic Society International Conference, San Diego, California.

Women who don't get much sleep, up to five hours each night, are much more likely to have put on 33lbs (15 kilos) over a 16 year period - 30% more likely when compared to the women who managed to get 7 hours sleep each night. Light sleepers also have a significantly higher risk of becoming obese.

What surprised the researchers was that sleeping patterns had a much greater influence on women's long term weight than eating habits or physical activity.

At the start of the study, the women who slept up to five hours a night weighed 5.4 pounds more than those who got 7 hours or more. They also put on 1.6 pounds more each year than the good sleepers.

The researchers stressed that the 1.6 pounds extra per year may not sound like much, but this was an average. Multiply this number by ten and you are beginning to have a sizeable weight gap. Imagine what the difference would be over 20 or 30 years.

Dr. S Patel, lead researcher, said that hormones which regulate appetite are affected after just a few nights of sleep restriction. What surprised the researchers was that those who sleep less actually eat less than those who get adequate sleep. This shows that sleep is a much greater contributor to your long term weight than diet.

Dr Patel said he believes that people who sleep well fidget more during their waking hours - this helps them consume more calories. It is also most likely that hormones are tweaked in such a way as a result of how much we sleep - and this has a bearing on how many calories we burn off each day.

In order to stay/get slim, people have to focus on three factors:

-- Adequate sleep
-- Nutrition
-- Physical activity

Ask any professional sportsperson what the secret of top fitness is, and they will all say it is a combination of good training, eating the right foods and sleeping well - get one of those three factors wrong and you seriously undermine your chances of winning a race.

Written by: Christian Nordqvist
Editor: Medical News Today