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Lack of Sleep can lead to Weight Gain

Feb. 7, 2005 - It sounds like the best diet plan of all time - sleep more, weigh less. It could be a reality, say researchers who have reported evidence linking less sleep to obesity in the Archives of Internal Medicine.

Study co-author Dr. Robert Vorona, an assistant professor of sleep medicine at Eastern Virginia Medical School, suspects that lack of sleep sets off hormonal changes that affect appetite.

"It's very possible that, over the long haul, restrictions in sleep could contribute to an overweight condition, and even dispose you to obesity," Dr. Vorona says.

Sleep Problems Abound in the United States

According to the National Sleep Foundation (NSF), about 70 million people in the US are affected by a sleep problem. About 40 million Americans suffer from a chronic sleep disorder, and an additional 20 to 30 million are affected by intermittent sleep-related problems.

However, an overwhelming majority of sleep disorders remain undiagnosed and untreated.

According to a NSF Sleep in America poll, nearly seven out of 10 Americans said they experience frequent sleep problems, although most have not been diagnosed.

The NSF states that before Thomas Edison's invention of the light bulb, people slept an average of 10 hours a night; today Americans average 6.9 hours of sleep on weeknights and 7.5 hours per night on weekends.

Dr. Vorona acknowledges that his findings sound a bit odd, especially considering that people use more energy when they are awake.

"It's counterintuitive that restricting sleep should lead to obesity, that sleeping more should make you more apt to lose weight," he says. "That doesn't sound like it makes sense."

Other researchers are on the same track, however.

"There's a mounting body of evidence that suggests the systems that regulate sleep and appetite are linked," says Dr. Joseph Bass, a professor of medicine at Northwestern University Feinberg School of Medicine who studies sleep.

Lack of Sleep and Endocrine System Changes

Dr. Vorona and his colleagues first became interested in the link between sleep and obesity after reading that insufficient sleep disrupts the body's endocrine system, which regulates hormone levels. Dr. Vorona says they decided to launch a study to see if weight was affected, too.

The researchers surveyed 1,001 people from southeastern Virginia about their sleep habits. They also checked where the subjects landed on the body-mass index scale, which uses a mathematical formula to indicate whether a person is of normal weight, overweight, obese, or severely obese. The typical subject was 48 years old and obese.

The researchers found that people of normal weight got more sleep than their overweight and obese counterparts, by an average of 16 minutes per night, or 1.9 hours a week.

The research reflected previous studies in Japan that linked lack of sleep to obesity in children, notes Dr. Vorona.

The next step, Dr. Vorona explains, is to launch more definitive studies that will closely track how much people sleep each day - instead of relying on their own memories - and examine changes in sleep and obesity levels over time.

It is possible that further research into the link between insufficient sleep and obesity may explain why shift workers - who often do not get enough sleep - are more likely to develop diabetes, says Dr. Bass, who wrote a commentary that accompanies Dr. Vorona's study.

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