Study questions link between sleep and obesity

Despite some international studies suggesting short sleep duration in children is associated with increased risk of obesity, the study found short sleep in adolescence had no relationship to obesity.

The study, which was published in Sleep, examined the sleep habits of 133 obese adolescents aged 10-16 at a weight management clinic in the United States.

Those taking part had their sleep monitored for a week by their parents and a wristwatch-sized device on their arms. Their weight was measured and each participant was tested for metabolic syndrome, a collection of risk factors including obesity and high blood pressure which increase a person's risk for developing cardiovascular disease.

Researchers found those taking part on average slept less than the recommended guidelines of more than eight hours a night. More than half experienced some degree of sleep disordered breathing and nearly a quarter had metabolic syndrome.

The researchers found no links between shorter sleep duration and more severe obesity.

Lead researcher, Dr Valerie Sung said based on their findings it was premature to expect that lengthening sleep will improve BMI [body mass index] for obese adolescents.

"My study showed that shorter sleep duration was not associated with more severe obesity, and longer sleep duration was in fact associated with worse cholesterol and triglyceride profiles, indicating that in this group of obese adolescents, lengthening sleep duration did not help with improving their metabolic risk or cardiovascular morbidity," she said.

"Despite evidence in adults that short sleep duration is related to increased metabolic risk factors, we did not see this relationship in teenagers - if anything, short sleep duration was associated with better triglyceride and cholesterol levels."