Less than 9 hours sleep linked to obesity in children

Last update: November 14, 2007 - 7:27 PM

Elementary school children who don't get enough sleep in third grade are more likely than their peers to be overweight in sixth grade, according to a large study believed to be the first to examine the relationship between excess fat and sleep in children. Studies of adults have found a similar association between sleep duration and excess weight.

Researchers led by pediatrician Julie C. Lumeng at the University of Michigan reported last week in the journal Pediatrics that children ages 9 to 12 who routinely got less than nine hours of sleep per night were at increased risk of being overweight, regardless of their sex, race, socioeconomic status or the level of chaos in the home.

Lumeng and her colleagues also found no association between sleep problems, such as trouble falling asleep or staying in bed, and excess weight.

Using data from a large federally funded study of youth development, researchers found that among sixth-graders, for every additional hour of sleep beyond nine hours, a child was 20 percent less likely to be overweight.

Half of the nearly 800 children in the study were boys, and 81 percent were white. Overall, 18 percent were overweight; boys were more likely to be overweight than girls.

The authors write that the findings suggest "a biological link between sleep duration and obesity" possibly caused by alterations in metabolism and the secretion of hormones that help control weight. Regardless of the mechanism, they conclude that their findings provide "an additional reason to ensure that children are receiving adequate sleep, primarily through enforcing an age-appropriate bedtime."

The National Sleep Foundation recommends that elementary school students sleep 10 to 12 hours per night.

WASHINGTON POST

SIGNS GET SHOPPERS TO TAKE STAIRS

Attention all shoppers: taking the stairs protects your heart.

That's the message researchers tried at a suburban shopping mall by putting up colorful signs along the steps of a staircase, and it worked. Over six weeks, use of the stairway next to an escalator more than doubled.

Normally, about 4 percent of people at the mall take the stairs but after adding the signs, that went up to nearly 10 percent. The findings were recently published in the American Journal of Health Promotion.

"A certain segment of the population clearly responds to these messages," said Frank Eves, one of the study's authors, and a senior lecturer in applied psychology at the University of Birmingham.

Eves and colleagues counted the number of people at a mall who climbed the 15 steps before the signs went up and after they were posted. They counted more than 82,000 shoppers at the mall in Coventry in western England. "If we can persuade more people to take the stairs, then we might really have something in the war against obesity," he said.

With fewer daily opportunities for physical activity in modern society, public health officials are increasingly focusing on stairs at schools, workplaces, and even the mall. Past studies have also shown that the decision to take stairs can be manipulated relatively easily with a few signs. Still, experts think that to change behavior long-term, the signs need to be seen regularly.

ASSOCIATED PRESS

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