Weight Loss Blog

Children lacking enough shut-eye face a greater risk of becoming obese than kids who get a good night’s sleep, according to a study released Thursday.

Each extra hour of sleep cuts a child’s risk of becoming overweight or obese by nine percent, according to an analysis of epidiomogical studies by researchers from Johns Hopkins Bloomberg School of Public Health.

By contrast, children who got the least sleep had a 92 percent higher change of being overweight or obese than children who slept enough, said the study published in the journal Obesity.

“Our analysis of the data shows a clear association between sleep duration and the risk for overweight or obesity in children. The risk declined with more sleep,” said Youfa Wang, a senior author of the study.

“Desirable sleep behavior may be an important low cost means for preventing childhood obesity and should be considered in future intervention studies,” Wang said in a news release.

“Our findings may also have important implications in societies where children do not have adequate sleep due to the pressure for academic excellence and where the prevalence of obesity is rising, such as in many East Asian countries.”

The researchers reviewed 17 published studies on sleep duration and childhood obesity.

Some research recommends that children under five years old sleep 11 hours or more a day, while children age five to 10 should get 10 or more hours of sleep, and children older than 10 should sleep at least nine hours.

Want to lose weight? Try sleeping more

If you want to lose weight, get more sleep. In a new article appearing in the current issue of Obesity Reviews, University of Michigan researcher Michael Sivak presents calculations showing that replacing one hour of inactive wakefulness—such as watching television—with sleep can result in a 6 percent reduction in caloric intake.
“Caloric consumption in a society with readily available food is likely to be approximately proportional to the number of hours of being awake,” said Sivak, head of the Human Factors Division at the U-M Transportation Research Institute. “By replacing one hour of being awake with sleeping, we forgo a significant consumption of food because of the resulting reduction in the opportunity to eat.”

Sivak says that a person who sleeps seven hours a night and consumes 2,500 calories during the remaining 17 hours of the day can cut 147 calories by simply sleeping an extra hour instead of watching TV. He calculated that such a decrease in caloric intake would result in a body-weight reduction of about 14 pounds per year.

“Recent research has suggested that the levels of the hormones leptin and ghrelin mediate an association between lack of sleep and weight gain. But this may turn out to be only part of the story,” he said. “The behavioral, non-hormonal relationship between sleep and weight is another possible connection.

“To the extent that a large proportion of the population is both overweight and voluntarily sleep-deprived, replacing some sedentary activity with sleeping might offer a practical behavioral solution for a large segment of the overweight population.”