Science & Research

Study links sleep and obesity

During weeks of increased sleep, children produced lower amounts of hunger-inducing hormone leptin

By
Contributing Writer
Friday, November 15, 2013

Getting adequate sleep “could help prevent excess weight gain over time” in children, according to a new study conducted by Chantelle Hart, a former assistant professor of psychiatry and human behavior who is now an associate professor at Temple University.

The study, published online Nov. 4, examined how changing children’s sleep duration affected food intake, weight and appetite-regulating hormones.

Over the course of the three-week experiment, 37 children between the ages of 8 and 11 wore a device on their wrist that estimated the time they spent sleeping by measuring movement, and they completed sleep diaries. The researchers also asked children to adhere to specific bed times and wake times each week so that they experienced alternating weeks of increased and decreased sleep, with a three hour difference between the conditions.

Families also reported the food children had consumed during each 24-hour period of the experiment. Once a week, experimenters measured children’s height, weight and motivation to obtain a food reward, Hart wrote in an email to The Herald. They also collected blood samples.

The researchers found that during weeks of increased sleep, children consumed fewer calories and had lower levels of leptin, a hormone that signals hunger. They also weighed approximately half a pound less than they did in weeks of decreased sleep.

The study builds on past research that found similar results in adults, Hart wrote.

“There’s a growing concern in our society about obesity in children,” said Mary Carskadon, professor of psychiatry and human behavior at Alpert Medical School and one of the paper’s authors. The study “is really the first one to look at these measure and procedures in school-age children,” Carskadon said.

The most difficult aspect of conducting the study was recruiting participants, Carskadon said. “It’s always a challenge to find people who are willing to make these kinds of contributions to science.” It might have been better to have more participants, but “there were enough in the study for the measures to detect changes and for the hypotheses to be tested adequately,” she said. “It worked superbly.”

The researchers said they were not surprised by the findings. “The results mirror what we see in adults,” Carskadon said.

But “the consistency of these findings regarding changes in weight was striking,” Hart wrote.

“The fact that there was actually a weight change in such a short amount of time was very interesting,” said Joseph Fava, research associate at the Centers for Behavioral and Preventive Medicine and the Weight Control and Diabetes Research Center at The Miriam Hospital and one of the study’s co-authors.

The results of the study have many implications for determining what type of intervention could prevent weight gain and even ultimately help weight loss in children, Carskadon said.

Previous research has found that sleep is important for regulating cognitive function, emotions and memory consolidation. This study “is another arrow in the quiver for why adequate amounts of sleep are important for children,” Carskadon said.

Eliza Lawson, a health policy analyst at the Rhode Island Department of Health who was not involved in the study, said it was “interesting,” because it treats obesity wih appropriate nuance.

“It’s so much deeper than just educating people on what to eat and being active,” Lawson wrote in an email to The Herald.  “It looks like there is evidence that sleep is an influencer as well, and is something obesity prevention programs and healthcare professionals should consider when dealing with obesity.”

Currently, Hart is investigating whether “behavioral sleep intervention can enhance sleep and produce similar benefits in terms of eating behaviors and weight,” she wrote.