Sleep May Help Kids Keep Slim

Children who get more rest less prone to weight problems, study finds.

By Juhie Bhatia
HealthDay Reporter
Wednesday, February 7, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

WEDNESDAY, Feb. 7 (HealthDay News) -- Eating right and being active are well-known ways to try to keep a child's weight in check, but a new study points to another potential weapon in the fight against childhood obesity -- sleep.

Researchers at Northwestern University found that children who get more sleep tend to have a lower body mass index (BMI, a ratio of weight to height) and are less likely to be overweight five years later, than kids who get less sleep.

Sleeping an extra hour a night reduced the chance of being overweight from 36 percent to 30 percent in young children, and from 34 percent to 30 percent in older children.

The study is published in the January/February issue of the journal Child Development.

"Our study adds to the growing literature about the connection between sleep and weight," said Emily Snell, the study's lead author and a doctoral student in Northwestern's department of human development and social policy. "Other studies have found that sleep and weight are related in adults and kids, but it's not clear if sleep affects weight, or vice versa. We accounted for that by factoring in how much the kids already weighed," Snell said.

The researchers did this by collecting data in two waves. They started by looking at 2,281 children from a national survey called the Child Development Supplement of the Panel Survey of Income Dynamics. The kids were ages of 3 to 12 at the start of the study, and follow-up information was collected five years later. Parents and/or the children were given "time diaries" to record sleep information, such as the total number of hours the child slept, bedtimes, and wake times.

Analysis of the diaries showed that children who slept less, went to bed later, or got up earlier during the first assessment had higher BMIs five years later and were more likely to be overweight. The research also showed that a later bedtime had a greater effect on whether children aged 3 to 8 became overweight, while earlier wake times played a greater role for children aged 8 to 13.