Preschoolers Who Sleep Less Weigh More by Age 7
Amount of Sleep Linked to Kids' Weight and Body Fat
Tracking Childhood Sleep and Body Weight
For the study, researchers followed 244 children from ages 3 through 7, regularly checking their sleep time, physical activity, diet, body mass, and fat distribution.
Unlike previous research, which has typically relied on parents to report how long children are sleeping, this study also used a more direct measure: movement sensors that were worn by the children around their waists.
Researchers found that children slept an average of about 11 hours daily, with nearly all children in the study sleeping somewhere between 9.5 hours and 12.5 hours each day, including naps.
Even after accounting for diet, physical activity, and a host of other factors known to influence weight, each additional hour of daily sleep children logged from age 3 to age 5 was associated with about a half-point drop in the kids' body mass index (BMI) by age 7.
In a child of average height, that amounts to 1.5 pounds.
Children at the low end of the sleep scale had more body fat than children who got more sleep. There was no difference in muscle between shorter and longer sleepers.
Advice to Parents
Though this study shows a link between children's sleep and body weight, it doesn't prove that getting less sleep causes weight gain. And the researchers stopped short of offering parents advice about how long kids should be sleeping or what to do if they are worried that their children aren’t sleeping enough.
According to the National Sleep Foundation, children need between 11 and 13 hours of sleep for kids ages 3-5.
If children don’t seem to be hitting those targets, Garrison says parents should look at lifestyle factors that might be hampering a regular sleep routine.
“For kids this age, a lot of things can affect sleep quality, like TV use and physical activity,” she says.