Infants and preschoolers who don’t get enough sleep at night are at increased risk for later childhood obesity, a new study suggests.
Over the past three decades, obesity rates have doubled among children age 2 to 5, and tripled among 6- to 11-year-olds. University of Washington maternal and child health researcher Janice Bell wanted to know whether sleep had anything to do with it.
For purposes of the study, the children were separated into a group of zero to 4 years old and an older group of 5 to 13 years old. Bell and her colleagues collected data first in 1997, and then again in 2002.
She looked at federal data collected on nearly 2,000 children and compared those who slept 10 hours or more a night with those who slept less. She also looked at how much the children weighed over the five-year period. The most striking findings had to do with infants and toddlers.
“They were nearly twice as likely to move from normal weight to overweight, or overweight to obese in that five-year period,” she says.
Bell’s study didn’t examine the reasons why children who sleep less have an increased risk of gaining weight within just a few years, but she does have some theories.
“It may be that children who don’t sleep enough at night are too tired to engage in the kind of physical activity that may prevent obesity,” Bell says. She adds that another reason may be the result of the relationships between hormones that control appetite and sleep.
Bell also says that napping isn’t a substitute for a good night’s sleep.
“Insufficient nighttime sleep among infants and preschool-aged children appears to be a lasting risk factor for subsequent obesity, while contemporaneous sleep appears to be important to weight status in adolescents,” Bell writes. “Napping had no effects on the development of obesity and is not a substitute for sufficient nighttime sleep.”
On average, doctors suggest children up to age 5 need at least 10 hours of sleep a night. Infants and young toddlers need even more.
The study appeared in an issue of Archives of Pediatrics and Adolescent Medicine.