CHICAGO — When babies sleep less, they may gain too much weight.
A new Harvard study finds that babies and toddlers who sleep less than 12 hours daily are at greater risk for being overweight in preschool, startling evidence that the link between sleep and obesity may affect even very young children.
TV viewing heightened the effect. The children who slept the least and watched the most television had the greatest chance of becoming obese.
“The two (behaviors) are acting independently. In combination, they are particularly risky,” said the study’s lead author, Dr. Elsie Taveras of Harvard Medical School.
The findings, published in April’s Archives of Pediatrics & Adolescent Medicine, are based on mothers’ reports of their babies’ sleep habits and TV viewing, and direct measures of the children’s height, weight and skinfold thickness.
Obesity was defined as having a body mass index in the 95th percentile or above. BMI is a measure that combines height and weight. A 3-year-old who is 3 feet, 3 inches tall and 40 pounds would be considered obese.
The researchers took into account other risk factors for obesity, including the TV viewing, and still found the children who slept fewer than 12 hours a day had a doubled risk of being obese at age 3.
Sleep’s impact on appetite hormones may explain the effect, Taveras said. In prior studies, sleep-deprived adults produced more hormone that promotes hunger, and less of a hormone that signals fullness.
TV viewing is thought to increase the risk of obesity because it takes time away from play and because of food ads for snacks and fast food.
