Scoffing down too much cake and candy may not be the only thing expanding Little Timmy's burgeoning waistline. Kids who aren't getting enough shuteye could also be at an increased risk for being overweight, according to research published in the November issue of the journal Pediatrics.
In a study that examined the relationship between sleep duration and overweight risk for third-grade and sixth-grade children, researchers from the University of Michigan C.S. Mott Children's Hospital discovered that children who got fewer than 9 hours of sleep each day were more likely to be overweight, regardless of gender, race, socioeconomic status, or quality of life at home.According to their findings, sixth graders who slept less were more likely to be overweight, while third-graders who got fewer hours of sleep, no matter what their body mass index (BMI) was, were more likely to pack on the pounds in sixth grade.
"Many children aren't getting enough sleep, and that lack of sleep may not only be making them moody or preventing them from being alert and ready to learn at school, it may also be leading to a higher risk of being overweight," said study lead author Julie C. Lumeng, M.D., assistant research scientist at the U-M Center for Human Growth and Development, in a press release.
"This study suggests that an increased risk for overweight is yet another potential consequence of short sleep duration, providing an additional reason to ensure that children are receiving adequate sleep, primarily through enforcing an age-appropriate bed time."
The study results further revealed that every additional hour of sleep in sixth grade made a child 20 percent less likely to be overweight; every extra hour of sleep in third grade resulted in a 40 percent decrease in the child's risk of being overweight in sixth grade.
"Sleep may have a behavior impact on children," said Lumeng. "In other words, children who are better rested may have more energy to get more exercise. For example, they may be more likely to go out and play, as opposed to lying on the couch watching TV. It also is possible that when children are tired, they may be more irritable or moody, and may use food to regulate their mood."
Lumeng points to emerging research that shows a connection between sleep disruption and hormones that regulate fat storage, appetite, and glucose metabolism. Because less sleep alters carbohydrate metabolism and leads to impaired glucose tolerance, it can affect a person's weight.
"So weight gain may not be a result of sleep's effect on behavior, but rather sleep's effect on hormone secretion in the body, specifically, leptin and grehlin," says Lumeng, who notes that sleep and leptin secretion in children is an important area for future research.
According to the National Sleep Foundation, these are the basic daily sleep requirements for children, adolescents, pre-teens and teens:
• Preschoolers: 11-13 hours
• Elementary school students: 10-12 hours
• Pre-teens: 9 - 11 hours
• Teens: 8 Â½ - 9 hours