NEW YORK (Reuters Health) - Consistently getting a good night’s sleep may help protect children from becoming obese as adults, a study published Monday suggests.
Researchers found that among more than 1,000 people followed from birth to age 32, those who got too little sleep as children were more likely than their well-rested counterparts to become obese adults.
Even with a range of other factors considered — like childhood weight and TV habits, and adulthood exercise levels — there remained a link between sleep deprivation during childhood and obesity risk later in life.
All of this supports the idea that early sleep habits have a direct effect on weight in the long term, according to Dr. Robert John Hancox, the study’s senior author.
“Although we cannot prove that this is a cause-and-effect relationship,” he told Reuters Health, “this study provides strong evidence that it probably is.”
Hancox and his colleagues at the University of Otago in Dunedin, New Zealand, report the findings in the journal Pediatrics.
A number of studies have found that sleep-deprived adults and children are at greater risk of being overweight. However, this is the first study to show a long-term relationship between sleep and obesity risk, Hancox said.
The study involved 1,037 men and women who had been followed since their birth, between 1972 and 1973, up to the age of 32. When the participants were 5, 7, 9 and 11 years old, their parents reported on their usual bed time and wake-up time.
In general, Hancox and his colleagues found, as childhood sleep time declined, adulthood body mass index, or BMI, climbed.
Adults who had been “short sleepers” as children — averaging fewer than 11 hours in bed each night — generally had a higher BMI than those who’d gotten more sleep as kids.
“Importantly, this is not because children who were short sleepers grew up to be short sleepers as adults,” Hancox pointed out. “In other words, inadequate sleep in childhood appears to have long-lasting consequences.”
The findings, according to the researchers, suggest that weight control may stand as another reason for children to get a good night’s sleep. Experts generally recommend that children between the ages of 5 and 12 sleep for about 11 hours each night, while teenagers should get 8.5 to 9.5 hours.
It’s thought that children today are getting less sleep than the generations before them did, Hancox noted. That trend, he added, could be helping to feed the rise in obesity.
No one knows for certain why lack of sleep is linked to heavier weight. One theory, based on research in the sleep lab, is that sleep deprivation alters the normal balance of appetite-stimulating and appetite-suppressing hormones. Sleepy children may also be too tired for physical activity during the day.
SOURCE: Pediatrics, November 2008.