The report is published online Jan. 24 in advance of print publication in the February issue of Pediatrics.
Gozal says that other studies have shown that inadequate sleep has biological effects, including high blood sugar and cravings for sweet and high-fat foods. Insufficient sleep also makes it harder to lose weight, he said.
"All this would suggest that sleep is an important regulator of metabolism," Gozal said. "If we abuse our sleep by not sleeping enough, then we are likely to pay the price by being heavy and being at risk for cardiovascular and all the other metabolic complications," he said.
Children are sleeping less for various reasons, Gozal said. Busy family schedules and electronic media -- cell phones, computers and TV -- interfere with healthy bedtime routines. The result is that sleep suffers, he said, noting that while bedtime can be extended, we still have to get up at the same time.
"Children should follow a regular [sleep] schedule," Gozal said. "Follow the rule of sleep and you will be happy," he urged.
Frederick J. Zimmerman, of the department of health services at the University of California Los Angeles, said the study largely confirms earlier research that found inadequate sleep is a risk factor for obesity among children.
The new research offers a "tantalizing suggestion that sleep that is inadequate both in duration and in consistency may have adverse metabolic effects," he added. However, it does not explain why obesity and sleep are related, Zimmerman said.
"It could be that obesity causes disturbed sleep or that inadequate sleep increases the risk of obesity. It could also be that a third factor, such as nighttime television, may lead both to obesity and to poor sleep," he said.
Despite these uncertainties, the consensus is that parents should create an environment in which children can consistently get adequate, restful sleep, Zimmerman said.
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