CHICAGO (AP) -- Writing in the journal Pediatrics, researchers have found that every additional hour per night that a third-grader spends sleeping reduces his or her chances of being obese in the sixth grade -- by 40 percent.
The lead researcher says the less sleep third-grade kids got, the more likely they were to be obese in the sixth grade, no matter what the child's weight was in the earlier grade. If there's a magic number for the third-graders, it's nine hours, 45 minutes of sleep.
A University of Michigan doctor who led the research says tired kids are less likely to exercise and more likely to sit on the couch and eat cookies.
An endocrinologist at the University of Chicago who wasn't involved in the new study says lack of sleep plays havoc with two hormones that are the "yin and yang of appetite regulation."
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