Mothers nagging kids to bed early is a common scenario. There are more significant reasons to it than to merely get rid of them and be relieved from babysitting. While the most popular benefit of sleep is to help kids grow taller and healthier, researchers have discovered that every additional hour per night a third-grader spends sleeping reduces the child's chances of being overweight in sixth grade by 40 percent.

According to Dr. Julie Lumeng of the University of Michigan, kids need at least 9 hours and 45 minutes of sleep everyday. The lesser they sleep, the higher the risk of obesity in sixth grade, regardless of the child's weight during third grade, said Lumeng who led the research.

This report will surely give a lot of parents additional reason to enforce early bedtime rules, restrict caffeine consumption as well as limit, if not totally prohibit, TV viewing in the bedroom.

Eve Van Cauter, an endocrinologist of the University of Chicago, may not be involved in the new study but according to her, lack of sleep plays havoc on two hormones, the ghrelin, which is responsible for promoting hunger, and the peptin, the one that signals fullness.

These two hormones are the “yin and yang of appetite regulation.” Based on Cauter's experiments, sleep-deprived adults produced more ghrelin, which makes you hunger for more food, and less leptin, which keeps you from feeling full. It also explains why they are less likely to exercise and would prefer to sit on the couch and munch on cookies, especially when they get tired.

According to Dr. Stephen Sheldon, director of sleep medicine at Chicago's Children's Memorial Hospital, children's sleep may be disturbed by breathing problems, some due to being overweight which has been associated with cases of sleep apnea. Others do not get enough sleep due to enlarged tonsils and adenoids.

With the help of data from an existing federal study, the research team focused on 785 children who lived in 10 cities of the United States with complete information on sleep, height and weight in the third grade and sixth grade.
Averagely, the third-graders got about 9½ hours sleep, but some slept as little as seven hours and others as much as 12 hours. About 12 percent of the children who slept 10 to 12 hours a day were obese by sixth grade. Moreover, about 22 percent were obese in the sixth grade of those who slept less than nine hours a day.

In addition, other risk factors for obesity such as the children's body mass index in third grade were taken into account, and still found the connection between less sleep in third grade and obesity in sixth grade. Nevertheless, these findings should not give parents a false notion that getting more than enough sleep will keep their kids from getting overweight. Researchers acknowledged that some factors they did not account for such as genetics and other environmental factors.