New York: Children aged four years and under who receive less than 10 hours of sleep each night has a tendency to be overweight (obese) in five years later. Researchers from the University of California and University of Washington in Seattle to see the link between sleep and weight in 1930 children aged 0-13 years who participated in the survey in 1997 and returned the survey five years later in 2002, according to Reuters Health.

For children four years old or younger at the time of the first survey, less than 10 hours of sleep per night associated with a nearly two-fold increased risk of becoming overweight or obese at the time of the second survey. In older children, sleep on the first survey did not related with weight status in both surveys but the latest research linking short sleep with the increasing possibility of a change from normal weight to overweight or from overweight to obesity. According to the National Sleep Foundation, infants aged from one to three years should sleep for 12-14 hours, kindergarten children aged 3-5 years should sleep 11-13 hours, and aged 50-10 years should sleep during the 8.5 to 9.25 hours per night.

Some studies have linked short sleep with obesity in children and adolescents, Dr. Bell and research partners. Frederick Zimmerman of the University of California has noted in their report. However, most of these studies only look at one time, cause it is difficult to determine adequate sleep causes children to become obese or vice versa. The findings, say the researchers, indicate that there is a critical time before the age of five years when enough sleep per night probably important in the context of healthy weight in the future. Bell said the study, according to a report in the journal "Archives of Pediatrics and Adolescent Medicine" in the September issue, can not show why short sleep at an early age could be at risk of increased body weight but there are several theories. "It may be that children who sleep less are too tired to do a number of activities that they need," said Bell. No longer sleep means more opportunities to eat. Finally, there is that proves that adults who sleep less have a different appetite and hormones associated with hunger, such as leptin and ghrelin, may occur in children as well, said Bell. (Reutr / Ant)