"In the United States, the sleep of our children is clearly not enough," said lead researcher Dr. David Gozal, chair of pediatrics at Comer Children's Hospital at the University of Chicago.
team monitored the sleep patterns of 308 children for a week and compared their sleep patterns with their body mass index (BMI), which is a measurement that takes into account height and weight.
The children, who were 4 to 10 years old, averaged eight hours of sleep a night.
"This is way lower than the recommended amount of sleep that kids should get, which is about 9.5 to 10 hours at this age," Gozal
Among the children who got the recommended amount of sleep, the risk of obesity, diabetes and cardiovascular problems was nil, Gozal
"But, as the amount of sleep became shorter and the regularity of sleep became less organized, the risk for obesity increased," he
"Kids who had the shortest sleep and had a more disorganized sleep schedule had more than a fourfold increase in the risk of being obese," he
These children also had increased risk for cardiovascular problems and pre-diabetes, Gozal
However, if these children consistently slept longer on weekends to compensate, the risk for obesity and metabolic problems was reduced to a 2.8-fold increase.
"It did not normalize it.
It's still a risk but not as much as keeping your crazy short sleep schedule even during weekends," Gozal
It is this combination of less sleep and irregular sleep that appears to result in metabolic problems, such as high blood sugar, Gozal
The report is published online Jan. 24 in advance of print publication in the journal Pediatrics
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
"All this would suggest that sleep is an important regulator of metabolism," Gozal
"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
Children are sleeping less for various reasons, Gozal
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
"Follow the rule of sleep and you will be happy," he
The study found that parents tend to overestimate the amount of sleep their kids get, usually by 60 to 90 minutes, Gozal