Obese children have a lower quality of life and poor sleep habits, according to new research being presented at a conference on sleep.

Kelly Ann Davis of St. Joseph's University focused on 100 children between 8 and 12 years old who visited doctors.

Children who were obese had more trouble going to sleep, more breathing problems, shorter sleep and more daytime sleepiness than children who were overweight or healthy weight.

A news release said that weight category was a significant predictor of quality-of-life scores.

"In this study, sleep and weight each contributed unique variance for quality of life scores, thus indicating the need to evaluate daytime functioning in children with both obesity and sleep problems," said Davis.

It is recommended that school-aged children get between 10 and 11 hours of nightly sleep and children in pre-school get between 11 and 13 hours.