"A lot of parents don't make the connection," said Dr. Judith Owens, who led the study. "They think if TV is sedating for adults, it is for kids, too."
Instead, she said, TV-watching seems to be a stimulant to some children.
Owens, a professor of pediatrics at Brown University and director of the pediatric sleep disorders clinic at Hasbro Children's Hospital in Providence, R.I., said parents need to ease their children into bedtime, instead of relying on television.
"I don't advocate completely turning it off in the evening, but there needs to be a clear demarcation," she said. "I would like to see kids being read to, or reading to parents or themselves. TV viewing has substituted for a lot of that. Kids need more of a calm-down, wind-down time."
The study adds to a growing amount of research on television's harmful effects on children. Previous studies have shown that heavy TV viewing may be linked to depression, anxiety and violent behavior, as well as obesity.
Last month, the American Academy of Pediatrics recommended that children under two not watch television at all, saying it interferes with the one-on-one interaction with others needed for healthy development.
Owens and Dr. Rolanda Maxim, a pediatrician at the Knights of Columbus Developmental Center in St. Louis, examined the sleep and TV habits of 495 youngsters in kindergarten through fourth grade. The research included the time spent watching videos, but not using computers.
The study appears in the Internet version of Pediatrics, a journal published by the American Academy of Pediatrics.
More than 76 percent of parents reported TV viewing was part of their child's usual bedtime routine, and 15.6 percent of children fell asleep in front of the TV at least two nights a week. Researchers also found that 26 percent of the children studied had a television in their bedroom.
About 40 percent of parents said their children had at least one sleep problem, such as struggles over going to bed or difficulty falling asleep.
Most of the parents said they believed that TV had nothing to do with their children's sleep problems. But the researchers said the evidence strongly suggests otherwise.
Dr. Stephen Sheldon, an expert on children's sleep disorders who was not involved in the study, said he has seen similar problems among young patients. He said one problem is that some children become dependent on television to fall asleep.
"Trying to fall asleep without it can be like trying to fall asleep without a pillow," said Sheldon, director of the Sleep Medicine Center at Children's Memorial Hospital in Chicago and a professor of pediatrics at Northwestern University.
Written By Tammy Webber