MONDAY, Oct. 3, 2005 (HealthDay News) -- Here's another reason parents might want to think twice about how much television their children watch: TV viewing by infants and children is associated with irregular sleep schedules, researchers have found.
"Children who are under the age of 3 who watch television are at higher risk of having irregular bed and naptime schedules," said lead author Dr. Darcy A. Thompson, a pediatrician and clinical scholar at the University of Washington in Seattle.
A regular sleep schedule is important, Thompson explained, because it affects the quality and quantity of sleep that children get. In addition, healthy sleep habits can prevent problems such as bedtime resistance or nighttime awakenings, she said.
The findings appear in the October issue of Pediatrics.
Previous studies have examined the effects of TV watching on older children and adolescents, showing, for example, an association with late bedtimes and sleep disturbances.
"This study sort of extends the age range where this does appear to be detrimental," said pediatric sleep specialist Dr. Daniel Glaze, director of the Texas Children's Sleep Center at Texas Children's Hospital in Houston.
Thompson and co-author Dr. Dimitri A. Christakis, of the University of Washington's Child Health Institute, examined data from the National Survey of Early Childhood Health for children 4 months to 35 months of age. The sample included data from parent interviews for 2,068 children.
Twenty-seven percent of children had irregular bedtime schedules and almost 34 percent had varied naptime schedules.
TV viewing, including the amount of time spent watching videos, increased with age. Infants, ages 4 to 11 months, viewed less than an hour of television a day, while toddlers in the 12- to 23-month-old age bracket watched 1.6 hours and children 24 to 35 months spent 2.3 hours in front of the tube.
While the number of hours of television watched was associated with a greater likelihood of varied naptimes and varied bedtimes, researchers were not able to establish a cause-and-effect relationship.
One theory is that television viewing causes irregular sleep schedules, Thompson noted. Another is that irregular sleep leads to increased TV viewing. More research is needed to determine the nature of the relationship between TV viewing and sleep in younger children, she said.
Another uncertainty is whether the timing of television viewing, say, before bedtime, has an impact on sleep. In theory, Thompson reasoned, children who watch a lot of shows with content that is violent or inappropriate for their age could have sleep disturbances no matter when they watched those shows. Others would argue that viewing disturbing content before bedtime impedes sleep.
Glaze, for one, said it's becoming clear that TV viewing and the use of other electronic devices, such as video games -- especially when they're used at night -- negatively impact on children's sleep by reducing the quantity, and disrupting the quality, of sleep. "And when kids don't sleep well at night," he added, "they don't do well during the day."
The study authors recommend that parents follow the American Academy of Pediatrics' guidelines for television viewing: No TV for children less than 2 years of age, and no more than two hours of viewing per day for older children.
The study also supports taking televisions out of kids' bedrooms, Thompson said. She cites a Henry J. Kaiser Family Foundation study that showed that 30 percent of U.S. children under 3 now have a TV in their bedroom.
Dr. William Kohler, a board-certified pediatric sleep specialist and medical director of the Florida Sleep Institute in Spring Hill, Fla., agreed with that advice. "The bedroom should be associated with sleep, not activities," he said.
It's not that all TV is bad, Thompson said, just that "parents need to think about the way that they're going to use television in a smart way."
The National Sleep Foundation has sleep tips for children.