The findings add to a growing body of research that kids' media use can disrupt their sleep. That's concerning, because sleep troubles early in life may increase the risk of problems later on, including obesity and failure at school, said the researchers from the Seattle Children’s Research Institute.
Doctors should advise parents to limit late-night TV time and violent programs in general for their kids, the researchers said. Such rules, they added, may be more achievable today than prohibiting TV altogether for young kids.
TV and sleep
The researchers surveyed the parents of about 600 preschool-age children. Parents were asked how often their children experienced sleep problems, including trouble falling sleep, nightmares, difficulty waking up or feeling tired during the day.
Parents also kept a diary of their child's TV viewing habits over one week. They tracked when their children watched TV, how much they watched, what the program was and whether the program was viewed with an adult.
Sleep problems were common —about 18 percent of kids had at least one sleep problem five to seven days a week, the researchers said.
Kids with TVs in their rooms watched more TV and were more likely to have sleep problems. For instance, about 8 percent of kids with a bedroom TV were tired during the day, compared with 1 percent of kids without a bedroom TV.
On average, children watched slightly more than an hour of TV per day, and most of the viewing occurred during the daytime.
The more TV that children watched in the evening, and the more violent content they watched during the day, the more likely they were to experience sleep problems. It didn't matter whether the violent programs were animated or live-action, or whether the kids were watching the shows with their parents, the researchers said.
Since the findings are based on parents' reports of their child's TV watching, it's likely the parents underestimated how much time their kids' watched TV and how much violent TV they watched, the researchers said.
What's OK to watch?
The finding "makes very good sense," said Dr. Neena Malik, a child psychologist at the University of Miami School of Medicine who was not involved with the study. Young children may not understand the difference between what's real and not real, Malik said. When this happens, "what you see is going to feel real to you, and it's going to scare you," she said.
In addition, preschoolers don't have the skills to calm themselves down and soothe themselves after they become "hyped up" emotionally by watching something intense. They may try to express their agitation physically, by crying or running around, Malik said.
"That's the antithesis of going to sleep," Malik said.
Malik advises parents to monitor what their children watch. And if the parents are feeling uncomfortable, "chances are their child is going to feel that way 10 times more intensely than [the parents] are," Malik said, and the program may not be appropriate.
Most of the violent content the children watched was actually children programming, said study researcher Michelle Garrison, of Seattle Children's. "It's just children's programming that's really more appropriate for 7 to 12 year-old children than it is for 3 to 5 year-olds," Garrison said.
Garrison recommends using the TV Parental Guidelines ratings as a proxy for the amount of violence in the program. "The majority of TV programming rated TV-Y will have minimal if any violence, whereas we do see significant violent content in programming rated for older children," including TV-Y7 or TV-PG, Garrison said.
The study was published online today (June 27) in the journal Pediatrics.