(HealthDay) -- There's more evidence that watching violent or age-inappropriate images on TV, in movies or on computers can significantly disrupt children's sleep.
Kids between 3 and 5 years old who were exposed only to age-appropriate viewing materials in the hour before bed were 64 percent less likely to have any type of sleep disturbance, such as trouble falling asleep, difficulty staying asleep or nightmares, according to a new study.
Perhaps surprisingly, "violent" media might even include popular kids' fare such as SpongeBob SquarePants, said the study's lead author, Michelle Garrison.
"Making a relatively simple change in what kids are watching is a change worth the effort," said Garrison, a principal investigator at the Center for Child Health, Behavior and Development at Seattle Children's Research Institute. "Sometimes parents feel overwhelmed by the idea of getting rid of TV altogether, but switching shows can make a big difference."
The study will be published in the September issue of the journal Pediatrics, and was released online Aug. 6.
Numerous studies have linked media use with sleep problems, but most of these studies have had children of various ages and varying media use. It also hasn't been clear whether watching something right before bed is stimulating in itself or if the content of the media plays a role.
The current study included nearly 600 children aged 3 to 5 living in the Seattle area. Families were randomized into one of two groups: One group received a home visit, follow-up phone calls and mailings with coaching about how to make better media choices for their young children; the other group simply received mailings about nutrition.
The researchers didn't attempt to reduce the total number of hours of media use. The goal instead was to reduce violent and age-inappropriate content.
The types of programming that are considered age-inappropriate might surprise you.
"An 8-year-old can watch superheroes and understand that it's not what happens in real life," Garrison said. "But the same content can be overwhelming and scary for a 3-year-old. The idea that people might just explode is scary for a 3-year-old."
Garrison said the research suggests that parents should instead select shows such as Sesame Street, Curious George and Dora the Explorer. "These shows can be beneficial for preschool children to watch, because they emphasize things such as literacy, numbers and social skills," she said.
"When kids in this age group watched violent or age-inappropriate media, they were more likely to have nightmares, have a hard time falling asleep and wake up during the night," Garrison said.
The researchers found the opposite was true when kids watched nonviolent, age-appropriate media. These youngsters were 64 percent less likely to have any sleep problems.
"Clearly, children process information while they sleep. If it's the last thing they do before bed, they'll be processing that as they sleep," said Dr. Sangeeta Chakravorty, director of the Pediatric Sleep Evaluation Center at Children's Hospital in Pittsburgh.
Ideally, Garrison said, children this age wouldn't be engaged with any media in the hour before bed.
"Even shows with really good content can still be a problem for sleep," she said. "When kids are reading a book or playing with toys before bed, they control the pace. But TV ramps their brains up when they're trying to slow down."
Chakravorty agreed. "Electronic stimulation at bedtime can affect your child's sleep and affect their thinking process," she said. "It's best to avoid exposure altogether at least an hour before bedtime. But if your children are watching something before bed, make sure it's age appropriate."
Explore further: Sleep, baby, sleep: parents' behavior has direct impact on children's slumber
To read more about children's sleep, visit the Nemours Foundation.