Time spent in front of the computer or television screen is associated with psychological problems in children, no matter how physically active the child is, according to a new study.
That means kids can't make up for lots of TV time by spending extra hours running around, the researchers report in the November issue of the journal Pediatrics. The findings also suggest that the way kids spend their sedentary time, not just how much of it they have, matters for mental health.
Previous studies have shown that physical activity is good for kids' psychological functioning, and that time spent in front of screens is bad for mental health. What researchers didn't know was whether one could cancel out the other.
"It wasn't clear whether having high physical activity levels would 'compensate' for high levels of screen viewing in children," study co-author Angie Page, a professor of exercise, nutrition and health sciences at the University of Bristol in England, wrote in an e-mail to LiveScience.
The researchers asked 1,013 British 10- and 11-year-olds how much time each day they spent in front of a computer or TV. The children also wore accelerometers around their waists for a week to track their physical activity and sedentary time.
In addition, participants filled out questionnaires with questions about their emotional difficulties, social relationships, behavior problems and hyperactivity levels. The answers from the widely used questionnaire are combined to create a score of each child's emotional and behavioral difficulties.
The study found that regardless of age, gender, socioeconomic status, or whether a child had hit puberty, more than two hours a day in front of a TV or computer was associated with more emotional and behavioral difficulties. Most importantly, the connection between screen time and psychological problems held regardless of how much overall physical activity the kids engaged in.
No other sedentary activities like reading or doing homework were associated with poor mental health, Page said. Nor was the total amount of sedentary time. That may mean that sedentary time and sedentary behaviors influence health separately, the researchers wrote in the paper.
"It seems more like what you are doing in that sedentary time that is important, i.e. if you choose to spend large number of hours screen viewing for entertainment, then this is associated with negative mental well-being," Page wrote in an e-mail.
The findings suggest that parents can't depend on soccer practice or a hiking trip to make up for multiple hours of computer games and television shows, Page said. Instead, she said, parents should keep promoting physical activity, but also turn off the TV and computer more often.