Aug. 4, 2009 -- Too much “screen time,” whether it's watching TV, using a computer, or playing a video game, may raise the blood pressure of young children, a new study shows.
This is true even if the children are not obese or overweight, researchers report in the August issue of Archives of Pediatrics & Adolescent Medicine.
The researchers say they found -- apparently for the first time -- a link between sedentary behavior and elevated blood pressure in children aged 3 through 8. The findings suggest that increased media exposure for children may be much worse for children's health than previously thought, the study's co-author Joe Eisenmann, PhD, says in a news release. Eisenmann is a professor in Michigan State University’s Department of Kinesiology and a former colleague of the study's lead author David Martinez-Gomez, BSc, of Iowa State University.
“We’ve known from previous studies that sedentary behaviors are linked to obesity, and that obesity is linked to high blood pressure, but this is the first time that we've linked those behaviors directly to elevated blood pressure,” he says.
Screen Time and Blood Pressure: Examining the Link
The children wore accelerometers -- a tool used for measuring movement -- to help determine how much time they spent on sedentary activities. Parents also reported the average time their children spent playing video games, watching TV, painting, sitting, or taking part in activities requiring little physical movement.
The children spent an average of five hours a day on sedentary activities, with screen time averaging 1.5 hours. The American Academy of Pediatrics recommends parents limit children’s screen time to a maximum of two hours per day.
The researchers found that children who spent the least amount of time watching television, using the computer, and playing video games had much lower blood pressure levels than those who spent the most time in front of a screen. Other forms of sedentary activity, however, were not significantly related to elevated blood pressure.
“It appears other factors, which occur during excessive screen time, should also be considered in the context of sedentary behavior and elevated blood pressure development in children,” Eisenmann says. “TV viewing often comes with unhealthy snacking behavior, and also can lead to stress responses that disrupt sleep.”
Elevated blood pressure has been increasing among U.S. children, the authors write. They advocate limiting screen time to less than 2 hours per day and balancing that by at least 60 minutes of daily physical activity.