You knew too much TV could be bad for kids in general. Now, hints a study released Monday, too much time in front of the tube, even playing video games, may increase a child's risk of developing high blood pressure.

The findings held regardless of whether the children were overweight or thin.

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, Dr. Joey C. Eisenmann of Michigan State University in East Lansing, who was involved in the study, noted in an email to Reuters Health.

In the study, Eisenmann and colleagues tracked the physical activity levels of 111 3 to 8-year-olds for one week. The children wore an accelerometer to determine how active they were and parents reported how much time their youngster spent watching TV, playing video games, painting, sitting or taking part in other low-exertional activities.

The results showed that the children were sedentary for an average of 5 hours each day and logged an average of 1.5 hours of screen time each day.

And while sedentary behavior was not significantly related to blood pressure, TV viewing and screen time -- but not computer use -- did seem to impact blood pressure.

Regardless of body weight, blood pressure was significantly higher in children who had the most TV and screen time compared to children with the lowest TV and screen time (less than 30 minutes per day, on average), the team found.

The researchers report their findings in the latest issue of the Archives of Pediatrics and Adolescent Medicine.

To combat the problem, Eisenmann stresses that parents and children need to adhere to limits set by the American Academy of Pediatrics of no more than 2 hours of TV watching per day and that needs to be combined with at least 60 minutes of physical activity a day.

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 said.

TV viewing often comes with unhealthy snacking behavior, and also can lead to stress responses that disrupt sleep, he explained. Less sleep has been tied to higher blood pressure.

SOURCE: Archives of Pediatrics and Adolescent Medicine, August 2009.

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