Television Viewing Linked to Blood Pressure Increases in Children

August 7, 2009
By RONI CARYN RABIN

Children who spend a lot of time watching television have higher blood pressure than those who watch less, even if the children are thin and get enough exercise, according to new research.

Earlier studies have found associations between television viewing and obesity, which is linked to higher blood pressure. But the new report suggests a more direct relationship between extensive TV watching and increases in blood pressure, the authors said.

Researchers at Michigan State University have been following a group of 111 children, ages 3 to 8, for about four years. The team asked the children to wear accelerometers — devices that record physical motion — for a week in order to objectively measure the amount of time that they were sedentary. The researchers also gathered information from parents about how many hours their children spent watching television, playing video games and using the computer. They also measured the children’s body fat.

Children who watched the most television (from 1.5 to 5.5 hours a day) had significantly higher diastolic and systolic blood pressure readings than those who watched the least television (less than half an hour a day), the researchers found. Data from the accelerometers showed that the increased blood pressure wasn’t associated with the sedentary behavior overall, but specifically linked to increased TV viewing.

Although this study did not report on the prevalence of hypertension and pre-hypertension, earlier research with a similar group of children found that one in five had high blood pressure, the authors said. Children generally have lower blood pressure than adults, and their blood pressure rises as they grow.

Extensive TV viewing may have harmful physiological effects because children often snack while watching TV, or perhaps because the programs are distressing to them, suggested Joey Eisenmann, an assistant professor of kinesiology at Michigan State University and the paper’s senior author. Watching TV late at night may cut into sleep time or disrupt sleep, he added; it’s also possible that watching television reduces the body’s metabolic rate more than other sedentary activities.

The American Academy of Pediatrics recommends that children watch no more than two hours of high quality television each day.

The study was published in this month’s issue of Archives of Pediatrics and Adolescent Medicine.

Fuente
www.nytimes.com