In the past I’ve discussed the studies showing that the more screen time kids have (TV, Internet, video games, cell phone), the more likely they are to be overweight or obese, the less sleep they will get, and the less well they will do in school. Now, new research is showing that 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.
More Information:
The most profound association in the past studies, as explained in the New York times, is the association between television viewing and obesity. And, obesity, as we know, is strongly linked to higher blood pressure.
But the new report suggests a more direct relationship between extensive TV watching (as well as other screen time) and increases in blood pressure.
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.
If you want tips on reducing or eliminating TV time from your home, I have gobs of them in my book SuperSized Kids: How to protect your child from the obesity threat and my health books for parents: God’s Design for the Highly Healthy Child and God’s Design for the Highly Healthy Teen.
I also have a number of past blogs on the topic:

• Yet another study suggests television viewing may impair children’s language development
• In summer, kids need real play time
• A Television-Free Home: Is It for You? (Monday, 7 April 2008).
• Tips for Taming the TV (Monday, 7 April 2008).
• Too Much TV and Web time harms kids’ health in almost every way (Wednesday, 3 December 2008).
• Study links teen pregnancy to sexy TV shows (Monday, 3 November 2008).
• Teens with TV in their bedroom highly unhealthy (Monday, 7 April 2008).
• Should Children Have TVs in their Bedrooms? (Monday, 1 September 2008).
• Background TV disruptive for very young children (Wednesday, 16 July 2008).
• Turn off TV during meals or kids may get fat: study (Wednesday, 9 July 2008).
• A Television-Free Home: Is It for You? (Monday, 7 April 2008).