April 20, 2011

Future Health Risks For Kids Who Watch Too Much TV

Children who spend too much time watching television have increased chances of heart disease, high blood pressure and diabetes later in life, according to a study conducted by researchers at the University of Sydney.

The study is reported this week in Arteriosclerosis, Thrombosis and Vascular Biology: Journal of the American Heart Association.

Declared as a world-first study, researchers found that six-to-seven-year-olds who spend most of their time watching television had narrower arteries in the back of their eyes that can present a high risk factor for their future health.

Each hour spent in front of a television was similar to that associated with an increase of 10 mm HG in systolic blood pressure, researchers say.

34 primary schools in Sydney participated in the study. Out of 1,500 six-to-seven-year old children, researchers found that those who regularly participated in outdoor physical activity had wider arteries behind their eyes, on average, than children with the lowest activity levels..

"We found children with a high level of physical activity had a more beneficial microvascular profile compared to those with the lowest levels of physical activity," says Dr Bamini Gopinath, lead author and senior research fellow at the University of Sydney's Centre for Vision Research.

"This suggests unhealthy lifestyle factors may influence microcirculation early in life and increase the risk of heart disease and high blood pressure later in life."

Cardiovascular disease and high blood pressure in adults is known to be marked by the retinal microvascular diameter. However, the link between a sedentary lifestyle in childhood and the narrowing of the vessels in the retina is a new finding.

Generally, 1.9 hours a day are spent watching television by children and about 36 minutes are used to participate in organized physical activity, reports the study.

The research found that children who engage in just over an hour or more of physical activity a day, had significantly wider average retinal arteries than those who spent less than half an hour a day on physical activities.

"Excessive screen time leads to less physical activity, unhealthy dietary habits and weight gain," Dr. Gopinath says.

Blood flow can be enhanced by physical activity, which has a positive effect on the linings of blood vessels.

"Replacing one hour a day of screen time with physical activity could be effective in buffering the effects of sedentary lifestyles on the retinal microvasculature in children."

He also says that, "Free play should be promoted and schools should have a mandatory two hours a week in physical activity for children. Parents need to get their children up and moving and off the couch."

"Parents can also lead the way by being more physically active themselves."


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