The more TV people watch, the greater the risk may be for venous thromboembolism

By Sally Robertson, B.Sc.Nov 13 2017

The risk of developing a blood clot in a vein increases the more time a person spends watching TV, even if they engage in the recommended amount of physical activity, according to research presented at the American Heart Association’s Scientific Sessions 2017, a global exchange of the latest findings in the field of cardiovascular science.

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Watching a lot of TV has already been linked to an increased risk of developing blocked arteries and heart disease, but this is the first study of a western population to assess the association between TV watching and risk of venous thromboembolism (VTE) - blood clot formation in the legs, arms, lungs or pelvis.

Estimates suggest that between 300,000 to 600,000 people in the U.S. develop a VTE every year, making it the most common vascular diagnosis next to heart attack or stroke. It is more common for people develop a VTE once they are aged 60 years or older, although it can happen at any age.

Co-author of the study Mary Cushman (Larner College of Medicine, University of Vermont, Burlington) says the act of watching TV in itself is not likely to be the problem, but more the fact that people tend to snack and sit still for a long time whilst viewing.

The study, which is called the Atherosclerosis Risk in Communities Study and involved 15,158 middle-aged (45 to 64 years) individuals, showed that compared with people who reported “never or seldom” watching TV, those who said they watched it “very often” were at a 1.7 times greater risk of developing a VTE. The increase in risk was similar (1.8 times higher), even when those who watched TV very often met the recommended guidelines for physical activity.

The VTE risk increased with more TV watching, both for life-threatening clots that form in the extremities and those that develop in the lungs. The study also found that although obesity was more common among those who watched more TV, it only accounted for 25% of the increased VTE risk.

Cushman advises that people make the best of their time by using a treadmill or stationary bike whilst they watch TV, for example, or delaying watching TV for 30 minutes while they take a walk.

“If you must see your favorite show, tape it while you are out walking so you can watch it later, skipping the ads," she suggests.

Cushman advises that healthcare professionals take time to ask patients about their time spent being sedentary and their fitness levels: "If you are at heightened risk of venous thromboembolism due to a recent operation, pregnancy or recent delivery, cancer or a previous clot, your doctor may prescribe blood-thinning medication or advise you to wear compression stockings.”

Aside from avoiding watching TV for long periods, other recommendations for lowering VTE risk include maintaining a healthy weight and continuing to engage in physical activity.