Watching Too Much TV Is Bad for You, Even If You Also Exercise

From TIME - November 14, 2017

The more time you spend watching television, the greater your risk may be for blood clots, according to a new studyeven if you get plenty of exercise. The research underscores the dangers of sitting too long, the authors say, and suggests that getting the recommended amount of physical activity may not be enough to counteract its risks.

The new study was presented this week at the American Heart Associations Scientific Sessions in Anaheim, California, and has not yet been published in a peer-reviewed medical journal.

To investigate the connection between television viewing and blood clots in the legs, arms, pelvis and lungsa condition known as venous thromboembolism (VTE)researchers from the University of Vermont examined data from more than 15,000 middle-age people who answered questions about their TV habits three times over about 20 years. During that time, doctors diagnosed 691 blood clots, or VTE events, in the group. (No one had blood clots at the start of the study.)

People who said they watched TV very often were 71% more likely to have developed a blood clot, compared to those who never or seldom watched. Among those who did the recommended 150 minutes of weekly physical activity, the disparity was even greater: Those who watched TV very often were 80% more likely to have had a blood clot than those who rarely or never did.

The link between TV viewing and blood clots could be partially explained by obesity, say the researchers. Sitting more and moving less can lead to weight gain, they say, and excess weight is a risk factor for blood clots. But adjustments in the analysis found that obesity could only account for about 25% of the increased risk, suggesting that other factors also play a role.

Most blood clots due to inactivity occur in the legs, says study author Dr. Mary Cushman, director of the Thrombosis and Hemostasis Program at the University of Vermont Medical Center. The veins are bringing blood back to the heart, so the blood has to go back up the legs against gravity, she says. When the blood is in a slow-flow state and the muscles arent working to keep it moving, its easy to see how clots can form.

This happens most commonly when a persons legs are immobilized because of trauma (in a cast after an injury, for example). But it can also occur during long periods of sitting in one position, which often goes along with TV viewingespecially in the age of streaming services available for binge-watching.


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