Extreme TV Watching Tied to Risk for Lethal Lung Clots

When you're binge-watching your favorite TV series, make sure to stand, stretch and flex your leg muscles between episodes. Maybe even take a short walk. That could lower your chances of ultimately dying from a clot in your lung -- a risk that rises with daily hours of TV viewing, according to a large, long-term study from Japan, released online Monday from the journal Circulation.

Researchers led by Dr. Toru Shirakawa at the Osaka University Graduate School of Medicine followed more than 86,000 middle-aged to older adults, starting in 1988. Participants reported their average hours of daily TV viewing along with other lifestyle factors. People fell into three groups: those who watched less than 2.5 hours, between 2.5 and 4.9 hours, and 5 or more hours of sedentary TV screen time each day.

For two decades, researchers tracked participants and collected data from their death certificates. In all, 59 participants died of a blood clot in the lung, or a pulmonary embolism, over the course of the study.

Compared to rates for light TV viewers, a pulmonary embolism was 70 percent more likely to be the cause of death for moderate viewers. Risk rose by 40 percent for each additional two hours of TV-watching, researchers found. People who watched the most daily TV were 2.5 times more likely to be killed by a clot in their lungs.

The reason for the results may be similar to higher clot risks previously shown for some long-distance travelers who are forced to sit still in confined spaces during flights, researchers suggested. Among other factors in the study, obesity was the second-most likely to raise the risk of a fatal pulmonary embolism.

When blood clots form in large veins in the leg, causing pain and swelling, it's called a deep vein thrombosis. If a clot breaks off and travels to the lungs, that's a pulmonary embolism, which is much more dangerous. Clots in the lung block the ability to breathe and people can die abruptly. Chest pain, sudden shortness of breath and cough are hallmarks of pulmonary embolism.

If anything, health consequences tied to viewing habits could be higher in the U.S., where people tend to watch more TV, an American Heart Association press release suggested. And with long periods of sitting still as the likely culprit, it's possible people are also building up blood-clot risk by being glued to their seats with laptops, tablets and smartphones -- a potential topic for future research.

9 Things You Didn't Know About Sickle Cell Disease

17 Way Heart Health Varies in Women and Men

Lisa Esposito is a Patient Advice reporter at U.S. News. You can follow her on Twitter, connect with her on LinkedIn or email her at lesposito@usnews.com.