People who watch television for five or more hours a day have more than twice the risk of those who watch half as much TV to die of a blood clot in the lung, a large Japanese study suggests. There are more than 200,000 cases of pulmonary embolism, which usually begins as a blood clot in the leg that travels to the lung, in the U.S. each year, according to the National Library of Medicine. It can permanently damage lung tissue, other organs, or cause death, but many people who have it have no symptoms. Other past studies have looked back at the lifestyle factors common to pulmonary embolism cases, but none had followed people over time to see if there was a link between their TV-watching time and their risk for embolisms, the study team writes in Circulation.

Researchers calculated that among people who watched less than two and a half hours of TV, the rate of deaths from pulmonary embolism were 2.8 per 100,000 people per year, compared to a rate of 8.2 deaths per 100,000 per year for those who watched five or more hours daily. Risk of pulmonary embolism death increased by 40 percent for each additional two hours of daily TV watching, they found. “Time spent watching TV is a pretty reliable way to measure how much time people spend sedentary, or inactive,” said Dr. Christopher Kabrhel, an Associate Professor of Emergency Medicine at Harvard Medical School in Boston who was not part of the new study. “If being sedentary puts you at risk for pulmonary embolism, and I believe it does, then it likely also puts you at risk of death from pulmonary embolism, as this study showed.”

Since U.S. adults watch more TV than Japanese adults, the results may be even more important to Americans, the authors said in a statement accompanying the study. “Nowadays, with online video streaming, the term ‘binge-watching’ to describe viewing multiple episodes of television programs in one sitting has become popular,” lead author Dr. Toru Shirakawa, a research fellow in public health at Osaka University Graduate School of Medicine, wrote. Travelers on long plane flights and people watching TV for long periods of time can stand up, stretch, walk around, or tense and relax their leg muscles for five minutes to reduce the risk of blood clots, they wrote. “The results do not seem to be country-specific,” Kabrhel told Reuters Health by email. “Being sedentary is bad for you wherever you live.”