Spending more than 2.5 hours in front of a television every day could increase your risk of dying from a blood clot in the lung, a new study suggests.

Between 1988 and 1990, researchers in Japan asked 86,024 study participants between the ages of 40 and 79 how much television they watched each day. Over the next 19 years, 59 participants died of a pulmonary embolism.

The study, published by the American Heart Association, showed that people who watched between 2.5 hours and 4.9 hours of television a day were 70 per cent more likely to die from pulmonary embolism than those who watched less than 2.5 hours a day.

A pulmonary embolism, or a lung blood clot, begins as a clot in the leg or pelvis due to inactivity. If the clot breaks free, it can travel to the lung where it can become stuck in a small blood vessel.

“Pulmonary embolism occurs at a lower rate in Japan than it does in Western countries, but it may be on the rise,” Hiroyasu Iso, co-author of the study and professor of public health at Osaka University Graduate School of Medicine, said in a news release.

According to the authors, the risk is likely greater than the study suggests as pulmonary embolisms are often unreported because diagnosis is difficult.

Common symptoms of a pulmonary embolism include chest pain and shortness of breath, which are also symptoms of other life-threatening conditions. Diagnosis also requires imaging that some hospitals may not be equipped with.

“Nowadays with online video streaming, the term ‘binge-watching’ to describe viewing multiple episodes of television programs in one sitting has become popular,” said Toru Shirakawa, lead author and research fellow of public health at Osaka University Graduate School of Medicine. “The popularity may reflect a rapidly growing habit.”

According to the study, watching television and leading a sedentary lifestyle is the number one cause of pulmonary embolisms, followed by obesity as the second leading cause. Diabetes, cigarette smoking and hypertension can also cause a pulmonary embolism.

The study does, however, note ways for people to reduce their risk of a blood clot. Similar advice is given to travellers on long flights.

“After an hour or so stand up, stretch, walk around or while you’re watching TV, tense and relax your leg muscles for five minutes,” said Toru Shirakawa. He added that drinking water and losing weight may also help reduce the risk of fatal blood clots.

According to the authors, new studies are needed to determine how new technologies such as computers, tablets and smartphones are affecting people’s lifestyles.