Americans spend most of their free time watching television, with a total of 2.8 hours on average each day, and according to a new study published in the journal Circulation, it could wind up killing us. The research, conducted by a Japanese team from Osaka University, found television may be luring people onto the couch and encouraging a sedentary lifestyle that causes deadly blood clots.

"Nowadays, with online video streaming, the term 'binge-watching' to describe viewing multiple episodes of television programs in one sitting has become popular," said the study’s co-author Dr. Toru Shirakawa, a public health research fellow at Osaka University Graduate School of Medicine, in a statement. "This popularity may reflect a rapidly growing habit."

For the study, researchers recruited more than 86,000 participants between the ages of 40 and 79 and asked them how much time they spent watching television over the course of two years. For 19 years, (beginning in 1988), researchers continued to keep track of the participants and found 59 of them had died of a pulmonary embolism, better known as a blood clot in the lung. Living a sedentary or generally physically inactive lifestyle causes blood flow to slow, which usually turns into a clot in the leg or pelvis. Once the clot breaks free, the person is at risk of the clot traveling to their lung and wedging itself into a small blood vessel.

Because pulmonary embolisms are almost always caused this way, they are largely preventable. According to the Mayo Clinic, people who are at risk may first experience shortness of breath, severe chest pains, and a cough that produces a streak of blood. They may also experience leg pain or swelling in their calf, along with discolored skin, fever, excessive sweating, rapid or irregular heartbeats, and lightheaded or dizziness. According to the Centers for Disease Control and Prevention, it is estimated that every year, more than 600,000 people in the United States develop pulmonary embolisms, and of them more than 60,000 die.

When researchers crunched the numbers, they realized the gravity of the situation. Participants were at a 40 percent increased risk of developing a pulmonary embolism for every two additional hours of television they watched compared to those who watched less than 2.5 hours each day. In total, 70 percent watched television from 2.5 to 4.9 hours, and those who watched five or more hours automatically increased their risk of developing a blood clot in their lung by 2.5 times.

"Pulmonary embolism occurs at a lower rate in Japan than it does in Western countries, but it may be on the rise," said the study’s co-author Dr. Hiroyasu Iso, professor of public health at Osaka University Graduate School of Medicine, in a statement. "People are increasingly adopting sedentary lifestyles, which we believe is putting them at increased risk.”

Preventing leg clots is key to lowering the risk of pulmonary embolisms. Physical activity is one of the best preventive measures; however, elevating the legs 4 to 6 inches can also help avoid the blood from clotting. Compression stockings can be an effective treatment, which work by gently squeezing your legs to increase circulation and keep the blood in your lower body from stagnating.

The only advice researchers currently have to offer couch potatoes is: “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.”

Source: Iso H, Shirakawa T, Yamagishi K, et al. Circulation. 2016.