Watching too much TV negates the effects of regular exercise. The new study presented this week at the American Heart Association’s Scientific Sessions in Anaheim, California investigated the connection between television viewing and blood clots in the legs, arms, pelvis, and lungs. Researchers examined data from more than 15,000 middle-aged people who answered questions about their TV habits over 20 years. During that time, doctors diagnosed 691 blood clots in the group. 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, those who watched TV very often were still 80% more likely to have had a blood clot than those who rarely or never watched TV. The study serves as a reminder that even physically fit people should avoid sitting in one position for too long.