A study made by the University of Osaka in Japan shows that watching more than 5 hours of TV results in a 5-fold risk of pulmonary embolism. PE is a blockage of the lung’s main artery or one of its branches by a substance that has traveled from elsewhere in the body through the bloodstream, and results from deep vein thrombosis (commonly a blood clot in a leg) that breaks off and migrates to the lung. It can be life-threatening and anyone with symptoms of PE should see a doctor immediately. Symptoms include chest pain and difficulty breathing. Pain in the legs as well as warm, blueish swelling in the calves can indicate a blood clot in the leg. Immobilization is one of the main causes of PE, so the best way of guarding against it is regular exercise.