每天平均看电视超过两小时以上将分别增加患糖尿病和心脏病的几率达20%和15%。

Apart from working and sleeping, the thing Americans do the most is watch TV—five hours a day on average. But all that time in front of the tube may up your risk of death, according to a review in the Journal of the American Medical Association. [Anders Grøntved and Frank Hu, "Television Viewing and Risk of Type 2 Diabetes, Cardiovascular Disease, and All-Cause Mortality"]

Researchers analyzed eight previous studies looking at the effects of TV on health. Together, the studies followed more than 200,000 volunteers over about a decade of their lives, and controlled for other risk factors, like age and smoking. The take-home? For every two hours of TV per day, subjects had a 15 percent higher risk of heart disease and a 20 percent higher risk of developing type 2 diabetes. That translates to a city of a million people having 1760 extra cases of diabetes compared to a city of a million who watch two hours less TV per day.

Previous studies have associated other sedentary activities, like sitting at a desk, with health risks. But the researchers say there's something unique about TV. Not only are we not exercising, but we tend to snack while watching. The prescription, in this case, is simple, and side effects are rare: get off the couch.

—Christopher Intagliata