It’s our guilty pleasure : Watching TV is the most common everyday activity , after work and sleep , in many parts of the world . Americans view five hours of TV each day , and while we know that spending so much time sitting 36 can lead to obesity( 肥胖症 )and other diseases , researchers have now quantified just how 37 being a couch potato can be . In an analysis of data from eight large 38 published studies , a Harvard—led group reported in the that for every two hours per day spent channel 39 , the risk of developing Type 2 diabetes Journal of the American Medical Association( 糖 尿 病 )rose 20 % over 8 . 5 years , the risk of heart disease increased l5 % over a 40 , and the odds of dying prematurely 41 13 % during a seven— year follow—up . All of these 42 are linked to a lack of physical exercise. But compared with other sedentary( 久坐的 )activities , like knitting , viewing TV may be especially 43 at promoting unhealthy habits . For one , the sheer number of hours we pass watching TV dwarfs the time we spend on anything else. And other studies have found that watching ads for beer and popcorn may make you more likely to 44 them . Even so , the authors admit that they didn’t compare different sedentary activities to 45 whether TV watching was linked to a greater risk of diabetes , heart disease or early death compared with , say , reading .