Americans do love their TV time, watching around five hours of programming a day on average. But this most beloved of passive pastimes may exact a high price, with new research linking TV viewing to a raised risk of diabetes and heart disease.
It's no secret that spending hours in front of the television isn't the healthiest of habits. Studies show that people are more likely to eat high-fat, high-calorie foods while watching the small screen—perhaps swayed in part by ads for soft drinks, chips, and convenience foods. And people who watch a lot of TV also tend to be less active, as more time on the couch can mean less time for exercise.
For these reasons, TV viewing is often blamed as contributing to the rise in obesity in the United States and other developed countries. And it's well established that being overweight or obese can lead to many health problems, including type 2 diabetes and heart disease. But how much of a person's risk of these problems might be traced to their level of TV viewing?
To find out, researchers pooled the results of eight large studies looking at the relationship between TV time and the risk of type 2 diabetes, heart disease or a premature death. The studies followed more than 200,000 people for seven to 10 years, on average, recording their TV habits and tracking their health. None of the participants had been diagnosed with a serious illness at the start of the studies.
Their findings? For every two hours of TV a person watched daily, their risk of developing type 2 diabetes went up by 20 percent, their risk of heart disease climbed by 15 percent, and their risk of dying early (from any cause) rose by 13 percent. The researchers estimated that for every 100,000 people, this would mean 176 new cases of diabetes each year, 38 new cases of fatal heart disease, and 104 premature deaths.
What's interesting about these findings is how closely TV viewing was linked to people's risk—the more they watched, the more likely they were to develop these problems. But we still can't say for certain why dedicated TV viewers had a higher risk. It's likely that their diet and activity level played a role, although most of the studies didn't take a close look at these factors. It's also possible that long stretches of sedentary TV time might have other effects on the body that we don't yet fully understand.
Bottom line. If you watch more than two hours of TV a day, you may have a higher risk of diabetes, heart disease, and an early death. However, we need more research to explore why TV viewing may increase the chance of these problems.
If you are worried about developing diabetes or heart disease, there are lots of things you can do to reduce your risk, including giving up smoking, exercising regularly, and slimming down if you're overweight. Watching less TV might also make a difference, particularly if it helps you adopt a healthier lifestyle in general.
Television viewing and risk of type 2 diabetes, cardiovascular disease, and all-cause mortality [Journal of the American Medical Association]
—Sophie Ramsey, BMJ Group
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