Excessive TV Watching Could Shorten Your Life

Jan. 12, 2009— -- Too much TV watching could mean a shorter lifespan, an Australian study has found.

Aussies who reported watching four or more hours of TV a day were 46 percent more likely to die during a 6-and-a-half-year period than those who watched less than two hours a day, according to David Dunstan of Monash University in Melbourne and colleagues.

The risk of dying from cardiovascular disease during follow-up was 80 percent greater in the excessive viewers -- although, statistically, the association was only slightly stronger than what could be chalked up to chance -- the researchers reported online in Circulation: Journal of the American Heart Association.

But the associations were seen even when leisure-time exercise and traditional risk factors such as smoking, poor diet, high blood pressure, and abdominal obesity were taken into account.

"Sedentary living provokes coronary artery disease," commented Dr. Gerald Fletcher, a cardiologist at the Mayo Clinic in Jacksonville, Fla. and spokesman for the American Heart Association. Fletcher was not involved in the study.

"Even if you exercise, if you have a lot of sedentary living with the things that go along with it -- the bad diet and everything else -- you still have a net degree of physical inactivity, which is a coronary artery disease risk factor," Fletcher told MedPage Today.

Previous studies had linked increased sedentary time, in general, to cardiovascular events and mortality risk. But but the relationship between mortality risk and television viewing -- the predominant lesiure-time sedentary activity -- had not been studied, Dunstan and his colleagues wrote.

To explore the issue, they turned to the Austalian Diabetes, Obesity, and Lifestyle Study.

Excluding those who already had a history of cardiovascular disease, the researchers asked 8,800 adults living throughout Australia about the amount of time they spent watching TV and followed them for an average of 6.6 years.

During follow-up, there were 284 deaths -- 87 from cardiovascular disease, 125 from cancer, and 72 from other causes.