Sedentary TV Time May Cut Life Short
 Couch potatoes beware: every hour of television watched per day may increase the risk of dying earlier from cardiovascular disease.
Australian researchers tracked the lifestyle habits of 8,800 adults and found that each hour spent in front of the television daily was associated with: • an 11 percent increased risk of death from all causes, • a 9 percent increased risk of cancer death; and • an 18 percent increased risk of cardiovascular disease (CVD)-related death.
Compared with people who watched less than two hours of television daily, those who watched more than four hours a day had a 46 percent higher risk of death from all causes and an 80 percent increased risk for CVD-related death. This association held regardless of other independent and common cardiovascular disease risk factors, including smoking, high blood pressure, high blood cholesterol, unhealthy diet, excessive waist circumference, and leisure-time exercises.
While the study focused specifically on television watching, the findings suggest that any prolonged sedentary behavior, such as sitting at a desk or in front of a computer, may pose a risk to one's health. The human body was designed to move, not sit for extended periods of time, said David Dunstan, Ph.D., the study's lead author and professor and Head of the Physical Activity Laboratory in the Division of Metabolism and Obesity at the Baker IDI Heart and Diabetes Institute in Victoria, Australia.
"What has happened is that a lot of the normal activities of daily living that involved standing up and moving the muscles in the body have been converted to sitting," Dunstan said. "Technological, social, and economic changes mean that people don't move their muscles as much as they used to - consequently the levels of energy expenditure as people go about their lives continue to shrink. For many people, on a daily basis they simply shift from one chair to another - from the chair in the car to the chair in the office to the chair in front of the television."
Dunstan said the findings apply not only to individuals who are overweight and obese, but also those who have a healthy weight. "Even if someone has a healthy body weight, sitting for long periods of time still has an unhealthy influence on their blood sugar and blood fats," he said.
Although the study was conducted in Australia, Dunstan said the findings are certainly applicable to Americans. Average daily television watching is approximately three hours in Australia and the United Kingdom, and up to eight hours in the United States, where two-thirds of all adults are either overweight or obese.
The benefits of exercise have been long established, but researchers wanted to know what happens when people sit too much. Television-watching is the most common sedentary activity carried out in the home.
Source: American Heart Association
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