Uh-Oh!

Couch time may cut life short, study suggests


CTV.ca News Staff

If you ever needed a reason to turn off that sitcom and go out for a walk, here's one: a new study finds that for every hour of TV someone watches, their risk of dying early from heart disease goes up more than 10 per cent.


It may hardly news that exercise is healthy, but this study is the largest study of its kind to quantify the risk of a sedentary lifestyle.

The research, reported in Circulation, a journal of the American Heart Association, finds that each hour spent in front of the television is linked to:

a nine per cent increased risk of cancer death.
an 11 per cent increased risk of death from all causes
an 18 per cent increased risk of cardiovascular disease (CVD)-related death
While the study focused on TV watching, the authors think that any prolonged sitting, such as at a desk or in front of a computer all day, poses just as much as a health risk.

And the longer the time spent sitting, the bigger the health risk, even for those who are not overweight.

The study, which looked at 8,800 adults, found that compared with people who watched less than two hours of television daily, those who watched more than four hours a day had a 46 per cent higher risk of death from all causes and an 80 per cent increased risk for CVD-related death.

The links held regardless of other risk factors for heart disease, such as smoking, high blood pressure, high blood cholesterol, and waist circumference.

For the study, the Australian researchers interviewed 3,846 men and 4,954 women over the age of 25. They reported their television-viewing habits for the previous seven days and were grouped into one of three categories: those who watched less than two hours per day; those who watched between two and four hours daily; and those who watched more than four hours.

People with a history of cardiovascular disease were excluded from the study.

During the more than six years of follow-up, there were 284 deaths -- 87 due to cardiovascular disease and 125 due to cancer.

While the link between cancer and television viewing was modest, there was a direct link between the amount of television watched and the risk of cardiovascular disease death. As well, there was a strong link with death from all causes -- even after accounting for lifestyle factors.

Prof. David Dunstan, the study's lead author and head of the Physical Activity Laboratory at the Baker IDI Heart and Diabetes Institute in Victoria, Australia, says the human body was designed to move, not sit for extended periods.

"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," Dunstan said in a news release.

He notes that many people spend their days simply shifting 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."

Dr. Beth Abramson of the Heart & Vascular Program at St. Michael's Hospital in Toronto, who was not involved in the study, doesn't think TV watching is the health culprit.

"It's not being sedentary that's the issue; it's the not being active," she told CTV News.

"Whether you are sitting in front of a TV or a computer screen, you are taking time away from being active and physically fit."

Dunstan says his team's 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.

Marco Buono of the Heart and Stroke Foundation says the implications are simple.

"We do need to get moving more. Our physical activity rates across Canada are declining rapidly year after year and we need to, as a general population, just be more active."

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Got to go for a walk now. Bye!