LONDON - The risk of dying from heart disease increases by almost a fifth from each hour of a day spent watching television, an Australian study has found.
Every type of sedentary behaviour, such as driving and sitting at a computer, also poses significant health risks, Australian researchers concluded.
They found that people who spent more than four hours a day sitting in front of the TV were 80 per cent more likely to die from a cardiovascular related disease than those who watched less than two hours.
Tracking the lifestyle habits of 8,800 adults over the past seven years, researchers also found they were also moderately more at risk of dying from cancer.
The study is published in this month's edition of the medical journal Circulation: Journal of the American Heart Association,
The study's lead author Professor David Dunstan, from the Baker IDI Heart and Diabetes Institute, in Victoria, said: "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."
"Even if someone has a healthy body weight, sitting for long periods of time still has an unhealthy influence on their body sugar and blood fats."
Researchers measured participants' cholesterol and blood sugar levels - key indicators of health - and how many hours they spent watching TV. During the six-year follow-up, 87 people died from cardiovascular-related disease and 125 died from cancer. The association held regardless of other risk factors like smoking and high blood pressure.
Researchers said people should avoid sitting for long periods of time to lower their risk of developing diseases.