TV addicts warned of strong link to fatal heart diseases

Couch potatoes were warned that their lifestyle also increased the risk of death from other causes including cancer. Individuals who spent hours watching TV greatly heightened the chances of dying early from heart attacks and strokes.

Compared with those watching less than two hours of TV, people who sat in front of the box for more than four hours a day were 80 per cent more likely to die for reasons linked to heart and artery disease.

Researchers in Australia monitored 8,800 adults for six years to see what impact watching TV had on their long term health.

They found that each hour spent per day in front of the TV increased the risk of death from all causes by 11 per cent.

It also raised the risk of dying from cancer by 9 per cent and the risk of heart disease-related death by 18 per cent. The scientists warned it was not only telly addicts whose lazy lifestyles put them in danger. Any prolonged sedentary behaviour – sitting at a desk or in front of a computer – posed similar risks. It made no difference whether or not a person was overweight or obese.

"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," said lead researcher Prof David Dunstan, from the Baker IDI Heart and Diabetes Institute in Victoria, Australia.

The average amount of TV people watch each day is three hours in both Australia and Britain, said the scientists. In the US, where two-thirds of adults are overweight or obese, some people spent as much as eight hours watching TV – the equivalent of a nine to five working day.

Prof Dunstan had one message for the public: "In addition to doing regular exercise, avoid sitting for prolonged periods and keep in mind to 'move more, more often'. Too much sitting is bad for health."