Watching too much television can be just as bad for people's health as smoking or obesity, according to an Australian study published Tuesday.
Experts from the University of Queensland, in Brisbane, found that on average, every hour of television a person watches reduced the viewer's life expectancy by almost 22 minutes.
The study, published in the British Journal of Sports Medicine, concluded that after the age of 25, six hours of daily viewing could cut a person's lifespan by almost five years.
Using data from a lifestyle study involving more than 11,000 people in Australia, combined with population trends and death rates, researchers found that being sedentary for long periods increased the risk of dying earlier.
The study said, "TV viewing time may be associated with a loss of life that is comparable to other major chronic disease risk factors such as physical inactivity and obesity."
It added that Australian trends were likely to be comparable to those in many other countries with similar patterns of television watching and diseases linked to sedentary lives, such as heart disease and stroke.
The findings also could be compared to other risk factors such as smoking, researchers said, with other studies showing that one cigarette cuts 11 minutes off a lifespan, equivalent to half an hour of TV watching.
Meanwhile, another study, published Tuesday in the medical journal The Lancet, found that as little as 15 minutes of physical activity every day could increase a person's lifespan by three years.
Every additional 15 minutes of daily exercise further reduced all-cause death rates by four percent. The trend continued until a person was exercising for 100 minutes a day, after which no further benefit was seen.