It is no surprise that spending long hours in front of a television is not doing us any favors when it comes to our health. But a new study links many hours of this sedentary behavior to increased risks for eight of the major causes of death.

Share on Pinterest Watching 3-4 hours of TV per day significantly increases risks for major causes of death.

The study, previously published online, will appear in the December issue of the American Journal of Preventive Medicine.

According to the study authors – who were led by Sarah K. Keadle, PhD, from the National Cancer Institute – on average, 80% of adults in the US watch 3.5 hours of television each day.

Previous studies have shown a link between TV viewing and poorer health; there are already established links between prolonged TV viewing and increased risk of death from cancer and cardiovascular disease, for example.

Because 92% of Americans have a TV at home, and watching it takes up over half of their leisure time, it likely displaces more physical activities, which is why there are associated health risks.

“We know that television viewing is the most prevalent leisure-time sedentary behavior, and our working hypothesis is that it is an indicator of overall physical inactivity,” says Keadle.

To further investigate, she and her team studied over 221,000 adults between the ages of 50-71 years old who were chronic disease-free at the start of the study in 1995. Study participants were followed until either death or December 31, 2011.