Watching TV for long periods of time could be as harmful to your health as smoking or obesity.
Researchers in Australia studied health surveys filled out by more than eleven thousand adults.
They found for every hour spent watching TV after age 25, a person lost 22 minutes of their life.
They calculated that people who watch six hours of TV every day live five years less than someone who doesn't watch any TV.
That is comparable to people who smoke or don't exercise.