You know that vegging out in front of the boob tube isn’t good for you. But have you heard about a disturbing new study from Australia suggesting that TV’s negative effects on life span are even worse than you probably imagined?

For the study, researchers analyzed data from an observational survey of more than 11,000 people ages 25 and older that began in 1999, cross-referencing against mortality figures for 2008.Findings: People who spent a lifetime average of six hours per day watching television died 4.8 years sooner, on average, than people who watched no TV. Also, every single hour of TV viewed after age 25 reduced the average viewer’s life expectancy by 22 minutes!

Explanation: It is an indirect link, according to study leader J. Lennert Veerman, MD, PhD, MPH, of the School of Population Health at the University of Queensland in Australia. The more time a person spends watching television, the less time she (or he) has for healthy behaviors proven to promote longevity, such as exercising and socializing. Also, Dr. Veerman noted, while researchers in this study adjusted for the effects of diet quality and waist circumference, other studies show that TV viewing typically is associated with a worse diet.

Bottom line: TV’s harmful effects on longevity may be comparable to the effects of major chronic disease risk factors such as obesity and physical inactivity—a fact worth remembering next time you are tempted to turn on the tube.

Source: J. Lennert Veerman, MD, PhD, MPH, is a senior research fellow at the Centre for Burden of Disease and Cost-Effectiveness in the School of Population Health at the University of Queensland in Australia, and leader of a study published in British Journal of Sports Medicine.