The researchers used population surveys to try to calculate how TV-watching affects mortality. Their conclusions: On average, it cuts 1.8 years from Australian men's lives and 1.5 years from Australian women's lives. And "On average, every single hour of TV viewed after the age of 25 reduces the viewer's life expectancy by 21.8 minutes."
The study has all sorts of limitations, but here's the basic message: "TV viewing time may have adverse health consequences that rival those of lack of physical activity, obesity and smoking." Of course, it may be mainly TV's obvious links to sitting, eating and smoking that most account for those ill health effects. Still, I was struck that the study refers to TV as a public health problem, and even compares it directly to smoking, equating an hour of TV with two cigarettes:
The average loss of life due to the smoking of a single cigarette has been estimated at 11 minutes, though this may be an underestimate. Our findings suggest that half an hour of TV viewing above age 25 may shorten life to a similar degree.
This sort of study is open to all sorts of challenges on the data, but doesn't it ring metaphorically true? When I watch junk TV, I really do feel as if I've just thrown away many minutes of my life...
This program aired on September 26, 2012. The audio for this program is not available.