Okay, you're thinking "Not. News." Watching TV and playing video games (pre-Wii fit) have long been blamed for health problems. I see where you're coming from, but.
A report from the Montreal Gazette suggests that researchers have found a correlation between sitting on your butt in front of a screen independent of other factors that affect health. Why is that a big deal?
Well, it's simple math that being sedentary is going to mess up your health. Finding a correlation between that and poor cardiovascular health is a no-brainer. However, as any stats prof would be eager to tell you, correlation does not prove a cause-and-effect relationship. It just means two things are related. Tall people tend to be heavier than short people, but gaining weight won't make you taller, even though the two are correlated. So it goes for sitting on your couch. You might say, "Well maybe couch potatoes have bad habits, don't exercise, or have health problems to begin with." According to the article, however, these researchers have found that there's still an effect once you account for factors like those. They surmise that two hours a day or more of sitting actually has a deleterious effect on your body. So while you could argue that people with poorer health are more likely to sit more, this article has accounted for that. There's something more going on.
The science itself will be published in the Journal of the American College of Cardiology on January 18. (The Gazette article doesn't name the study authors other than Emmanuel Stamatakis of University College London.) I'd like to get a closer look at the study design and data, and if I can I'll post a closer analysis.