Right - it's the sitting. It couldn't possibly be that the kind of person that watches hours upon hours of TV each day just might have other unhealthy habits...
Two groups - one spends 4 hours per day watching TV and the other spends 2-4 hours per day doing something more active. Did it really take research to highlight which was more beneficial to life expectancy?
I wouldn't call what cyclists and rowers do "sitting." But, more to the point of your comment and its parent, does anyone have any carefully gathered figures on differences in mortality between Buddhist monks and other residents of countries the monks live in, or between cyclists and rowers and their compatriots?
What makes you think that the careful body balance of the buddhist monk and the graceless laying down of the couch potato are the same thing? They both are called "sitting" because share the same pivot point (the buttocks), and both are motionless too; but one requires much more effort and energy expenditure than the other.
"Although it is possible that people who were already ill watched more television than those who were healthy, the researchers tried to rule that out by excluding subjects who already had heart disease.."
This is a typical same old correlation - causation confusion. There are many more "althoughs" and all of them have to be excluded before the title can be justified.
