Here's a new write up by the James Krieger on the harmful effects of sitting.
http://weightology.net/weightologyweekly/?page_id=665
From the article:
It is becoming more clear that prolonged inactivity and low NEAT result in detrimental changes to the body that are not necessarily counteracted by a typical structured exercise program. In other words, inactivity and a lack of exercise are different concepts. Too many people think sedentary means lack of exercise, but instead sedentary means prolonged periods of inactivity. The human body is meant to engage in regular movement, and when it is forced to be sedentary, such as with today’s office jobs and prolonged periods in front of TV’s and computers, there are adverse consequences to health.