I have a The North Face ad hanging on the wall of my cubicle at work that says "Sit for Your Job, Run for Your Life." Only in the last 100 years would you see a slogan like that. "Sit for Your Job." 100 years ago, nobody sat for their job. People worked in plants or mines or farms. Very few people worked in offices. In fact, the only one I can think of off the top of my head had the surname "Scrooge."
A 2010 study in the American Journal of Epidemiology found that men and women who sat for more than six hours per day were respectively 18 and 37 percent more likely to die during the study than those who sat for fewer than three hours per day. Surprisingly, this number was completely unrelated to the amount of time subjects spent exercising.*