Here's a link I just found on Drudge: you can die from sitting at the computer too much: http://sanjose.bizjournals.com/sanjose/stories/2003/01/27/daily44.html
But I watch football on TV; doesn't that count as exercise ? Yes, sedentary activity will kill us in the 21st century. That’s why it’s important to exercise and to eat sparingly, something that Americans are unacquainted with. I usually swim a mile at lunch and walk a mile in the evening and lift weight three times a week.