The numbers are scary, but the physiological impacts of sitting are truly sobering. As the New York Times article notes, the act of sitting almost immediately shuts down electrical activity in muscles. Calorie consumption falls to "about one per minute," and the level of enzymes that draw fat out of the bloodstream declines precipitously.
Even with regular exercise, it's clear that long hours at the desk can take a real physical toll. Personally, I've taken to making motion a part of my home office routine. During phone calls, I make a point to stand and walk around (enabled, I might note, by my cordless Plantronics Calisto Pro phone and Bluetooth earpiece, reviewed here), and to take occasional breaks from sitting. I've even gone so far as to set up an ad-hoc standing desk, setting my laptop on a file box so I can work on my two feet.
What are your thoughts on the allegedly lethal risks of sitting at a desk all day?