The Washington Post published a really nice info-graphic on the health implications of prolonged sitting. They recruited a panel of experts, of which I was lucky to be a part. They did a knock out job with it, and I won’t take any more of your time other than to point you to the original source here.
Cliff Notes version: doing too much of one thing…..ANY one thing…..is not good for us. Motion keeps your muscles active to keep your body stable, your joints lubed, and your internal organs primed for normal body upkeep. Check out the link for the full monty.
PS – after you read it, get up and walk around!