I went from a pretty physically active job in facilities management to an IT role working from home about 3 years ago and have had a slew of physical issues that I think are related to sitting down 10+ hours a day such as sciatica. I real a book called "Deskbound: Standing Up to a Sitting World" by Dr. Kelly Starrett and it's pretty damning. Similar to the old comparison that smoking a cigarette takes ~7 minutes off of your life, they claim that every hour you sit down takes ~11 minutes off of your life.
Regardless of everything I have read about sitting down being terrible for you, I just can't seem to get into a routine of standing up. Once I sit down for an engagement / lunch / etc., I just simply don't make it back up that day. I have become terribly lazy, I guess.