A recent article in the newspaper announced that, according to researchers, sitting is the new smoking? Huh? The sub-title explains: “Sedentary behavior raises health risks.” And don’t I know it! (Although I do think the health risks from smoking far outweigh those from sitting.) I am writing this while standing, and hope that my knees and back appreciate it. Let me tell you my experiences with a sedentary lifestyle, something that is typical of us writers.
In spring of 2008 I started a new job which requires me to sit at a computer all day. Mostly a paperless office, I don’t have too many reasons to leave the keyboard to find hard copies of documents, and even communication within the office is frequently done by email and instant message. On top of that, the job is fast-paced and often high-pressured. Yet I did consistently take a thirty minute walk every day at lunch time.
In the spring of 2009, after noticing that in certain rare movements my left upper arm and shoulder were quite painful, I was diagnosed with “frozen shoulder”. The details of the therapy for that problem are another story. Anyway, one day in the fall the frozenness of the joint started to thaw, and I gradually regained complete use of that arm and shoulder.
Early in 2010 I was dealing with sore wrists and a painful right arm, just inside my elbow. The therapist said I didn’t have carpal tunnel, but I did have tennis elbow in both elbows. No fair! I hadn’t even been playing tennis across the street because the weather was so bad, and now that the snow was finally melting, I still wouldn’t get to play! The therapist also explained to me that if your muscles are constantly in one position most of the time (and mine were, at work and at home), those muscles and ligaments that are not being used actually shorten. So I started paying a lot of attention to stretching my wrists, fingers and arms, and walking away from the computer for breaks.
Later in 2010 I got a sudden sharp pain in my knee out of the blue, just walking from one room to another. It went away as fast as it came, but returned now and then for short periods of time. For weeks it was merely a curiosity, but one day I had to leave work from the pain. X-rays showed a build-up of cartilage. Yes, I know I’m aging and I’m falling apart. But this was yet another voice from my body telling me to make some changes. So I negotiated with my company and started taking one day off per week, and now I take off two days a week. I supplement my income in non-sitting jobs (as much as possible). When I am sitting, I have some wonderful Outlook tasks that pop up and tell me to stretch, so I now take more breaks (and longer breaks) to stand and stretch and walk around the office. Here is a wonderful website (coincidentally, the website’s main function is to feature books) that has stretches you can do at work. The sheet on Desk Stretches is my favorite. 
Maybe this will be helpful to you. I hope so!
Happily Writing 