As a writer, I find it hard to fit in time to exercise. I'm home much of the day, working at the computer, but when I'm not, I fill my non-writing time with cleaning, shopping, the usual mundane things. Exercise, to me, is not fun. I count it as one of those mundane tasks of the lowest order - ironing, scrubbing the shower, weeding. You get the idea.
Up until a couple years ago, I belonged to a health club. I enjoyed it for the most part, but driving fifteen miles to get to it ate up too much time and gas (I live in a rural area). I have since forced myself to walk two miles a few times a week around town. I also love to bike when the weather permits (since central Illinois didn't have a winter this year, biking season lasted longer than usual!), walk the dog, and do gardening/yard work.
So even though I don't like exercise in the traditional sense, I try to stay active. I guess my 'fitness plan' works for me. Even with frequent stops at the pantry for munchies when I'm stuck on a scene, the exercise I do get seems to keep me at a healthy weight.
How do you stay active when your job or hobby keeps you sedentary?