Let's face it: writers are not as likely to be tremendously physically fat as, say, rock climbing instructors. Katherine O. Huether over at Absolute Write has some ideas for keeping yourself in shape (or at least, keeping some sort of shape) despite your hours in front of the computer.

In addition to her ideas, I recommend buying a pedometer. 10,000 steps equals 3.5-5 miles, so if strap one one and see that you've already racked up 4,000 steps by midafternoon just by walking around, you'll have more impetus to step outside and get a little walk on.