People increasingly live in cities. There's a good chance that if you're reading this, you live in a city. That's good for exchanging ideas and stimulating opportunities, but it often means we don't get as much movement as we'd like or as would probably benefit us.
So here's a little trick I've used for the past three or four years. First off, you shouldn't be working uninterrupted for much longer than 45-60 minutes at a time. When you take a break from work, get up and move your body. Ideally, leave the house or place where you're working, walk round the block or the building. That shouldn't take you much longer than 5 or 10 minutes. If you're working for 45-minute segments, it's an ideal amount of time and it'll refresh you physically so that your next session isn't hampered by waning energy levels.
Try it out and let me know how you find it...