In my last job before I started my own business one of the benefits was a membership to the YMCA and we used to take a break during the work day and go workout at the Y. I really liked this because when you work in front of a computer for hours and hours a day you don't tend to get much physical exercise and over many years you find yourself feeling really out of shape. So during my first year in business for myself I joined a nearby gym and made it a general habit of going to the gym 3-5 days a week and power walk on the treadmill to get some cardio exercise.
I was really disciplined about it for the whole year and I figured by the end of the year I was not in too bad physical condition. So I was surprised when I went and spent an afternoon walking around the Renaissance Festival with my Dad and then my legs were sore for the next 3 days. I mean after a year of vigilant treadmill power walking I thought I would be in good shape.
I think the problem is that treadmill walking is not like real walking, there are different muscles used to coordinate walking on real terrain. So this year when my membership at the gym came due for renewal I didn't renew. Instead I now go to a nice hiking trail only 5 - 10 minutes drive from my house. After a month of walking there I'm glad I made the switch. Walking through trails is much more enjoyable, I get fresh air and sunshine and I think it is therapeutic for my vision as well. When you focus on an array of computer monitors all day your vision is always focusing in a narrow range of depth and walking outside give you opprotunites to focus your vision on objects of varying distance. I also find that during the walks I can ponder difficult technical problems and come back with fresh ideas to try.