I try to take a walk five days of every week. The course is approximately three and one-half miles and crosses some beautiful terrain in the valley where I reside. It goes one direction and then reverses itself. During one part of the walk, the wind will be behind me, assisting by allowing me to move at a faster and brisker pace. It is always enjoyable when this happens, as I appear stronger and quicker than normal. When the course reverses itself, the wind is in my face. Now, this experience changes. Instead of assisting me, I am now walking into a headwind, slowing my speed and making the...