I find that a consistent exercise routine helps to implement good habits in other parts of my life, such as making good food choices, sleeping well, etc. And it certainly spills over into my work, as well. I just have more confidence and improved sense of well being. One thing that keeps me going is keeping in mind the long-term benefits. Not only will it improve my day, but I have a goal of living a long life with all my capacities.

I've recently started swimming and love it. If you have access to a pool, I cannot recommend it enough. I'm also in the middle of the "100 Pushup Challenge."