How do you glorify God through exercise?
1. It fosters gratitude for legs, heart, and lungs. The older I get the more keenly aware I am of how fragile I am. And every breath I take, if I were able to maintain consciousness of truth, I would give thanks to God that he has given me these.
2. What are your motives in doing it? [Is it] the desire to be both mentally and physically at peak performance for Christian ministry.
3. How [do] you do it? [Modest attire? Noisy? Too rough?]... In other words, are you exercising in a loving way?
4. Finally, do you have an eye to turning it into ministry? In other words, can you draw somebody in with you who needs some help with their discipline? Are you willing to stop along the way to help somebody, like the good Samaritan? Are you willing to do some evangelism along the way so that you stop and share Jesus?
John Piper