"I clock countless hours in the gym, where log thousands of r..." — David Goggins quote meaning

I clock countless hours in the gym, where log thousands of reps and run and ride my bike obscene distances, to cultivate believe, Despite what you may think, I don't consider myself an ultra-athlete because those races are not who I am. They are tools. Each one provides me a stockpile of faith so when I get stuck in the maze of life like a broke-down savage, I still believe I am capable of achieving my unreasonable goals, such as becoming a smokejumper at forty-seven years old, no matter what society or the good doctors say.