As a lifelong atheist I have no use for faith, in the literal sense of the word. I do not believe things which logic and evidence suggest are not true. Indeed, it is a central tenant of my life that faith is the opposite of reason, and something of which I want no part. I have even less use for religion, which includes as a key element a priest, rabbi or other leaders telling a group of followers what to believe, on faith and against all reason. I realize that this may make me seem cold and shallow in the eyes of some, and I think I know why.
The word "faith" has several meanings, and even more connotations. To many people, it means or implies a sense of humility, wonder and appreciation for the gift of life. Similarly, religion often serves as a vehicle for faith, in this broader sense, as well as for creating other valuable things such as a sense of community and connection to others, and to something larger than oneself. I wholeheartedly agree that these are all good things, and I have found that I can get them from running.
So, in this looser sense, running is my faith and my religion. It brings me humility, wonder and an appreciation for being alive and healthy. It connects me to a community of people who challenge themselves the same way I do, and who experience the same highs and lows. Running is how I bring meaning to my life.