I spent my twenties running long distance, but gave up four years ago. The frequent injuries were just too much. A bad injury once had me off training for four months. Going from feeling like a machine to someone who can't manage a jog in the space of an afternoon seriously messed with my emotional state.

I'm writing this on a recumbent bike. I've averaged ninety minutes a day for four years without injury. I've also read a ton of books on my kindle.