Yeah, I remember in high school when I rode my bike an incredible amount of miles every week I was around 50 bpm. I guess some of it can be chalked up to genetics too.

I did a "century" ride just before my senior year of high school. I'd like to train enough this summer to do another one. People still get amazed at the concept of riding a bike for over 100 miles through the hilly Appalacian mountains! Guess they've just never spent that much time on a bike...