I know I could lose a couple lbs and was thinking about how I view mountain biking. At its core I see it as an outdoor hobby that allows me to get in touch with nature and also have fun. I also see riding as a way to exercise. The problem with the latter is that riding once per week is not really going to make a huge dent on your fitness past a certain level.
What about you, do you use mountain biking as your primary exercise vehicle or does it fall into the active hobby category?