Okay anyone got some suggestions? Currently getting my bike very soon, and though I am young [under 20] I am quite unfit. I want to be able to ride at a comfortable speed, but able to go longer and faster. I'm not doing this to lose wieght as i am not overwieght, it is simply to get fitter and more healthy. But obviously i don't want to get on my bike and try to go as fast as possibly and as far. I want to build up gradually, any tips?