Join Date: Aug 2005
Location: Central Virginia, USA
If you add exercise, your metabolism should be fine. What you may want to try, though, is adding some weight-training to your routine in addition to your runs. Are you near a gym, or can you get some free weights? If your goal is to build muscle, you will reach it faster with some weights.
I would aim for running for a length of time rather than a specific distance because that way you'll naturally add some distance as you become more fit and you run faster.
It is our choices that show what we truly are far more than our abilities. ~A. Dumbledore