How to become an exercise addict

We all have friends who, despite hectic schedules, never miss a day at the gym. Who can't stop talking about the next 10K.

http://www.foxnews.com/health/2013/09/28/how-to-become-exercise-addict/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+foxnews%2Fhealth+%28Internal+-+Health+-+Text%29