Hey Kdances,
This is an interesting thread because I was thinking the exact same thing. I teach three times a week and I'm also training for a marathon. I'm pretty active in general and I need a physical outlet. I understand I won't have tons of time to run 20 miles on a Saturday morning, but I thrive on the benefits of working out. I love getting paid to workout and I'm planning to teach at least twice a week when I'm in school. I just need to find out the info from the gym at PCOM.
Good luck, and it sounds like you and I need to workout so I say go for it, make a few extra bucks. How can you go through med-school without some type of stress reliever?
Besides, it's all about time management.