Hi, I have been walking and/or jogging on my lunch for about 4 1/2 years now. It is such a great break from work (I sit all day). It has been the best thing I have done for myself. When I started I was 60 pounds overweight after my first pregnancy (& did WW, lost 40), then walked until the day before I delivered my second child. I walk with my boss and other co-worker, we motivate each other when one of us doesn't feel like going.
Good luck to you!!! It is a great habit to get into!