I started out my life as a non exerciser because I had asthma as a kid. This was in the days before thay had all the nifty inhalers and such to control it. Whenever I exerted myself, my bronchial tubes would clamp shut and I spent much of the time feeling like I was drowning. I wouldn't wish that feeling on my worst enemy and I went to great pains to avoid it. As an adult, I was put on inhalers and that helped alot. pregnancy helped also. The lamaze breathing techniques just seemed to help when my tubes would seize up, and also the experience of pushing past pain was helpful in putting the pain of exercise in perspective. If I could live through labor, I could live through an uncomfortable aerobics class. I'm in an active phase right now, but I know from my own history that it is easy to fall out of the habit of exercising--even though I am fully aware of how much I enjoy it now--and it is bloody difficult to get back into the habit when you have fallen off.