First off--even though it has been said before many times-- excellent topic. That can't be said enough.
Second,
I'm quite surprised that your superiors were shocked by such a request, and I think they should reconsider how they "play officer". Seriously--kudo's to you for coming to the realization that you may need to go exterior/take it slow. You've achieved the first step in improving yourself and your lifestyle by coming to that realization, and reaching out to your friends on this forum.
Why am I surprised? I'll tell you (and i'm not necessarily picking on you here Moose--this is a general statement. I hope no offence will be taken, based on the fact that you started this post). Obviously, our own health and safety is vitally important to us. If we do not feel comfortable in an environment, or not physically fit to do a task, then we should not do it--especially if both things are the case. However, I do understand that there will most likely be a short in manpower with volunteer departments, so situations may arise in which we are needed, regardless if we cannot perform well. Ignoring my slight digression, the point I am trying to make is that being physically unfit is not only a danger to ourselves, but is also equally dangerous to our fellow brothers and sisters who work with us on a scene. I have a fella' in my department who could lose a good amount of weight, but has made no effort in doing so--they eat like crap (McDonald's, Garden Catoring, etc), and take no initiative to excercise. Not only are we concerned of something happening to them in the field, but also something happening to us BECAUSE something happened to them (i.e., heart-attack while on the line/searching, etc). Not only do we have a fire scene to deal with, but now we have a medical emergency; the fact that it is one of our own only makes matters worse. It's a very difficult fact to realize, but it had to be said, and I have yet to see anyone else on this thread comment about it.
Moose, I congratulate and thank you for bringing this issue to everyone's attention. I hope that this will inspire others to not only follow your lead, but also learn to recognize these problems, and help educate others in achieving a healthier lifestlyle.