Green_Archers,
I totally agree with you about being fit to be a DM or Rescue Diver. I do work out every day. I have just about completed 8 weeks of the "Insanity" workout and feel great. I also am a member of the local gym where I work out.
That being said, even as a kid I was never able to tread water very well. I was never taught how or technique. When I tread water I move so fast with my legs and hands it tires me out quickly. I think a person can be physically fit and still tire while trying to tread water or swim for great distances.
This was the reason for the original post. As a DMC, I am looking for guidance on floating, treading water etc. I have the other skills and fitness handled with no issues.