txhunter58---I've also read various studies where they say certain people are prone to it, regardless of their age or shape. I think we're all in agreement that you should be in the best shape possible and then when a first timer gets out there he needs to know the signs of it to be ready to do what's necessary, including go down low ASAP. I read not too long ago about a guy going to CO on a high country guided hunt and he was so bad the outfitter forced him to let them take him down and he was then taken to a hospital for several days because of the severity. I'm going on a horseback hunt next September for mulies down in the high country of Region G in Wyoming and I'm going out a full week early to get acclimated so what happened this past season up high in the BigHorns doesn't happen down there!