I do not think of myself as a "Mountain Climber" in the way I think you meant it, 'tho I have climbed mountains (real mountains, not piles of naked rock). I don't think everyone who does that stuff fits in the same mold. Some are true adventurers. Some are total jerks (not too many that I have seen). Others fit in neither group. And I cannot explain the "dudes" at all, because I truly don't have a clue about the motivations behind hiring an "expert" to "guide" one - that's not an indictment; I simply do not understand.<br><br>I think I do understand the adventurers, but I don't think I can explain it in words. Remind me not to tell you about some of my trips <grin>...<br><br>FWIW, my notes and recollections from hypobaric (?sp? - long time ago) chamber experiences leads me to conclude that something more like 20,000 feet starts weeding people out very fast. A surprising number of folks cease to function effectively by then - with some folks it is subtle and with others it's very obvious. I recall very few disfunctional folks that remembered it like it was - many had to be shown video tapes of themselves before they believed what they were told about their behavior. It gets worse very rapidly with increased altitude. Has nothing to do with "being tough" but I dunno about being in shape - all the vols were in great condition. We used the hyperbaric chamber to weed out potential team members for a high altitude rescue team as well as establish some other non-trivial individual information (like who needed to start prophylaxis when and how long that was effective). Anyway, serious altitude problems happen to a surprising number of folks before 25k. No telling who will be affected - very Darwinian.<br><br>Interesting questions you raised. Wish I knew/could explain the answer(s).<br><br>Regards,<br><br>Tom