' Round here Tim we see lots of folks who get the full boat of symptoms as low as 8,000' . Kids seem to be more suceptible than anyone, Overweight Men 35 years plus next. I must respectfully disagree with your assertion that physical conditioning does not play a significant role in suceptibility to altitude related problems as do the large cadre of world-class mountaineers that live in my area, and the SAR teams. I would, however concede that real hard-core mountaineers have a tendency to push themselves very hard at times in very high and harsh environments, making them prone to serious altitude problems. (but that is usually a psychological/ego based elevation of risk)