I've done Pisco in Peru (5772m, 18,937ft), failed a summit of Orizaba and Chimborazo (made it over 20,000 feet but had splitting headache and felt really sick), and made it up Cotopaxi (5897m, 19,347 ft). I came close to dying on the way down Chimbo because i was a bit disoriented and really fatigued. Made a mistake and almost paid for it. It takes so much energy to climb in that low O2 air that you just lose everything. Most people aren't used to 12+ hours of any kind of exercise, much less carrying a decent amount of weight when your body isn't digesting food right and you can't retain water well. Add it all up, and you make mistakes or just slip at the wrong time. It's a dangerous sport. These are risks you take.

Also likely has something to do with alkalotic blood. As you breathe in high altitude, the pH of your blood rises.

They may not be scientists, and they may not have a whole lot of scientific training, but they HAVE had more training and exposure to science than Joe the Plumber. To say otherwise is to be dishonest. And the next sentence, "...doctors doing active medical research have limited scientific faculties..." is totally unfounded. What you've heard from your friends who didn't understand what somebody told them or what you read on the internet are all anecdotes. You think docs are DUMB because they are doing research?? Indeed, take everything you hear FROM ANYONE with a grain of salt, but don't use that as your justification to mock people who are, for the most part, trying really hard and doing the best they can.

It's the same as the "amalgam dental fillings cause xxxxxxxx...." stories. Never mind that after those patients have their fillings taken out at huge expense and recover (placebo effect) and go on 60 minutes and look great, they then relapse and are way worse off a few months later. You'll almost never see a retraction of the original story.