As said, different individuals have vastly different abilities to handle higher altitude,. Some people will die at elevations others don’t notice. If in doubt, head to lower elevation, NOW! A teenager climbing 12,000 foot Mt. Adams died overnight of altitude sickness at what sounded like 8 or 9,000 feet according to the news story.
Two examples of people prone to altitude sickness:
My wife is hyper sensitive. Some days she gets sick at elevations above 3,000 feet, yet once in awhile she will do fine on the rim of Bryce Canyon at nearly 10,000. In Quito she ended up in the ER with apparent heart attack. Docs took one look and said, “Another tourist with altitude sickness.” They gave her some pills that helped till she could fly home, don’t know what they were. Another trip she got so sick in Banff, which I’d guess is 3500 -4000 in elevation, that we canceled the rest of our stay and headed home to sea level. One time driving through the high plains of Wyoming she got slightly mind fuddled and her vision greyed out till she was looking through a horizontal slot blacked out on top and bottom. We boogied for the Snake River canyon and she got better by the mile as elevation dropped. Forced over hydration ahead of the sickness, not allowing a chance of dehydration helps- sometimes. She avoids high country anymore.
At 7,000 feet when deer hunting in California, a hunter near me went into chest pains and I rushed off of the mountain to take him to an ER because I was sure he was having a heart attack. He insisted that it was altitude sickness and merely needed to get home to sea level. By the time we got down to 1500 feet he was fine.
