Alright sir, if you don't get on oxygen you're going to die. [YT] Destin Sandlin of "Smarter Every Day" goes into a high altitude simulation chamber where he demonstrates why you should definitely, always, put on your own oxygen mask first. The chamber is set to the equivalent of 25,000 feet (7,620 meters) after a slow decompression, which allows 3 to 5 minutes of consciousness. The video points out that "most airliners travel at 35,000 feet" (10,670 meters), and under a real scenario you may get only 15-30 seconds of useful consciousness.
Based on a comparison of suicide rates at sea level and at areas above 2,000 feet, living at a high altitude may make people 30% more likely to commit suicide. Neuroscientist Perry Renshaw believes that it's due to the impact of altitude on the brain.
Tibetans May Be Fastest Evolutionary Adapters Ever. "A group of scientists in China, Denmark and the U.S. recently documented the fastest genetic change observed in humans. According to their findings, Tibetan adaption to high altitude might have taken just 3,000 years. That's a flash, in terms of evolutionary time, but it's one that's in dispute."