https://www.youtube.com/watch?v=nn6kdPUS1bM
++++++++++++
Just to elaborate a bit.
The north slope that he skied was between 29,000 to 20,000 feet.
There are 5,280 feet in a mile so that 9,000 feet down was close to 2 miles.
Apparently he also had a rope available on the way down that he used as assistance with the most steep and dangerous places.
It's almost impossible just to climb to the summit.
++++++++++++++
How much oxygen is in the air at the top of Mt. Everest?
Answer: NOT MUCH! Actually only around 25% of what we have at sea level. Obviously, they came with tons of O2 tanks and trained for many months at high elevations to raise their bodies hemoglobin levels.
The higher the hemoglobin is in your blood, the more oxygen it can take from your lungs (higher efficiency of your body’s cardiopulmonary system and ability to deliver O2 thru the rest of your body.)
++++++++++++
https://nyaspubs.onlinelibrary.wiley.com/doi/full/10.1111/nyas.14136
