The biological secrets that make Sherpas superhuman mountaineers

Photos:
Everest is the tallest mountain in the world, at 8,847 meters above sea level. Low oxygen at that altitude pushes human endurance to its limits. Pictured, Sherpa mountaineer Pemba Dorje Sherpa and others on Everest, 2009.
Hide Caption
1 of 9

Photos:
Having lived in the Himalayas for centuries, Sherpas have adapted to easily breathe the thin air.
Hide Caption
2 of 9

Photos:
In 2013, the Xtreme Everest research team conducted experiments on Sherpas and other volunteers at high altitudes to discover how Sherpas thrive at such heights.
Hide Caption
3 of 9

Photos:
Researchers set up their laboratory at the highest altitude possible -- Mount Everest base camp.
Hide Caption
4 of 9

Photos:
The secret behind this ability lies in their cells; Sherpas have differences in their mitochondria, which means they use oxyg