What Makes Sherpas SuperHuman Mountaineers?

Making use of oxygen

Presenting her findings at the World Extreme Medicine Expo in London, last month, Levett identified differences in the parts of human cells that respire to generate energy — known as mitochondria. The Sherpas’ mitochondria were much more efficient at using oxygen.

“They’re like a fuel-efficient car,” said Levett. “You get more energy for less oxygen.”

In addition, the team studied blood vessels under the tongue and other locations in the body, to monitor blood circulation within the organs — known as the microcirculation. This form of blood circulation occurs in the smallest blood vessels and determines how well oxygen reaches muscles, tissues and organs — so how well your body actually functions.

At high altitude, the blood flow within these small blood vessels was found to slow down in the non-Sherpa volunteers, but remained normal in Sherpas.

“This higher speed at which the blood can flow around allows you to deliver more oxygen to the tissues more quickly,” explained Chris Imray, professor of Vascular and Renal transplant surgery at University Hospital Coventry and Warwickshire, UK, who accompanied Levett on an expedition up Everest in 2007.

Levett said this is the first time physiological differences have been identified to explain Sherpas’ apparent superhuman abilities at high altitudes.