Sherpas, an ethnic group from the mountains of Nepal, really are extraordinary mountain climbers, but it may be because they have a special advantage.
Their cells are actually different than other people’s, meaning they’re able to climb to high altitudes without running out of energy, a new study led by researchers at Cambridge University has found.
The higher people climb, the less oxygen is available, so the body has to work harder to make sure the oxygen is distributed around the body.
This is why other climbers who travel to the Himalayas and other high mountain ranges have to take time to acclimatize to the altitude and often carry oxygen with them to help them get to the summit.
But ethnic Sherpas don’t need to. And now scientists might understand why.
The research team traveled to Mount Everest Base Camp at an altitude of 5,300 meters, carrying out blood and tissue tests on two groups of people as they gradually made the ascent.
The first group was made up of 10 “lowlanders” – researchers who operated the laboratory at Base Camp.
The second group comprised 15 Sherpas who lived at relatively low altitudes, compared to the “elite” Sherpas who scale Everest while working as guides.
The researchers wanted to understand how efficiently the participants’ cells produced energy, that is, how mitochondria (the powerhouses of cells) use oxygen to make a molecule called ATP that is essential for metabolism.
So they measured the metabolism of the two study group participants before the expedition set off (the baseline reading), on arrival at Base Camp, and two months after being at Base Camp.
The researchers found that even at baseline, the Sherpas’ mitochondria were more efficient at using oxygen to produce ATP, and didn’t really change at Base Camp.
The lowlanders, though, did show a change with time, indicating that their bodies were adapting to the higher altitude.
“Sherpas have spent thousands of years living at high altitudes, so it should be unsurprising that they have adapted to become more efficient at using oxygen and generating energy,” says Dr Andrew Murray from the University of Cambridge, the study’s senior author.
“When those of us from lower-lying countries spend time at high altitude, our bodies adapt to some extent to become more ‘Sherpa-like’, but we are no match for their efficiency.”
As well as ATP production, the researchers studied other metabolic indicators, such as how much the participants generated energy from burning fat or sugar, with sugar being the most efficient mechanism. Again the Sherpas showed more efficiency, with low levels of fat oxidation.
They hope the results will have medical applications to help treat people suffering from hypoxia – a lack of oxygen. This is a particular problem for critically ill patients in intensive care units (ICUs).
“By understanding how Sherpas are able to survive with low levels of oxygen, we can get clues to help us identify those at greatest risk in ICUs and inform the development of better treatments to help in their recovery,” said study author professor Mike Grocott from the University of Southampton.