People living in the Himalayas have an incredible ability to cope at an altitude that would leave most of us gasping for breath. Now, researchers have delved into the physiology of the Sherpas from Nepal to uncover the metabolic tricks their bodies use to survive thousands of meters up.
This new study, published in the Proceedings of the National Academy of Sciences, looked at the intricacies of how their physiology adapts to cope with an oxygen-deprived atmosphere. Not only do they have fewer red blood cells and higher levels of nitric oxide (which helps keep blood vessels open), but they found that the Sherpa are simply far more efficient at producing energy than people from the “lowlands”.
Previous research has already looked at the genetics behind how Sherpas and the people of the Tibetan plateau have evolved to cope with the high altitude. Evidence suggests that people have lived in the mountainous terrain for over a period of 30,000 years, settling permanently some 9,000 years ago. This has left its mark on their genome, with a recent paper finding at least five different genes thought to confer them high-altitude advantages.
“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 senior author Dr Andrew Murray in a statement. “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.”
The researchers from the University of Cambridge compared the metabolic differences between lowlanders and Sherpas. They found that the Sherpas' mitochondria more efficiently used oxygen and produced ATP, the energy used to power our cells. They also found that the Sherpas displayed lower levels of fat oxidation, which again implied that their bodies were more efficient at producing energy.
One of the key findings was that Sherpas' phosphocreatine levels also increased with time, while in the lowlanders it plummeted after two months. Phosphocreatine is an energy reserve that helps the muscles contract when ATP is absent. To add to the Sherpas already impressive physiology, their free radicals remained low, which is good news as they can damage cells and tissue.
The information gleamed from the study could have applications in modern medicine. As many as one in five people admitted to intensive care in the UK will die, with a significant proportion of patients in the ICU suffering from hypoxia. The researchers hope that if they can understand what it is that allows the Sherpas to cope in extreme low-oxygen environments, then it could help save lives in slightly more conventional settings.
