It has become known why Sherpas have an easier time tolerating altitude

Their study also illustrates why Sherpa people living in Tibet are much better able to tolerate thin air.

In their paper, published in the journal Proceedings of the National Academy of Sciences, the researchers describe how they studied participants' blood and breathing as they gradually climbed to an altitude of 4,300 metres in the Himalayas (Nepal). The experiment involved two groups: "plain" (people unaccustomed to mountain environments) and "mountain" (Sherpas whose ancestors have lived in high-altitude areas for centuries).

What the scientists found
Sherpas demonstrated a faster and more extensive reorganisation of the acid-alkaline balance of the blood when oxygen is deprived. Simply put, their bodies coped more effectively with the reduced oxygen content in the air. This was possible due to the coordinated work of the respiratory system (which tries to intensify ventilation of the lungs) and kidneys (they regulate the acid-alkaline balance of the blood, getting rid of excess acids or alkalis).

As a result, the Sherpas had already stabilised their blood pH levels at 4,300 metres, but the "plain" participants continued to have problems with "alkalising" their bodies (they remained in a state where the blood was too alkaline).

Why it matters
Today, more and more people are living or travelling to high altitudes, where low oxygen levels can pose serious stress to the body. Understanding the mechanisms of acclimatisation not only helps to develop guidelines for those who want to safely 'conquer' mountains, but also provides new insights into the workings of the kidneys, respiratory system and the whole of human physiology.

What's next
The results of this study indicate that high-altitude peoples such as the Sherpas have developed particular 'genetic' and physiological advantages related to kidney function that allow them to better cope with oxygen deprivation. According to Dr Day, the work shows exactly what kind of "selection pressure" (selective pathway) produced this ability.

Mount Royal undergraduate students Nicole Johnson and Jessica Dickenson were the first authors of the study, along with their mentor and other colleagues. Their findings will help scientists better understand how different groups of people adapt to life in the mountains and what can be done to protect the health of hikers and mountaineers when climbing to high altitudes.

Source: Proceedings of the National Academy of Sciences (2024). DOI: 10.1073/pnas.2412561121