Sherpas could well be considered superhumans. They are one of the ethnic groups that have lived in the Himalayan plateau, mostly in the eastern region of Nepal, for about six thousand years. They live about 5,000 meters above sea level; an altitude at which the average person would suffer from hypoxia, suffer from a lack of oxygen and consequent exhaustion. But not the Sherpas. Not only do they live there, but they move heavy loads from one place to another as if it were effortless.
“The Sherpas we saw during our study walked incredibly fast on the mountain trails, which are also very steep. “We saw some of them carry more than double their own body weight,” he said. Federico Formentiprofessor and researcher of Physiology at King’s College London, in dialogue with Infobae.
Formenti carefully investigated how Sherpas have this extraordinary ability to withstand hostile conditions. He made different expeditions, which lasted three or four weeks, to carry out an experiment: he placed GPS signals, measured oxygen consumption and electrical muscle activity in Sherpas who retraced mountain trails at more than 5,000 meters above sea level, with a steep slope. , and transported loads of up to 45 kilos.
“In a few days I managed to acclimatize to the altitude, but I ran out of breath as soon as I tried to walk quickly,” the researcher recalls. “Spending time with such a different culture taught me some of the most important lessons of my life. I felt very welcomed by the Sherpas. I think that depends on the way you present yourself to the community. In my case I brought some gifts and details.”
Formenti is dedicated to sports science. Therefore, his capacity for amazement at extraordinary physical prowess is higher. But the Sherpas managed to break that threshold. People who live at low altitudes, like him, like most, face endless risks when they pass 2,500 meters and access to oxygen begins to become scarce. Symptoms often include headaches, dizziness, poor appetite, and trouble sleeping. In the most severe cases it can even cause swelling in the brain, a condition called high-altitude cerebral edema, or fluid in the lungs.
The Sherpas do not seem to care about meters above sea level. They live as if conditions were ordinary. How do they climb the highest mountains, Everest among them, without getting tired? Where do they get oxygen?
-The key for Himalayan populations is biological adaptation – Formenti responded -. Tibetans have more efficient lungs, lower hemoglobin levels, greater plasma volume, and more circulating nitric oxide, all physiological traits that increase blood flow and restore, at least in part, the body’s oxygen supply. Sherpas also have higher levels of myoglobin (oxygen storage in muscles) and protection against tissue damage caused by reactive oxygen species.
-In that extraordinary performance, how much is there of training and how much of genetics?
-Both training and genetics have an impact on the performance of Sherpas. Caucasian climbers go through intense training like Himalayan Sherpas, but fail to match their performance. With genes that support life at altitude, Sherpas perform superiorly.
Their study showed that Sherpas produce 30% more energy than average mountaineers, who use and need less oxygen to do the same task at height. The answer, it would be confirmed almost a decade later in other research, lies in the genes of the Tibetans who, after living for thousands of years in a hypoxic environment, adapted to survive. They mutated to become the masters of the mountain.
Tatum Simonson is a researcher at the University of California, San Diego. During her career she dedicated herself to studying the genetics and physiology of populations that adapted to high altitudes: the communities of the Andes, the Ethiopian highlands and the Tibetan plateau, especially the Sherpas.
As director of the study, Simonson and her colleagues strengthened ties with the Sherpa community. For months they conducted interviews, physiological measurements and genetic analyzes with those Tibetans who gave their consent. The research team scanned their genomes and found a series of genes with different mutations that are directly linked to oxygen metabolism and that allow them to live in a hypoxic environment as if it were normal, as if they were on the plain.
“Sherpas have lived in high-altitude regions for hundreds of generations, and many current inhabitants inherited adaptations that mitigate the physiological challenges imposed in this low-oxygen environment. “Some of these adaptations involve improved oxygen delivery and utilization, which are attributed to variation in breathing patterns, blood transport, and energy metabolism,” Simonson explained in conversation with Infobae.
The comparison of the analyzes between the Caucasian mountaineers and the Sherpas showed obvious results.. The former’s body adapts to the lack of oxygen by increasing the number of red blood cells in the blood and thus, in turn, increasing its ability to breathe. The Sherpas, on the other hand, have thinner blood, with less hemoglobin. That uniqueness allows their blood to circulate easily and put less pressure on the heart.
“He EPAS1 It is one of the most notable genes associated with adaptation to high altitudes in humans, as well as other highland-dwelling species. It decisively influences the hypoxia-inducible factor (HIF) pathway. This gene encodes part of a HIF complex that regulates the body’s response to lack of oxygen by activating gene expression in hundreds of genes, causing physiological changes. Studies relate this gene to hemoglobin concentration,” Simonson warned.
A few years later, in 2017, it was discovered that Sherpas also have a metabolic adaptation linked to a gene called PPARA. This mutation is associated with greater efficiency in oxygen utilization in the muscle. Let’s say, in automotive terms, that it allows them to do more kilometers per liter of gasoline.
One fact that caught the attention of the researchers is that the metabolism of the Sherpas seems to lose its “power” when they go down to the plain. The genetic differences of Tibetans are activated when the environment puts pressure on them, when they are thousands of meters high and their body needs to obtain oxygen to transport loads that sometimes exceed their own weight.
-Could this discovery, the genetic mutations of the Sherpas, help other people in some way?
“Yes,” Simonson said. Gaining a greater understanding of the mechanisms underlying adaptation to high altitudes could lead to the development of therapies tailored to people who move to such environments or to those who have low blood oxygen levels due to various pathologies, such as heart, lung or Sleep apnea. By identifying and manipulating relevant genetic pathways, we can improve oxygen transport and utilization. That, consequently, can improve a person’s health and quality of life.
