Cambridge University researchers studied the metabolic adaptations Sherpas (and Tibetan populations) possess, then compared them to that of lowlanders. The scientists followed two groups of climbers as they made a gradual ascent up to Everest Base Camp. The lowlanders group was made of 10 investigators who worked the Everest Base Camp laboratory, and the Sherpas group comprised 15 climbers living in low-lying areas.
The scientists took blood samples and muscle biopsies of the lowlanders group in London for a baseline measurement and in Kathmandu, Nepal for the Sherpas, then again at Everest Base Camp, and a third time two months post-trek. For the Sherpas, measurements taken at altitude rarely changed from baseline, suggesting they were born with their metabolic differences. But, for lowlanders, the measurements changed over time at altitude, suggesting that their bodies started adapting and mimicking the Sherpas.
Sherpas, an ethnic group from the mountainous regions of Nepal, are renowned for their exceptional climbing abilities, particularly in high-altitude environments like the Himalayas. Their biological superiority as mountain climbers is attributed to a combination of genetic adaptations and physiological traits that enable them to thrive in conditions that would be challenging for most people.
Sherpas have undergone significant evolutionary changes over thousands of years, allowing them to efficiently cope with low oxygen levels at high altitudes.
EPAS1 and EGLN1 genes are associated with hemoglobin levels and oxygen utilization. Sherpas possess variants that optimize their blood’s ability to transport oxygen without the excessive production of red blood cells, which can lead to chronic mountain sickness.
Studies indicate that Sherpas have more efficient mitochondria, which are the cell’s powerhouses. This efficiency allows them to generate energy more effectively from oxygen, enabling sustained physical performance even under hypoxic conditions.
Physiological Traits
Several physiological characteristics further enhance the Sherpas’ climbing capabilities, Sherpas produce higher amounts of nitric oxide, a molecule that dilates blood vessels and improves blood flow. This trait helps maintain energy levels and enhances endurance during climbs.
Unlike many lowlanders who rely heavily on fat oxidation for energy, Sherpas exhibit lower fat oxidation rates. This suggests they are better at utilizing carbohydrates for energy during intense physical exertion, which is crucial for high-altitude climbing.
Phosphocreatine acts as an energy reserve in muscles. While levels tend to drop significantly in lowlanders after prolonged exposure to high altitudes, Sherpas maintain or even increase these levels, allowing for better muscle function and recovery during climbs.
At high altitudes, the body can produce harmful free radicals due to low oxygen levels. Sherpas have been found to maintain lower levels of free radicals compared to lowlanders, which protects their cells from damage during strenuous activities.
The combination of genetic adaptations and unique physiological traits makes Sherpas exceptionally suited for high-altitude climbing. Their bodies are not only adapted to survive but also to excel in environments where most others struggle.
