Himalayan powerhouses: how Sherpas have evolved superhuman energy efficiency

Sherpas have evolved to become superhuman mountain climbers, extremely efficient at producing the energy to power their bodies even when oxygen is scarce, suggests a new study led by University of Cambridge and UCL researchers, published today in the Proceedings of National Academy of Sciences (PNAS) . The findings could help scientists develop new ways of treating hypoxia - lack of oxygen - in patients. A significant proportion of patients in intensive care units (ICUs) experience potentially life-threatening hypoxia, a complication associated with conditions from haemorrhage to sepsis. When oxygen is scarce, the body compensates by producing more red blood cells, which are responsible for carrying oxygen around the body. This makes the blood thicker, however, so it flows more slowly and is more likely to clog up blood vessels. The research team sought to understand why Sherpas, an ethnic group from the mountain regions of Nepal, are able to live at high altitude with no apparent consequences to their health. Previous studies have suggested differences between Sherpas and people living in non-high altitude areas, known collectively as 'lowlanders', including fewer red blood cells in Sherpas at altitude, but higher levels of nitric oxide, a chemical that opens up blood vessels and keeps blood flowing.