Mountain Everest is one of the greatest things humans have challenged themselves with. People die from many things there: from injuries to hemorrhage (blood flowing out from a ruptured blood vessel). Altitude sickness is very common here because some people struggle to adapt to low oxygen levels. However, there are some people who are biologically different from everyone else on Earth. These people are called Sherpas.

Sherpa is a group of Tibetan ethnic groups that are native to the Himalayas and other mountain regions of Nepal. What is so special about them? They are extremely good climbers due to centuries living in these areas and adapting to them. Their bodies behave slightly differently than ours, for example, and that is what makes them very adaptable to climbing high altitudes.

In our blood, red blood cells pick up oxygen molecules you inhale by binding it to a special oxygen-carrying protein called hemoglobin. Hemoglobin helps transport oxygen from our lungs to any other cells that need it for metabolism, which is extremely important for your body's functioning. When the supply of oxygen is low, the body compensates for it and produces more red blood cells to carry more blood to the organs. This is what makes the blood of non-Sherpa people thicker and can be potentially dangerous - if the blood slows, blood vessels can be clogged, leading to blood clots and death. Sherpas have thinner blood, which means they have fewer red blood cells with less hemoglobin due to less oxygen in high altitudes.

The fuel for your muscles to move is to either get energy from glucose (or other sugars) or from burning fat. Our bodies usually get their energy from burning fat. However, it required more oxygen than the breakdown of glucose. So, in high altitudes with less oxygen supply than usual, people can become tired and have fatigue. Sherpas have adapted to burn sugars more than fat. It means that they generate more energy per oxygen molecule breathed than non-Sherpas! Generally, Sherpas work as guides in Himalayas and Everest due to their amazing abilities to survive in high altitudes!