The increased number of red blood cells in the bodies of higher-altitude inhabitants is purely down to the height above sea level that they live. As one gets higher and higher above sea level, further up into the atmosphere, the air gets thinner. This means that the there is simply less oxygen in any given space.
- Red blood cells<br>
Red blood cells are the way the body carries oxygen through the different cells and organs. Red blood cells are transported through the bloodstream. As oxygen is scarcer at higher altitudes, the body creates more of these cells to offset this.
People who live in higher altitude locations actually have better and larger lung capacities then those who live closer to sea level. This is due to the fact that the air is thinner at higher altitudes, therefore more air needs to be drawn into the lungs each time a breath is taken.
Because the air pressure is lower at higher altitudes, there is less oxygen in the air, and each blood cell picks up less oxygen during the passage through the lungs. Since the body cannot increase the amount of oxygen each red blood cell can take on, the only way to transport more oxygen is to create more blood cells to transfer the same amount of oxygen required for normal body functionality. The chemical erythropoietin is released from the kidneys. This then stimulates bone marrow to create more red blood cells. People who are born at high altitudes also produce more red blood cells.
- High altitude training<br>
Athletes use high altitude training as a very good way to train their body to perform in a low-oxygen environment. By attempting to replicate their best times with a decreased oxygen intake, this allows them to excel as soon as they are returned to a normal oxygen environment. Their hemoglobin concentrations (the amount of red blood cells in the body) will increase through this training, and help give them an edge during competition. High altitude is classified as any height above 1200 meters above sea level.