Why do so many elite runners live above 2,000 meters?
The underlying mechanism is hypoxia, the reduced oxygen availability at altitude, which stimulates the body to produce more red blood cells and increase hemoglobin mass over time. More hemoglobin means more oxygen-carrying capacity per liter of blood, which is directly useful in an endurance event. This is not a fringe theory. It is the basis for the live high, train low model formalized by researchers Benjamin Levine and James Stray-Gundersen in a study published in the Journal of Applied Physiology that has shaped altitude camp design for three decades, and it is the reason towns like Iten sit where they sit on the map of world distance running rather than somewhere lower or higher.
