In Tignes, the athletes enjoy the altitude, which is ideal if you want to benefit from the "oxygenation” effect and improve your hematocrits. Since the air pressure decreases, its density also decreases reducing the amount of oxygen in the respiratory tract. After a few days the body adapts by producing additional red blood cells. The transport of oxygen in the blood becomes more efficient. Endurance capacities are improved once the athletes return to their usual altitude.