Altitude effect on athletic performance

Spending several days at higher than normal altitude will stimulate erythropoiesis, due to the lower oxygen concentration in the air, which when breathed would result in hypoxemia. Athletes would be less competitive if they competed at a higher altitude than that in which they lived or trained, and more competitive if they lived and trained at a higher altitude than that in which they competed, at least in theory. While students may not know this, experimental results support the best regimen for maximizing performance at a low-altitude competition to be living at high altitude but training at low altitude. Neither living and training high nor living and training low achieved the same results. High-altitude training is necessary, however, for high-altitude competition. This is a matter of opinion, but most people would probably argue that these training regimens are natural, and therefore not a type of doping.