High-altitude training benefits endurance athletes by enhancing oxygen uptake and efficiency. As athletes train in lower oxygen environments, their bodies adapt by increasing red blood cell production, improving oxygen delivery to muscles. This acclimatization can lead to enhanced performance upon returning to lower altitudes. Additionally, high-altitude conditions promote mental toughness and endurance, helping athletes push through challenging training. However, attention must be given to acclimatization to avoid altitude sickness and maximize the benefits.