Altitude training (reduced oxygen supply to the body – hypoxia) has established itself as an integral part of successful competition preparation in almost all endurance sports. Artificial altitude is also used in alpinism to prepare for high-altitude camps in the mountains. Correct acclimatization in an altitude tent, for example, can reduce the occurrence of altitude-related illnesses. The partial pressure of the air is no different than at sea level, only the oxygen content is reduced as at high altitude. There is no such state in nature. However, the effect is the same.