Abstract: There are various approaches to the classification of ergogenic agents used to improve the physical capabilities of athletes. Mainly, ergogenic agents of five different classes are considered: food, physiological, psychological, pharmacological, mechanical. This article analyzes the results of recent scientific publications concerning the use of physiological ergogenic agents by highly qualified athletes. The study showed that the use of a hyperoxic gas mixture has a directed effect on the functional capabilities of the cardiorespiratory system, optimizing vegetative support. The use of oxygen support before maximum exercise helps to increase the performance of the oxygen transport system, the overall performance of the heart, as well as reduce the limiting capabilities of the respiratory system. Breathing a hyperoxic gas mixture for 20 minutes after maximum exercise accelerates the processes of urgent recovery of the cardiovascular and respiratory systems.