[Changes in the sensitivity of the human respiratory system to hypercapnic and hypoxic stimuli during repetitive exposures to physical loads of different intensities].

Variability of the responses to CO2 and hypoxia was revealed in strenuous physical load. The dynamics of the CO2 responses was found to be regular during the recreative periods specific for training sessions in cycling sports. Changes of the CO2-H+ response seem to be determined by optimisation of the CO2 dynamics in the body.