[The regulation of respiration under the conditions of the altered density of a gaseous environment during muscular work].

In 10 young healthy subjects, both at resting and in muscular work, the substitution of air by a helium-oxygen mixture reduced the central inspiratory drive, the work of breathing, and electrical activity of inspiratory muscles, whereas the inhalation of elegas-oxygen mixture led to obvious opposite effects: the effort for even the least maximal inspiratory flow increased in the same lung ventilation as when breathing air and in constant chemoreceptor stimulus; the central inspiratory activity increased nearly three-fold. The mechanism of the load compensation and of the respiratory system's load seems to be mediated mainly through the afferents from the respiratory muscles' proprioreceptors.