[Effectiveness of a helium-oxygen gas mixture in transverse accelerations]

Healthy male test subjects, aged 20 to 45, were exposed to acceleration of +6 Gx for 1200 sec and of +10 Gx for 60 sec. Three gradients of the centrifuge acceleration were used in the latter case. In every experimental run the test subjects were exposed to accelerations while breathing air or a helium-oxygen atmosphere. The positive effect of the helium-oxygen atmosphere was seen in an increase of the respiration intensity and in an elevation of pulmonary ventilation and gas exchange. This may be associated with a decline of the aerodynamic resistance to breathing. The positive effect of the helium-oxygen atmosphere was more pronounced during accelerations of +4 to 8 Gx and depended on the total exposure time.