title: The application of positive pressure breathing for improving +Gz acceleration tolerance.
abstract: Investigations on +Gz acceleration tolerance were carried out in pilots using various values of positive pressure breathing (PPB) during centrifugation. The greatest improvement of +Gz tolerance--2.2 +Gz--was achieved while applying PPB=45 mm Hg and using a counterpressure suit. PPB prolonged the time at +5Gz from 2 min 35 s under control conditions to 6 min 53 s at PPB=45 mm Hg. The author discusses the mechanism of the increase in acceleration tolerance at PPB, stressing its protective effect on the circulatory system.
mesh_terms: D000054:Acceleration / Q000009:adverse effects*; D000328:Adult; D000337:Aerospace Medicine; D006112:Gravitation; D005676:Gravity Suits; D006339:Heart Rate; D006801:Humans; D008297:Male; D011175:Positive-Pressure Respiration / Q000295:instrumentation / Q000379:methods*; D011312:Pressure; D013997:Time Factors