Self-protective anti-Gz straining maneuvers (AGSM) physiology

Results on anti-G straining maneuvers (AGSM), which utilize the 3-5 second duration increase in arterial pressure which can be produced by a proportionate increase in airway pressures, are presented. Previous studies have confirmed that the successive Valsalva and positive pressure breathing maneuvers can be performed safely when used simultaneously with a G suit and are as effective and less fatiguing than the M-1, particularly when used with a counter-pressure chest jerkin; this has established these two as the AGSMs of choice for pilot training. It is further noted that, although the M-2 maneuver is very revealing concerning the neurogenic, hemodynamic determinants of Gz tolerances in relaxed healthy humans, it is not practical for tactical, operational use. A safer, effective self-protective strategem, the F-1 maneuver, is recommended for training purposes and operational trails