title: Mathematical models for predicting G-level tolerances.
abstract: The mathematical models developed in this article predict the following human G-level tolerances: 1) rapid onset relaxed (ROR); 2) gradual onset relaxed (GOR); and, 3) straining-rapid onset. Included in the model are specific functions of: 1) anti-G suit; 2) positive pressure breathing (PBG); 3) baroreceptor reflex; 4) handgrip reflex; 5) anti-G straining maneuver (AGSM) increasing intrathoracic pressures (Pi); 6) leg elevation; and, 7) reclining seatback angles < or = 55 degrees. These functions are based on sound physiologic principles. Also discussed in the development of this model, but not included in the models, were: 1) isometric muscle contraction reflex; 2) Qigong (Q-G) maneuver; and, 3) straining GOR tolerances. The straining GOR tolerance profile was calculated to be a measure of G-duration tolerance and not G-level tolerance. A maximum P of 125 mm Hg from the AGSM was used in these models that could be augmented with PBG to 185 mm Hg. G-level tolerance predictions using this model were validated with published data.
authors.affiliation: Human Effectiveness Directorate, Air Force Research Laboratory, Brooks AFB, TX, USA. rrbslb@aol.com
authors.forename: R R
authors.initials: RR
authors.lastname: Burton
mesh_terms: D000222:Adaptation, Physiological; D000337:Aerospace Medicine; D001359:Aviation; D006801:Humans; D018471:Hypergravity; D008962:Models, Theoretical