Research progress in relationship between cardiopulmonary reserve and G-tolerance in pilots

Fighter pilots often experience positive acceleration (+ Gz) in the air, which can result in increased hydrostatic pressure of blood column and redistribution of blood, thus making the cardiovascular system bear great pressure. G-induced loss of consciousness (G-LOC) or almost loss of consciousness (A-LOC) may occur when the decrease of cerebral blood flow caused by + Gz load leads to cerebral hypoxia-ischemia. Cerebral hypoxia-ischemia is the root cause of G-LOC/A-LOC, but there are many factors affecting cerebral hypoxia-ischemia and the relationship between cerebral hypoxia-ischemia and G-tolerance remains to be fully elucidated. This paper further sorts out the relationship between cardiopulmonary reserve and G-tolerance by reviewing reported effects, in recent years, of heart rate variability, blood pressure, cardiac systolic function, ECG index, pulmonary function, pulmonary gas diffusion and blood flow on G-endurance.