What physiological effect does the AGSM primarily aim to counteract?

The AGSM, or Anti-G Straining Manoeuvre, is specifically designed to counteract the effects of g-forces experienced during high-performance flight. The primary physiological effect that the AGSM aims to prevent is g-induced loss of consciousness (GLOC), which occurs when the body's blood flow to the brain is inadequate during rapid acceleration.

When pilots experience high g-forces, especially in maneuvers such as tight turns or rapid climbs, the increased acceleration can cause blood to pool in the lower body. This pooling reduces cerebral perfusion pressure, leading to a state of hypoxia in the brain, which can result in loss of consciousness. The AGSM involves a specific technique of straining and breathing patterns that help maintain adequate blood pressure and cerebral perfusion, thus reducing the risk of GLOC.

While hypoxia, dehydration, and fatigue can be important factors in flight physiology, they are not the primary focus of the AGSM. The manoeuvre is specifically tailored to address the unique challenges posed by high g-forces, making the prevention of g-induced loss of consciousness its main goal.