Flying a fighter jet is among the most physically demanding and dangerous occupations in the world.  

The human body has not evolved to meet the physical demands of flying a fighter jet. High G-forces, high altitude, low oxygen—the fighter jet places the human body in an environment and in situations far removed from what that body is built to withstand. Put simply, without specialized training and equipment, the environment is not compatible with life. This is why flying a fighter jet is among the most physically demanding and physically dangerous occupations in the world.  

G-Force Stress

The most obvious danger facing fighter pilots is exposure to G-force stress. When a jet is yanked or banked hard in a rapid maneuver, the pilot may experience up to nine times the force of gravity (9G), meaning, in that moment, the pilot’s body will feel as though it weighs nine times more than it does. Under such conditions, blood is pulled away from the brain and eyes, drained downward toward the legs and abdomen. This is a problem as the brain needs blood to function, and the eyes need blood to see. Of course, the pilot needs the brain and eyes to fly. With degraded function, the results can be catastrophic: first, the vision grays out, before tunneling and then finally disappearing entirely, leading to a condition known as G-LOC, or G-induced loss of consciousness. Even a moment or two of G-LOC, when operating at supersonic speeds or at low altitudes, can be fatal. So, to prevent G-LOC, pilots train intensively in the Anti-G Straining Maneuver (AGSM), a coordinated technique in which the pilot tenses their muscles and forces their breathing in a way designed to keep their blood circulating in the upper body, rather than draining downward. Pilots also wear a specialized G-suit that uses inflatable bladders to apply pressure to the legs and abdomen, which helps reduce the amount of blood that pools in the lower portion of the body. Still, the margin for error is quite small; the threshold between controlled strain and a total blackout can be crossed in mere seconds. 

Oxygen-Related Threats

Fighter jets often operate at altitudes where the oxygen is too thin to support human life. Accordingly, modern fighters rely on onboard oxygen generation systems to sustain the pilot’s life. But that creates dependency on a system, with the potential for failure, to sustain life. In the event of a system failure that leads to oxygen interruption, the symptoms of hypoxia (oxygen deprivation to the brain) can appear rapidly. Symptoms include dizziness, euphoria, confusion, and poor motor control—all problems when operating a fighter jet. The danger is further compounded by the fact that hypoxia often dulls self-awareness, meaning the pilot is less likely to diagnose their own condition. Training regimes emphasize early warning signs of hypoxia through repetitive drilling in chamber exercises (as seen in An Officer and a Gentleman), where pilots are deliberately exposed to low-oxygen settings in a controlled environment, in the hopes of teaching pilots their own unique tendencies when oxygen-deprived.

Through training and specialized equipment, pilots are able to reduce the physiological risk associated with flying the world’s most advanced aircraft, although the risks are ever-present and impossible to eliminate fully as long as a human is still in the cockpit.