Just as gravity pushes you down against the Earth, inertia pushes you back against your seat. We experience higher or lower g forces when we are rapidly changing speeds or directions. Normal humans can withstand no more than 9 g's, and even that for only a few seconds.

Surviving 16 Gs (sixteen times the force of gravity) is technically possible, but only for a matter of seconds and typically only in specific, highly controlled scenarios like a fighter jet ejection. At 16 Gs, the human body's weight is effectively multiplied by sixteen; the heart cannot pump blood to the brain, and the lungs can collapse under the pressure of the chest wall. Most "sustained" G-force limits for trained pilots and astronauts are around 9 Gs. At 16 Gs, a human would experience G-LOC (G-force induced Loss of Consciousness) almost instantly. However, humans have survived much higher "instantaneous" Gs during crashes or ejections—for instance, John Stapp survived a test sled stop that reached 46.2 Gs. But "surviving" and "operating" are different things; at 16 Gs, a person would be physically incapacitated, likely suffering from broken blood vessels (petechiae) and potential internal organ damage. In 2026, advanced G-suits and pressure breathing techniques help pilots push toward the 10-G mark, but 16 Gs remains a "lethal" or "injury-heavy" threshold for any sustained duration.