"G-force" means gravity force. A high G-force from rapid acceleration can have serious ramifications. It can cause pilots and others on board an airplane to lose consciousness during flight. This phenomenon first became an issue during World War I. It was originally referred to as “fainting in the air.” One G-force is comparable to the regular pull of the Earth’s gravity on your body. You experience high G-forces on rides at the amusement part. Problems occur when a person is subjected to high G-forces for longer periods of time, which can result in blacking out and other health problems.
G-forces have to do with acceleration more than with speed. Acceleration is defined as the change in speed over time, and is the change in the velocity of an object. Types of acceleration in this sense include slowing down, speeding up and changing direction. G-forces are tolerated differently by different people. The effect depends on the number of G’s involved, the G-forces that are being felt, and how long the G-forces last, explains PBS.org.
The Way the Force Hits You
No one is expected to withstand and survive 18 G’s, which is 18 times the force of gravity at sea level. However, some people have survived such forces.
The way G-forces affect you depends on how your body is oriented when the acceleration occurs. You can experience G-forces front-to-back, head-to-toe or side-to-side.
Vertical forces affect your blood pressure. At 2 G's you need twice the pressure to pump blood from your heart to your brain. At 3 G’s you need three times the pressure. Most people pass out at 4 or 5 G’s because the heart can’t produce the pressure needed to pump blood to the brain. When exposed to such force, the blood pools in the lower extremities, and the brain stops working because it isn’t getting enough oxygen.
Princess Diana was a victim of G-forces, according to Peter Tyson, editor in chief of of the Public Broadcasting Service's Nova Online. It was determined that her chest was slammed with approximately 70 G’s, which tore the pulmonary artery in her heart. Her head was struck with 100 G’s. Wearing a seat belt would have reduced the G force to about 35 G’s and she might have survived, Tyson wrote.
It is very possible to survive high G forces for a brief period of time. However, when G forces remain high, this creates problems for humans. When G forces get over 3, this starts to put stress on the body.