Even with the human body’s natural ability to adapt, we aren’t exactly made to withstand too much g-force. You can chalk this up to humans’ inability to fly or run at supersonic speeds. So, why do some folks even bother going to high-G training? Well, it’s to up their g-tolerance before getting in an aircraft. But how do they do it? And how did it start?

In the 1950s, pilots would willingly strap themselves to rocket-propelled sleds and would get boosted across vast open areas. After attaining the specific amount of g, the sled would slow down with help from water troughs. Needless to say, it wasn’t the safest method in the world for g-force training.

Nowadays, aircraft pilots and astronauts train using a human centrifuge – a machine that spins them around at increasingly fast speeds. By gradually increasing the speed, people inside the centrifuge can practice proper routines without the fear of crashing a million-dollar aircraft.

YouTube video

Thanks to the Royal Air Force, YouTuber Tom Scott was able to take a ride in their human centrifuge to see how much g-force a normal person can withstand.

human centrifuge

Of course, you need at least some form of basic training before getting in the centrifuge. Spinning in a rapidly accelerating capsule causes the blood in your body to flow towards your feet, so you need to tense your muscles to keep some of that blood in your upper regions. To be more precise, tensing your buttocks and legs forces the blood to go back to your head.

human centrifuge

Another exercise involves a breathing method that increases the strain in your upper chest. This not only increases the blood pressure in the greater blood vessels, but also makes sure your brain stays awake.

If you haven’t figured it out by now, the one big thing astronauts and pilots are trying to avoid is passing out. G-LOC, short for g-induced loss of consciousness, occurs when your brain doesn’t have enough blood. If your body fails to adapt to the g-forces properly, your brain undergoes cerebral hypoxia and you pass out. Apparently, you don’t want that when you’re hundreds of feet above the ground.

Even with the proper exercises, it takes time for the body to get accustomed to the g-forces exerted on it. Pilots normally can withstand up to 5gs. They can also tolerate up to 7gs with a special g-suit that restricts blood from leaving the upper body and brain.

human centrifuge

Unfortunately, Tom, who doesn’t have that much g-force training nor a g-suit, passed out from only 3.7 g-forces. When you compare his limit to that of John Paul Stapp’s record at 25 g-forces, you can see just how useful proper training and preparation can be.


Carlos wrestles gators, and by gators, we mean words. He also loves good design, good books, and good coffee.