How Many G’s Are You Pulling And How Much Can Your Body Take?

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Our favorite NHRA drag racer, Terry McMillen reaches between 3 and 3.5 Gs in his Top Fuel drag racing car

I saw an interesting report on CNN the other day. Dr. Sanjay Gupta was talking about G-force.

Gravitational force has always been interesting to me — ever since Jim told me that our favorite NHRA driver, Terry McMillen reaches between 3 and 3.5 G’s behind the wheel of his Top Fuel drag racing car each time he goes down the track.

But I’ve never really understood how G-forces work and how many G’s do what to your body — until now.

Here’s what I’ve recently learned about Gravitational force…

What Exactly Is Gravitational Force?

I bet you’re asking, “What is G-force, anyway?”

These 2 points have helped me understand what Gravitational force means:

#1 – Here’s how G-force relates to your body weight:

4 G’s means 4 times the force of gravity — which alone is a force to be dealt with. That means: If you weigh 100 lbs, you would weigh 400 lbs. at 4 G’s.

#2 – Use this as a baseline for understanding G-force:

The force of gravity when you sit, stand or lie down is considered 1 G. In our daily activities, we rarely experience anything other than 1 G.

From a medical standpoint, at 4 G’s, you will start to lose color vision, which is why it is called “graying out” — 4.5 G’s and you may lose vision all together. Higher G’s and your lungs start to collapse, your esophagus stretches, your stomach drops and blood pools significantly in your legs. It’s hard for the human body to take, although my pilot seemed to be enjoying it and joking the whole time, sometimes at my expense. 

— CNN Report: Dr. G and the G Forces

How Gravitational Forces Affect Your Body

roller coaster g force causes excitement in some and fear in others

Here are some G-force examples:

As you pull more G’s, your weight increases correspondingly. Your 10-pound head will weigh 90 pounds when you pull 9 G’s! If you continue to pull high G’s, the G-force will push the blood in your body towards your feet and resist your heart’s attempts to pump it back up to your brain. You will begin to get tunnel vision, then things will lose color and turn white, and finally everything will go black. You’ve just experienced the onset of Gravity Induced Loss of Consciousness (GLOC).

Aerodynamics and G-Forces

Must read: How Safe Is A Roller Coaster In The Sky?

GLOC Captured On Video

GLOC is the Gravity-Induced Loss of Consciousness.

Watch as this guy experiences GLOC and passes out at 8 G’s:

Ways To Combat G-Forces

G-force is so strong, it is pushing this guy's face back

I figured there were some “tricks of the trade” to help you combat the effects of the G-forces.

But I had always thought they revolved around pre-gravitational force activities — like working out, bulking up, and doing some breathing exercises.

As it turns out, there are things you can do right at the moment you start experiencing the effects of the G-forces:

[There are] breathing techniques and exercises that help one combat G forces. Simply tensing your leg muscles and trying to stand up against the 12 point harness will force blood into the upper part of your body, including your heart and brain. Contracting your stomach muscles and saying “hick” loudly also does a good job of keeping that blood where it needs to be. 


How To Experience Weightlessness Yourself

Of course, on the other end of the spectrum, there are places that let you experience weightlessness (or zero gravity).

See how it’s done… How zero-gravity flights & weightlessness work.

~ Johnathan Strickland

Here are some places where you can experience weightlessness for yourself:

See how to float like an astronaut in the promo video for Zero G:

More About Gravitational Force

In addition to the links I’ve included above, following are some other resources to help you understand G-force better: