G force has always been interesting to me — ever since Jim told me that our favorite IHRA driver, Terry McMillen, reaches between 3 and 3-1/2 G’s behind the wheel of his Top Fuel drag racing car each time.
But I’ve never really understood how G-forces worked and how many G’s did what to your body.
So here’s what I’ve recently learned…
Remember: 4 G’s means 4 times the force of gravity — which alone is a force to be dealt with!
Which means: If you weigh 100 lbs, you would weigh 400 lbs. at 4 Gs.
Use this as a baseline…
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 4G’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 G-Forces Affect Your Body
Astronauts aboard a Space Shuttle reach about 3.5 G’s.
Here’s the inside scoop about astronauts and G-force.
Amusement park riders on roller coasters pull various levels of G’s, but they rarely get much beyond 4 G’s according to Sanjay Gupta.
Airline passengers aboard a commercial airline reach about 1.5 G’s.
Professional pilots like the Blue Angels can top 6 G’s. Under special circumstances (and in training) they can approach up to 10 G’s.
More about G-forces on Blue Angels rides.
As you pull more Gs, your weight increases correspondingly. [At 9 G's], your 10-pound head will weigh 90 pounds when you pull 9 Gs! If you continue to pull high Gs, 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 finaly everything will go black. You’ve just experienced the onset of Gravity Induced Loss of Consciousness (GLOC). — Aerodynamics and G-Forces
GLOC Captured On Video
Watch this guy pass out somewhere between 7 and 7-1/2 G’s:
Ways To Combat G-Forces
I figured there were “tricks of the trade” to help you combat the effects of the G forces, but I had always thought they revolved around pre-G-force activities like working out and bulking up and breathing exercises. Turns out, there are things you can do right on the spot, at the moment you start experiencing the effects of the G-forces.
According to Dr. Sanjay Gupta:
[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.
Experience Weightlessness Yourself
On the other end of the spectrum, there are those places that let you experience weightlessness (or zero gravity) like:
- Zero Gravity Flights
- NASA’s Commercial Weightless Flights
- Northrop Grumman’s Weightless Flights of Discovery
See how it’s done… Check out Simulating Weightlessness: How Zero-Gravity Flights & Weightlessness Work
Here is the promo video for Zero G:
More About G-Force