How does G-force affect the body?

  1. What do G-forces, both positive and negative, do to the human body? I have heard a retired driver state that he retired due to health problems associated with the G forces. Anyone out there know anything about this topic?? Thanks for your input!
    Last edit by Huganurse on Jun 30, '02
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    About Huganurse

    Joined: Apr '01; Posts: 334; Likes: 5


  3. by   kewlnurse
    Not sure about positive g's (acceleration) but i know negitive g's (braking) can cause retinal detachment, this happened to "Big Daddy" Don Garlits a few years back and he had the choice to stop racing or stop seeing, also from a former drag racers stand point there isn't much of a better natural rush than positive g's off the starting line.
  4. by   CC NRSE
    G-force is the gravitational pull on the body. Positive g-force is what pilots (jet) experience can cause many things, biggest one---blacking out. Negative g-force is weightlessness, like what you experience going down a hill on a roller coster, or what the astronaunts experience in space. With negative force, for extended periods, it causes muscle atropy. I'm sure there are many other effects, those are just the main ones I always think of.
    Last edit by CC NRSE on Aug 8, '01
  5. by   fiestynurse
    Oh! I love physics!

    Positive 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.

    Negative Gs will push the blood up into the head, just the opposite of positive Gs. However, while the body can stand up to 9 positive Gs without severe consequences, blood vessels in your eyes will start to rupture when you apply as little as 2 to 3 negative Gs. This is known as redout.. A pilot who pushes too many negative Gs will be seeing the world through bloodshot eyes.

    Here's a handy little G-force table:

    Ultracentrifuge 300,000 G
    Baseball struck by bat 3000 G
    Soccer ball struck by foot 300 G
    Automobile crash (100 km/h into wall) 100 G
    Parachutist during opening of parachute 33 G
    Gravity on surface of Sun 27 G
    Explosive seat ejection from aircraft 15 G
    F16 aircraft pulling out of dive 8 G
    Loss of consciousness in man ("blackout") 7 G
    Gravity on surface of Earth 1 G
    Braking of automobile 0.8 G
    Gravity on surface of Moon .17 G
    Last edit by fiestynurse on Aug 8, '01
  6. by   Huganurse
    Thank you!! I knew someone out there on this BB would know something about G forces. The amount of force that these race car drivers go through is 3 on acceleration, and 5 to 6 G's when the chute is pulled. I now remember about Garlits and thank you Kewlnurse for jogging my memory. I keep thinking that if G forces can detach retinas, what else is it doing to the brain and other internal organs like the heart? This is very important for me to know, maybe there is a USAF nurse out there who knows more? These drivers may do this up to 5 or 6 times per weekend and up to 30 weekends per year. They frequently clock over 300 mph in the quarter mile. Other questions that come to mind: Is there any difference in risks for men vs women? Does any risk increase with the amount of time that the body is subjected to the G force?
  7. by   Huganurse
    Hey fiestynurse! I knew you'd help me out. I was writting my last message when you posted yours. Sounds like there are some risks involved, but at the lower G's (compared to jet aircraft) the risks are probably minimal. Glad to know! Any more info out there?
  8. by   misti_z
    wonderful info--thanks..........something my husband thought was interesting (and didn't have to fake it!!!)
  9. by   fiestynurse
    Makes me wonder what's happening to my kid's brain when she goes on all these scary amusement park rides. Does anybody have any information about that? Are there any set limits on G forces for amusement park rides? Some of these rides are becoming pretty extreme!
    Last edit by fiestynurse on Aug 9, '01
  10. by   Huganurse
    Last edit by Huganurse on Jun 30, '02
  11. by   CraigB-RN
    There was a report I rmember hearing about that mentioned a higher incidence of brain injury from the new extreme roller coasters. I'm looking for it now, but I'm in the middle of moving and I think I packed it already.
  12. by   prmenrs
    Recently, a woman died on one of those rides--an UNKNOWN brain anuerysm (sp?)!!

    I hate those things--my son loves them, b/o his shunt, he can only go on the tamer ones at the fair--no super duper hurl-o-matics, please, but someone else has to take him, I don't even want to be at the same park or whatever.
  13. by   Huganurse
    Went surfin for more info and found this site which has alot of the answers to our questions at