• Question: How Much Force Does It Take To Make Someone Black Out ?

    Asked by gonegaming to Ben, Dave, Ed, Sam, Susana on 19 Jun 2013.
    • Photo: Sam Horrell

      Sam Horrell answered on 19 Jun 2013:

      So G force is the force of acceleration felt as weight. Or in other words, if you’re going faster you get heavier, as we were told by good old Albert Einstein.

      A fellow called John Stapp who tested rocket sledges experienced 25 g for 1.1 second with a peak of 46 g and was fine. Probably a bit ill after I imagine. There’s quite a difference in tollerance depending if the g force is horizontal or vertial.

      An upward vertical g force forces blood into the feet, and a person normally blacks out from this at around 5 g, but training and special suits can raise this to 9 g. downward vertical g forces blood into the head and the limit is between -20 and -30 g before you get something called a red out. Your vision goes read because of the extra blood around your eyelids and the extra pressure can cause blood vessels to swell and burst. very unpleasent.

      we can handle horizonal g (like John Strapp in his sledge) much better.

    • Photo: David Briggs

      David Briggs answered on 19 Jun 2013:

      As a rule of thumb, airforce pilots who experience high g forces tend to black out at +9g or -3g. But there exceptions to this rule.

    • Photo: Susana Teixeira

      Susana Teixeira answered on 20 Jun 2013:

      Wow, and to think that some roller-coasters go over 5gs!

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