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Comment by cgijoe | Hacker News Reader

Agree, and I just saw that caving docu-movie (The Last Descent) about that poor guy who got stuck upside down deep in the cave and couldn't move. He died in under 24 hours I believe.

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Why would hanging upside down for 24 hours kill you (serious question)? Doesn't the heart pump blood with the same efficiency regardless of its orientation?

The heart isn't responsible for pumping blood through your body all by itself, it's supported by the skeletal-muscle pump - but that only works when your're moving. Hanging the right way up is in fact even worse and can kill you in less than an hour through something called a "suspension trauma".

I wonder if this is why sitting at a desk is so bad for us. Half way to torture.

Yes indeed.

The word for paid work in French is travail, which has the same Latin base as the word torture.

I didn't know about that but you are right. Not only French, also Spanish, Portuguese, Catalan, Galician, and maybe other language. It comes from a torture instrument called "tripalium", literally "three sticks".

Thats why you need foot straps on your fall arrest harness. https://www.nationalsafetyinc.com/mobile/ReliefStep-Fall-Pro...

I thought that happened with fall arrest harnesses as the leg straps cut off the blood supply through your inner thigh. It's not so much the suspension, but where the straps cross.

No,that's not true. The femoral vein is too deep to be cut off. The position of the leg straps is relevant because proper leg straps allow you to hang in a sitting position.

Huh. I suppose thinking back the guy that told me that generally didn't know what he was talking about. I never bothered to double check. I don't do anything that I need a fall arrest system anymore, but maybe I should do some reading.

That's not true, I've definitely spent more than an hour hanging around in a rock climbing harness.. and that's just two thigh straps + waist.

It absolutley is true. The thigh straps are exactly what prevent suspension trauma because they allow you to take a sitting position rather than having your legs hanging straight down, so there is much less distance to overcome. Besides, you generally move around while rock climbing, so the skeletal-muscle pump is engaged.

Your lungs can get squished (as was hypothesized to be the case with the aforementioned caver), bursting blood vessels in the brain, and (news to me) according to the article below, your heart eventually has trouble pumping when you're inverted.

https://science.howstuffworks.com/innovation/science-questio...

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