How does extreme pressure effect the human body?


Hi! I’m writing some body horror fiction, and am trying to figure out what happens to the human body when exposed to tremendous pressure, equivalent to being 1.6 kilometers underwater. I can find some dry descriptions, but nothing quite as detailed as I require. Help?

In: 5


Not that much on its own. Humans quite possibly can survive such pressure and even some more; I don’t think we ever got that extreme, though. One third that pressure was done, I think. Most importantly they need to carefully adapt to it and need very special air supply, maybe even some extra treatment.

However, the change, especially if quick, is what really causes much of the issue. It can very easily mess up all steps of how oxygen gets to the cells, leading to asphyxiation as well as clogging, hence strokes. Typically, death follows.

The force itself is equalized out over your body, coming from all directions equally. If for some reason there is a difference, water/air will try to flow through and the tremendous force will not really stopped by a human; they will get squished, broken and turned into pulp if necessary.

Unless there is a very rapid change of pressure nothing visible happens.

For a rapid change of pressure read up on the Byford Dolphin accident…..

When breathing normal air, oxygen and nitrogen becomes toxic at higher pressures.

There is something referred to as partial pressure, it basically means that normal air at normal pressure is roughly 21 percent oxygen and 78 percent nitrogen. Thus the partial pressure of oxygen is 0.21 atmospheres. If you double the pressure as you go 10 meters below the water the partial pressure of oxygen goes up to 0.42 atmospheres, and ther eis a point where the nitrogen and oxygen reaches partial pressures where they become harmful.

That is why divers who go very deep need special mixes of gas with a low percentage of oxygen and nitrogen, with other gasses like helium mixed in.

I dont know the exact depth or mixes, but I am sure someone more knowledgeable than me will provide some more information on that.

For very deep dives, Google “Comex record” as far as I remember that have set som crazy records for living and working in the deep oceans.

With regards to the horror part, nitrogen psychosis is a real thing and cave diving and some of the accidents that have happened when cave diving is truly horrific, but that relates more to the isolation and darkness than to extreme depths.

I read a story about a guy who got lost cave diving and when they found his body he had Ben trapped there for multiple weeks and died of either first or exposure. Is absolute darkness.

It would be likely impossible to function or even survive due to several factors. Every air-filled cavity (lungs, sinuses, etc) would be completely crushed at that depth unless breathing some gas at the same ambient pressure (160 atm at 1.6 km). At such high pressure the gas mix would be very dense and likely difficult if not impossible to breathe effectively. Also, the gas mix would have to have a minute concentration of oxygen at surface (1 atm) in order to make it safe to breathe at depth, without risking oxygen toxicity (partial pressure kept below about 1.4 atm), somewhere no greater than 0.00875% concentration at surface, likely difficult to achieve. The rest of 99.99125% of the gas mix would have to be mostly helium and/or hydrogen, as nitrogen would be incapacitating above partial pressure of 10 atm. However, helium exposure below 300 m (30 atm) is associated with HPNS, again likely incapacitating. To prevent HPNS, hydrogen can be used, but used below 500 m (50 atm) it will cause narcosis similar to nitrogen.

So, realistically, the only way for humans to safely achieve such depths would be in a sub or similar that would withstand ambient pressure while keeping inside pressure at 1 atm.

Didn’t Mythbusters test something like this with a human analog in a deep sea diving suit…
When they deliberately failed the pressurization the entire analog was crushed into the helmet.