I was reading some stuff on how humans can adapt to living at high altitudes, such as in the Andes mountains. Has anyone determined the maximum air pressure that humans can adapt to? Some of the web pages on diving physiology talk about some of the problems, such as nitrogen narcosis and high pressure nervous syndrome. What if we sent an expedition to another planet that had high air pressure, or to a permanent underwater habitat on Earth? Assume that the gas mixture could be adjusted for maximum pressure tolerance.
IANAD, but it seems to me you’re asking a circular question here. If the gas mixture is adjusted to optimum, living even long-term for years and decades (like on another planet, but in a controlled habitat) will not change body physiology. And if one element of the mixture (e.g. nitrogen) causes long-term health problems, you would leave it out, because replacing trained astronauts/other experts every 20 years because they age faster/ get ill would be more costly.
The people living in the Andes and the Himalaya mountains do adapt to less pressure (= less oxygen, which is the problem in that instance, not high pressure and associated issues) because they don’t have access to pressure-controlled habitats. So to get enough oxygen, their body produces more red blood cells.
The wikipedia article on high altitude problems (and death zones - the maximum in one direction) mentions interestingly enough that the ability to adapt quickly to the high altitude in Himalayas and not suffer greatly from Altitude sickness is not related to physical fitness, but some people simply have the inborn ability to suffer less (which is why only a handful like Reinhold Messner could summit Mt. Everest without additional oxygen).
I know that in the Himalayas (with money from commerical expeditions, and partly to help them) a High Altitude rescue clinic has been operating since the mid-80s, and they’ve collected as much data from the climbers coming there as possible (they even did a big medical study once, taking lots of blood samples to measure the different saturation levels at different heights). However, I don’t know if they’ve yet done a study to determine if the native Sherpa people, who have lived in the Himalayas for centuries:
- live longer or shorter because of the stress the higher altitude issues put on their bodies (difficult to determine, since you have to factor out problems like malnutrition, poor health, too hard work due to poverty).
- have significantly higher instances of the above-mentioned inborn-ability to not get altitude sickness and adapt quicker to great heights (above the 4 000 m where their villages are).
As for traveling to to other enviroments like planets - I assume once we have the technology to travel these great distances, we will also have the technology to genetically manipulate the settlers/astronauts to cope with the different pressures/air mixture.
There is a maximum pressure, and it’s likely less than 2000 bar (29,000 psi).
Proteins pick up more water of hydration as pressure increases, and this alters their structure: The solution structure of bovine pancreatic trypsin inhibitor at high pressure.
If the structural alterations go too far, a perfectly good enzyme can become nothing but a useless chain of amino acids. This can be unhealthy for whatever cell uses the enzyme in its metabolism.
High pressure treatment is actually used commercially to sterlize foods:
How can “pressure” be used on lunchmeat?
There’s this thing called oxygen toxicity due to higher pressures which occurs when scuba divers go below 70 meters under the surface of water. That pressure is approximately 7 atmospheres or bars. Or around 100 psi.