Can Humans Live Underwater?

[Marat]

Fish and other sea creatures extract oxygen from the water to survive, and the human lungs can do this as well, although the amount of oxygen extracted would be inadequate for higher brain functions. I have seen it proposed that if a human were to drown in fresh water, and the person were able to overcome through some profound self-discipline the natural shock response at drawing water into the lungs and displacing their air content, then that person could continue living at the bottom of the lake or stream, provided it were warm enough.

 

I wonder what other aspects of physiology would complicate this effort? E.g., the nature of human kidney function has been described as the response to the need to manage water and electrolyte content during long periods away from the water after humans evolved from the sea, so living in water would force the kidneys to work overtime to maintain the physiological levels of electrolytes required for neurological and muscle function.

[Moontanman]

Fish and other sea creatures extract oxygen from the water to survive, and the human lungs can do this as well, although the amount of oxygen extracted would be inadequate for higher brain functions. I have seen it proposed that if a human were to drown in fresh water, and the person were able to overcome through some profound self-discipline the natural shock response at drawing water into the lungs and displacing their air content, then that person could continue living at the bottom of the lake or stream, provided it were warm enough.

 

No, this is simply not true, the human lungs are not designed to use a liquid and water would have to contain far more disolved oxygen that is can possibly contain for this to work.

 

I wonder what other aspects of physiology would complicate this effort? E.g., the nature of human kidney function has been described as the response to the need to manage water and electrolyte content during long periods away from the water after humans evolved from the sea, so living in water would force the kidneys to work overtime to maintain the physiological levels of electrolytes required for neurological and muscle function.

 

Your kidneys would be a problem if you tried to live in freshwater or salt water but not breathing would trump any possible kidney problems...

 

Now it is possible to breath certain halogenated carbon compounds but they carry far more oxygen than water can, possibly this is what you are referring to when you say it's possible to breath water, it is a liquid but not water...

[DJBruce]

Fish and other sea creatures extract oxygen from the water to survive, and the human lungs can do this as well, although the amount of oxygen extracted would be inadequate for higher brain functions. I have seen it proposed that if a human were to drown in fresh water, and the person were able to overcome through some profound self-discipline the natural shock response at drawing water into the lungs and displacing their air content, then that person could continue living at the bottom of the lake or stream, provided it were warm enough.

 

Do you have a source saying human lungs can extract oxygen out of water at a rate fast enough to maintain life? As far as I know I am pretty sure this is not actually possible, so the biggest risk to your body would be you drowning very very quickly.

 

As for liquid breathing I do not think total liquid ventilation has every been successfully tested on humans.

[insane_alien]

As for liquid breathing I do not think total liquid ventilation has every been successfully tested on humans.

 

even on animals it tends to damage the lungs on short order as the muscles have to do a lot of extra work just to keep you alive. it is doubtful humans could keep it up either.

 

but really, if we could breath the same water fish breath then nobody could drown in fresh water and we'd probably even have a few settlements in freshwater lakes.

 

as this is not the case i'm gonna hazard a guess and say no, we cannot live underwater without the aid of either a submarine or a more permanent submersed air containing structure.

[Cation]

I think that our lungs and the way we inhale oxygen is not the only problem. The human's skin for example is not ideal for all that water, after some time complications with the skin would develop, also, the human body cannot withstand such pressure, even in prolonged situations a higher pressure than that at sea level can badly affect the human body.I also believe that our body's respones will change, what i mean is that under water you'r going to lose more energy therefore rest more, and that kind of stuff. Your breaking a whole evolutionary process. I'm not saying it's impossible, everything is possible with science.

[jimmydasaint]

May I mention again the artificial gill, which has been used to extract oxygen from water. I read about this in New Scientist and cannot recall the date. However, the interviewed inventor mentioned that his dog was able to be immersed underwater and sit for 20 minutes before being raised to the surface.

 

This invention, if it overcomes teething issues could allow people to exist, and be mobile underwater, for considerable amounts of time. This device, below is either the New Scientist device, or something similar.

 

Abstract:

 

The invention provides a system whereby oxygen can be derived from seawater or from thin air at higher altitudes while simultaneously eliminating carbon dioxide from the blood. This allows prolonged underwater liquid breathing at greater depths without suffering from the bends or, alternatively, the ability of workers to breathe underwater or at high altitudes without having to rely upon air tanks or the like. The artificial gill comprises a plurality of concatenated modules each containing a semi-permeable membrane operative to transfer oxygen in a first direction and carbon dioxide in a second direction across the membrane. By providing multiple concatenated interconnected modules, oxygen becomes concentrated to allow breathing thereof. Because the system is connected in series with a person's blood supply, CO2 produced in the body is extracted and disposed of via the artificial gill. The semipermeable membrane preferably comprises a plurality of tubular fibers, each with a relatively large lumen when compared to present day blood oxygenators arranged as a bundle in a housing such that seawater or rarefied air passes over the exterior surfaces of the fibers while blood or Hgb flows through the lumens. The larger diameter fibers reduce hemolysis and clotting.

 

Link

Edited July 21, 2010 by jimmydasaint