Do organs compress whilst diving?

[NAM001]

The only things compressable are air cavities

 

[Dan]

Immersion Diuresis (Urge to Urinate)
Organs do not compress, nor do the lungs on a scuba dive. Anyone thinking otherwise needs to go back for some remedial dive physiology lessons.

Unless you are free diving, right? If the air in the lung is compressed to 4 bars at 30 m depth and you are not getting fresh air from a scuba tank, you are just keeping & using whatever air volume in the lung before you get into the water, then from Physics, Boyle's law - Wikipedia, the free encyclopedia the lung volume should be compressed down by 4 times (25% of its size at the surface) as the water pressure is increased from 1 bar at the surface to 4 bars at 30 m depth.

 

[fmerkel]

Sure, but I said scuba dive, not free dive.
The comment about air cavities, might be amended to [air cavities NOT connected to ambient air]. If you are free diving, nothing is connected. If you are scuba diving and an air cavity is not connected you have the potential for painful if not damaging squeeze.....pre-farts being somewhat excepted.

 

[Dan]

Sure, but I said scuba dive, not free dive.
The comment about air cavities, might be amended to [air cavities NOT connected to ambient air]. If you are free diving, nothing is connected. If you are scuba diving and an air cavity is not connected you have the potential for painful if not damaging squeeze.....pre-farts being somewhat excepted.

This reminds me of common diver ear problem. I had ear pain after a poor habit of equalizing, when I started learning how to dive. That ear pain ended up causing me to miss a couple days of diving. Ever since that incident, I made a habit of equalizing my ears once for every 1 m descending, regardless I feel the pressure in the ears or not. One time I had to abort a dive when I couldn't equalize (might be due to a slight congestion after a cold night sleep & long flight on the day before). It turned out to be a good decision. I was able to resume diving a few hours later & for the rest of the week of the liveaboard trip.

 

[jonhall]

In theory
I don't think compression is the only factor, but also loss of a gravity, which is usually what keeps a proportion of your venous blood in your limbs rather than your core.

Gravity? Can't lose gravity. It is always there. The water presents a force that opposes gravity, but it would have to be explained to me that gravity is lost. Would even say the pull of gravity is stronger when deeper in the water.

 

[Kevrumbo]

With regard to the Lungs -yes and no:

In free diving (breath hold), as a diver descends, his lungs decrease in size according to Boyle's Law. But this isn't the case when using scuba because a diver fills his lungs completely with every breath supplied by the regulator at ambient pressure.

So, each lung (left & right sides) of a free diver would be about 25% of his / her original size (about the size of a fist) at 100' deep?

Blood Shift and the Spleen Effect in Freediving

 

[fmerkel]

Interesting. I didn't know about the blood shift to alveoli, or the spleen effect.

 

[Dan]

Blood Shift and the Spleen Effect in Freediving

Learning something today. Thanks Kevrumbo.

"...The spleen itself shrinks as it empties blood into circulation.

The spleen effect may increase the length of breath-holds and the time at depth during freedives by properly distributing red blood cells throughout the body."... and preventing the rib cage from getting crushed under water pressure when the lung shrunk. After all, we all were swimming inside our mother womb before we were born so we still have those instinct. Very interesting.

 

[toby43]

If liquids at the extremities don't compress, why is there increased blood flow?
Also, when running on a treadmill there is increased blood flow - does that expand the heart also?

Ask your local garage how disc brakes work, then you'll know.

 

[mattia_v]

Gravity? Can't lose gravity. It is always there. The water presents a force that opposes gravity, but it would have to be explained to me that gravity is lost. Would even say the pull of gravity is stronger when deeper in the water.

True, poor phrasing on my part - on land you are generally vertical (at least partly) when awake, and your blood pools at the lowest point and a large reservoir - your legs. Suspended in water that also exerts pressure to a compressible department and in good trim with your legs possibly above your torso, this does not apply. Position is what matters in that regard.