How does it work? (Freediving/ Expansion)

[TyTy]

I am just watching my PADI certification DVD and starting to read my book in preperation for my Open Water Diver certification class. They kept stressing that if you hold your breath your lungs will overexpand as you surface and coulr rupture.

So...leads me to the question of how freedivers lungs dont expand and rupture?

Also on a sidenote, what is the deepest freedive ever? Isnt it over 400 ft?

Thanks, just curious.

 

[D_O_H]

I am just watching my PADI certification DVD and starting to read my book in preperation for my Open Water Diver certification class. They kept stressing that if you hold your breath your lungs will overexpand as you surface and coulr rupture.

So...leads me to the question of how freedivers lungs dont expand and rupture?

Also on a sidenote, what is the deepest freedive ever? Isnt it over 400 ft?

Thanks, just curious.

I'm sure you'll get a nice scientific explanation, but the simple one is: freedivers breathe air at the surface (1 atmosphere of pressure). The air compresses when they go deep and then expands to its original size when they return to 1 atmosphere at the surface. People on scuba below the surface breathe air at greater than 1 atmosphere (it's already compressed). When they ascend to a lower pressure, the air expands and can cause the lungs to overexpand.

 

[RickSp]

As long as you don't breathe compressed air at the bottom, the air in your lungs will only expand back to their normal size when you surface. The reason scuba divers are told to never hold their breaths is because they are breathing compressed air.

The record depth for the dangerous sport of no limits free diving by a woman is 125 m. (411 ft.) by Audrey Mestre Ferrera at La Palma, Canary Islands, Spain on May 13, 2000. Taking just one single breath she was underwater for 2 min. 3 sec. The depth is greater than Japanese submarines reached during World War II.

Guiness Book of World Records

 

[jonnythan]

Inflate a balloon at the surface and take it down with you, then back up. It gets smaller as you go down and returns to the original size when you go back up.

Now if you inflate the balloon to normal size when you're at the bottom, then bring it up to the surface, it gets bigger than it was before and might burst.

Get it?

 

[jonnythan]

BTW, Tanya Streeter hit a new no-limit record of 525 feet a couple of years ago.

 

[rex_b]

Very interesting. Can you actually feel your lungs expand and contract when this is all happening? And how would you know when your getting to the limit?

 

[FreeFloat]

Very interesting. Can you actually feel your lungs expand and contract when this is all happening? And how would you know when your getting to the limit?

Yes, to some extent. Unpracticed freedivers pushing their limits can suffer from lung compression injury. Also, there's a phenomenon known as 'lung squeeze' where the lungs begin to fill with fluid if kept under pressure for too long - kind of the same way a blocked diver's ear might if the diver dives anyway despite not being able to clear the ear.

There are a variety of signs that a freediver is approaching their limit - these sypmtoms vary and are pretty much individual for each diver. I'd like to think that fredivers tend to be much more in tune with their bodies than scubadivers (generally) since a scuba diver has life-supporting equipment to rely on but a freediver doesn't........

 

[Ber Rabbit]

Scuba divers who ascend while holding their breath will probably not feel any discomfort before they rupture the alveoli in their lungs. This is called a lung overexpansion injury and it can be fatal. Never hold your breath while scuba diving.
Ber :lilbunny:

 

[TyTy]

Scuba divers who ascend while holding their breath will probably not feel any discomfort before they rupture the alveoli in their lungs. This is called a lung overexpansion injury and it can be fatal. Never hold your breath while scuba diving.
Ber :lilbunny:

That makes sense, cool and thanks! Fast response too

I should have thought of that but my mind isnt 'in the game' yet, just looking at it.