Hard Breathing

[cldSCUBA]

I just noticed this yesterday.... I was diving in the river when we heard a boat coming. I turned on to my back to see if I could watch him go over, and It was suddenly harder to breath from my reg (not a big difference but noticable). Is this normal? I use a new Mares v16 proton xl. The depth was only 20ft. Thank you.

 

[do it easy]

I think that most regs breath harder when you look straight up since the gas trapped in the reg pushes up on the diaphragm. When you inhale, you have to overcome this extra force.

The opposite usually makes most regs free flow when you put them mouthpiece up in the water.

 

[captain]

The vertical distance between the regulator diaphagram and your lungs determines the breathing resistance. When you are face down your lungs are higher than the diaphragm and under a lower pressure so it is easier to inhale but harder to exhale. When you are on your back your lungs are below or deeper than the diaphragm and under more pressure so it is harder to inhale but easier to exhale. It's that 4 to 6 or so inches of pressure difference between the diaphragm and your lungs.

 

[seadoggirl]

I like to hang upside down on the anchor line for safety stops. Yeah, I've noticed it but it could be fun.

 

[cldSCUBA]

Thank you for the quick responses..... I thought there was something wrong, but that makes sense after I think about it.

 

[halocline]

The vertical distance between the regulator diaphagram and your lungs determines the breathing resistance. When you are face down your lungs are higher than the diaphragm and under a lower pressure so it is easier to inhale but harder to exhale. When you are on your back your lungs are below or deeper than the diaphragm and under more pressure so it is harder to inhale but easier to exhale. It's that 4 to 6 or so inches of pressure difference between the diaphragm and your lungs.

I'm not so sure about this. Of course you're right about the relative depth of lungs vs reg, but what about when you're upright in the water? Then your lungs are really lower than the reg, and the increased resistance doesn't happen. It's got to be about the air under the diaphragm. There's another effect called "case fault geometry" that DA aquamaster has posted about, that I believe has to do with the relative positions of the diaphragm and exhaust valve. I think that would more affect changes in breathing resistance when the diver is upside down, vertical vs horizontal, etc.

 

[CrazyScuba]

Yes, you're pulling buoyant air downhill. All regulators, when inverted, become harder to inhale and much easier to inhale.


Britt :fish:
:fish:

 

[halocline]

All regulators, when inverted, become harder to inhale and much easier to inhale.


Britt :fish:
:fish:

Hmmmmmmm.....I guess this is something of a zen puzzle

 

[Nemrod]

It is normal, when yuor upside down as you describe the second stage diaphram is at a lesser depth (and pressure0 than your lungs thus you must literally suck the air. When you stand on your head your second stage diaphram is lower (and greater pressure) than your lungs and sometimes it may free flow and it will be easy to breath. In a normal swimming position the second stage diaphram is at the same position as your lungs in the water column and therefore behaves as your accusrtomed to it doing. This used to be covered in scuba courses and there are diagrams in the older "New Science of Skin and Scuba Diving" book that illustrate these relationships for both souble hose and single hose regulators. N

 

[Creed]

This used to be covered in scuba courses and there are diagrams in the older "New Science of Skin and Scuba Diving" book that illustrate these relationships for both double hose and single hose regulators. N

Sad state of affairs, isn't it?