Overbreathing my regulator

[Hatul]

Someone once said here that it's almost impossible overbreathe a regulator.

Yesterday I was swimming on my back in heavy swells breathing off my Oceanic Delta 2 piston and it was definitely hard to breathe and tiring breathing off that thing. It made a huge difference breathing without the reg and with the reg. I've noticed this before both when swimming hard on the surface and at depth. And yes the reg gets regular service.

So I'm sure I can overbreathe this reg. I wonder if you guys with the newer high end regs like the Atomics and Zeagle have the same issue?

Adam

 

[scubassplayer]

Hi, I haven't experienced that feeling yet. I am an old overweight diver. I currently use Zeagle flasthead Vl, but I previously used my 1976 agualung and no issues with it either. I could understand if you are breathing out of the water on your back...but you say you also experience this a depth..perhaps more experienced divers could chime in?

 

[Doubler]

Might be that it is not the regulator but you. Hyperventilation and build up of CO2 may be the issue. My advice would be to slow your breathing, breath in breath out. I dive an Atomic and have never had an issue.

 

[rstofer]

Hi, I haven't experienced that feeling yet. I am an old overweight diver. I currently use Zeagle flasthead Vl, but I previously used my 1976 agualung and no issues with it either. I could understand if you are breathing out of the water on your back...but you say you also experience this a depth..perhaps more experienced divers could chime in?

A regulator with the demand diaphragm in front will always breathe harder when you are on your back. In normal, face down, operation, the diaphragm is a couple of inches of water below the middle of your lungs. The regulator is adjusted to not freeflow in this orientation.

When you turn on your back, your lungs are a couple of inches of water below the diaphragm and have to provide the additional inhalation effort to cause the diaphragm to operate. Your lungs can feel the difference.

Conversely, a double hose regulator, with the demand diaphragm behind the diver, will freeflow when you turn on your back.

I don't doubt that your reg is harder to breathe on your back but I don't believe you can demand more air than the regulator can deliver. If that were the case, you wouldn't get any air at some considerable depth (say 100') where the reg needs to deliver 4 times as much air as at the surface.

Richard

 

[Walter]

I have a 25 year old Mark 10. I can't over breathe it.

Usually when someone takes about over breathing a regulator, they are not over breathing the regulator, they are merely breathing too fast and too shallow. Next time you have that feeling, concentrate on breathing slowly and deeply. This will purge carbon dioxide from your lungs and do away with the feeling you can't get enough air.

 

[diversteve]

I've never been able to overbreathe my Atomics. (B1 and now T2) Even in ripping high currents a couple of times while kicking against it. I may have experienced it once years ago with an old Dacor reg.

 

[LeadTurn_SD]

I have a 25 year old Mark 10. I can't over breathe it.

Usually when someone takes about over breathing a regulator, they are not over breathing the regulator, they are merely breathing too fast and too shallow. Next time you have that feeling, concentrate on breathing slowly and deeply. This will purge carbon dioxide from your lungs and do away with the feeling you can't get enough air.

Exactly.

Now on the surface, it is in most cases a bit easier to breath with the regulator out of your mouth. No matter how finely-tuned the regulator, you still have to overcome the resistance of the 2nd stage spring, which while slight is still present; and you have to overcome the slight resistance of the exhaust valve to exhale. If you are breathing hard, this will lead to a feeling of not getting enough air, since you hard having to work slightly harder to get it.

Also, many (most) regulators will breath "easier" underwater than on the surface, at least in a normal horizontal swimming position. A regulator set to "crack" at 1.5"/H2O pressure on the surface may crack at .5" (or less?) due to the 2nd stage case geometry and the effect of water pressure on the 2nd stage diaphragm once you assume a normal swimming postion underwater. So inhalation effort underwater is generally less than on the surface.

Underwater, as Walter said, all modern regulators will supply more than enough air for two hard breathing divers at recreational depths.

Best wishes.

 

[Hatul]

A regulator with the demand diaphragm in front will always breathe harder when you are on your back. In normal, face down, operation, the diaphragm is a couple of inches of water below the middle of your lungs. The regulator is adjusted to not freeflow in this orientation.

When you turn on your back, your lungs are a couple of inches of water below the diaphragm and have to provide the additional inhalation effort to cause the diaphragm to operate. Your lungs can feel the difference.

Conversely, a double hose regulator, with the demand diaphragm behind the diver, will freeflow when you turn on your back.

I don't doubt that your reg is harder to breathe on your back but I don't believe you can demand more air than the regulator can deliver. If that were the case, you wouldn't get any air at some considerable depth (say 100') where the reg needs to deliver 4 times as much air as at the surface.

Richard

It may be that the reg does not work well with the diaphragm above water, without water pressing against the outside of the diaphragm. When I take the reg out of my mouth I can feel a drop in resistance.

I also think you're underestimating the effect of heavy exercise on SAC. Just look at the METs of different exercise-which is directly related to the O2 consumption.

MET: Calculating calories burned during physical activity

With heavy exercise your O2 consumption goes up by a factor 6 or more, and that's forgetting about depth or hyperventilation. At say 99 feet (4 atm) your regulator has to deliver 24 times the air of someone doing light exercise on surface. And that's forgetting about hyperventilation which is often part of the course of working hard at depth.

Adam

 

[Walter]

At say 99 feet (4 atm) your regulator has to deliver 24 times the air of someone doing light exercise on surface.

Many regulators are designed to deliver that much air. I know mine can deliver enough for me and and out of air diver at 100 ft.

 

[LeadTurn_SD]

It may be that the reg does not work well with the diaphragm above water, without water pressing against the outside of the diaphragm. When I take the reg out of my mouth I can feel a drop in resistance.

I also think you're underestimating the effect of heavy exercise on SAC. Just look at the METs of different exercise-which is directly related to the O2 consumption.

MET: Calculating calories burned during physical activity

With heavy exercise your O2 consumption goes up by a factor 6 or more, and that's forgetting about depth or hyperventilation. At say 99 feet (4 atm) your regulator has to deliver 24 times the air of someone doing light exercise on surface. And that's forgetting about hyperventilation which is often part of the course of working hard at depth.

Adam

Adam,

Look at my prior post regarding breathing your reg above and below the surface.

My understanding regarding regulator performance at depth: As far as increased respiration rates and volume of air moved.... the regulator is moving the same volume per breath, there are just more molecules compressed into each breathing cycle. A good quality reg is very capable of doing this. The intermediate pressure rises proportionately with increasing depth, allowing it move proportionately more air; but eventually you'll run into problems with increased density trying to move through the tiny orifices in the reg... but this is below recreational depths.

Again, you do have to overcome the slight resistance of the 2nd stage spring and the exhaust valve with each breath..... the regulator can supply tons of air, but there is a slight bit of work involved to move that air.

Walter (as usual) nailed the actual problem that most folks associate with "overbreathing" a regulator: Rapid, shallow breathing resulting in inadequate gas exchange in the lungs, and CO2 buildup.

It feels like you are starving for air, when in fact you just need to slow down your breathing so you can completely fill and empty your lungs so that efficient gas exchange can occur.

Best wishes.