Air consumption vs regulator ease of breathing

[Eric Sedletzky]

You use what you use, and trying to squelch that down leads to nothing but increased CO2 buildup, stress, misery, and finally panic. It will create a doom loop that you will be very lucky get out of alive.
Regulator companies are trying to constantly make easier breathing regs for a very good reason.

 

[Nemrod]

The three components of regulator WOB (work of breathing) performance are:

1. Cracking effort
2. Venturi assist
3. Exhalation effort

The easier, lower effort and less work to maintain an inhalation (low cracking effort to initiate and effective Venturi to sustain) and the easier it is to exhale the breath the less air you will use when diving. WOB, if it takes more work to do any or all of those three things then you will use MORE air, not less. Anyone saying different is misguided.

 

[grf88]

If you want to reduce your SAC rate concentrate on buoyancy, trim, efficient propulsion and most of all SLOW DOWN.

 

[Pearlman]

I dont think that is a stupid question at all.

All the comments above relating to work of breathing of course are correct. We certainly do not want to have the reg set to the point where it is difficult to inhale.

But myself personally, i also do not set my dial on the 2nd stage to the absolute minimum resistance either. Hopefully yours has that feature (not all do) so you can adjust it as you require.

I was in this camp for more than a decade … purposely setting the adjustment knob to breathe a bit harder, but I actually have just started veering in the direction well articulated by BlueTrin below.
More practically now ever since I got my own regs, I still tend to dynamically set the adjustment knob to the point it won’t freeflow in the currents underwater or because of the waves on the surface. Otherwise I am working on tuning them to a more easy breathing state than I ever did in the last decade, using the adjustment knob.

I think over time you’ll develop a pattern of breathing that works for you (for me it is still a work in progress).

So yea I think there is a possibility you breathe a bit faster at first if you are a heavy breather naturally (like me) but longer term it’s better to reduce your work of breathing if that makes sense?

I discovered this about myself after I dived with my first set of own regs last year, and still working on finding that balance to just enjoy the effortless WOB without feeling like I am wasting gas. My SAC rate is slowly improving over the last 40 dives…

I still don’t disagree with rick1967 rather I am just in the process of adapting myself to an easier WOB as more promising (via my own intuition and experience with my new regs) and logical action in the hope of improving my sense of relaxation and thus also my SAC rate…

 

[dmaziuk]

The easier, lower effort and less work to maintain an inhalation (low cracking effort to initiate and effective Venturi to sustain) and the easier it is to exhale the breath the less air you will use when diving. WOB, if it takes more work to do any or all of those three things then you will use MORE air, not less. Anyone saying different is misguided.

I had rental regs freeflow into my mouth, out the nose, and out of the mask at the end of inhalation -- to the extent that I would misguidedly ask the op for a detuned replacement. "Too easy" is a thing IME.

 

[TrimixToo]

By definition, the WOB is work. Work requires power, and power oxygen, so a lower WOB equals lower gas consumption. Not complicated. QED.

But while I prefer an easy-breathing reg for a number of reasons, I have never seen the WOB quantified as a percentage of the gas consumption total, either at rest or at different levels of activity. So I don't know to what extent a lower WOB helps reduce gas consumption. I'd love to see measurements someday...but they could be significant, or a just rounding error, despite how much a low WOB has been touted by reg manufacturers.

Anybody got data?

 

[Nemrod]

I had rental regs freeflow into my mouth, out the nose, and out of the mask at the end of inhalation -- to the extent that I would misguidedly ask the op for a detuned replacement. "Too easy" is a thing IME.

I think you might be extrapolating from what I mean to something beyond what I mean .

All the anecdotal stories to the contrary I will stand with what I have said.

 

[Sensorone]

The three components of regulator WOB (work of breathing) performance are:

1. Cracking effort
2. Venturi assist
3. Exhalation effort

The easier, lower effort and less work to maintain an inhalation (low cracking effort to initiate and effective Venturi to sustain) and the easier it is to exhale the breath the less air you will use when diving. WOB, if it takes more work to do any or all of those three things then you will use MORE air, not less. Anyone saying different is misguided.

Regulator tuning is a personal thing IMO. Stability vs ease of breathing/exhalation is the quest.

 

[lexvil]

Free flowing is much different than hi performing easy breathing.

 

[Nemrod]

Regulator tuning is a personal thing IMO. Stability vs ease of breathing/exhalation is the quest.

A scuba regulator that is not stable and cannot mimic as transparently as possible the divers demand is a regulator I do not want. And all the anecdotal evidence to the contrary will not change anything. A higher WOB will result ultimately in a higher air consumption. Nobody, including me, is recommending tuning the regulators outside of service manual specification to achieve some breathing nirvana. Some weird ideas get promoted herein, example that hard breathing regulators reduce air consumption, and hairs get split to the purpose of argument. I stand with exactly what I said in post #32.

And no, it is not a personal thing, it is a service manual thing and the limits of the particular regulator. If you do not like the result of tuning per specification maybe it is time for another regulator. The goal is transparency to your demand cycle.