I don't understand: breathing deeply and using breathing for buoyancy control seem to contradict each other

[dmaziuk]

I was a competitive swimmer from age 4 through high school. I was certified at 16. My buoyancy and gas consumption have always been good

Not-quite-6 through high school here. I don't have gills but as long as my gas mileage matches my perma-buddy's, I'm fine with it.

 

[The Chairman]

First rule of Scuba: don't hold your breath.

That doesn't mean you can't pause your breathing as long as you don't occlude your glottis.

Being truly horizontal helps. The drag of your entire body moving up or down is immense compared to being even at a small incline. That means there will be a subtle delay resulting in natural hysteresis, going both ways. I don't breathe at the same pace. Every depth corresponds to a specific lung volume, which becomes my pause volume. Sometime that volume is at the natural end of my breath, either mostly full or empty. Sometimes it's in the middle.

It's important to not let this method devolve into skip breathing. While my Zen approach to diving reduces my overall metabolism by reducing my use of muscles, I take care to breathe to sufficiently get rid of CO₂. It's often been pointed out that I am the laziest diver many have encountered.

 

[CG43]

First rule of Scuba: don't hold your breath.

That doesn't mean you can't pause your breathing as long as you don't occlude your glottis.

When the diver's breathing pauses, the sum of the inward-directed forces on the respiratory organs is equal to the outward-directed forces.
The water pressure acts inward, the elastic forces of the respiratory organs can act both inward or outward depending on the filling state of the lung. The internal pressure acts outward.
Since the regulator cannot take the elastic forces into account and its position (depth) relative to the respiratory organs depends on the diver's position in the water, the regulator cannot establish an exact pressure for a force equilibrium.

There is the possibility that the diver achieves a balance of forces through his respiratory muscles.
This means constant tension of the respiratory muscles during the breathing pause.

The second possibility is the closure of the airways, as this automatically establishes a balance of forces. However, the closure must be maintained throughout the entire breathing pause, which first does not sound very appealing.

When I dived today I tried unsuccessfully to find out how to take my breathing pauses.
For this I also dived in positions with max. pressure difference of the reg. to the lungs / diaphragm. Subjectively, I had the feeling that both my respiratory muscles and my larynx were relaxed, but strictly speaking this cannot be true.
I continued the trials on land where I tried to breathe in and out against a slight laryngeal obstruction. When inhaling, the obstruction opened at a slight overpressure and I could exhale with an ugly noise. During inhalation, the obstruction initially closed stronger , and with strong sucking, it could still be opened with a very ugly noise. This reminded me of an incident where the regulator unexpectedly shot water into my larynx and I couldn't breathe at all for about 2 minutes.
Now I think that the diver does indeed make a laryngeal closure during a breath pause , but this closure is not a binary on/off action; instead, it is adjusted very finely and quickly to the necessary degree , not more and is therefore not perceived at all.
These abilities are certainly present, as humans constantly use them for speaking, making sounds, singing, and playing musical instruments. And we also do this here without conscious intentional control .

I am interested in your experiences with breath pauses . How do you do it?

 

[dmaziuk]

When I do a breath-holding lap underwater I try to keep my larynx open and do it with the breathing muscles only. It takes practice, but it is perfectly doable.

The downside is if you're used to doing it, your regs will be freeflowing into you at the end of the inhale.

 

[CG43]

If you do not close the airways during the breath hold, the regulator determines the pressure in the lung.

The lung volume that results depends on the position of the regulator relative to the lung,
the respiratory muscles, and the elastic forces of the respiratory organs.
Depending on the diver's position in the water, this can be suitable or not.
If not your breathing muscels will have no rest .
In the past, some divers took advantage of this with double hose regulators by turning onto their side to inhale while swimming (horizontal position). The inhale membrane was then neutral to the lung. To exhale, they would turn back to a normal position because then the high-mounted exhalation valve allowed for easy exhalation.