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

[JoeTPhilly]

This video may be of interest:

 

[pdwh]

I am confused about how using breathing for buoyancy control interacts with breathing deeply to be efficient with air usage.

In my training dives I found that I was eventually able to stay in a relatively still horizontal position, without flapping my arms and legs around. However, when I took a deep breath in, I would go up, and when I breathed out again, I would go down. The only way for me to stop yoyo-ing up and down was to take small breaths in and out. The problem with that, of course is that it's a really inefficient use of air, due to dead space. The advice I see is to take deep breaths in and out (4, 5, 6 seconds each).

Could people help me see what I am missing here? How do I breath in and out deeply, without yoyo-ing up and down?

Thanks for asking the question. I've wondered the same thing and this thread has been pretty good and educational. I sing (took voice lessons, etc.) so that probably helped me quite a bit along the way but I've got a lot more to learn and practice. I guess I'll just have to dive more.

 

[swan_diver]

Thanks for asking the question. I've wondered the same thing and this thread has been pretty good and educational. I sing (took voice lessons, etc.) so that probably helped me quite a bit along the way but I've got a lot more to learn and practice. I guess I'll just have to dive more.

this whole thread is awesome, I'm in the midst of my ow training and had the same exact thought. I too have decades of singing/woodwind training and felt like I could control my breath very well, first pool class I was able to fin pivot immediately which boosted my confidence, however the bcd control was even more laggy by comparison. but the video above and technical explanation (i'm an engineer too lol) was just what I needed to clarify some of my lingering questions.

 

[CG43]

Breathing must never be the slave of buoyancy !
Don't kill yourself by shallow breathing at greater depths !

If you want to see what realy good breathing under water is see this videos .

Huge air consumption even after +200 dives​

• Thread starterTycksel
• Start dateDec 7, 2024 page 5

On these videos we see a diver who exhales a good amount of bubbles in a short time after a long breathold . We do not hear the inhalation, but it will probably be as long (or short) as the exhalation.
This is anything but like " first rule of scubs diving is never hold your breath " but there are good reasons why this way of breathing is so effective .

Let's assume that : 1.) the strongest respiratory stimulus is the PPCO2 in the body and thus also in the lungs.
2.) Our body body produces a constant rate of CO2 .

The PPCO2 in the lungs depends only on the total pressure and CO2 concentration, not on the amount of air in the lungs.
When we start exhaling depends on the CO2 concentration, no matter how full or empty the lungs are.
Exhalation changes the total amount of CO2 in the lungs, but not the CO2 concentration.
In order to effectively reduce CO2 concentration, the residual air remaining after exhalation must be diluted by the amount of inhaled air.
After inhalation (CO2 dilution), the greater the volume of air in the lungs, the slower the CO2 concentration will increase.
If you now bring all the influences together, the most effective breathing consists of deep exhalation, deep inhalation , breathold deep exhalation ........
The average CO2 level is medium, because it is approximately in the middle between the lowest possible value and the respiratory stimulus threshold.

Unfortunately, there are problems to realize this breathing in practice,
because the human being is not a machine.
Being able to breathe deeply with perseverance requires practice and relaxation at the same time. You can also practice this on land.
Nevertheless, when diving, you should only breathe as deeply as is comfortable and relaxed.
A bigger problem is the inhaled breath holding .
When the airway is blocked, anything that compresses the diver can create pressure in the chest cavity, thus disturbing blood circulation and the diver's relaxation. This can be a tense respiratory muscles, a tight diving suit, straps or a BCD. It may be enough to breathe in a little less deeply. If you don't feel comfortable with the breathold, then insted exhale slowly. A diver who does not feel comfortable will never breathe effectively.
The most important thing is whether you like these breathing pauses or not.
There are pictures of the happy submerged breathold babies. Are you such a baby ?
What is predisposition and what can you train? Everyone will have to try that out for themselves, and my recommendation as usual is freediving.

 

[EdMcNeill09]

Thanks for all your input everyone. This has been a revelation. Key takeaways are

1. Breathing should be normal tidal volume, not anywhere near maximum forced in/out.
2. PHASE!!!

Not exactly. Actually tidal volume varies quite a lot. I recently posted a video on teaching people with big lungs how to dive. It goes further into the issue of Tidal Volume. You might find it helpful.

 

[CG43]

Actually tidal volume varies quite a lot. I recently posted a video on teaching people with big lungs how to dive. It goes further into the issue of Tidal Volume. You might find it helpful.

Let's consider how to reconcile the requirements of rinsing the lung well and not having much buoyancy.


After exhalation, there is always a volume left in the lungs and airways that is diluted by CO2-poor air during inhalation. Let's assume that after inhalation, the concentration of CO2 should only be 50% of the exhaled air.
Diver1 has a minimum residual volume of 1.5 L and a maximum lung capacity of 6 L.
Diver2 has a residual volume of 2 L and a maximum lung volume of 8 L.
If Diver1 now exhales to a volume of 2 L, he must inhale 2 L (for 50% CO2), his total volume will be 4 L.
If he exhale only to 3 L he must inhale 3 L up to 6 L what is his max lung capazity .
Diver2 may exhale to 2,5 liter , inhale 2,5 L to 5 L . When he exhale to 3 L and inhale 3 L ,
he don't reach his full lung capazity of 8 L .
For good lung ventilation and little buoyancy, it is important to exhale well.

A german instructor is promoting a breathing system that he calls "Diving without Lead."
I only know this system from a second hand and I apply it when I am too light at a shallow depth (e.g. deco) . It is : Inhale, exhale, rest, inhale , exhale , rest....................
Here, the diver has exhaled for the longest time, which significantly reduces their average buoyancy.
In order to dive with pleasure exhaled, some practice is required.
For example, I dive in the pool with exhaled distance and inhaled distance,
holding breath while exhaled and inhaled.

 

[scubadada]

I inhale-pause-exhale-inhale-pause-exhale. I believe that maximizes gas exchange. It comes naturally to me. I'm not a small man, my average RMV over the last 2,027 dives is 0.36 cu ft/min or 10.2 L/min. My buoyancy is adjusted to my breathing pattern, does not vary much unless I want it to.

 

[BRT]

Let's consider how to reconcile the requirements of rinsing the lung well and not having much buoyancy.


After exhalation, there is always a volume left in the lungs and airways that is diluted by CO2-poor air during inhalation. Let's assume that after inhalation, the concentration of CO2 should only be 50% of the exhaled air.
Diver1 has a minimum residual volume of 1.5 L and a maximum lung capacity of 6 L.
Diver2 has a residual volume of 2 L and a maximum lung volume of 8 L.
If Diver1 now exhales to a volume of 2 L, he must inhale 2 L (for 50% CO2), his total volume will be 4 L.
If he exhale only to 3 L he must inhale 3 L up to 6 L what is his max lung capazity .
Diver2 may exhale to 2,5 liter , inhale 2,5 L to 5 L . When he exhale to 3 L and inhale 3 L ,
he don't reach his full lung capazity of 8 L .
For good lung ventilation and little buoyancy, it is important to exhale well.

A german instructor is promoting a breathing system that he calls "Diving without Lead."
I only know this system from a second hand and I apply it when I am too light at a shallow depth (e.g. deco) . It is : Inhale, exhale, rest, inhale , exhale , rest....................
Here, the diver has exhaled for the longest time, which significantly reduces their average buoyancy.
In order to dive with pleasure exhaled, some practice is required.
For example, I dive in the pool with exhaled distance and inhaled distance,
holding breath while exhaled and inhaled.

If you want to get the most O2 out of your air and get rid of the most CO2 when you exhale, you will pause after the inhale, not after the exhale.

 

[RobPNW]

I find that I can create a "phase shift" between my vertical movement and my actual breathing. It's hard to explain but when you're moving up or down due to your breathing induced buoyancy, your body has a certain amount of momentum that continues the movement even after you shift your breathing in or out. In other words, you can still be dropping as your inhaling and rising when you're exhaling because it takes a few moments for your change in buoyancy to stop your momentum in the other direction. If I time this right, it seems the amplitude of my up and down movement is minimized. I hope that made sense to anyone because it sounds crazy.

Also, I don't breath deeply, I breath slowly and in a relaxed way.

 

[CG43]

If you want to get the most O2 out of your air and get rid of the most CO2 when you exhale, you will pause after the inhale, not after the exhale.

To get the most O2 out of your air is never nessesary because even in shallow depth you have more then enought O2 .
When you dive inhalation, exhalation, pause, you start your breathing cycle with the same low CO2 level as if you were diving in inhalation, pause, exhalation, and therefore have the same average CO2 level.
The only difference is that your CO2 rises faster during the breath hold because the CO2 is now flowing into a smaller air volume. In other words, you exhaled good CO2-poor air, thus only wasted some air.
But fighting against unwanted buoyancy or ascending during the deco is a real problem.
That is the reason why it can be advantageous to react flexibly with the breathing technique.