Breathing

[Altissimus]

Hi,

I posted this in the "advanced" forum because I'm after reasonably "technical" responses. This may at some levels be a basic question, but I think there's lots more that can be covered on this topic.

Mr. Padi tells me that it's a good idea to "breathe slowly and deeply"...or at least, I think Mr. Padi said that, I must admit I dozed quite a lot during those Open-Water-with-cheese videos so many years ago. Well, what is "slowly and deeply" exactly? Do I take a "deep" breath? Do I hold it at all?* Do I breathe fast, or slowly? Do I let out the breath slower than I take it? Do I "hold" my breath in-between breaths (on empty lungs)? I have no idea.

When diving, especially at depth, what is the most effective way of breathing to conserve air?

Just to put this in perspective, I'm a reasonably experienced diver (90+ dives) and I have good buoyancy control. I understand that I can use my lung capacity to make minor adjustments to buoyancy (breathe with empty lungs / breathe with half-full lungs to control my buyoancy, for example). But I find myself swimming along at 26 meters and thinking "ok, so....shallow breath?...no no. Deep breath?...ok that's my air for the next 5 minutes used up. I'll not breathe for a while. Hmmm. Greying out here..."

Overall, my air usage seems to be quite good (on air consumption I can generally keep up with my fiancee` who is half my size) but I would still like to know what the "correct" answer should be....if there is one.

Over to you!


Thanks,
A.






* please note that holding your breath is generally a bad idea and will get a frown from your dive master, and if you ascend may be accompanied by a loud popping sound as your lungs explore the benefits of inflation. But you can still "hold" your breath by letting only a continual trickle of air escape.

 

[g1138]

The correct answer is to not think about it and breath as often as you normally do. With more experience and comfort you will breath normally. You, yourself may already be at this point.

There's a difference between holding your breath and keeping your airway open with your diaphragm fully extended. The latter still keeps your airway open and feels like your still trying to lightly inhale when there's no more room to do so; the former uses your epiglottis to close your airway which is where you can get into serious trouble.

You should not skip breath at all or alter your breathing heavily. Breath as much as your body tells you to. Long deep-slow breaths aren't always the answer and neither are short rapid ones. I just breath without thinking about air conservation or rate.

The only times I believe you should think about your breath rate are when negotiating depth changes or when you're stressed and breathing heavy.
With depth changes you will need to breath more with the top of your lungs to rise, or exhale more to fall etc. With experience this too will also be a natural reaction and won't even come to mind.
When you're stressed it might be a good idea to take a deep breath, sigh, and try to control your breathing to calm yourself.

 

[Altissimus]

Hi g1138,

Thanks for the reply.

The correct answer is to not think about it and breath as often as you normally do. With more experience and comfort you will breath normally. You, yourself may already be at this point.

This is the bit that gets me, to be honest. I don't know how I breathe normally. As soon as I think about breathing, I do something different. Not thinking about it would be the solution, but as I sit at my desk in the office typing this, I find it easier to not think about my breathing then when I'm 20 meters down breathing through a reg with my mouth (rather than through my nose without impedence) and sounding like Darth Vader with a cold.

Breathing with a reg is an effort that, at least to me, forces me to think about my breathing. Also, because of the nature of the apparatus, there is a much larger space of "dead" air than there is when one "breathes normally" out of water.

It's probably also worth pointing out that most of us don't breathe "properly" - we do as kids, but as we grow older we get lazy and tend not to use our lungs to their potential. We don't breathe with our diaphragms; we breathe from the top of our lungs. We don't use our full lung capacity; we lazily use the top 25%. We don't utilise the bottom half of our lungs where the maximum efficiency of oxygen intake can be accomplished. If we were to do all these things "naturally", then we would all be masters of air consumption - and probably naturally better at buoyancy control to boot.


Admittedly I do naturally control my breathing to better control ascent/descents. It's actually when I'm maintaing depth and just swimming along that I think about this more.

Regards,
A.

 

[HBDiveGirl]

Great thoughts here from both g1138 and Alti, already.

I think I remember the zone you're describing very clearly.
100 dives into the adventure, putting together hints and feedback loops from experience as well as purposeful thought.

My biggest breakthroughs were:
1. Learning to breathe abdominally most of the time when underwater. My gas consumption rate went down, I think because there's less work of breathing when breathing abdominally. Chest breathing works against the wetsuit (or drysuit) and the traditional BC more than does abdominal breathing.

2. Leaning when to use the finer control of chest breathing for precision buoyancy control. Abdominal breathing feels like the gross focus knob, and coupled with purposeful chest breathing you get very fine control.

3. Learning that I was consistently colder when I "tried" to "breath less" to extend the gas in my cylinder. Breathing "normally" for the dive resulting in my being warmer.

4. Learning to work really hard in the gym, so everything got easier underwater.
Diving a lot is great practice for diving.
Diving is NOT the strength or cardio workout needed to make an optimal diver.
Work in the gym.
Relax purposefully underwater.


You're asking great questions.
It's so exciting to learn this stuff.

I'm still learning and loving it more everyday.

~~~~~~
Claudette


"If you can't explain it simply, you don't understand it well enough."
--Albert Einstein

 

[TSandM]

It's actually an interesting question, and I'm not sure there's a precise answer to it.

If you want to analyze breathing, you have to start with the recognition that a certain volume of gas has to pass through the gas exchange chambers in the lungs (the small air sacs, or alveoli) per minute, to keep the level of carbon dioxide in the blood constant -- and that is something the body really needs and wants to do.*

But the air that passes through the large airways (trachea and bronchi) doesn't participate in gas exchange, so it's wasted, or "dead space". Therefore, to make the most efficient use of the gas in your tank, you'd like to maximize the ratio of alveolar ventilation to dead space ventilation. This would actually be best done by taking huge breaths, and few of them. But there are a few problems with doing that . . .

First off, we don't breathe that way on land. Of course, on land, air isn't limited, so there was no evolutionary pressure to be most efficient in its use. Instead, the breathing pattern we use on land is designed to get the job done with the least work possible, and breathing is most comfortable when it's as passive as it can be. Try it while you're reading this -- try taking some huge, deep breaths, and blowing them entirely out, and then holding your breath for a couple of seconds and doing it again. I'll guarantee you that it won't be long at all before you feel air hungry and miserable. We just don't breathe that way.

In addition, if you try to use that breathing pattern underwater, you have two problems. One is that you have to spend periods where you are not breathing at all, or you'll hyperventilate, which can make you feel lightheaded and shaky. Holding your breath for seconds at a time underwater really isn't a great idea -- it's all too easy to forget to keep the glottis open. Another is that those huge changes in lung volume really affect your buoyancy, and when you have to hold your breath for several seconds, you've given those volume changes a lot of time to work.

But you'll remember, if you ever did the fin pivot exercise, that there is a pattern of breathing you can use, where just as you begin to move up, you're beginning to exhale, and just as you begin to sink, you're beginning to inhale. That minimizes the buoyancy excursions.

So the ideal breathing pattern underwater would be one which minimizes dead space ventilation, and follows a rhythm that minimizes up and down motion in the water column. I suspect that, for each diver, there is a rate and volume choice that gives you the best you can of both, and that with diving experience, most of us find it. It's a little deeper than the completely passive breathing pattern you use on land, and a little slower, but it's not extreme.

 

[HowardE]

I think an important part of the breathing process is the gas exchange, and complete exhalation and inhalation at a relaxed pace, as opposed to rapid shallow breathing is best to avoid CO2 retention, or rebreathing the CO2 that you don't fully exhale.

Often times divers ask, "how can I breathe better?" and/or "How can I use less gas?" and really the answer is: Better breathing comes from more experience, which there are no shortcuts to. I use a lot less gas now than I did with 100 dives or even 500 dives. It's just part of experience and comfort. Even when we think we're comfortable in the water with 100 dives, we still find we use more gas than we do when we have 1,000 dives.

 

[g1138]

Breathing properly (really the term effectively should be used) is of course open to debate. It depends on the context of the situation.

As TSandM said, it takes a lot of energy to fully exhale and inhale with each breath. You can try doing it right now when sitting down. Eventually you will feel a lot of relief when you return back to breathing with just the top part of your lungs. You will even notice your heart rate has increased a bit if you've been fully breathing for an extended period. This is because you need the added blood flow to work you diaphragm.

When we're in a resting phase we don't need that large amount of air exchange. So to be energy efficient, we breath at the top of our lungs. The primary purpose of breathing fully when exercising is to rid us of CO2, it's not that we need more O2 into our lungs. You might recall that CO2 is our trigger to breath. More strenuous exercise, means more CO2 buildup.

Our bi-directional respiratory system is really ineffective at utilizing all the oxygen in our lungs. You can hold your breath on land until you pass out, and there will still be a fairly large percentage of O2 in your lungs; just not in enough concentration of the entire volume for you to absorb it to sustain consciousness.

Also if you were breathing fully underwater, you would be maximizing your air consumption. Using the most air per breath that you possibly can; fully filling and empty your lungs. This would of course elevate your "resting" SAC rate. Once you add in the added energy and effort of doing this: you will probably elevate your heart rate, increase your CO2 production, which would mean you'd need to breath more often.

So really if you want to keep your SAC rate low, it would be wiser to not breath at all (which is not something I would not recommend for obvious reasons). A more practical suggestion would be to breath as much as your subconscious tells you to. Which is to say, don't focus on it at all.

This is harder for some than others, particularly nose breathers. For me, when I transition into water, my mouth is naturally my primary orifice for air exchange. I can't explain how it worked out that way except possibly that I've been an active submerged swimmer since I can remember. As a kid, it was just a whole lot easier to avoid sucking water through my tiny nose when I used my bigger mouth instead.

 

[ajtoady]

From my classes I remember the breathe slowly and deeply routine. My personal experience and opinion is as follows; 1) it has a calming effect on the new diver who is anxious in his or her new environment. 2) It makes you aware of how useful your lungs are in buoyancy control.

 

[Altissimus]

Having had a bit of a read around the various thoughts and opinions on the WorldWideInterWebHighway, I found this article which personally I think is extremely helpful and covers this at a good level for both beginners and advanced divers alike: Breathing for Scuba « Precision Diving

 

[skankpile]

..... good read