Breathing for Scuba

I want to get into more detail about the breathing we should be doing when we scuba dive.  As I mentioned in my first post, it is our first and most important foundational skill.  Well, not that they are not all important, but pretty much everything in Precision Diving is based and results from how we breathe and the choices we make around that.

I mentioned the foundation of the performance mindset as well.  I will be coming back to that in a future post very soon.  I thought it would be a good idea to begin this more specific discussion related to breathing sooner rather than later.  This relates to open circuit scuba breathing.  Rebreathers I will address later.  A few slight and not so slight differences there.

At my presentation at OZTek 2011 the vast majority of participants when I asked how we are told to breathe said slowly and deeply.  When I asked, “Have any of you ever actually been shown what that truly means or been taught it or had it demonstrated to you, ever?”  That moment is a good moment, perhaps many of you had that when you read the first post or you are having it now.  That realization of hey wait a minute, really, yes, wait, HEY, it never happened.  Fun to see that lightbulb go on for people.

If you are highly experienced you might find you are feeling a bit of resistance about now.  Don’t worry it is fine.  This too shall pass.  It is not to indite the industry or wave my finger at it.  I am part of it.  I simply point this out because if we are not aware of it we cannot be open to talking about it.  We think we know, we assume that since we have been breathing, for the most part since the day we were born and it is automatic, that surely we must know how to breathe properly.  Well, we don’t, well unless you were trained how somewhere usually.  If you already get it, great.  Perhaps after this there will be some common language or structure to at least be able to more easily talk about it in the future.  At worst, you might pick up a few new details.  For the rest, you should see a decrease in how much gas you use while diving almost immediately.

I am not pretending that I am inventing most of this.  I am just bringing a language and a structure to it that we can use to talk about it more easily.  So much of this stuff I struggled with trying to make it come to life in my clients until I understood we were missing the common framework and language to speak from.  It was like not being fluent in the same language and carrying on a conversation when there was no obvious common references to work with.

So, I bring this concept forward early in the discussion because it is so critical.  Breathing is the metronome and cadence of our diving.  I will bet that if you have ever had a not so happy dive, that when you think back to it, it is very likely that your breathing was not ideal.  In fact, I bet that your breathing was all messed up.  So, if our breathing is messed up, it is likely that the diving is not too far behind it.

Diving is a powerful thing.  It changes you forever.  Do we ever want to risk  having such a powerful thing be a negative in our lives?

If we are aware of breathing and gain full access to all the confidence and control it can bring for our diving, you will look back and wonder how you ever managed to enjoy it as much as you do now.  It is the most intimate and quickest way to make small and large adjustments in buoyancy, trim and help or hurt how we move through the water.

Think back to your open water course (beginning) and remember that we are told to move up a bit if we have difficulty equalizing our ears or sinuses.  Generally, we are told to add some air to the BCD or swim up a bit.  We are not told to use our breathing to focus on cycling through a more full lung volume.  Or we are told if we begin to move toward the surface without wanting to because of a bit of positive buoyancy, we should let some air out of our BCD.  Why not tell the diver to cycle breathing momentarily on the lower part of their lung volume?  Of course, it is important to make the adjustments eventually with the gear.  But, what is more accessible to the diver, their external kit or their lungs?

Effectively, if we learn to use our full lung volume and can control it, it can be like adding or removing five pounds (2 kg) of buoyancy far more quickly and controllably than waiting to find and fix the kit.  With the lag in changes in buoyancy there is time to find and fix the kit if we can mitigate the issue with how we breathe.  Rather than, especially the new diver or student diver who might not be automated with where to find and adjust their kit, having to make sure they are in correct position and have the correct bit in the right place.  This more immediate control and ability to make more major adjustments will allow you more control and that brings with it confidence.  There are of course limitations to how much we can affect change with how we breathe, but it is certainly more than most of us are aware of or has ever been actively mentioned to us.

renjith krishnan / click on Image for portfolio.

The nice thing is that these types of minor corrections and getting the hang of things becomes easier because we can be less quick about it potentially.  Instead of worrying that if we miss the correction a few times we will have more and more difficulty.  We can use how we breathe to create that space where we can take a pause to think through what needs to be done correctly.  We can mitigate the issue and with it be more likely to be able to address it the first time.

Breathing is critical and will be discussed many more times.  Once you begin to master your breathing you will begin to see just how many ways it has impacts on your diving.  As it becomes more automated, you will not have to think about it as much and the adjustments will also come without having to think about it.

This is when you have the appearance that things do not affect you like it does other divers.  They will be thrown a bit by some surge or waves above and you don’t really move.  They might find it is a bit of a struggle and feel like they have less control.  We will talk about it in a future post, but as you evolve with the skill the levels of detail gets deeper and deeper.  Like so many of the others things in diving, we are training new default responses.  This is one of them, just like the rest.

Below is a piece I wrote for instructors about teaching breathing for scuba over six years ago.  It never ran with the publication that asked me for it.  While it is not geared toward the diver, it gets the details across and I think you will find it an informational resource.

Breathing for Scuba:

Lessons from those who only have one breath to do what they have to do.


Freedivers do their dives relying only on the breath they carry with them.  So, you can bet they make the breaths leading up to a dive really good ones.  In fact, freedivers actively work on how they breathe.  The old adage in scuba of deep slow breathing is true, but only scratches the surface of what is involved.  It is almost universal that breathing is not really taught in a scuba course.

Freedivers use deep breathing techniques prior to a dive to optimize the gas exchange in their lungs.  They use their physiology to its full advantage to insure they have the maximum use of their last breath.  Scuba divers benefit from these techniques while diving gaining maximum breathing efficiency and extending the duration of their gas supply.  Unfortunately, the vast majority of scuba divers are never learning how to breathe properly.  This becomes very apparent when diving with virtually any group of divers.  Breathing remains one of the great under utilized tools of diving.

Simply put, the visual image used for proper breathing is to fill your lungs from the bottom and empty them from the top.  Seems simple enough, however very few ever seem to master the technique or more appropriately are never taught the technique.

The proper technique is known as diaphragmatically initiated breathing.  It takes advantage of lung physiology.  It is important to understand a bit about the lungs to understand why how you breath is as important as breathing at all.  All parts of the lungs are not created equal when it comes to gas exchange.  Most divers breathe primarily in the top of their lungs.  This technique reverses that.  The bottom one third of the lungs is responsible for seventy percent of gas exchange in the lungs.  This is why it is critical to keep the lower third of the lungs occupied with gas for as much of the breathing cycle as possible.

So, the next time you teach an open water course, spend some time teaching your clients to do something they think they already know how to do, teach them to breathe properly.

Have your clients begin to fill their lungs from the bottom first by actively extending their diaphragm out while not using the chest at all.  Now, this is not the sexiest way to look, but it does allow the lungs to fill from the bottom up.  Have them concentrate on just using their diaphragm to breathe with.  This looks like a pooch in the belly moving in and out.  Once they are able to just breathe from their diaphragm, have them add their chest to the inhalation about half way through the expansion of their diaphragm.  Once they have a comfortable full breath they should pause in a relaxed way for a second or two.

The number one rule in scuba is to never hold your breath.  This is not a forced hold of their breath, but rather a pause in a relaxed way.  If a depth change were to occur the air would simply be exhaled.  It is important to emphasize to your clients that they should never forcefully hold at the top of the breath.  It should be relaxed enough to allow for any expansion of gas in the lungs to easily pass and be exhaled.

The next step is to extend their exhalation.  This can be done using the tongue on the roof of their mouth.  Freedivers use pursed lips, but that is tough with a regulator in your mouth to do.  The diver should feel as if the gas is leaving their lungs from the top to the bottom.  The ideal is to keep the lower lung inflated for as much of the breathing cycle as possible.  Once mastered this new breathing technique will take anywhere from ten to fifteen seconds to complete.

When done properly, the diver begins to develop a breathing parameter.  The concept of a breathing parameter is an important concept to introduce at all levels of training.  A breathing parameter is the rate, depth and way you breathe while you dive.  We need to optimize our BPs at all times when we dive.

When diaphragmatically initiated breathing is used in scuba, the diver does not need to change breathing parameter when experiencing changing workloads as there is no more efficient way to exchange gas in their lungs.  Considerable work, time and effort should be used during all training to correct the diver’s psychological urge to lose ideal breathing when experiencing exertion.  There is no reason to go back to rapid shallow breathing when faced with increased workloads as that is only going to use gas faster and make the diver feel worse and more starved for gas.  This is mental training as much as it is physical training.  We need to reverse the tendency of divers under stress to consume gas rapidly with the least efficient way of breathing possible.

This is a foundation of becoming a good scuba diver.  There is no better place to introduce foundational skills than at the very beginning.  It is important to establish this foundation and emphasize that your clients should go back to this as soon as they realize they are out of ideal breathing.  There are times when all divers leave ideal BP.  Teaching divers to correct bad performance is often more valuable to them than just learning the ideal performance.  The easiest way for someone to regain ideal breathing when breathing rapidly is to extend exhalation.

The active component of our breathing is the inhalation phase, exhalation is actually the relaxation phase of breathing.  So, it is very important to minimize any effort while exhaling.  Regulator quality has a great deal to do with exhalation resistance more so than inhalation effort.  So, to regain proper BP, it is better to begin to relax exhalation.  Teach your clients to begin to extend their exhalation on each breathing cycle.  As they begin to relax, they will regain their ability to use ideal breathing.  It is generally a good idea to have them stop their activity while they regain their BP.

Now, there are times when scuba divers want to not be in their ideal BP.  This occurs when adjusting buoyancy and controlling tight hovers.  Extending inhalation or exhalation is still fine.  Just make sure that your clients do this still filling from the bottom and emptying from the top.  Teach them to not hold their breath to hold position but to maintain a tighter range of lung volume while doing so by inhaling sooner and/or not exhaling completely.

As divers gain experience and rise in the ranks, proper breathing becomes even more paramount.  At advanced technical diving levels the maintenance of BP can mean the difference between life and death.  So, work with clients from the beginning to help them establish the breathing foundation needed for them to be confident and effective.  Freediving provides a great training ground to continue to work on ideal breathing.


I hope that helps shed some light on using breathing to improve your diving.  It helps a great deal to work with someone that can help you to learn to control your breathing muscles and work with you on breathing. There are many activities that utilize proper breathing techniques and will lend to improving your breathing for diving.

14 Comments on “Breathing for Scuba”

  1. Jeff says:

    The way I was taught for proper breathing for scuba diving in all the scuba diving courses that I have taken, ranged from nothing at all to taking deep breathes and releasing them slowly. Unhappy with this information I decided to Google “proper breathing for scuba diving” which then I came across your article on “Breathing for Scuba” (Which I found to be very informative). While reading your article on “Breathing for Scuba” I was introduced to the concept of diaphragmatic breathing (Please excuse my ignorance here, I assumed breathing was just breathing and not realizing that there was such a thing as Chest breathing vs. diaphragmatic breathing). After reading your article I Googled “diaphragmatic breathing” and came across, while at this site I came across many interesting articles, but two of which were of interest to me for the discussion of proper breathing for scuba diving, their description of Normal Breathing and their article on the Deep Breathing Myth.

    Here is an excerpt from on their definition on normal breathing.

    Normal Breathing: Respiration Rates, Durations, Volumes, Chart, …

    Normal breathing, as we discussed, is strictly nasal (in and out), mainly diaphragmatic (i.e., abdominal), slow (in frequency) and imperceptible (or small/shallow in its volume).

    And their article on Deep Breathing Myth: “CO2 Is a Toxic, Waste, and Poisonous Gas”

    Unless I missed it, after reading “Breathing for Scuba” I was still left with the impression that deep breathing was still part of the proper technique for breathing during scuba diving. Is deep breathing the proper technique for breathing during scuba diving? After reading the articles from I don’t believe so, is this the correct assumption on my part?

    • Grant W. Graves says:

      I am going to post about buoyancy soon and that should help deal with some of these questions. I have not had time to follow your string of references and am not able to comment on them without reading them first. I would say deep breathing as defined by filling from the bottom of the lungs and letting go from the top is ideal for scuba. From the limited reference you provide in quotes here, we cannot nasal breathe in scuba and the gear itself with the water resistance provides different issue than that which is faced on land. So, I would caution about taking too much from references to land physiology too specifically to underwater.

      Once I have more time to look at the string you provide, I will try to get back and clarify if there seems to be confusion. Ideal breathing for scuba is for scuba. I find it can be useful in other applications and it really began with freediving as I stated. If someone is going to hold their breath for a long time (world class freedivers do just that), then you can be sure that given the option their breathing prior to the breath hold will be the best possible for the activity.

      I will discuss breathing more in the near future. I will leave it at that for now until I have more time to follow up on what you have been reading. More soon.

    • Andrew says:

      Another important reason for deep breathing during scuba and snorkelling is that use of a snorkel or regulator artificially increase the dead space where air exhaled is inhaled on the next breath. With most chest breathers, the dead space in the windpipe is barley overcome, and they will breath much more deeply when breathing naturally, diaphramatically. How deep is deep? As deep as is comfortable, relaxed, yet controlled and not overly throwing off your buoyancy. An unnaturally deep and elongated breath can be just as bad as an unnaturally shallow chest driven breath. “Breath Naturally” is the correct advice, its just that most people don’t know what a natural breath is…

      • Grant W. Graves says:

        It is best not to say things like breathe naturally as it simply is not natural or more would be doing it. It is a very unnatural act. It is the best way to breathe physiologically, but the use of the word naturally is what keeps even the top experts in the industry believing it does not need to be taught. If it is natural everyone should know how to do it automatically. That is just not the case. It is a case of people believing they know what to do and having no clue. Our first rule of scuba is never hold your breath, but it is not being taught. Why aren’t we teaching the most foundational skill in scuba?

        Lung volume swings can be quite large and affect buoyancy and trim very much. Even how and where you dwell with lung volume can change center of buoyancy (more about this in my next post on swimming and trim). Full lung volume breathing can be done at deeper depths with less impact on positioning. The key is to learn what is ideal, so decisions to deviate from ideal is a choice rather than a “happy accident”. One is repeatable and provides control and confidence. The other is well, a “happy accident”, neither controllable or reliably repeatable.

        It is important that the breathing is relaxed. There is no need to do a full top on each breath. That requires accessory muscle use requiring more energy than return and is uncomfortable as well. The more important key is that the exhalation is relaxed as that portion of our breathing cycle does not require work. Providing for dwell time in the bottom of the lung allows for better and the best gas exchange. Fill from the bottom and empty from the top.

        The dead air space issues are important and by moving greater volumes of gas than most do with chest breathing the impact of that dead space becomes less impactful. This is not as big an issue on scuba, but most experienced freedivers do not use a snorkel or do not use it during their final breathe up. The breathing resistance is also an issue and even more so the exhalation resistance. Since exhalation is the relaxed portion of the breathing cycle.

        Using ideal breathing is the best way to deal with both of these issues. It gives the gas time to move and since more gas is moving and the gas exchange is much better, these impacts are less. Especially during deep open circuit dives. It can be literally a survival skill. On most dives, it means more relaxed and longer dives, so more fun.

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  8. Ricky White says:

    A friend of mine taught me about diaphragmatic breathing before and it helped me breathe while underwater better than the normal way of breathing. It even saved my life once when I was almost at the brink of panicking because of how deep our dive was but remembering what my friend told me kept me in check.

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