holding my breath while taking a photo

[gr8fuldiverNC]

i hesitate to post this here, dont wanna encourage bad habits, but technically speaking holding your breath is not an issue per se, even while ascending. it is the closing of the airway (ie closing the glottis) that is the issue, and that is how most people hold their breath. breath holding using just your diaphram and costal muscles is safe, as the airway remains open, and excess air can trickle out. however, do not try this, as most people cant tell the difference, and even small depth changes with a closed airway will have serious consequences, especially when shallow. a pause between inhalation and exhalation is perfectly ok, even desireable as it allows for greater gas exchange in the lungs, as long as the airway is open.

 

[Dtaine]

Quotations that prove you should not hold your breath underwater?? Do I really need to do that?

Well, no, but that wasn't exactly my point.

Yes, we all agree that holding breath is only an issue if the ambient pressure should drop and cause air volume expansion inside the lungs, where the glottis is sealing the airway.

Ascent is the primary cause of this reduction in ambient pressure. But not the only one. Large surface swell could have a similar effect.... I know that these situations are so unlikely as to be virtually infeasible - but they do exist and they could be fatal.

True

Sorry, I don't mean to be pedantic about this..... but I strongly believe that cardinal rules exist for valid reasons. To say they only apply to novice divers reeks of a complacent attitude and, from my experience, belies the sort of short-cutting and rule bending of divers who have gained confidence in the water, but yet to encounter the realities that these rules exist for.

I wonder when this started to be considered a "cardinal rule". There's clearly a bunch of people who don't consider it to be a set in stone law of diving.

I have a reasonable amount of experience in the water now.... and I still hold true to these cardinal rules. I would think that some of the less experienced divers posting on this thread could benefit from some re-assessment of their percieved capabilities and take the opportunity to go back to basics.

Lets leave dive count out of this shall we, after all it's really a discussion about physiology, gas laws, etc.

 

[DevonDiver]

i hesitate to post this here, dont wanna encourage bad habits, but technically speaking holding your breath is not an issue per se, even while ascending. it is the closing of the airway (ie closing the glottis) that is the issue, and that is how most people hold their breath. breath holding using just your diaphram and costal muscles is safe, as the airway remains open, and excess air can trickle out. however, do not try this, as most people cant tell the difference, and even small depth changes with a closed airway will have serious consequences, especially when shallow. a pause between inhalation and exhalation is perfectly ok, even desireable as it allows for greater gas exchange in the lungs, as long as the airway is open.

Nice post.

I was under the impression that - when not actively breathing - the default position of the glottis is closed to the airway. So, if you are not actively exhaling or inhaling...then the glottis is shut and lung injuries are possible.

I was not aware of any technique used that would allow people to manually control the glottis...which I believe was an autonomous muscle/valve that functions due to swallowing reflex and breathing pattern.

 

[MXGratefulDiver]

I was under the impression that - when not actively breathing - the default position of the glottis is closed to the airway. So, if you are not actively exhaling or inhaling...then the glottis is shut and lung injuries are possible.

I was not aware of any technique used that would allow people to manually control the glottis...which I believe was an autonomous muscle/valve that functions due to swallowing reflex and breathing pattern.

I'm not aware of any "default" position ... I can open or close my glottis at will.

Then again ... I can wiggle my ears too ...

... Bob (Grateful Diver)

 

[ScubaDocER]

i hesitate to post this here, dont wanna encourage bad habits, but technically speaking holding your breath is not an issue per se, even while ascending. it is the closing of the airway (ie closing the glottis) that is the issue, and that is how most people hold their breath. breath holding using just your diaphram and costal muscles is safe, as the airway remains open, and excess air can trickle out. however, do not try this, as most people cant tell the difference, and even small depth changes with a closed airway will have serious consequences, especially when shallow. a pause between inhalation and exhalation is perfectly ok, even desireable as it allows for greater gas exchange in the lungs, as long as the airway is open.

I have concerns about this philosophical point of view. The glottis is defined as the combination of the vocal folds and the space in between the folds (the rima glottidis). It is merely the opening through which air moves back and forth from the oropharynx (mouth) into the trachea. Holding your breath simply means that you are not moving air out, but forcing the air within your lungs to remain there. Opening your glottis and ascending does little to allow the air in your lungs to escape unless you are exhaling, which means you are no longer holding your breath. You cannot let air "trickle out" as you are ascending. This is extremely dangerous and increases your chances significantly of getting a chest tube and a trip to the chamber.

Closing of the glottis does indeed trap air within the lung cavity. Opening the glottis and ascending while trying not to exhale is suicide IMHO. The air with the trachea may escape, but the air within the alveoli will expand and rupture.

Pauses between inhaling and exhaling are rarely if ever recommended in scuba diving. Not only do they lead to an increase in CO2, they also increase your risk of a lung over-expansion injury if you are inhaling and ascending simultaneously.

I will admit that divers may inhale and pause to take a picture, or prevent themselves from getting to close to the bottom, but this should be done with the understanding that you are never ascending while you are doing it.

Unless you have impaired lung function (COPD, fibrosis, etc.) gas exchange within the lungs usually occurs at a maximal rate. Pauses between inhaling and exhaling actually worsens the process because they delay the inhalation of oxygen and delay the expulsion of CO2.

While I am trying to understand the thought process of using just your diaphragm and intercostal muscles to affect respiration while not closing your glottis, I think it is a dangerous gamble to assume that merely opening the glottis will be enough to vent the accumulated pressure built up in your alveoli, bronchioles, bronchi, and trachea without causing a traumatic tear, unless your are intentionally exhaling.

Sorry but I am not sure I completely understand or would truly support this line of thinking.

 

[SharkDiver36]

.... but I strongly believe that cardinal rules exist for valid reasons. To say they only apply to novice divers reeks of a complacent attitude and, from my experience, belies the sort of short-cutting and rule bending of divers who have gained confidence in the water, but yet to encounter the realities that these rules exist for.

Well said.

Love the technical explanations in the responses.

KISS - Keep it stupid simple. (gentler version than 'keep it simple stupid').

Don't hold your breath Makes it simple and easy for the average person and recreational diver.

 

[MXGratefulDiver]

OK ... I understand you're a doctor and I'm not ... but a couple things you said here don't make any sense to me ... would you please elaborate?

Pauses between inhaling and exhaling are rarely if ever recommended in scuba diving. Not only do they lead to an increase in CO2, they also increase your risk of a lung over-expansion injury if you are inhaling and ascending simultaneously.

This seems to suggest that we should only exhale on an ascent ... which isn't how it works. We breathe continuously ... both inhale and exhale ... as we're ascending. Lung overexpansion doesn't occur because our regulator is compensating for ambient pressure as we ascend, and the gas we're inhaling is at a lower ambient pressure than it was at a deeper depth.

I will admit that divers may inhale and pause to take a picture, or prevent themselves from getting to close to the bottom, but this should be done with the understanding that you are never ascending while you are doing it.

Of course ... that's what everyone's been saying. But that's not the reason why you pause breathing to take a picture ... depending on the shot you may need to be as close to the bottom as you can get without damaging something or silting the place up. You pause your breathing because in order to get the shot as you want it framed you need to be able to hold absolutely STILL for a couple to a few seconds ... and you CAN'T DO THAT if you are breathing ... because doing so changes your buoyancy.

Seriously ... it's a simple concept.

Unless you have impaired lung function (COPD, fibrosis, etc.) gas exchange within the lungs usually occurs at a maximal rate. Pauses between inhaling and exhaling actually worsens the process because they delay the inhalation of oxygen and delay the expulsion of CO2.

That's not how I understand it works. The alveoli are permeable membranes. Gas exchange is occurring constantly between the two sides of that membrane. The rate of gas exchange is dependent on the difference in partial pressure between dissolved gases in the blood on one side, and inspired gas on the other ... they want to equalize, so any component gas with a higher partial pressure will migrate across the membrane toward the side with the lower partial pressure. Inhaling increases the difference in partial pressure, exhaling decreases it. So while it is true that holding your breath will ultimately result in a buildup of CO2, it is also true that a brief pause after inhale will temporarily increase the rate of exchange, due to the higher partial pressure differential between the gases on either side of the alveoli. So the exchange process isn't as simple as you make it out to be ... because the rate of exchange is not constant, but rather is dependent on variable partial pressures of the component gases on either side of the membrane. And whether it's helpful or harmful really depends on the length of the pause, and the partial pressure difference in CO2 between the gases(and therefore the exchange rate) at any given moment.

While I am trying to understand the thought process of using just your diaphragm and intercostal muscles to affect respiration while not closing your glottis, I think it is a dangerous gamble to assume that merely opening the glottis will be enough to vent the accumulated pressure built up in your alveoli, bronchioles, bronchi, and trachea without causing a traumatic tear, unless your are intentionally exhaling.

This would suggest that the passage between lungs and bronchial passages is a closed system. I'm quite certain I didn't study anatomy to the degree that you did, but as I understand it, there are no obstructions that would prevent a free passage of gas from a healthy lung to the tracheae. I do not understand how a completely open system can result in the pressure buildup you suggest.

Sorry but I am not sure I completely understand or would truly support this line of thinking.

I believe you misunderstood the question ... which had nothing to do with ascending while not breathing, but rather with pausing your breath while taking a picture.

Photographers do it routinely. I've done it literally thousands of times ... and yet I'm here, breathing normally and typing this response. According to your logic, I should be dead.

... Bob (Grateful Diver)

 

[dumpsterDiver]

when I was a teenager, I did a lot of snorkeling. One time I forgot to exhale while comming up kinda fast from a shallow scuba dive. I was solo diving, messing around jumping off the bottom toward the surface and doing underwater flips or something in less than 20 feet (stupid kid).

I was playing and apparently so used to freediving that I held my breath. I very quickly felt an uncomfortable over expansion of the lungs and (because I did not have the glottis locked down) the air just popped out, without me realizing what was happening. it came out as an involuntary ah sound.

I've only done this once, and over pressurizing your lungs is probably not a good thing to do, but from my personal expereince, air can naturally come out on ascent, even when you are not breathing as long as you are calm and relaxed.

You can easily test this effect while on land, take a really large breath, hold it and then "gulp" some more air into your lungs, you are essentially filling them more than is comfortable. As soon as you relax (un lock the epiglottis) , the air just comes out on its own without any effort to exhale.

For the DOC to say that you should never pause the inhalation and exhalation cycle is just silly.

As for deliberately holding your breath while scuba diving, spearfisherman do it all the time to stalk fish. I will do it commonly for over 30 seconds some times. Pausing to take a picture (as long as your depth is maintained) is fine.

 

[Darnold9999]

I must be missing something. If there was something beside the glottis bloking air transfer then how does air escape when you breath out using your diaphram.
What exactly is the mechanism that opens up the passages from the trachea to the lungs.

While it is possible that the default position of the glottis is closed when most people are not breathing. It takes almost no effort to learn how to keep it open - as pointed out earlier marksman do it all the time. One of the first things I was taught when learning how to shoot. Don't hold your breath - just stop breathing. Less tension in your body. Having said that it is not the default position for me but I am a wind player so it is possible that I am not normal in this repect and have learned to change the default.

I don't believe that there is "something" other than the glottis that would prevent air moving out of your lungs. Try it - push air out with your diaphram with the glottis open - or get someone to squeeze your lungs and see if you can stop the air from exiting - without closing your glottis. Please define the "something" a little more clearly. Keep in mind your mouth is open witha reg in it and your nose is also open as few people can dive if their sinusus and nose is plugged up.

A swell could cause an over expansion injury. Possible, but you would have to be very very near the surface in a significant swell for this to happen - personally I am not taking pictures in these conditions and if you stop breathing as opposed to holding your breath still not a problem.

I think NWGratefulDive described it best. As a beginner you need an iron clad rule. As you gain experience and understand the reason behind the rule you can modify your behavior. Being careful not to modify it to be careless.

Can't say I have done this thousands of times, but I can say that I do it all the time when taking pictures. How else would you stay in the same spot while adjusting focus etc???? Grab hold of the reef???

 

[ScubaDocER]

Hello Bob,

I'll try to answer your questions from my perspective. Being a Doc makes me knowledgeable in some areas, but certainly not an expert in all.

This seems to suggest that we should only exhale on an ascent ... which isn't how it works. We breathe continuously ... both inhale and exhale ... as we're ascending. Lung overexpansion doesn't occur because our regulator is compensating for ambient pressure as we ascend, and the gas we're inhaling is at a lower ambient pressure than it was at a deeper depth.

You should not intentionally pause between inhaling and exhaling while ascending. A pause in this case would be an intentional interruption in your breathing cycle instead of breathing as you normally would. There is no benefit from it that I can perceive and the risks of doing so could be catastrophic. Of course we inhale and exhale while ascending. That is a normal breathing cycle. I was implying that you should not consciously interrupt your normal breathing cycle with intentional pauses while ascending. Sorry if that was unclear.

Of course ... that's what everyone's been saying. But that's not the reason why you pause breathing to take a picture ... depending on the shot you may need to be as close to the bottom as you can get without damaging something or silting the place up. You pause your breathing because in order to get the shot as you want it framed you need to be able to hold absolutely STILL for a couple to a few seconds ... and you CAN'T DO THAT if you are breathing ... because doing so changes your buoyancy.

Seriously ... it's a simple concept.

I agree completely. Never stated to the contrary. We are on the same page in this regard. When I am taking pictures, I inhale, hold the breath, steady myself, take the picture, exhale slowly, and continue on to the next shot. I am not ascending while doing this. Not sure I understand where you feel that it was a concept I did not comprehend.

That's not how I understand it works. The alveoli are permeable membranes. Gas exchange is occurring constantly between the two sides of that membrane. The rate of gas exchange is dependent on the difference in partial pressure between dissolved gases in the blood on one side, and inspired gas on the other ... they want to equalize, so any component gas with a higher partial pressure will migrate across the membrane toward the side with the lower partial pressure. Inhaling increases the difference in partial pressure, exhaling decreases it. So while it is true that holding your breath will ultimately result in a buildup of CO2, it is also true that a brief pause after inhale will temporarily increase the rate of exchange, due to the higher partial pressure differential between the gases on either side of the alveoli. So the exchange process isn't as simple as you make it out to be ... because the rate of exchange is not constant, but rather is dependent on variable partial pressures of the component gases on either side of the membrane. And whether it's helpful or harmful really depends on the length of the pause, and the partial pressure difference in CO2 between the gases(and therefore the exchange rate) at any given moment.

Not only is the rate of gas exchange dependent upon the pressure gradient that exists between the the gases in question, they are also dependent upon the bodies utilization of the gases in question and the metabolic processes that are occurring within the body itself. While you are holding your breath, the production of CO2 continues. The body is still breaking down carbohydrates and burning fuel to sustain you. This results in an increased production of CO2 that has no means of escaping. This increases the pressure gradient to try to expel CO2. I agree with you that pressure gradients can affect the rate at which gases move across membranes. The body in it's normal state will maximally exchange the oxygen and CO2 that you produce. As your level of activity increases, so will the rate of exchange as long as nothing impairs with that process, such as underlying lung diseases, or intentionally holding your breath. This disrupts the body's ability to equilibrate these gases appropriately. My statement still stands that the lungs function at a maximal rate. They are designed to accommodate changes in the level of activity to meet the body's demands to eliminate CO2 and increase O2 availability.

This would suggest that the passage between lungs and bronchial passages is a closed system. I'm quite certain I didn't study anatomy to the degree that you did, but as I understand it, there are no obstructions that would prevent a free passage of gas from a healthy lung to the tracheae. I do not understand how a completely open system can result in the pressure buildup you suggest.

Allow my to elaborate. Firstly, I never suggested the system was a closed system. The lungs are not really a simple container. The lungs themselves are permeable throughout. Think of a sponge instead of a static flask or beaker. The alveoli that exchange the gases are like tiny balloons that contain the gases. If the pressure gradient within the the alveoli increases faster that the air can leave the balloon, then the balloon ruptures. The other problem is that the gases diffuse within the lung parenchyma itself. Not just within the tubes that carry the gases in and out of the body. Again, think of the lungs as a sponge that absorbs gas instead of a solid structure. An ascent without allowing these gases to reenter the bronchial system can result in a lung over expansion injury. Clearly there is some theory to this process and it is each divers choice as to whether or not to hold their breath and ascend, or just to go through the normal breathing cycle and ascend. It is not an all or nothing approach. Divers have done it without incident. If I had to make a choice or to make a recommendation to a diver I would suggest the latter.

I believe you misunderstood the question

I believe you have misunderstood to whom I was responding. My response had little to do with the concept of holding one's breath while taking a picture. It had to do with the statements made by gr8fuldiverNC which I disagreed with. I understand the concept of holding one's breath to take a picture. I have done it several times myself with good success. I disagree with the concept that "holding your breath is not an issue per se, even while ascending". As well as "a pause between inhalation and exhalation is perfectly ok, even desireable". Intentionally interrupting your breathing cycle is never desireable. People do it and often do ok with it, but it is not how the body was intended to function. It does lead to an increase in CO2 build up. Now where or not this is problematic is a subjective and depends on what else you are doing, your work load, and your position in the water. I would never recommend that a diver be ok with holding their breath while ascending. I think you may be confusing the original intent of this thread with the comments made by gr8fuldiverNC. That is what I am addressing.

Photographers do it routinely. I've done it literally thousands of times ... and yet I'm here, breathing normally and typing this response. According to your logic, I should be dead.

... Bob (Grateful Diver)

If you are holding your breath while ascending then you are lucky that you aren't dead. That is my logic.