Question Decreasing the Breathing Reflex....Possible?

[Rick204]

Take up smoking. Based on what I’ve seem smokers have a lower SAC rate than non smokers. Maybe it’s the higher blood concentration of CO2 and CO from the smoking that makes them more tolerant to the natural co2 trigger to breath.

 

[John C. Ratliff]

Take up smoking. Based on what I’ve seem smokers have a lower SAC rate than non smokers. Maybe it’s the higher blood concentration of CO2 and CO from the smoking that makes them more tolerant to the natural co2 trigger to breath.

I put a “sadness” emoji onto your post, as my Mom died of lung cancer and emphysema caused by smoking in her late 70s. My grandma, on her side, lived into her 90s. I know you were posting this somewhat in jest, but for me it isn’t funny.

SeaRat

 

[Rick204]

I put a “sadness” emoji onto your post, as my Mom died of lung cancer and emphysema caused by smoking in her late 70s. My grandma, on her side, lived into her 90s. I know you were posting this somewhat in jest, but for me it isn’t funny.

SeaRat

Sorry for your loss John

 

[justinthedeeps]

Breathing patterns in scuba diving seem largely governed by habits, and surely also by some subconscious effects from immersion (e.g. the famous "inversion" from inhale - exhale - pause - inhale... to inhale - pause - exhale - inhale...) that happens for many folks.

[Reading back thru this interesting thread]
What you describe here seems interestingly true.

On land, at rest, indeed I am inhaling, immediately exhaling, and then pausing--sometimes for quite a while--before the next inhale.

Whereas on open circuit SCUBA underwater, it can commonly occur that breathing turns into "hits from the bong" [air tank], i.e. inhale, --hold--, exhale. Not always, but it is a relatable thing for many divers, I suspect.

Is that just a psychological thing?
Is one better for ventilation & CO2 removal? Probably the former? Is there actually data on that?

On a closed circuit rebreather, the breathing pattern is more normal (for me, at least). No need for weird 'gas conserving' breathing tricks, or habitually compromising breathing patterns for buoyancy tweaks etc

Speaking of CCR, it is ever theoretically possible that a rebreather could be too effective at removing CO2, thereby also reducing the breathing reflex?

 

[rjack321]

Speaking of CCR, it is ever theoretically possible that a rebreather could be too effective at removing CO2, thereby also reducing the breathing reflex?

definitely not. Inhaled CO2 is zero in a fully functioning CCR,
CO2 in blood is dictating respiratory drive (in most people with some exceptions that shouldnt be diving)

 

[justinthedeeps]

definitely not. Inhaled CO2 is zero in a fully functioning CCR,
CO2 in blood is dictating respiratory drive (in most people with some exceptions that shouldnt be diving)

My experience agrees with this assumption, under normal conditions.

But for a large scrubber that removes 100% of CO2, regardless of high ventilation rate etc. Shouldn't this have a similar effect on breathing reflex as ordinary hyperventilation? Combined with high ppO2? I would not be surprised to see a decreased breathing rate.

Maybe one these folks with a background in medical ventilation has something interesting to add

 

[steinbil]

But for a large scrubber that removes 100% of CO2, regardless of high ventilation rate etc. Shouldn't this have a similar effect on breathing reflex as ordinary hyperventilation? Combined with high ppO2? I would not be surprised to see a decreased breathing rate.

There's also no significant amount of CO2 in the air you breathe on the surface, so why would it be different on a CCR? The CO2 builds up in your body, not in the gas you inhale (except in cases like scrubber failure). The scrubber removes CO2 from the air you exhale, it doesn't affect the CO2 produced in your body (other than maybe work of breathing leading to more CO2 production in your body).

 

[Dominik_E]

Whereas on open circuit SCUBA underwater, it can commonly occur that breathing turns into "hits from the bong" [air tank], i.e. inhale, --hold--, exhale. Not always, but it is a relatable thing for many divers, I suspect.

Indeed. Looking into our heritage, this is very normal! A human that is suddenly submerged (e.g. from a fall into water) has to immediately and effectively hold his or her breath. Full lungs mean life in that situation.

Our reflexes do not inutitively know that there is a very ample supply of good gas in a tank available. But this can be overcome, with training. Our mind and body can learn that this part of the diving reflexes -- the breath hold -- is not necessary when scuba diving. Overcoming is very much worth it: The inhale -- hold -- exhale sequence leads to an additional air volume in the lungs that is not needed, but makes stable buoyancy harder to achieve. One way is to consciously, just or a few minutes per dive, think about the effect, observe what the body is doing, and gently motivate oneself into the relaxed breathing style we have on land.

On CCR, the breathing indeed for many is more "continuous".

 

[NW Dive Dawg]

The science of holding your breath: How could Kate Winslet stay underwater for over 7 minutes in Avatar 2?

Kate Winslet held her breath for an impressive 7 minutes and 15 seconds while filming, but the current world record is over 24 minutes. Here’s how people learn to stay underwater for extended periods of time.

theconversation.com

 

[John C. Ratliff]

Indeed. Looking into our heritage, this is very normal! A human that is suddenly submerged (e.g. from a fall into water) has to immediately and effectively hold his or her breath. Full lungs mean life in that situation.

Our reflexes do not inutitively know that there is a very ample supply of good gas in a tank available. But this can be overcome, with training. Our mind and body can learn that this part of the diving reflexes -- the breath hold -- is not necessary when scuba diving. Overcoming is very much worth it: The inhale -- hold -- exhale sequence leads to an additional air volume in the lungs that is not needed, but makes stable buoyancy harder to achieve. One way is to consciously, just or a few minutes per dive, think about the effect, observe what the body is doing, and gently motivate oneself into the relaxed breathing style we have on land.

On CCR, the breathing indeed for many is more "continuous".

Concerning the heritage, and instinctively holding one’s breath, that only holds for a sudden submergence into deep water if the water is warm. If it is cold, or icy, there is an immediate and instinctive inhalation reflex, which can be life threatening.

Okay, you can actually measure my breathing rate in this video. There are times where I purposely held my breath to get the GoPro camera closer to these small redside shiners. I then would take a few deeper breaths to ventilate my lungs of the built-up CO2.


You will notice that at times I very briefly held my breath, and at others in this video there was no skip breathing. It simply depended upon what I was doing at the time. Now, if you look at the U.S. Navy Lung Volume chart, when diving I purposely increase my tidal volume, so that I inhale deeper than I would normally in air, and exhale more fully. You can see that with the exhalation bubbles; they are not a small bubble stream.

I cannot comment on the rebreather discussion, as I have never used one. But I suspect deeper breathing happens in the rebreather too (rebreather divers are welcome to either confirm this deny it).

SeaRat