Dive reflex not always helpful?

[atomichaggis]

LOL... now that is observant. first the Sam Still gag now this. It is just a bad habit like... that.
I never felt that the owner of the first person pronoun should be more important than the second or third person so they got a capital and all of Their posessive pronouns as well... i guess it falls under the 'Important words' rule.
I might be a little abrasive at times but I find having more capitals than others a bit arrogant. Don't let it bug you too much.
Lousy grammar and reasoning is to be expected from someone who never finished school.

[wet]

Lucia, are you a regular member of an ochestra, playing a brass instrument or woodwinds, where air pressure is required to produce sounds? If so, it possibly might conflict with breath holding, not the length of time, but rather the effects of air pressure on the larynx, pharynx, epiglottis, etc. (Is your packing similar to a wind instrument pressure? When you breathe up, do you pressurize the throat, or keep it about the same as outside air pressure?)

2% of humans develop a laryngocoel (sp), most often related to wind instruments or balloon inflating or similar activities. (from Tecumseh Fitch, Speech and Language, IIRC) This is a little air sac in the larynx that inflates when pressured, it was greatly enlarged in our hominoid ancestors, but reduced to a vestige like the appendix in humans.

[wet]

Originally Posted by naiad

Then that is an important safety consideration for diving and other watersports.

What a useless reflex, I don't know how it could possibly be good in any situation to gasp when falling into cold water.

Feet first: gasp, wading in cool water
Face first: MDR, diving in cool water

It's actually the same reflex, maximizing oxygen retention, but face-first shuts off the inhalation phase, while feet-first exaggerates the inhalation phase.

Your best MDR response might be this approach:
(with a buddy at poolside watching and estimating time, not a small crowded pool)

1) NO wetsuit, just swim suit, warm and dry, no nose/ear plugs/mask/cap.
2) PLAN only ONE dive, (afterwards hit the hot shower, then dry and leave).
3) NO breathe up, just walk to the edge of deep end, casually deflate lungs while leaning forward, and pushing gently off into the water, entering face-first with arms down at your sides, to between 1/2 to 2 meters deep, glide down and forward until stopping, then casually but with strength, kick a few times while gliding hydrodynamically, then, when ready to climb, [*see note below] bring your arms forwards and SLOWLY power stroke laterally at sides (no more kicking) diagonally or vertically up to the surface, turn onto your back and inhale a few slow moderate breaths (not deeply) while laying flat like a board on the surface relaxing, backstoke over to the edge and climb up and leave pool. You did it. Shower, dry, go home, forget it.
4) It's not the length of time or distance, it's the technique, 20 seconds submersed is fine. 1' MDR > 2' HV.
5) That night, dream the dive again, let the experience come back, learn from it subconsciously while sleeping, adjust little things (slower or faster kick, hear echoes under water, sense difference between surface temp. and depth temp. etc.).
6) Repeat pool dives often, after the first day, 2nd and 3rd dives are ok, but stay focussed on technique, hydrodynamics and sensing conditions. No more dry/wet statics until normal dives are smooth enough to make a dolphin smile.

* Assuming no intruders and not close to wall, close eyes during ascent and allow face skin to inform you of your position. Your ears know the depth and body orientation via the eardrums and the 3 semicircular canals of the inner ear, your hair/forehead/eyebrows/eyelids/eyelashes know the speed and the difference between water and air temperature and pressure, rely on this sensitivity. Once in backfloating position and ready to scull to the edge, only then open the eyes and go.

(If what I say doesn't make sense, don't do it. Only under supervision in optimum conditions.)
DDeden

[naiad]

Originally Posted by wet

Lucia, are you a regular member of an ochestra, playing a brass instrument or woodwinds, where air pressure is required to produce sounds?

No, never played a brass or woodwind instrument, except a few recorder lessons when I was a kid.

Maybe I will try the one-dive approach, with a buddy. I am still a bit scared of getting into cold water, because for me the gasp reflex happens even if I put my face only in the water. It is not so bad if I take a deep breath and hold it, and much worse with empty lungs.

[wet]

Originally Posted by naiad

No, never played a brass or woodwind instrument, except a few recorder lessons when I was a kid.

Maybe I will try the one-dive approach, with a buddy. I am still a bit scared of getting into cold water, because for me the gasp reflex happens even if I put my face only in the water. It is not so bad if I take a deep breath and hold it, and much worse with empty lungs.

I played trumpet a couple years, but not enough to cause laryngocoel. I think it only happens to people with unusually thin or weak larynx tissue or something.

I fully empathise with the dislike of cold water immersion. The reason I mentioned it was because I assume your available pools aren't really warm and the pumps keep moving the water around. The ideal would be very very warm at the surface (6" 15cm) and quite cool just above the pool floor, with the water almost still and thermally stratified, like in a sunlit tropical lagoon completely surrounded by reefs.

By breathing up, and then filling the lungs with air, the body's sensors read "low CO2 so plentiful O2", and keep burning O2 at a regular non-MDR pace.
Then when the CO2 rises due to the fast O2 burning, contractions or air hunger starts.

OTOH, having the MDR/gasp occur right away with empty lungs forces O2 conservation, burns O2 slowly and builds CO2 slowly. This registers in your mind as discomfort because you haven't gradually habituated to it. The same physiological gasp that tries to suck in air to the lungs is actually pumping O2 from the extremities. By sealing the mouth and nose (with tongue in back), the coldwater gasp has nowhere to come from but the blood cells and muscle cells rich in O2 in the limbs, biochemically kicking them to move faster towards the core to ease the pH differential.
DDeden

[naiad]

Originally Posted by wet

OTOH, having the MDR/gasp occur right away with empty lungs forces O2 conservation, burns O2 slowly and builds CO2 slowly. This registers in your mind as discomfort because you haven't gradually habituated to it. The same physiological gasp that tries to suck in air to the lungs is actually pumping O2 from the extremities. By sealing the mouth and nose (with tongue in back), the coldwater gasp has nowhere to come from but the blood cells and muscle cells rich in O2 in the limbs, biochemically kicking them to move faster towards the core to ease the pH differential.

Interesting. That makes sense. I remember that when I was a kid, if I was outside and there was a cold wind blowing, I would get an uncontrollable apnea reflex, which was unpleasant but bearable. It must have lasted for a few seconds. It still happens occasionally, but much less. It was very similar to the feeling I now get when I put my face in cold water.

[trux]

Originally Posted by wet

2% of humans develop a laryngocoel (sp), most often related to wind instruments or balloon inflating or similar activities. (from Tecumseh Fitch, Speech and Language, IIRC) This is a little air sac in the larynx that inflates when pressured, it was greatly enlarged in our hominoid ancestors, but reduced to a vestige like the appendix in humans.

Quite interesting, David! Can you tell us more about the laryngocoel? Do you know what did the big laryngocoel serve for at our ancestors? How does it collide with freediving? Wouldn't it be rather helpful - for example as an additional store of air for the ear equalization? Personally, when younger, I played quite a bit on diverse wind instruments (recorders, traverse flute, clarinet, saxophone), but never felt that it collided with my diving. Quite the opposite - it helped me greatly to use my breathing efficiently. However, I believe that the laryngocoel you mention is more of a problem at brass instruments like trumpet where a rather high air pressure is needed. Still, I bet that a trumpet player like Dizzy Gillespie could go easily 300m deep with a single mouthfill:

dizzy.jpg

[wet]

Originally Posted by naiad

Interesting. That makes sense. I remember that when I was a kid, if I was outside and there was a cold wind blowing, I would get an uncontrollable apnea reflex, which was unpleasant but bearable. It must have lasted for a few seconds. It still happens occasionally, but much less. It was very similar to the feeling I now get when I put my face in cold water.

Right, the fast combined thermal and pressure change on the face, and also in the throat triggers the reflex.

When you hold your breath with full-lungs, I think you are getting about 1/2 of this effect due to air pressure on baroreceptors in the mouth/nose/throat/lungs.

When you did empty-lung breath hold, that 1/2 effect was missing, so you only felt the struggle phase, without the benefit of the 1/2 effect.

What I've been saying, is that by first being warm and dry, and knowing that soon you will again be very warm in the shower afterwards, then, casually diving in slightly cool water, that if you relax and accept the "switch-over" discomfort, knowing that it's just a temporary adjustment your body makes as it "becomes one with water" (no longer bothering to carry this huge "bubble" of excess air in the lungs down under the surface), and let your body feel the water as you glide through, and limbs smoothly power you along, and then rising up again to the surface, you are fully aware and sensitive to your immediate environment, and gracefully exchange the gift of air. Upon contacting the surface, you will want to exhale, but don't push it out, just exchange it gratefully.

As you climb out of the pool, your body which was adapted to the cool water during the dive, is now warming up due to the aerobic metabolism required to deal with moving in regular terrestrial gravity, so do a brief stretch of arms and legs and trunk, and a moderate aerobic breathe-up (no forced inhale, just a yawn), this should give a blush or flushed face and a tiny sweat reaction (the opposing reflex of the gasp), and then go take a warm shower and dry off.

Actually, I think that both of these reflexes release biochemicals into the bloodstream including micro-doses of endorphins and natural steroids, that help relax during stress.

Anyway, like I said, if something doesn't sound or feel right, don't do it, take time to figure out what's happening. Don't rush a dive, relax a dive. Those super-fast dolphin's ancestors 50 million years ago were once very slow divers too, as were our ancestors at the seashores 1 million years ago. It takes time. Dive with dolphins, backfloat with sea otters, blow bubbles with koi, breathe.
DDeden

[wet]

Originally Posted by trux

Quite interesting, David! Can you tell us more about the laryngocoel? Do you know what did the big laryngocoel serve for at our ancestors? How does it collide with freediving? Wouldn't it be rather helpful - for example as an additional store of air for the ear equalization? Personally, when younger, I played quite a bit on diverse wind instruments (recorders, traverse flute, clarinet, saxophone), but never felt that it collided with my diving. Quite the opposite - it helped me greatly to use my breathing efficiently. However, I believe that the laryngocoel you mention is more of a problem at brass instruments like trumpet where a rather high air pressure is needed. Still, I bet that a trumpet player like Dizzy Gillespie could go easily 300m deep with a single mouthfill:

Attachment 15632

Thanks Ivo! For you and other DB members, I added some further info.

Correct spelling is laryngocoele. It is a laryngeal ventricular saccule, or, overextended air sac in humans, sometimes found in trumpet players and traditional glass blowers, but seen in other people as well, sometimes congenital. The article below shows a trumpet player doing a valsava manuever with resulting "balloon" air sacs visible in the neck xray. He changed his method, and the problem was resolved. As you can see, it's in the neck, not the cheeks as in Dizzy. Our mammalian primate relatives, especially the anthropoids, and most obvious in the hominoids like the siamangs (see photo below of dueting siamangs above open water, with inflated air sacs) and orangutans, have much larger versions than humans ever have. A large male orangutan can hold 6 liters of air in the laryngeal air sacs (not including air in the lungs or trachea). [A large walrus can hold up to 50 liters of air in a different pouch called the pharyngeal air sacs, which it can inflate and then sleep in water with head above surface].

The laryngeal air sacs in Hominoids were most likely selected for head-up vertical flotation combined with bipedal wading (and resulted in the complete loss of the tail), but long preceded the uniquely human regular diving/backfloating phase, and by then were vestiges as they are today, except as I noted in 2% of the population. I would not recommend attempting to use them for air storage at depth, due to internal fluids entering the sacs when upside down and not being able to exit, potentially causing infections. I'd think that prolonged yelling and loud vocals might predispose one to laryngocoeles as well, but haven't read anything on it.

Let me repeat, AFAIK, laryngocoeles are not good for free diving, but at least hypothetically could be used as head-up float support (as they once likely were) like a life jacket, except their size has reduced very much compared to body size.

DDeden

Article: 2 page [PDF]
What a blow!
http://bjr.birjournals.org/cgi/reprint/71/847/799.pdf

[trux]

Thanks, David, for the details. Yes, I understood that laryngocoele is in larynx and not the cheeks. I just posted the photo of Dizzy to show a case of extreme mutation at a trumpet player due to the air pressure. If Dizzy, with such cheeks did not have also an extreme laryngocoele, than I do not know who could have it. I also posted it to show what I believe - that such malformation (regardless if just laryngocoele or also such cheeks) might be actually helpful for freediving, better told for the equalizing. It is still not clear to me why you wrote that it might conflict with breath holding, and why you think it could suppress the dive reflex.

[wet]

Originally Posted by trux

Thanks, David, for the details. Yes, I understood that laryngocoele is in larynx and not the cheeks. I just posted the photo of Dizzy to show a case of extreme mutation at a trumpet player due to the air pressure. If Dizzy, with such cheeks did not have also an extreme laryngocoele, than I do not know who could have it. I also posted it to show what I believe - that such malformation (regardless if just laryngocoele or also such cheeks) might be actually helpful for freediving, better told for the equalizing. It is still not clear to me why you wrote that it might conflict with breath holding, and why you think it could suppress the dive reflex.

Ivo,

I don't know where all the baroreceptors are in the tissues of the oral and nasal cavities, nor exactly what triggers which reactions. I associate inflated air sacs with floating, not sinking/diving/breath holding. I don't know if it suppresses the reflex, but considered it a possibility that it might affect it or interfere with it.

Although it might sound like laryngcoeles/air sacs would be a convenient air storage place, there are at least 2 problems : fluids (mucus) entering the air sacs while inverted (upside down) in a dive would likely be difficult to remove, thus potentially infected with bacteria, and, air sacs can be internal or external or both, I think the internal sacs constrict the larynx when fully inflated, not good since they are not well controlled by the musculature. At depth under high pressure and cold temperature, some condensation might occur as well.

So far I'm convinced that their flotation function, associated with stress (emotional, temperature, pressure), was limited to head-up posture.

But then again, Johnny Weissmuller, the olympic swimmer and movie star Tarzan, often beat his chest after swimming onscreen. Gorillas do this while calling, this releases the air from the air sacs. Perhaps Tarzan knew something I don't? Do you think AIDA would approve of chest beating & loud calling after a dive? AaaAaaAaaAaa [sound of chest thumping and elephants rumbling by]

DDeden

[wet]

I'll just add a bit more. The thermoreceptors and baroreceptors of the face, mouth, throat are involved in the early part of the MDR empty lung dive.

The chemoreceptors in various places where blood flows through are involved in the next part of the dive. They are affected by the pH changes, as CO2 accumulates, diaphragmatic contractions and/or air hunger due to higher CO2 concentration gets stronger. It is the MDR gasp all over again, but this time triggered internally at the core, rather than externally at the skin surface of the face.

Since most people aren't used to making their blood send O2 more efficiently, we tend to get a "shock" when getting contractions. But the contractions simply move O2 towards the lungs. By propelling while matching these "convulsions" to a frog kick or arm stroke might make them less noticeable and might even adds some extra kick.

DDeden

[naiad]

After many seemingly random good and bad static sessions, I have worked out an important factor for my static performance, and possibly for dynamic too. I can do much better when the air and water temperature are both as close as possible. If there is any contrast between warm air/cold water or cold air/warm water, this reduces my performance.

I am happy to have worked this out, as it makes me understand a bit better what makes a good or bad session.