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Mammalian Diving Reflex just a Romanticism?

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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tylerz

tylerz

Well-Known Member
Jun 19, 2002
733
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Oh, the whole point of mentioning the actual pressure comparison of normal blood pressure versus the water pressure at 2 Atm was to clarify that blood pressure is a relative measurement of pressure. It is generally taken relative to atmospheric pressure, but the absolute pressure of your blood is 760 mmHg + your relative blood pressure (ie. 760 + 140 = 900mmHg). At 2 Atm your body would operate as it would in 1 Atm, so you could do a relative blood pressure test to 2 Atm finding your blood pressure unchanged at 140 mmHg, but the absolute values would add another 760 mmHg.
 
Bill

Bill

Baron of Breathold
Oct 17, 2001
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Not to disagree but I offer two observations. The comparison with an hydraulic system may not be valid because the arteries have flexible walls and gravity affects the blood in the legs. We are 'standing on our head' when we start a dive and that will cause a blood shift.
Aloha
Bill
 
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adax

New Member
May 23, 2006
47
0
0
Since I've got interested by freediving (a few months ago), I think a lot about things mentioned in this thread.

Still not having many apnea experience I think the following:
1) diving reflex at depth is a combination of body reaction to apnea (let us say 90%) and pressure (10 %). The first is physiological response to apnea (body tries to maintain balance), the second is purely mechanical reaction to pressure.

2) where else in nature can you experience apnea than in water? I do not imagine apes dry breath-holding just for fun...

So I think the connection between apnea and water immersion is quite clear, but it is not kept in genes but much simplier water is the only natural substance that can efficiently and 100 % stop animals' or human breathing. So by doing dry static you are simply modeling the water environment.
 
tylerz

tylerz

Well-Known Member
Jun 19, 2002
733
114
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The flexibility of the arteries shouldn't change the circumstances from a hydraulic system, since all that happens is the arteries flex until their increasing tension equalizes with the pressure exerted upon them by the blood. That is what is demonstrated by the ballon example.

The gravity effect on blood could be significant especially since we hang out in that position for a long while. Although that would suggest somebody who does a feet down free immersion (ie. Herbert) should not be getting that effect and brings up the question of whether he has a blood shift and if so, then gravity could not be the only cause.

As well, I previously discovered that on 50m inhale dives I did not seem to have any significant blood shift, yet on shorter 30-40m half inhale dives, I was eventually getting what seemed like significant blood shift. This I was speculating based upon the sensation of burn in the legs shortly after turning and kicking from the bottom. It should be noted that the sensation of oxygen depletion at the end of the dives was relatively equal and therefore for the burn, during the half inhale dive, to be caused by a difference in O2 uptake by the muscles, from the blood alone, without a difference in blood shift, I would have anticipated a significant increase in O2 craving at the completion of the half inhale dive.

Maybe, to see if there is an immediately significant gravitational effect, I will go do a comparison of:
1. 1:30 static, followed by a set of squats for 1:30.
vs.
2. 1:30 static standing on my head, followed by a set of squats for 1:30.

Be back soon... ;)
 
S

SEDATE

Well-Known Member
Feb 6, 2005
744
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thnx info tylerz and folks..really good thread....
 
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naiad

Apnea Carp
Supporter
Oct 11, 2003
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Isn't it different to be upside down in a weightless environment than in a weighted one? I thought it didn't make much difference in a weightless environment, because there wouldn't be a gravity effect on blood.
 
BennyB

BennyB

will freedive for beer
Sep 25, 2004
3,099
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Tyler's been gone for a while.... hope he's not blacked out on his head somewhere...:ko
 
Apnea_Addict

Apnea_Addict

Well-Known Member
Nov 27, 2004
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As far as I understand it, you are not really weightless under water - just reduced weight.

Holger
 
W

wet

Freediver82 - water borne
May 27, 2005
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I haven't done any SCUBA. Do deep scuba divers or air-hose divers (hooked to air pumps in boats) have any diver's reflex? Since they don't use apnea, any physiological changes would be due to: change of gravity-buoyancy, temperature differential and pressure differential. Any know about this?

I don't think any apes do apnea, except maybe for a few seconds, but there are some African gorillas that daily go to the local pond for aquatic herbs, so maybe they hold their breath for a moment while pulling underwater plants. There is a diving macaque monkey that forages for underwater food, it holds it's breath, I don't know how long, maybe 30 seconds.

I agree about the modelling concept. DDeden

adax said:
Since I've got interested by freediving (a few months ago), I think a lot about things mentioned in this thread.

Still not having many apnea experience I think the following:
1) diving reflex at depth is a combination of body reaction to apnea (let us say 90%) and pressure (10 %). The first is physiological response to apnea (body tries to maintain balance), the second is purely mechanical reaction to pressure.

2) where else in nature can you experience apnea than in water? I do not imagine apes dry breath-holding just for fun...

So I think the connection between apnea and water immersion is quite clear, but it is not kept in genes but much simplier water is the only natural substance that can efficiently and 100 % stop animals' or human breathing. So by doing dry static you are simply modeling the water environment.
 
W

wet

Freediver82 - water borne
May 27, 2005
1,179
96
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I think this theory may be correct, although I don't know. I'm not good at biomechanics or parts of systems, just whole systems, like organisms, (amoeba, fish, diver).

Nitric oxide behaves like a hormone in the respiratory-circulatory system, as a vasodilator. Maybe it is activated primarily in the core blood vessels?

Anyway, what you wrote seems sensible. My only question is, doesn't bradycardia & vasoconstriction occur virtually instantaneously sometimes? Hormones, as opposed to nerves, take a bit of time to process. Maybe the hormone release follows a nerve action, and then the lymph system (spleen) follows the hormone release, in a sequence? DDeden

tylerz said:
A thought/theory just occurred to me. It is possible that a certain state of mind, or partial pressure of gasses, or a combination thereof triggers the synthesis and release of hormones. As they are released into the blood these hormones induce a vasodilation of core arteries and therein giving the effect of the blood shift which we, maybe mistakenly, take to be caused by vasoconstriction.

The rationale:
- hormones would reach the core arteries first and be used up before reaching further along the arteries towards the extremeties, therefore the vasodilating effect would be isolated.
- control of the release of hormones is often affected by states of mind.
- hormones are also released in response to variances in chemical substances or properties.

Anything that suggests it can not be so?
 
tylerz

tylerz

Well-Known Member
Jun 19, 2002
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2) where else in nature can you experience apnea than in water? I do not imagine apes dry breath-holding just for fun...
Forest fire, wrestling with a bear and you get your mouth full of fur, weight lifting, falling on or being hit in your chest having the wind knocked out of yourself, choking on food or tongue, sleeping, contractions of mother while being born, playing dead, attempting to be utterly silent, attempting to be utterly motionless.
 
tylerz

tylerz

Well-Known Member
Jun 19, 2002
733
114
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naiad said:
Isn't it different to be upside down in a weightless environment than in a weighted one? I thought it didn't make much difference in a weightless environment, because there wouldn't be a gravity effect on blood.
Water is not a weightless environment, even at your neutral buoyancy point. The shell of your body is not experiencing movement towards the core of the earth, but it is not because you are weightless and there is no force pulling you towards the core; it is because multiple forces have reached equal magnitude in opposite directions. Both forces are acting on your body and its contents.

I believe you would call a weightless environment, any environment where the nature of the environment does not apply a center of force which acts upon an object's mass.
 
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tylerz

tylerz

Well-Known Member
Jun 19, 2002
733
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BennyB said:
Tyler's been gone for a while.... hope he's not blacked out on his head somewhere...:ko
Oh geez... is it morning... why am I laying crumpled on the floor against the wall... oh right, I was... :(

It was really late, and eventually without anything significant to report yet, I went to bed! :D

Attempted it again this morning, and didn't seem to experience any significant difference between the two. Although in both I could definately feel changes in my extremities. That sensation of becoming heavy and slightly buzzing/tingling. No hyperventilation involved.

However, I did realize that even if during the descent gravity induced a blood shift, if no other factors were involved, this action would be reversed as one began surfacing.
 
S

SEDATE

Well-Known Member
Feb 6, 2005
744
59
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tylerz me also try to understand all your post .,
it is over my capacity:head ,
i believe that how we manage to stay 9 monts living in water without O2 (in womb) and should be 9 min breathold would be, never stop! me last find out something it is not related how much we breath into our lung, all adaptation against water and how much we know each part of our body ,
you have extra advantage and other folks , too
have you ever think maybe apnea ability coded our DNA in this period(i mean when we were in our mother abdomen) what you think on this subject mate, all the best
 
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naiad

Apnea Carp
Supporter
Oct 11, 2003
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SEDATE said:
i believe that how we manage to stay 9 monts living in water without O2 (in womb)
Living in water, yes, but not without O2!!!
 
G

ggarrett

New Member
Feb 13, 2005
113
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naiad said:
Living in water, yes, but not without O2!!!
Living in fluid, not exactly water.
Not exactly breath-holding either.

Peace,
Glen
 
S

SEDATE

Well-Known Member
Feb 6, 2005
744
59
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ggarrett said:
Living in fluid, not exactly water.
Not exactly breath-holding either.

Peace,
Glen
Glen
if you know where we get 02, tell us
my brain mixed:) :head
 
tylerz

tylerz

Well-Known Member
Jun 19, 2002
733
114
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SEDATE said:
i believe that how we manage to stay 9 monts living in water without O2 (in womb) and should be 9 min breathold would be, never stop! me last find out something it is not related how much we breath into our lung, all adaptation against water and how much we know each part of our body
Sorry, Sedate, I do not really understand what you intended to say here due to the grammar. :(

you have extra advantage and other folks, too
have you ever think maybe apnea ability coded our DNA in this period(i mean when we were in our mother abdomen) what you think on this subject mate, all the best
I am not inclined to believe too many people in the freediving community have any significant advantage over the average person, at least at this point in time. I think we are still in a process of maturing to what our potential is, and even those who may have genetic advantages would not even be hitting the max potential of the average person.

In the womb we are fed oxygen through the blood of our mother, passed to us through the placenta/umbilical cord.
 
S

SEDATE

Well-Known Member
Feb 6, 2005
744
59
118
tylerz said:
Sorry, Sedate, I do not really understand what you intended to say here due to the grammar. :(

Tyler , you definataly right.,
my grammar is really very bad., sometimes i do not write what exactly i mean., it is absulately true mate! i learned talking before grammer., i can talk but not write very well (grammer) :)
 
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