Get high and get on down: a response

[tylerz]

It was found that freedivers have a significant increase in ability to ventilate CO2 when compared to a person without any ventilating practice. Combine that with each of us having different abilities to buffer CO2, differing blood acidity, and different CO2 tolerance levels, then one's personal ability to ventilate enough CO2 can and does vary greatly.

By the way, what seems to be your difficulty that you associate with CO2 tolerance?

Cheers,

Tyler

[cdavis]

Tyler,
Is a free diver's improved ability to ventilate co2 simply a matter of increased ability to get air in and out quickly or are there more complicated physiological adaptations going on?

Thanks

Connor

[tylerz]

Originally Posted by ADR

perhaps better for the majority of freedivers if it does actually produce adaptations

Actually this skepticism is quite an interesting point. Generally we think of the body adapting due to stress, therefore a lot of techniques are developed simply to simulate stresses that logically, and through experience, suggest a path to the adaptation. Thus devised the exercise I have presented.

Yet, there is a possibility that the body has much more complex cues for these adaptations and targetted stress without the presence of other variables, could well lack the ability to produce the adaptations. This seems unlikely to me, but definately possible.

In the exercise I presented the reduced breathing and dramatic fluxuations in CO2 levels, creates an unnatural environment when compared with IHT equipment and actual high-altitude training. Therefore the body may have some use of these variables that comes into play when producing the conditions for adaptation, and being an unnatural condition in the exercise, the variables may not be correct.

It has also been suggested in other threads, by Laminar as the reasoning for a non-hyperventilating breathe-up. The foundation of the reasoning was the idea that low CO2 induced by hyperventilating would create an unnatural environment as the low O2 conditions would be occurring much sooner than the normally associated high CO2. Once again suspecting that the unnatural environment would affect the strength of adaptation.

So, as much as I don't suspect that will be the case, it is a possibility and one that could possibly be easily checked through a comparison of this technique I presented and the use of IHT equipment. The result could be very important to our understanding of stress training.

Cheers,

Tyler

[tylerz]

Originally Posted by cdavis

or are there more complicated physiological adaptations going on?

Connor, I do not think this has been attempted to be determined. However, definately freedivers will end up being more aware and practiced at breathing than the average person, so definately that could include larger transfer of air and more efficient use of muscles (a lower CO2 production during ventilation).

As far as physiological adaptations, one such manner that could occur is if there was a higher capacity of the blood to carry CO2. Haemoglobin can carry 4 molecules of CO2, water molecules can combine with one, and CO2 disolved in plasma is the rest. So, there are various possible ways that physiologically one could adapt leading to more CO2 ventilation, such as an increase in blood volume combined with an increased blood stroke volume. Or a shift in ratio of the 3 carriers of CO2. I don't know what adaptations are realistic for us though and if they occur. I believe Bicarbonate(water + CO2) is the most efficient in terms of the carrier volume to CO2 molecules carried.

I don't have a realistic clue in this matter though of what is practical and whether we have a physiological adaptation in this area.

Cheers,

Tyler

[ADR]

Hi Tyler,

I had my blood drawn today and will have the results on Thursday and will post them as soon as I get them....it will be interesting to see if all the huffing and puffing amounted to anything

On the CO2 front I have the following issue:
With some sympathy to Pete Scott's great comments on CO2 tolerance in the no warm up static thread I regard CO2 tolerance as having 2 key components (maybe over simplifying here) - physiological tolerance and psychological tolerance.

I determine my physiological tolerance by when contractions start and how quickly they escalate in frequency and strength and I determine my psychological tolerance by how far I can go with contractions (time & number). Without warm up or breathe up, over the past 2 years my psychological tolerance has increased by these measures ie(1 min of contractions to 2.5 mins of contractions, 50 contractions - 160 contractions)
My physiological tolerance on the other hand has reduced by these measures for no warm up no breathe up ie(contractions start earlier 1min now - before 1:45, and they are stronger and faster at the 40-50 contractions mark than they use to be)

Interestingly I have no doubt that I now have a more pronounced dive reflex than those early days and I wonder if this has somethiing to do with it. My psuedo science goes something like this. If the body was buffering CO2 across not only blood and then you have a significant dive reflex causing strong vasoconstriction and blood congregating at the core, would not the CO2 levels rise significantly at this point and would you not notice this given the CO2 receptors are at the core at the base of the brain stem? If this is the case it would explain why my physiological tolerance seems to have decreased while my physiological tolerance has improved. Psuedo science I'm sure and I'd be very interested in your thoughts on it.

Andy

[tylerz]

Originally Posted by ADR

If the body was buffering CO2 across not only blood and then you have a significant dive reflex causing strong vasoconstriction and blood congregating at the core, would not the CO2 levels rise significantly at this point and would you not notice this given the CO2 receptors are at the core at the base of the brain stem?

I would think that the congregation of blood at the core would actually produce lower CO2 levels than without the vasoconstriction since the blood is retrieving less CO2 from metabolism at the extremeties. There is less overall metabolism in the vicinity of blood, therefore less CO2 in the blood. The congregation at the core definately suggests more volume of blood at any given location yet if I recall correctly the receptors are triggered by pH levels, not specifically detecting CO2. That is CO2 in ratio to O2 shifts the level of pH (along with other molecules). Since the volume of blood has risen and not specifically the ratio, there should not be a change in pH for that reason alone.

Cheers,

Tyler

[ADR]

Hi Tyler,

At the point just prior to the vasocontriction the blood has a given CO2 concentration. If the vasocontriction was milliseconds for arguements sake that blood shunted to the core should have the same CO2 concentration (or PH) as before because the volume is the same just the location of the blood has changed......is that right?

Now the CO2 produced can't be buffered by cells(body water) on the other side of the vasoconstriction so wouldn't the CO2 concentration curve at the core steepen if CO2 production remained constant?

Andy

[tylerz]

Originally Posted by ADR

...the same CO2 concentration (or PH) as before because the volume is the same just the location of the blood has changed......is that right?

I agree.

Originally Posted by ADR

Now the CO2 produced can't be buffered by cells(body water) on the other side of the vasoconstriction so wouldn't the CO2 concentration curve at the core steepen if CO2 production remained constant?

I follow you. That requires that the CO2 being buffered at the extremities is greater than or equal to the total CO2 produced at the extremities. Is this the standard case? I was assuming it would be less.

Cheers,

Tyler

[donmoore]

I don’t have any results to report on doing exhale statics to simulate IHT training. I faithfully did them for three weeks with purposively doing no a full-breath statics to give it time. Then on the fourth week, this week, I caught a cold , which looks like it has destroyed the experiment.
don