The effects on hyperventilation on O2 saturation

[harrychamas]

Hay guys

I'm trying to find any scientific evidence on the effects of hyperventilation on your O2 saturation in arterial blood flow. But i'm having some trouble and was hoping someone out there could point me in the right direction.

we have all been told that there is no effect on O2 during our freediving education, but if you speak to a Yogi they will tell you that one of the benefits of Pranayama is to oxygenize your body. So somebody has to be wrong.

Also if you think that the gasses inside our body are made up of O2, CO2 and N and since Nitrogen is fixed, any CO2 will be taking up PP that would be O2 otherwise. therefore to reduce CO2 would make more "room" for O2.

I'm looking for studies, numbers, cold hard facts. I know how excited people get about hyperventilation here but please spare me the sermons on the negative effects of hyperventilation with freediving because i know them all and that is not what i am asking for.

Thanks in advance

Harry

 

[baiyoke]

I don't have references for your initial question, but about your last one, you have to take into consideration the Bohr effect. Look it up. That's why you can faint even fully O2 saturated...

 

[baiyoke]

One more thing, the qoute below is so vagely stated and open ended that it would be good to clarify. Fx what does it mean to "oxygenize yout body"? Is it tissue or blood?

Hay guys


we have all been told that there is no effect on O2 during our freediving education, but if you speak to a Yogi they will tell you that one of the benefits of Pranayama is to oxygenize your body. So somebody has to be wrong.

The way I see it both can be right if freedivers talk about blood saturation, and yogis about tissue saturation.

Interesting thread though, I'll follow. I've done some thinking about this topic myself.

 

[harrychamas]

The way I see it both can be right if freedivers talk about blood saturation, and yogis about tissue saturation.

Interesting thread though, I'll follow. I've done some thinking about this topic myself.

I would assume Yogis would be talking about tissue saturation as blood saturation alone wouldn't have any benefits as far as i can tell.
I understand the Bohr effect will play a part in hyperventilating in reality, it would be interesting to compare any O2 gain from hyperventilating (if any) compared to the resulting ph change of the blood over time.
Also to do with the Bohr effect i have to wonder that if the ph change is very slight, it will be corrected during the breath hold as CO2 starts to build up and then the extra O2 in the lungs will start to be absorbed by the hemoglobin and passed onto the tissues. but that is another question for another thread

Thanks for the input.

 

[MarcinB]

With hyperventilation you can increase O2 saturation of the arterial blood by 1-2% depending on its basal level (checked with professional pulse oximeter). However, since arterial blood constitutes only ~25% of total blood volume this change is completely insignificant. Saturation of the venous blood is another story. It is normally around 75% so there is some space for improvement. Hyperventilation markedly increases cardiac output which results in increased oxygen delivery to tissues. If oxygen demand remains constant this should theoretically lead to decreased oxygen extraction and increased saturation of the venous blood. However, things are a bit more complicated. In some organs hypocapnia induces strong vasoconstriction and as a result saturation of venous blood drained from these organs decreases upon hyperventilation. This is scientifically confirmed for the brain and heart. So saturation of the venous blood can either decrease or increase depending on the organ or tissue. To find out what is the net result you have to measure O2 saturation of the mixed venous blood, that is the blood in the right ventricle or better in the pulmonary artery. I found only one human study where it was measured after hyperventilation. There was an increase but it was fairly modest (only 3-6%). The effect likely depends on the extent of hyperventilation so maybe it can go up a bit more than that. Assuming increase from 75 to 82% total blood oxygen content would be increased by 7.5%.

Another important thing to consider is O2 partial pressure in lungs. It is normally around 100 mmHg. Hyperventilation could theoretically increase it up to 150 mmHg but it would mean that no CO2 is present in the lungs. I've seen a study where pCO2 dropped to 10-12 mmHg after extreme hyperventilation, so lets assume 140 mmHg is the highest value that is possible to achieve. That would mean a huge 40% increase in lung O2 stores. However, it should be noted that even a single full breath (which is done by most freedivers before a dive) increases pO2 to around 130 mmHg. If you take this situation as a basal level the increase in lung O2 stores with hyperventilation becomes much smaller (~8%).

Of course there is also myoglobin, however, it is almost fully saturated at normal tissue pO2 so there is not much space for increase. The content of O2 physically dissolved in tissues can also increase if hyperventilation is sufficiently long. However, considering total body oxygen stores it is completely insignificant.

 

[cdavis]

Sorry, can't site you any studies. Wish Efattah could answer this one as he posted some of his experiments and research. My memory of his posts were along the line of MarcinB. Prolonged hyperventialtion can increase the amount of 02 carried by the blood(heamaglobin and plasma), both arterial and venous, but not enough to overcome the negative effects of hyperventilation.

 

[baiyoke]

Perhaps this is what you are refering to cdavis, something for you also harrychamas

https://forums.deeperblue.com/threads/co2-compartment-hypothesis.41696/

 

[cdavis]

You have a very good filing system. That is not the one I was thinking of, but darn interesting, thanks.

 

[harrychamas]

Thanks for the replys

Thanks Baiyoke, that EFattah thread is great reading.
So:-
MarcinB spoke about the effect on arterial blood, Venus blood and the PP of O2 in the lungs.
EFattah spoke about how hyperventilation effects the PH in your body.

But how about our tissues saturation? is the increase in O2 in our blood and lungs mirrored in our tissues? - I'm thinking no since there is so little change in our arterial blood saturation.

Which would lead me to say that the benefits from pranayama should not include O2 saturation of the tissues. right?
The various changes in the PP of O2 that occur during Pranayama will only come into play during Kumbhaka (breath retention).

If anybody has some thoughts on that i'd love to hear them.

 

[MarcinB]

Hemoglobin saturation of arterial blood cannot increase much with hyperventilation, however, pO2 can increase to a much greater extent (almost the same as in the lungs) because it is not limited by hemoglobin. So extra oxygen will dissolve in tissues and pO2 at the tissue level will increase as well. But in my opinion it takes some time. Nevertheless, from our point of view it is completely insignificant. O2 solubility in plasma and other body fluids is very low, only 0,003 ml of O2 per 100ml of fluid for each mmHg of pO2.

Average man (70kg body weight) has around 40L of water in his body. pO2 in tissues at rest in most cases is between 20 and 30mmHg. So even if it increases 2-fold in response to hyperventilation (IMO very unlikely), the total increase in the O2 volume dissolved in body fluids is only ~36ml.

 

[harrychamas]

Hemoglobin saturation of arterial blood cannot increase much with hyperventilation, however, pO2 can increase to a much greater extent (almost the same as in the lungs) because it is not limited by hemoglobin. So extra oxygen will dissolve in tissues and pO2 at the tissue level will increase as well. But in my opinion it takes some time. Nevertheless, from our point of view it is completely insignificant.

Thanks for your answers MarcinB, i'm just about keeping up with the science (with the help of youtube).

So to put that in laymen's terms after hemoglobin is saturated, blood plasma can be concentrated by almost 40% extra O2. but since blood plasma contains only 2% of the O2 in the blood, that is just a 0.8% gain. so not much to be excited about for health or freediving.

But maybe there is more to it than just blood and tissue saturation. Blood isn't circulated efficiently all the time, that is one reason why it is good to exercise, the increase heart rate pumps blood to places than may not of been getting enough, i have been told that is why you get that itchy feeling when you start running again after a long time off.

These parts of your body which haven't been getting the required circulation could be O2 starved. Perhaps the increase in Hear rate caused by HV/vitalising pranayamas re-oxygenates these neglected body parts.