Hyperventilation good or bad

[efattah]

Originally Posted by cdavis

Thanks Wal, fascinating numbers, especially the HCO3 buffering. I think that explains much of why tolerance training works so well.

Not in any way disagreeing, but how does slow off gasing of co2 square with short surface intervals leading to BOs from low 02? It almost seems like it is a two stage process, you get most of your 02 back very quickly, but to fully replenish 02 levels takes longer than getting rid of co2.

Connor

If you accumulate lactic acid, that takes ages to clean out, and cleaning it out burns O2. Creatine phosphate is a major fuel used while diving, and it takes 5 minutes to fully recharge. Further, blood shift (i.e. lack of blood flow to the arms & legs) dramatically slows the cleaning out of waste products.

[cdavis]

Thanks Eric

Connor

[naiad]

I have noticed that the effect of hyperventilation increases with repeated static attempts. This happens when I do dry statics. If I do one or two warmup statics and then breathe up with fast deep breaths for 2:00 and do 5:30, I should finish clean, and with no hypoxic feeling. If I do the same again a few minutes later, I will probably finish clean, but with a 'spaced out' hypoxic feeling. If I do the same time again for a third attempt, I will feel strongly hypoxic after 5:00, and would probably samba if I did 5:30.

If I reduce the amount that I breathe up for each attempt, I should feel the same way each time, and would be able to do the 5:30 three times, even though it is close to my max. (I would not normally do that in training, as it is a lot of long statics!)

This is something that I have to be careful about in pool training - it has an even stronger effect in the pool. My best pool statics are done with short breaks in between and as little hyperventilation as possible. My static PB in the pool was done this way - I did 4:30 static, then about 1:00 rest, then 2:00 breathe up, then 4:45 static. It was one of the nicest pool statics I have done, and I didn't feel close to the limit at all.

[fcallagy]

i tried the soda pop method but at 25m the can burst open so i couldn,t drink it
thanks eric

[trux]

I would just like to add some more data and links to the info Eric Fattah and Walrus so nicely put together:

In the atmosphere, there is normally about 0.03%-0.06 of CO2. In exhaled air there is around 4.5% (I do not know how high the value is after an extreme apnea - others may fill in). 5% level of CO2 is already considered dangerous/toxic for inhaling.

CO2 binds to hemoglobin in a quite different way than O2 - it binds to another side of the molecule than oxygen. Although it is still true that it does have influence on the O2 binding, it is false that it replaces O2 in hemoglobin, as some could assume. The influence is rather of chemical character (see allosteric regulation), than pure physical replacement of O2 molecules by CO2. Lower CO2 level causes increased binding of O2 to hemoglobin. Higher CO2 level causes offloading of O2 from hemoglobin (already by Wal mentioned Bohr Effect; see also related Haldane Effect which describes offloading of CO2 in presence of O2). So in other words, by hyperventilating you lock up the oxygen in your blood, and tissue (brain, muscles, ...) starves of it ... and you black out before you even feel it coming.

As Wal wrote, CO2 is only partially transported by hemoglobin. In WiKi, I found slightly different values, but they are principally in accord with Wal's data (better told, they claim even much less CO2 transported by hemoglobin):

1. 80% to 90% of CO2 is transformed into bicarbonate ions HCO3 by the enzyme carbonic anhydrase in the red blood cells
2. 5%–10% is dissolved in the plasma
3. 5%–10% is bound to hemoglobin as carbamino compounds

So from all those numbers (especially the very low level of CO2 in lungs in comparison to O2, further greatly reduced by the partial transfer by hemoglobin), you can very easily see that by hyperventilating you will increase the physical O2 volume only minimally. What you achieve is stronger binding of O2 (higher O2 saturation in blood), which alone would be quite nice, if it did not also mean, exactly as Eric explained, that the O2 without sufficient level of CO2 cannot be easily released where needed (brain, muscles,...).

Besides it, there is another effect of higher CO2 levels - if it is high, the arteries, veins, and capillaries expand to allow a greater blood flow, helping so also the O2 transport. And vice versa - as also previously mentioned by cdavis, low CO2 level causes the opposite effect - contraction of arteries, veins and capillaries; hence cutting the tissue off of oxygen (critical especially for the brain). This is also the reason you feel "ants" in your extremities when hyperventilating, or have vision problems, or dizzy feelings at extreme hyperventilating.

Well, I know I just repeat what Eric, Wal, and Cdavis already explained, but I think it is an important issue, and the proper understanding of it is crucial. Hence more details and especially further reading when following the mentioned links (and the links on that pages, or elsewhere) are necessary.