Question on Hyperventilation

[Kin]

Usually I don’t have any breath-up technique before dive. I just relax and breathe naturally. Before dive I have 2 or 3 deep and quick breaths. My question is do I hyperventilate? Are those 3 breaths dangerous even if done with the worse possible way? I never force my self when diving but I have greater bottom times by using them than without them.

 

[trux]

Plenty of info on DB on hyperventilation already. Just type the term into the search box above, and you get plenty of interesting threads. The following one is one of the latest, and rather complete, so be sure to read through it:

http://forums.deeperblue.com/freediving-science/77624-hyperventilation.html

Basically, yes, you do hyperventilate. And it is definitely safer to dive with higher CO2 and perhaps even force little bit into the discomfort phase, than diving with low CO2 after purging or hyperventilating and staying all time in the comfort phase. High CO2 allows the brain to sustain higher hypoxemia, hence it protects your from the blackout.

 

[Kin]

Ok thanks for the fast response.

 

[fireant]

My sincere apologies for cutting-in. I understand this is a thread on the scientific intricacies of varying degrees of hyper-v...however, am I off-base in asking where the "packing" process comes in?

Is it just understood that most are including this at the end of the breath-up because I have always understood this to be a separate process.

Sorry for the unscientific interruption.

 

[rxcnc2]

Fireant,
packing (lung packing) is the process of fitting more air in your lungs. So naturally it is the last step before breath hold, at the end of the breath up sequence.
Some people might do "lung stretching" by packing air in the lungs over the maximum natural volume and then releasing it, maybe 2-3 times before the breath up.
Packing should be done carefully, and under supervision. By compressing the heart and the blood vessels around it, it can lead to "packing blackout".

 

[trux]

Besides what rxcnc2 wrote, packing has partially similar effects to hyperventilation: by increasing the air pressure in lungs, the increased PAO2 leads to quicker disassociation of CO2 from blood, which then would lead to pH change with the same effects as hyperventilation (i.e. the vasoconstriction of carotids). In contrary to hyperventilation though, at packing, the CO2 released from blood does not leave the body - it remains in lungs, and hence this effect is just temporary. As explained though, together with other effects, it can lead to a packing blackout.

 

[fireant]

Besides what rxcnc2 wrote, packing has partially similar effects to hyperventilation: by increasing the air pressure in lungs, the increased PAO2 leads to quicker disassociation of CO2 from blood, which then would lead to pH change with the same effects as hyperventilation (i.e. the vasoconstriction of carotids). In contrary to hyperventilation though, at packing, the CO2 released from blood does not leave the body - it remains in lungs, and hence this effect is just temporary. As explained though, together with other effects, it can lead to a packing blackout.

So I take it that you don't recommend it as an application for diver's below the level of, say, "very experienced"?

 

[trux]

Packing bears many more risks and disatvantages than just that, so indeed I discourage freedivers from using it. Packing only make sense for experienced competitive freedivers, and even there you can find competitors who can make top performances without it.