Question about intense ventilation before dive

[Simos]

Hi Wal

Why does HV help with deep EQ? Is it just that you are more relaxed?

Also it's interesting what you say about narcosis - do you think it's due to lower CO2 or maybe the stronger O2 binding you think?

Looks like overall some level of HV is/can be beneficial in practical terms so I guess it's not necessarily a bad approach to experiment with different breathups to find out what works for each (I will be crucified by the master of AIDA courses for saying this lol). Does anyone know of ANY top freediver that dives without any breathup?

I guess the alternative is to learn from day 1 NOT to use any breathup and try to progress like that, which in theory should lead to better results...


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[Mullins]

Will talk to you in a couple of days Wal, but I found that HV didn't really help with narcosis. What made a huge difference was diving lighter and reducing descent speed.

There does seem to be a big genetic difference because some can clearly get away with huge HV and (seemingly) little or no performance loss. Might affect people less if they have a lower diffusion capacity? It's a bit of an uncontrolled experiment though because both S and H might still pick up a little performance if they breathed less.

 

[Simos]

Dave out of curiosity did you ever verify whether keeping a constant descent speed (instead of just slower) reduces narcosis? The theory if I remember correctly being the more regular formation of N bubbles...
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[Simos]

Just to correct the above - the theory was that varying descent speeds were leading to irregular N compression - original thread here if interested:
http://forums.deeperblue.com/freediving-training-techniques/89570-dealing-narcosis-deep-dives.html
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[trux]

There does seem to be a big genetic difference because some can clearly get away with huge HV and (seemingly) little or no performance loss.

Not only genetics, but also the diet. The respiratory quotient (RQ, the ratio between CO2 produced to O2 consumed) greatly vary not only between individuals, but also from day to day, depending on the diet, and other factors. So someone with low RQ, can produce several tens of percent less CO2 during the same time, than another person with high RQ. It means he will have also much lower blood acidosis, weaker right shift of Bohr's dissociation curve, and hence less hypoxic tolerance.

So perhaps feeding on high-RQ food would allow you using the advantages of hyperventilation, while your body would create more CO2 to allow you going deeper into hypoxia.

 

[Simos]

Are burgers and pizza good or bad?

Trux does the above have anything to do with why some people really 'feel' it on their legs when they do 'pain walks' (repeated fast walking on passive exhale) whereas others (like me) hardly feel anything?
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[trux]

I'd tell the pain is rather acid lactic than CO2, and may be more about the lactic tolerance, but there may be some relation too.

 

[Simos]

Yes the theory is that lactic causes a acidosis and hence the pain but I remember reading somewhere (I think wikipedia) that contrary to popular belief high lactate concentration was not what was causing acidosis but there was actually another mechanism - don't remember the details but the two factors that were leading to acidosis were intramuscular lactate concentration and PCO2 (hence the possible connection?)
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[Walrus]

Hi Dave,
for me slighty faster descents seems to cause less narcosis ?
This seems to be really different for so many people......

See you soon

 

[Simos]

Don't know if I am completely wrong but if the above is true, do you think that HV can actually help against the muscle pain experienced when the body works hard during apnea?
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[Walrus]

On HV helping out EQ. I tend to get early contractions, if I get them on the descent most of the time I loose the mouthfill.

 

[Simos]

Makes sense thanks Wal (by the way I know you are not a beginner - maybe intermediate I would say lol if I ever do 50% of what you do I'll be a very happy freediver)

Narcosis is an interesting subject - if you weren't powering yourself (eg sled dive) on one hand it would make more sense to go faster and hence spend less time at depth - I remember reading about herbert's 1000ft attempt and one of the key factors for DCS and narcosis was to make the sled go faster... Also interestingly wouldn't Herbert take out air at around 20-25m into a plastic bottle - obviously for EQ but also to reduce narcosis (apparently). So maybe the optimum speed of descent for each individual depends also on other factors like lung capacity and perhaps how much CO2 is produced..
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[ImmersionFD]

Well this is getting a bit Off Topic.
I do not remember the details of the article.
I just remember that a scientist, probably Italian, claimed to have solved the problem of death in freediving: NEVER STAY UNDER LONGER THAN 60 SECONDS. Because he had proven that O2 levels NEVER could go to critical levels within 60 seconds. I wrote the magazine claiming that I could get a BO within one minute if I hyperventilated and did apnea under heavy workload. The scientist was not impressed by that.

Here is an article that sounds like the one your mentioning.

http://www.divewise.org/articles/Proposed_60_second_dive_limit.pdf

 

[trux]

Here is an article that sounds like the one your mentioning.

http://www.divewise.org/articles/Proposed_60_second_dive_limit.pdf

Incredible! I just finished reading it, and can't believe my eyes. Frank Butler may be an excellent ophthalmologist, but he has absolutely no clue about freediving physiology, and should absent from writing articles about it. The article is full of factual errors, wrong interpretation of facts, incomplete information, and false claims.

I just wrote to a person quoted in the article, who I was just recently in contact with for other matters, and who I hope is in the position to have the document removed. I hope he'll be able to take care that the document is taken offline quickly.

 

[ImmersionFD]

I'm of course used to seeing all sorts of outlandish information about freediving but its was odd to see such a scientific article with such good research studies in it have such what I would consider wrong information and wrong conclusions.

Also surprised to see that from DAN.

They have be interested in freediving lately. Niel Pollock from DAN came down two years ago to a PFI competition in Cayman to do doppler testing. This year he will be down again doing other testing. I'm not sure what they will be testing this year but I"ll let folks know when I'm down there.

 

[Simos]

I had a similar reaction as Trux quite amusing to read actually and clearly written by someone that doesn't freedive (or at least sounds like it!!). Do bear in mind that it was written in 2004 though...

In fact, while reading it, I had a brilliant idea on freediving safety that will definitely keep you safer than the 60 second rule: the 50 second rule

 

[cebaztian]

This started as a failed aprils fool joke:
Ganja Diving - A way of living

I thought maybe one or two would be upset by a company freediving with marihujana as a concept, but it seems ventilation on pure air is a much more controversial subject.

Sebastian

 

[Simos]

Well it seems like noone had the necessary knowledge to argue against diving after a bong session Sebastian. AIDA courses are clearly lacking coverage of this subject.
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[x_yeti]

I thought maybe one or two would be upset by a company freediving with marihujana as a concept...

Having met quite a few freedivers and freediving instructors, I'd say the use of ganja is actually not that uncommon. AIDA should follow the example set by the Dutch government and establish a 2 Star Ganja Freediver Course.