Static breathhold while scuba diving

[wdaf]

Hi Guys,

didnt find the topic covered yet.

You learn "never ever hold your breath while doing scuba."
lung over expansion injury, bla,bla, ... .

But in some cases Scuba divers want to hold their breath.
To get nearer to fish for example.

What are the differences to static breathhold on the surface?
Safety aspects?

 

[trux]

Well besides the risk of direct barotrauma, with holding your breath you increase your CO2 level, which strongly amplifies both nitrogen narcosis as well as the risk of DCS.

 

[wdaf]

would need more info on that.
any reference/link/forum entry?

thx, Wolfgang

 

[wdaf]

would need more info on that.
any reference/link/forum entry?

thx, Wolfgang

 

[trux]

Try these ones:
dcs @ APNEA.cz
narcosis @ APNEA.cz

And then look up the freediving science subforum here on DB for narcosis, dcs, and co2 related threads. And google "CO2 retention scuba" -you'll get plenty of documents.

 

[Don Paul]

But in some cases Scuba divers want to hold their breath.
To get nearer to fish for example.Quote:wdaf

Freedive

Don Paul

 

[island_sands]

would need more info on that.
any reference/link/forum entry?

thx, Wolfgang

You might find it in the PADI Encyclopaedia or any Scuba diving science manual.

There is also Dr. Lindholm or DAN who might answer your question scientifically.

 

[Old Man Dave]

When I was involved in commercial diving for scallops and flatfish I used to extend my air consumption by shallow breathing and not breathing (holding my breath). This was usually at a fixed depth i.e. on the bottom, not during ascent. No point in doing it in the deeps as you're limited by deco times. However in 30 to 40 foot I would sometimes make a tank last twice as long as other divers. This meant covering twice the bottom on one tank. I never really did it consiously more as a natural instinctive thing as I was also a keen freediving spearo. Main result was always the mother and father of all headaches, presumably from low oxy levels. Sure it wasn't good for me but that was then and we are all stupid when we are young. Mind you some of us never grow up .

Dave.

 

[trux]

Main result was always the mother and father of all headaches, presumably from low oxy levels.

That's actually more likely from the CO2 excess. O2 should be sufficient to oxygenate your brain even with skip breathing, because the PaO2 is higher, but the high CO2 will cause headachess easily. But as I told, the main dangers are the higher DCS risk, earlier narcosis, barotrauma, and even CO2 intoxication or blackout (in extreme cases).

 

[apneaboy]

When I was involved in commercial diving for scallops and flatfish I used to extend my air consumption by shallow breathing and not breathing (holding my breath). This was usually at a fixed depth i.e. on the bottom, not during ascent. No point in doing it in the deeps as you're limited by deco times. However in 30 to 40 foot I would sometimes make a tank last twice as long as other divers. This meant covering twice the bottom on one tank. I never really did it consiously more as a natural instinctive thing as I was also a keen freediving spearo. Main result was always the mother and father of all headaches, presumably from low oxy levels. Sure it wasn't good for me but that was then and we are all stupid when we are young. Mind you some of us never grow up .

Dave.

Yeah Trux is right, it increases the likelihood of an O2 hit deep or on Nitrox too.

 

[apneaboy]

Scuba, never hold your breath underwater

Freediving, never breath underwater

Save you trawling all those threads

Whats a FAQ?

 

[ReefTroll]

Scuba, never hold your breath underwater

Freediving, never breath underwater

Save you trawling all those threads

Whats a FAQ?

It's like having a FAP, but over the same gender.

I've never found much of an issue getting near things due the the scuba bubbles, but more to do with your general manerisms. Maybe I have only seen friendly fish.

 

[wdaf]

That's actually more likely from the CO2 excess. O2 should be sufficient to oxygenate your brain even with skip breathing, because the PaO2 is higher, but the high CO2 will cause headachess easily. But as I told, the main dangers are the higher DCS risk, earlier narcosis, barotrauma, and even CO2 intoxication or blackout (in extreme cases).

i understand the O2 and CO2 thing.

but for
... DCS risk, earlier narcosis, ... and even CO2 intoxication or blackout (in extreme cases) ...
i didnt find scientific explanations/sources or cases.
?

also ... likelihood of an O2 hit deep?
you refer to oxygen toxicity, right? Why should the likelihood be bigger?


BTW: interesting Article: truth and myths about risk factors for DCS:
http://home.vicnet.net.au/~dandoc/pdfdoc/dci3.pdf

 

[apneaboy]

Without digging my books out I believe CO2 affects the rate of absorbtion and release of all gases due to it being a capillary dilator.

More O2 = hit
More Nitrogen and quicker release (slow release is essential remeber) = DCS
Posted via Mobile Device

 

[wdaf]

Main result was always the mother and father of all headaches, presumably from low oxy levels.
Dave.

Reason for my question:
scuba divers (spearos) asked me if they can use freediving breath hold techniques while using scuba.
So they dont do skip breathing, they just hold their breath for the time they approach a fish.
i guess that will be 15 seconds to maximum 2 minutes (?) in depths of 30-50 meter, using air. only 1 to maybe 5 times during one scubadive.
i dont wanna tell them "dont do it because ..." they do it anyway already now, but without propler knowledge.

 

[Spear0Joe]

To me wdaf, scuba divers with a gun arent classed as spearos, they are lazy guys who cheat.

 

[Tunny]

To me wdaf, scuba divers with a gun arent classed as spearos, they are lazy guys who cheat.

I'll second that and more importantly if several experienced freedivers on this forum are saying don't do it then maybe your only advice in terms of their safety should be do not do it! - Simples...

 

[wdaf]

I'll second that and more importantly if several experienced freedivers on this forum are saying don't do it then maybe your only advice in terms of their safety should be do not do it! - Simples...

so many wise guys out there ...

some of these scuba divers spearfish since more then 20 years!
Some got tuna of more than 80kg using scuba.
i for myself dont wanna play wise guy, so i dont tell them what is right or wrong, lazy or not.
they are very good fishermen, very good scubadivers, and actually it is sometimes harder to get fish with scuba than freediving. (Yes, i tried both, but i prefer freediving because i get more fish)

sorry for being so ... straight ... and maybe thats the start of another long discussion ...

but: please leave your personal opinion regarding spearing scuba/freediving to yourself.

i didnt ask for that. and i wont reply to any concerns regarding scuba+spearing=bad

also: i personally dont like the philosophy: lets not talk about or just forbid it completely because its bad.

(didnt really work out with drugs, alcohol and teenage pregnancy)

my opinion: educate about what are the risks, why it could be dangerous and how to prevent problems.

 

[apneaboy]

Holding your breath on Scuba is dangerous, I refer you to the reasons given some moments ago.

I am a Scubie too, nearly 20 years experience. In Scuba we call people who have a dangerous attitude strokes, it may be its personality, it may be that historically they have got away with stuff that they have done wrong time after time. We are taught not to dive with strokes as inevitably someone will get hurt.

Morally and ethically any safety info you have should be passed on, if they won't listen what can one do. Maybe they are safe but misinformed or simply don't know.

If you want straight, just take the advice. Not about philosophy about physiology
Posted via Mobile Device

 

[trux]

Wdaf, I already gave you some links, and if you google CO2 retention on scuba, you will get many scientific studies on this topic. Holding the breath is the same thing as skip breathing - both of them increase CO2, which is simply a bad idea when on scuba. And the deeper you are, the worse effects it has.