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BS or not??

Thread Status: Hello , There was no answer in this thread for more than 60 days.
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T Ash

Freak on a Leash
Sep 29, 2004
Hey all, was at the book store looking around last night and found a diving book, name escapes me now. It had a chart showing breath hold time for different aquatic mamals. The author claimed that some one breathing pur oxygen for fifteen minutes held their breath for 15 minutes. Is this total B.S. or is there truth to it???
Bill Strömberg from Sweden has done 13'05" with 4 min of pure oxygen inhale before start.

holding your breath while being on oxygen is easy. We tried it out for fun and I did a 10min Static, litterally without much struggle (1min of breathing oxygen before). It's a bit boring towards the end, though :hmm . Wonder how Tom Sietas copes with that being standard :eek: ...
My "normal" breathhold time was about 4:00 to 4:30 then, so my breathhold time on O² a little bit more than doubled (with small LMC, I must admit). Was the same with the others who tried it. So a 15min breathhold should be well within reach.
Mind you though that you should have a really good spotter since your breathhold is rather terminated by lack of O² than the urge to breathe caused by CO². How far you (can) push it is not a matter of self discipline but risk taking :(. So kids don't try this at home :) !

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US Navy reported 22 minutes with a subject back in the 70's!
Erik Y.
Damn, 22 minutes, that is just plain ugly. Do you still contractions or no?
Yes, but they are not nearly as uncomfortable.
The funniest thing was that we all got contractions at the time we normally get them without O², but they stopped again after a very short period of time. So I guess contractions must somehow be a learned thing as well as a physiological one. The "real" contractions started much later and were by far not as ennoying as without O².


P.S.: I forgot to mention that I was told that the buildup of the normal CO² level after breathing O² takes about 12 to 14 minutes. So doing a static after an O²-static within this time and thinking you don't have to be spotted closely any more is an unwise idea, too.
I would be a bit careful here though, as breathing pure oxygen can have some detrimental effects. It can affect your eyesight if done for too long a period (this may be age related - anyone know of the specifics?).

Yes, but the typical negative side effects of breathing O² (like lung damage) only occur after about half an hour of continuous O²breathing. Even when you are really on O² for longer (which I would consider most unlikely in freediving and probably rather is an issue at e.g. decompression), O²-breaks of about five minutes every 30 minutes solve that problem, at least for quite a while.
Nevertheless, O² is a thing that can be both heaven- and hell-sent. So Ben for sure is right if he says that it's something that should be handled with care and wisdom.


P.S.: ...and trying out that stuff is at your own risk of course, and if you fry your lung on O² with such a BS don't blame me ! :t
Not something I ever plan on trying. Just wondered if dude was blowing smoke in his book.
Sorry T Ash, I guess I didn't put it the right way. With "you" I didn't mean you but "one" :duh - *ummh* however... what I wanted to do is to put a disclaimer in here. I think that a lot of things can be done safely as long as you know the risks and respect the limits, but who knows who might be reading this in the future :confused: , doing strange stuff but then claiming "but they told me that...".

Pure O

Tom and Veronika,

I can attest to what Veronika experienced with her trials of pure Oxygen. In 1998 I was invited by Duke University to the Hyperbaric Chamber Unit for a clinical study funded by DAN and none other than the US Navy for a cooperative study that was later published in some Journal of Science on the effects of pure oxygen on experienced breath hold divers. Basically, they were trying to figure out (DAN and the Navy) from a base premise of breath holding on pure oxygen how much variability you would have and what the side effects would be of pure Oxygen to later help them solve the mysteries of predicting and being able to accurately come up with somewhat accurate tables for mixed gas diving. In other words, trying to figure out if some guidelines depending on what data they gathered, could be produced for mixed gas diving.

My static breath-hold at the time was around 5 minutes and that was under the controlled environment at DUKE. In fact I never recommend anyone try to figure out their static breath hold in a pool alone or without someone watching closely. The tests were composed of a kill switch if I lost consciousness that would catapult me out of the water in the eventuality of a black-out, a catheter in my arm to draw blood and take samples, and under several sets of other conditions like bringing the chamber to one ATM (33ft) or pressure, exercising during breath hold, hyperventilation before breath hold and a few others...

For me personally with a minute of hyperventilation before hand with normal air and one final inhalation before breath hold of PURE 02 my best breath hold was nearly 12 minutes (11:49).
Its a very surreal calm feeling holding your breath for that long inside a trippy chamber with lights underwater. Compared to my best static breath hold, that was a remarkable difference compared again to a few of the recruited subjects who had longer static breath holds than I did whose breath hold time with a pure O2 inhalation only improved by a couple minutes.

What did these tests prove ultimately? I'm not sure since I never caught a chance to read the post study results and considerations made by the scientists and MD's, I think also because DAN and DUKE never came to any certain conclusions based on such discrepancies between divers breath hold times and differences.

What I can tell you is that you definitely run a great risk of killing yourself trying it spearfishing since pure O2 is toxic at depth and causes Oxygen toxisity :D and our bodies have an amazing ability to keep us conscious and feed the brain with extremely low levels of oxygen before passing out. And lastly repeating what Veronika said: more than extra caution needs to be taken under an experiment of this sort (a dumb and dangerous one unless its for science) because instead of having pre black out signals/warnings/shortness of breath symptoms caused by C02 a pure O2 breath hold gives you a very short-or-no such warning or feeling of shortness of breath, and this can be lethal since you are actually on fatally low levels of Oxygen.

Clear waters,

Just toying with the idea. Would there be a potential use for nitrox in recreational freediving? Much like in scuba. Say 32% or 40%.

Basically, extended bottom time and short recovery with lowered risk of DCS, provided the depths remain reasonable and someone did the math.

Of course there are problems and once you introduce a tank, it's always less "free". Maybe "freeishdiving". But would be fun to try sometime...

I must attach a disclaimer though. Don't try this, even if you think you know what you're doing. This is purely hypothetical...
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My friends and I are investigating the possibility of various esoteric freediving techniques (air bladder, nitrox, etc.), to sell as commercial skills for salvage or other types of commercial diving.

Using a breath of nitrox and then using an air bladder to exhale the air into, you eliminate freediving DCS, amplify blood shift, increase dive time to more than 4 minutes, and so on, all at an extremely low cost compared to expensive commercial scuba operations. Best of all, there are no dumb AIDA rules to worry about.

However, please don't do such experiments on your own!
The idea for the experimental air bladder is simple; it is a bladder which fits under your wetsuit. You take your last breath, pack, then dive, and as early as possible you exhale most (or all) of your air into the air bladder. So, you are now doing a full exhale dive, but you can suck air out of the air bladder to equalize (never bring it into your lungs).

The idea is that the blood shift comes much faster & stronger, and there is almost zero nitrogen absorption, and NO narcosis or O2 toxicity because your air is in the air bladder, not your lungs.

On the ascent, as you pass around 20-30m, you re-inhale from the air bladder to avoid the blackout at the surface. (alternatively you could 'pack' from the air bladder to avoid the end-of-apnea reflex which occurs during an inhalation).

Please don't try this EVER! This is an experimental technique for commercial freediving....
Even without the nitrox the air bladder is a great addition to everyday freediving so long as it is completely empty when you leave the surface
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