pure oxygen...

What are you going to do, swim with an O2 bottle?

Using a scuba tank can dramatically increase your bottom times as well.

I think there is more risk using pure O2.

No need to jump on Davie for making a joke. He is an excellent spearo with great fish sense, and a good diver that we can all learn a lot from. You have to realize that asking about "freediving" with an O2 bottle sounds ridiculous to us, especially after only freediving for a year and not having reached anywhere near your potential actually freediving. What you're suggesting is just not done. However maybe these guys will know something about it http://spearfishing.world/divi…mpetitive-freediving.html

On a serious note freedive spearfishing is risky enough, what you're suggesting can only make it more dangerous. I wouldn't do it. There are a few methods that can be used to go deeper when necessary, variable ballast, a partner that will pull you up with a rope, all advanced techniques for experienced divers.

if you use more o2 before u make a dive is no going to make any diferente cus a freedive is base on air comsuption of you body by move and how much you can store in your lungs . and with time an practice you can improve that . is simple but risky .

que viva la pesca :cuba:

nonsense

Quote from fishhound

Thank you captain obvious. No need to reply if you don't have any real info to share on this. ie you have done it or know other people who have or know hte science behind why it's good or bad. Thanks

As a matter of fact I've been researching what happens.

Hyperoxia= Oxygen excess

partial pressure of oxygen exceeds 360 mm Hg

At
23ft – the process of receiving O2 and releasing CO2 is hindered
50 ft – this process stops so that cells cannot accept oxygen despite of its abundance

Symptoms

at first – discomfort, nausea, spasms of lips and eyelids, disturbances in eyesight, sleepiness;
later – stiffness of muscles, convulsions (similar to the epileptic ones), blackout, death

So it won't matter how much oxygen is in your lungs your body won't be able to use it.

However I found very little info on how long exposure factors in and if the damage is cumulative or recedes after each dive.

Fishhound,
Sounds like you should just exercise and practice static tables if you want to improve your bottom time. Comp freedivers use O2 but its not practical in spearfishing. Play it safe.
Nic

May I ask what it is that you want to achieve in 40ft of water after sucking on pure O2? with a little practice most people can stay at 40ft for more than 2 minutes so what exactly are you wanting to get out of this? are you spearing? just hanging out? what.

My biggest concern (assuming you stay shallow enough you don't have to worry about oxygen toxicity), is that you'd be throwing off all your body's urges to breath. You've spent your whole life learning what high/low O2 and CO2 feel like (whether holding your breath, physical exertion, etc.) when breathing air, and now you'll have to relearn those responses with only oxygen. And where you'd be learning them is not very forgiving to mistakes.

I don't really follow all the O2 static record attempts and their techniques, but I'm guessing that since a lack of CO2 in the bloodstream hinders O2 transfer, they probably have to worry about blackout at the beginning of the breathhold - similar to how someone hyperventilating can pass out. It would seem that diving after purging with O2 would significantly increase the chance of blacking out at the onset of a dive.

As far as sucking on O2 in the boat, that will decrease your bottom time, as you need acidic blood (high CO2) for good O2 transfer. Breathing up is a balance of keeping blood CO2 high and lung CO2 low.

Fishhound what world record holder? yes O2 toxicity is a problem and it is not so much the O2 amount you bring down with you (it does help) but more the amount you spend while down. You could suck on O2 for half and hour, but, it does not make any difference if you dont know how to minimize your O2 consumption...especially when spearing. The trick David Blaine did were he held his breath for 15 minutes or so was done by him sucking on pure O2 for awhile, but, he sat there motionless for 15 minutes!!
Sucking on pure O2 is NOT a safety measure for swb and it would do you good my friend to learn more about the physiology of apnea and swb. Everyone is always looking to cut corners with freediving or freedivespearfishing and usually it is the younger crowd or those who feel they can make it easier...there is no tricks or secrets or magic pill, what there is is education, expierience, dedication and and most of all an understanding of yourself and what you are capable of all learned in time from the afermentioned. Our sport is already a very dangerous one and many of our brothers and sisters die each year from it, so in my humble opinion it is best to forget about this and simply work on improving your capabilities in time.
Comfort while diving deeper comes in time and becomes more rewarding, if 40 to 50ft is uncomfortable or extremely short bottom times then it is your bodys way of saying I am not used to this and there are avenues you need to work on in order for your body to come to terms with that depth and longer bottom times and it will happen believe me, but, there is no trick whether it be pure O2, eating sodium bicarbonate, massive alkaline diet, baking soda or anything else that will get you to a more comfortable place and enjoyment while spearing than plain old diving...diving...and more diving. Be safe my friend and have confidence that you can get deeper and longer with time.

Learn about acidic and alkaline blood levels and what happens when you dive, when you exert energy, the bohr effect and other things like that and you will see what I mean.

Quote from seaweed

As a matter of fact I've been researching what happens.

Hyperoxia= Oxygen excess

partial pressure of oxygen exceeds 360 mm Hg

At
23ft – the process of receiving O2 and releasing CO2 is hindered
50 ft – this process stops so that cells cannot accept oxygen despite of its abundance

Symptoms

at first – discomfort, nausea, spasms of lips and eyelids, disturbances in eyesight, sleepiness;
later – stiffness of muscles, convulsions (similar to the epileptic ones), blackout, death

So it won't matter how much oxygen is in your lungs your body won't be able to use it.

However I found very little info on how long exposure factors in and if the damage is cumulative or recedes after each dive.

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Just thought I'd add some info based on my understanding of Hyperoxia (Oxygen Toxicity) from my scuba diving background, where it is an important factor.

First off, this science is still evolving, and there's a lot that isn't yet truly understood. It is pretty commonly accepted that once the partial pressure of oxygen reaches 1.6 atmospheres, the prevalence of symptoms as a result of Hyperoxia increases. This is at about 20 feet. Thus, most scuba diving agencies recommend staying within 1.4 atm ppO2. With that said, there are plenty of divers that have gone well beyond 1.6 atm without symptoms, and some that have had OxTox problems before 1.6 atm. Just as an example, in the Navy Dive Manual, there are still guidelines for dive times for excursions to up to I believe 50 ft (haven't read it in a while) one pure oxygen rebreathers. That's a ppO2 of about 2.5. I'm sure there are technical divers that have temporarily had ppO2's much higher than that due to mistakes in bottle switching, and I'm sure some of them came out okay.

Basically, the point there is that it's possible to dive symptom free with significantly higher ppO2's than the recommended limit, but there's a bit of chance involved and it typically involves more risk than the civilian diving world really wants to deal with, as there's no real need to.

With that said, one of the recent findings I remember reading was discussing the differences in the prevalence of symptoms between breathing a leaner mix (less O2) deeper vs. a richer mix shallower if both have the same ppO2. I want to say that they found symptoms more likely with the richer mix, but I don't remember it well enough to say for sure.

Next thing to say--I've read no definitive information on how the subject affects freedivers. I mean, Herbert Nitsch has dove to 700 feet. That's a ppO2 of about 4.6, and yet he suffered no convulsions on the dive. Until they figure out the physiology between hyperoxia and freediving with air in your lungs, I doubt they'll really understand it with pure O2, as not many people really do that.

Note: This is all about CNS Oxygen toxicity. Pulmonary Oxygen toxicity is another thing, to do with breathing high ppO2's for long periods of time. As far as I know, the CNS damage is typically not considered cumulative, but there aren't very many people that regularly have Oxygen toxicity problems, so it's hard to say.

in this sport there are no short cuts take a freediving course your life is in your hands find out from the pros .like PFI .... if you want bottom time just keep diving safe as much as you can the rest will come in time maybe after some years of diving and getting to know your limit ..but a course will help you so much it has for me and many others... also look up on swb no longer you stay on the bottom u will pay later when you are coming back up ..... dam just take the cousre..............

I guess we do this for fun . Why complicate things?. I'm not intersted in diving with any kind of addition . just keep it simple and have fun. I always thought that pure O2 gets you high , or sleepy ...

Quote from pantoja

I guess we do this for fun . Why complicate things?. I'm not intersted in diving with any kind of addition . just keep it simple and have fun. I always thought that pure O2 gets you high , or sleepy ...

x2. Keep it simple!