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negative pressure dives

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

Well-Known Member
Jul 21, 2001
When the divers did their warm-up dives, they did the negative pressure dives. I want to ask what is the procedure about this dives, or simple, how do they look like?

negative pressure dives?

I've also had that question: what are the negative dives they talk about in competitive freediving?
Need to be shown how to do them, not just a description

I would ask those who respond to this question please be aware that if I feel that the advice given begins to get into advanced training techniques, I may have to edit accordingly to remove potential liability to those involved with the day to day operations of Deeperblue.net

I apologize in advance if this offends anyone, but it is for the safety of those concerned and potential liability of the publisher and myself.

I learned the proper way to do negative pressure dive's at the Performance Freediving Clinic I recently attended and they really should be taught to someone first hand and not just described.
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Information sources

In light of Cliff's words, then I suggest that you go to another source for your information... www.freedivehawaii.com/training/matt_briseno.asp
There are some really good training articles in the Apnea and physiology sections.
This is a great technique for stretching your lungs, and simulating great depths in very shallow water. I do 2 negative dives to 8 metres at the beginning of every session. Besides the simulation of depth, which will let you practice equalizing for depth, it has the advantage of kick-starting your dive reflex, thereby eliminating 45 minutes of diving until your reflex starts.
Also, feel free to email me at greatspirit63@hotmail.com or private message through Deeperblue, and I will treat you with the respect that is due to someone with enough insite to ask the question. I learned this technique on my own, with no information from anyone. I figured it out for myself, but was angry that nobody had shared this simple and effective technique with me before, for whatever their misguided reasons. I take it as an insult that someone with knowledge would withold that information to "protect me". This is an "advanced technique" because someone has labelled it as such. If you've never held your breath underwater, then ALL freediving is an "advanced technique". If you spend 4 days with an instructor, then on the 4th day do you become an "advanced student", and are capable of understanding and using the mysterious technique that the instructor will dispel? Please, spare me from the hierarchial crap. Like any freediving technique, go slowly at first and have a good buddy to help if you have some problems. With negative pressure dives, you will run out of equalising air VERY shallow, so watch your ears.
Erik Y.
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Sorry to all if I seem a little skittish about this info - Trying to draw a line as to what to post and not post is by trial and error for us here on deeperblue.

I'm not trying to be a jerk. But to imply that somehow information is being witheld due to being misguided is really an inflammatory statement to make.

I have discussed this issue at great length with many people, including several well known and not so well known instructors in both tank and freediving and their conclusion was basically the same - be very careful with what you tell people. You take on a huge responsibility if somehow they do the technique you explained to them wrong.

Because YOU become fully liable for the aftermath of it.

Fair enough Cliff. The country you live in is renowned throughout the world for the legal abuse of freedom by some of it's citizens. I do understand your position, as your name is on the webpage, and I did not mean that you were witholding information for personal gain or otherwise. I was speaking in a general term. So, my response for those who seek the info is to go elsewhere. FreediveHawaii doesn't seem concerned, or if they are, they are not afraid of repercussions from abusers of your legal system. I'm not afraid either, so ask me, I'll tell you what I know. I still think that if you're concerned about legalities, then put up a disclaimer page upon entry to the site, not just a note at the top of the page. At least a claimant could not deny that they elctronically signed their way into the forum.
You can probably tell I have a problem with supression and opression.
There is enough misinformation in our media; I would prefer that freedivers could step above that and talk like adults. It's supposed to be fun, and we should act like a community, not a business.
Erik Y.

I have some opinions on what should and should not be shared, or learned in person.

In my case, I have never taken a scuba or freediving course. Everything I know, I either figured out myself, or learned from the internet. And, despite never taking any courses, I eventually managed to break a world record (!) I think this shows that anything can learned over the internet.

Having said that, there are some advanced techniques which I might be hesitant to share. However, negative pressure dives are not, in my opinion, an 'advanced' technique---they are not a beginner technique either, they are an intermediate technique. It is also true that extreme negative dives could cause muscle or tissue damage if not done properly, but those people who instructed me over the internet on negative dives told me to go slowly, so I did.

My definition of advanced techniques are techniques where a single failure of execution causes almost certain death. Right now the only such technique I know of is 'water equalizing'. I won't even describe what it is, but those of you who know, also know that it is only performed deep, and failure of execution can cause drowning at depth. That's the only technique I would be hesitant to share on a public forum. However, even that could be shared privately, if the student were sufficiently advanced and had previously shown adherence to proper safety protocols.

Eric Fattah
BC, Canada
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Thanks for the clarification Eric

Thanks for putting that into perspective, Eric.

Erik Y. - I understand your position - I forget that many who participate on the forums do not reside here in the states, so those laws regarding law suits is different than here in the states.

That said - I detest the supression of information as much as you do. I was formally a photojournalist for a number of years working in newspaper and feel very strongly about freedom of information, but otoh, too much information can be as detrimental as too little from my own discovery.

I so much don't want to treat this as a business, but than again, there are those in todays society (at least here in the States) who could care less what we call it - a business or community - who would still prefer to seek legal action regardless if it meant an easier way to make a quick buck.

Hence my apprehension - I apologize if I came across as trying to withold information on purpose - I was just trying to Cover my A$$ (so to speak)

Make sense?

This sucks having to go this route... :(

Interesting thread, it begs the question about terms of engagement. Does anyone want to attempt to identify
those skills that are basic, intermediate, and advanced?
In many ways this is a very fundamental question that has been answered in particular ways in the scuba community already, eventhough such issues as solo diving are on the board. The US Navy has already done this for freediving, but not everyone is happy with the result, e.g. depth limits for spearfishing competitions. It would be interesting to see wlhat we might come up with.

Best wishes,

Interesting comment

I totally agree with freediver48 on this issue - how does one determine where to draw the line? One persons view of being intermediate could be anothers view of advanced. Yes - the other agencies you mentioned have clearly delineated definitiions of each level of training, and they have proven that this method works, although there are still accidents and deaths that do occur, but I am sure that they would be much higher without this standardization of training.

Experienced divers like Eric Fattah did raise the issue quite well - but there again, this is still only one persons POV (sorry - no attack meant by this statement). This is a debate that I think needs to be addressed - where DOES one determine where the various levels of training and techniques begins and ends?

This makes for a compelling reason for some type of official training for freediving - not so much to regulate it, but to standardize the information in such a way that it is easily understood by those who want to learn to freedive or improve their freediving with more advanced training techniques.

I use to be one of those who felt that I could learn this on my own. But after attending the clinic, I have had to revisit this way of thinking and conclude that, even after combing the internet for as much information as I have found over the past few years, that the clinic was far more valuable a resource than all my hours of searching on the net for it. And I learned to do it properly, and was corrected by a live instructor where needed.

That is something you cannot get from a book or reading off of a website.

I will attend the clinic again within the year to solidify what I learned previously and hopefully attain my target depth that I missed at this clinic.

I think it is crucial to my success for safe freediving.

Anyone else want to comment on this?
Let's keep it in perspective

Right, I don't want this to get out of hand again - this subject has been discussed in depth in another thread.

We have implemented a disclaimer and ever member who joins these forums have agreed to a series of terms and conditions. Since non-members can't post, anything posted is the thoughts and views of that specific member and although there could be an argument that Deeper Blue could be held responsable for running these forums, i'm happy with the legal coverage we have.

Saying that, we are not going to stop any free discussion. We will allow debates to go on, and only in the event of blatantly dangerous advice would we take any action such as moderating the posts. I have informed all moderators of the site policy on this and if you have any problems at all with this, please take it offline via Private Message to myself and I will happily discuss it with you...or move this discussion to the Support or General forums.

Let's get these forums back on track about discussing the sports that everyone on here wants to talk about, not forum policy.
Did anyone answer your question?
Find about 3 meters of water, preferably a pool, with a good buddy and do a breathe up for a dive. Lie on the surface and exhale as far as possible. Keep things comfortable until you've done a few. Now if you slowly descend to the bottom you will simulate the part of a deep dive from about 30-40 meters, depending on many variables.
You will have to clear on the way down and it will require a new technique that is explained on the Hawaii website. It's easier if you go feet first, at first. The body switches into the dive mode fast.
With this practice the bottom part of a deep dive will be easier but, these things are a lot more strenuous than you think.

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Thanks for the answer.

Thank you Bill. Appreciate the good clear answer. Yes, I found that the freedivehawaii site (as directed by Erik in his answer) gives information a little more freely and I learned what a "negative pressure dive" is.

Understanding what they are now, I have to wonder what the big deal was in not wanting anyone to know. (It smacks of cheap magicians wanting to protect cheesey tricks -- "pay no attention to that man behind the curtain.")

I've practiced with less than full breaths and also after completely exhaling. I just didn't know the technical term: "negative pressure dives". When I saw it mentioned in stories of record dives, which are plastered all over the internet, probably on this site too, it never explains what they are. Wihtholding the information might be a better way to egg on a law suit, instead of just giving someone a clear definition of something.

It seems a rediculous notion that any statement on this forum could make anyone legally liable for an accident. If that were the case no journalist or writer or coach or anyone else could ever speak or write another word about technique in any sport where there is any risk of death -- they might be liable if someone gets hurt trying it.


Actually you could simulate dives deeper than 70m / 240 feet quite easily. It's important that it's done very gradually with slowly increasing depth of your exhalations and I would start with a 1/2 lung full and work progressivley from there.

Most importantly with this exercise is ALWAYS WITH A BUDDY. Even though it seems pretty simple in a pool, there are some things that could happen and it's important to agree with your diving buddy as to how long you'll spend on the bottom. I start usually with around 10seconds on the bottom then ascend.

It's important that the breathing is done relaxed and NO PURGING or HYPERVENTILATION be done to extend your bottom times. Keep in mind your heading down with little air in your lungs and because of the increased pressure on the chest wall it helps induce bradycardia (slowing of the heart). When you hyperventilate you decrease CO2 and therefore can cause vasocontriction (reducing blood flow). This on top of aggressive hyperventialation could potentially cause a blackout upon descent. I tell you this one from experience.

One thing you might experience is a immediate sharp pain on the side of your chest about 3-4 inches above your hip bones. This can be felt if not done progressivley and I believe it involves the gastrointestinal tract (GI) as well as lack of blood shunt. Keep in mind that the only airspace in the body that is under the simulated pressure is the lungs and not for example the gastrointestinal tract (GI) which is a compressible airspace. So the lungs can be simulated down to 70m while the GI is only at the bottom of the pool at 3m.

Whether it's an advanced, basic or intermediate skill, all freediving skills have potential problems no matter how simple they seem and must be done with direct supervision from a buddy if done in the water. Keep in mind that this skill is having you experience simulated depths as deep 70m in only a couple of seconds. 0-70m in 5 seconds? Not only is the potential for blackout, but more likely equalizing problems, chest wall compression or lung squeeze, etc.

Maybe to avoid peoples problems with names I should call the programs, shark, seal and whale like kids snorkeling programs :>)

Hope this helps,
Many Thanks!


Many thanks for answering the question! As always, it's good to have a professional teacher on the forums to chip in with advice.


The key thing is to make sure that your safe! As Kirk says, the Buddy rule should always apply.

The main issue people have with liability is if something happens to someone else and fingers start getting pointed. Believe it or not, journalists and instructors have been the subject of lawsuits for giving advice which was interpreted wrongly and resulted in injury or worse. I myself have seen first-hand a fellow Scuba instructor (highly trained and teaching for over 8 years) nearly be the subject of a minor injury due to mis-interpretation of information taught to them. :duh :head
Thanks for all the ansewers about this question. I'm scuba diver eight years and freediver about twenty years. Last two years i go for freediving more seriously, because I realise that I see more things underwater while freediving, then scuba. I also learn all new things about freediving on this forum. So thanks all the experts of freediving, who explains our questions or theirs own experiences about freediving.
Thanks and Sorry.

Thanks everyone (Erik Y., Eric F., Cliff, Stephan, Kirk) for your time answering questions, making this forum available, and participating in it. Your thoughts are very helpful to us with less experience.

Sorry, my snide remarks above sound pretty sarcastic and disrespectful, reading it the day after I wrote it. I've been thinking more about it since and remembering the stack of legal papers you have to sign to get someone to take you tandem-skydiving -- it's worse than buying a house and you sign every freakin' page.
Boo, Cliff!

As tactfully as I can, may I offer that your saying you know, but won't tell, smacks of the juvinile "naa-naa, I've got mine" mentality that does us and this forum no good. "I'm reminded of the saw, "Sometimes the best thing to say is nothing"...
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For all those people moaning...go somewhere else. This is an awesome free service and you have to respect the rules.

I can see quite good arguments for both sides of the story. But i don't put what I imagine is countles, unthankful hours into maintaining this site.... Therefore I have 100% respect for whatever guidelines are thrown at us, and keep my correct or incorrect opinion to myself.

Of course there has to be an opportunity for input. But the wining and smartarse remarks I have seen here are pitiful. Grow up. No wonder they don't want to give you info.

Kirk, thankyou for your reply. It is important not only to know what the technique is but what the dangers are.

This site is excellent.
Keep up the good work.
Originally posted by king pete
For all those people moaning...go somewhere else. This is an awesome free service and you have to respect the rules.

I can see quite good arguments for both sides of the story. But i don't put what I imagine is countles, unthankful hours into maintaining this site.... Therefore I have 100% respect for whatever guidelines are thrown at us, and keep my correct or incorrect opinion to myself.

Of course there has to be an opportunity for input. But the wining and smartarse remarks I have seen here are pitiful. Grow up. No wonder they don't want to give you info.

Kirk, thankyou for your reply. It is important not only to know what the technique is but what the dangers are.

This site is excellent.
Keep up the good work.

Well said, King Pete.