Can freediving cause DCS?

[unobreath]

Unobreath - Interesting to hear about that study, I sure wouldn't like to be one of the workhorses they used as subjects! A 45m dive every 6mins for 5 hours.....

As a high level freediver you would be in a position to do dive sequences that I would like to do, but avoid due to perceived DCS risk - the sort of sequence I mentioned above, give or take a few m. I am interested to hear if you dismiss DCS risk as a factor when you decide how you are going to train? This would put you at odds with the majority of divers at or near your level, so the more info you can provide about this the better. E.g. "I did x dives to xm with x interval and suffered no ill effects." There is no reason to keep quiet about your freediving experience.

The risk of BO is something we have pretty much under control. We know roughly why and when it is likely to happen, and can plan for when it happens (I'm talking comp. diving here, spearfishing is obviously different). DCS risk we know relatively little about, hence all the questions.

To say DCS is unlikely was due to my understanding of DCS.The reason I said it was unlikey is becuase you have to be doing some serious diving to deep depths with short surface intervals in rapid succession to get your tissues saturated enough with N2. That plus rapid ascent are all factors that can lead to DCS. But in the end it is all about body chemistry. What your body can handle, as it is different from what my body can handle. This is what ultimately leads to success in our sport so to say. Training will only take you so far.

Having gotten a little background info on the kind of dives you guys are doing I could understand why this may be a concern to you.

As for myself I like to spearfish and I take it to the limit alot(I think thats all I have to say)

So BO is much more of a concern than DCS as I am not going to 100m to spearfish.

To be honest I never had a concern with DCS and freediving until I read this thread just because in my community we dive to 100-300ft and hang out for 30 minutes to hours then do 7 hours of decompression. So it never really came to mind that DCS was likely when freediving. As I have a lot more to worry about when diving with a hard hat on.

As for my training I do alot of out of water training. I do high intensity workouts to where my heart is pounding (190 bpm) and then I work on my breath hold. mostly gettin my body to consume energy at a slower rate. I do yoga in 120 degree sauna mostly breathing exercises and lung expansion. (bikrams yoga) you should take a look at it. exteremly helpful.
I do some ice torture breath holding as well. cooler of ice water, breath up and stick my head in it and see how long I can hold my breath. I dont really have a training plan for x amount of meters for x amount of time with x amount of SI. I dont train in succession like you do (i.e. 80m x 4 with 6 min. SI) I've never found it help full, and most of my friends arent really into going past 120ft, so I spend more time out of the water working on ways for my body to work off of less.


The only thing I can say is you will never know your limit unless you push it. some people push it to far and some never push it at all. DCS is a limiting factor when it comes to how you would like to train as susceptibility to DCS would be different due to our genetics.
Hope this helps.

 

[trux]

Even after reading a few of the posts and links, I still would say it is unlikely to get DCS from breath hold diving.

Which of the 21 documents about DCS in freediving listed at dcs @ APNEA.cz did you exactly read? Did you read for example these?:
Nitrogen tensions in brachial vein blood of Korean ama divers -- Radermacher et al. 73 (6): 2592 -- Journal of Applied Physiology
Decompression sickness following repeated breath-hold dives -- Paulev 20 (5): 1028 -- Journal of Applied Physiology
Central chemoreflex sensitivity and sympathetic ne...[J Appl Physiol. 2008] - PubMed Result
http://docs.ksu.edu.sa/PDF/Articles34/Article340661.pdf
Journal of Occupational Health:   (2001) , 
Decompression sickness following seawater hunting ...[Res Sports Med. 2007 Jul-Sep] - PubMed Result
Decompression Sickness Following Breath-hold Diving - Research in Sports Medicine: An International Journal
Science Links Japan | Decompression illness caused by breath-hold dives.
Can Freediving Cause DCS?
divess.htm

In many of them DCS cases are documented, and the possibility of bents is shown theoretically. Do you disagree with all of them?

Your claims about the unlikelihood of DCS at freediving is very important and very serious, especially because you tell you are an expert in this field. I'd tell it is ground-breaking, because until now freediving medicine experts seem to have a different opinion. Would you mind posting your name, and a list of your diplomas and publications? Please do not take it for an offense, but on the Internet it is not easy to see who we speak with. At such extremely important issue, when you seem to be denying the results of research of several experts in freediving physiology, I admit I am little bit hesitant trusting an anonymous forum member.

 

[Mullins]

I mentioned before that it sounded like you hadn't had much involvement with the kind of freedivers who are most risk of DCS i.e. those competing at a reasonably high level. I'm still a little unclear on this following your last post. If you could give some indication of your experience with deep freediving that would be helpful. When I asked about training I was really just interested in depths, surface intervals and repetitions i.e. the main factors relevant to DCS (leaving out ascent rate for the time being)

 

[unobreath]

Which of the 21 documents about DCS in freediving listed at dcs @ APNEA.cz did you exactly read? Did you read for example these?:
Nitrogen tensions in brachial vein blood of Korean ama divers -- Radermacher et al. 73 (6): 2592 -- Journal of Applied Physiology
Decompression sickness following repeated breath-hold dives -- Paulev 20 (5): 1028 -- Journal of Applied Physiology
Central chemoreflex sensitivity and sympathetic ne...[J Appl Physiol. 2008] - PubMed Result
http://docs.ksu.edu.sa/PDF/Articles34/Article340661.pdf
Journal of Occupational Health: * (2001) ,*
Decompression sickness following seawater hunting ...[Res Sports Med. 2007 Jul-Sep] - PubMed Result
Decompression Sickness Following Breath-hold Diving - Research in Sports Medicine: An International Journal
Science Links Japan | Decompression illness caused by breath-hold dives.
Can Freediving Cause DCS?
divess.htm

In many of them DCS cases are documented, and the possibility of bents is shown theoretically. Do you disagree with all of them?

Your claims about the unlikelihood of DCS at freediving is very important and very serious, especially because you tell you are an expert in this field. I'd tell it is ground-breaking, because until now freediving medicine experts seem to have a different opinion. Would you mind posting your name, and a list of your diplomas and publications? Please do not take it for an offense, but on the Internet it is not easy to see who we speak with. At such extremely important issue, when you seem to be denying the results of research of several experts in freediving physiology, I admit I am little bit hesitant trusting an anonymous forum member.

I said it was possible. I said it was proven in a study. I said the reason that it does happen and how. What you don't seem to understand is that the rate that people on gas and off gas is different. there is no way to tell who gets bent and who doesn't. If you make enough repetitive dives with short surface intervals there is a possibility you may get bent in theory. now I am saying that the likely hood of YOU getting bent is not likely at all. unless you are making dives likes the ones described in the study. 150ft dives with very short SI for 5 hours straight. 40-60 dives to well over 150ft in 5 hours.

if you ask for my opinion I will give it. There is no need for me to give my name or certifications I hold because what's the point. Will it make my opinion any different. I dont understand why you would believe something you read on the internet anyway.
It was my opinion that DCS is unlikely because first of all not a lot of people even know how to diagnose DCS, and secondly dcs involves on gassing an inert gas (nitrogen) and not allowing proper off gassing. which would take a lot of deep dives one after the other to accomplish. and thirdly everyones body chemistry is different. My point of view and opinion is based on what I know about DCS.

I dont know why you two are obsessed with the fact that high risk freedivers are the ones that dive extremely deep. The thorns in the rose is that you can get bent in shallow water too. its not likely but there are plenty of published cases of dcs happening in shallow water. the fact that so many freedivers dive extremely deep and the number that get bent is very small that would make it unlikely yet possible that you could get bent. this isn't rocket science it was a generalized answer for a seeming generalized question. yet it has evolved into a thread that could go on forever.

 

[trux]

... I dont know why you two are obsessed with the fact that high risk freedivers are the ones that dive extremely deep...

It is simple - there are numerous cases of DCS documented at freedivers, spearfishers, amas, pearl divers, and other breath-hold divers. And this is nothing new. The term Taravana was used for describing DCS symptoms among Polynesian native divers since centuries. There are numerous scientific research works documenting DCS at freedivers, and they definitely come from people with sufficient skills to recognize bents. There are even reports from our fellow freedivers who suffered DCS.

Even if at some of the cases, the real reason for the DCS symptoms may have been a barotrauma, DCS and bents still remain a serious risk at competitive or extreme breath-hold diving. We all know the mechanism of bents, the reasons, and the different conditions. We also know that bents are a bigger problem at scuba. And we definitely also know that SWB is a more important risk for freedivers. That's why we always use safety divers at freediving trainings and freediving competitions - the risk of death or injury due to SWB is so minimized. The safety divers though may not help avoiding the risk of DCS. That's exactly why AIDA defines and teaches surface intervals, and that's why there are "decompression" tables for freedivers.

And now, a freshly new member of DB, self-described expert in the field of DCS, jumps in and tells us that we are all band of naives fearing bents without any reason. I asked your name and references, because before accepting your claim that bents are unlikely at freediving, I would like to compare the research you have done in the field of breath-hold diving and DCS, and would like to compare it with those already done and published.

I trust you that you have great experience with deep diving and with bents, but I am not so sure that you are sufficiently aware of the differences of physiology, cardiovascular responses, and metabolic chemistry during freediving - these may have great influence on the way freediver's body saturates and desaturates nitrogen, and may lead to DCS in situations that would not be a great issue at a scuba diver.

You probably did not realize how dangerous your claim was. Competitive freedivers rely on sufficient surface times, and/or dive on empty lungs to minimize the risk of DCS. Now you come and tell us that it is all BS, and that we do not need to fear DCS at freediving. I am afraid that we could see more accidents if people take your word for it. And that's the exact reason why we are "obsessed" with it, ask references from you, and do not let posting such claims without sufficient evidence.

 

[rafacuatic]

I suffered 3 DCS spearfishing.All in a 25-30m and 2'30-3 min range.So no too deep....Shorts intervals in surface + deshidratation+too tired, may be the cause.
Rafa

 

[dotey]

iam glad i came across this post i learn something new everyday thank you guys for putting this here for us to read

 

[ricki]

I had three high nitrogen alarms on my Oceanic Geo while doing free dives between about 105 and 125 ft. among a bunch of other dives within that range and less. Surface intervals were ten minutes or more as a rule with the last SCUBA dive being about a month before. The meter is back with Oceanic right now as I don't quite understand what to think or necessarily do, if the alarm goes off again.

I am not certain how vetted the deco algorithm is for free diving or more particularly, residual nitrogen remaining from SCUBA and free diving. Elected not to do that later regardless of what the meter might have to say about it btw. Too many minor hits in my past and unusual stories of accidents when mixing residual N from SCUBA and free diving for my liking.

 

[unobreath]

Given this, it seems a bit unwise to suggest DCS is unlikely. An "I don't know" sounds much more accurate?

Also, it's not a 'what if'. That example is quite a similar to how I would actually be training were I not worried about DCS risk. I'm going to train CW this weekend - would you suggest I tried it? I hope not.

this is for you...this is a doctor performing a doppler on a freediver who made a dive to 165 meters. A doppler, if you do not know what it is, is used to fin bubbles in your body. It is 100% the only way to know for sure your residual nitrogen in your blood.

CASE STUDY
By: Dr Hossam Nassef
(Head of Patrick’s medical team)

As Patrick Musimu started training for his record, Deco International offered him and his team Hyperbaric Medical support as medic first aid evacuatrion was already secured by the search and rescue (SAR) team. And as Patrick and I spoke, I found out that he conducted one deep breath-hold dive every third-fourth day and still breathed pure oxygen for one hour after the exposure to reduce the amount of the build-up nitrogen that all breath-holders expect to have after repeated relatively shallow exsposures or more dramatically after a very deep single exposure. He even spoke about chamber rides during the course of his training for nitrogen washout and as I was not that much convinced with the harmful excess of nitrogen in the tissues of breath-hold divers and as we already had research going on with a team of cardiologists measuring bubbles in the hearts of SCUBA divers.

I took the team together with the portable Doppler echosounder on Patrick's boat and did a bubble count on him upon completion of his 165 meters dive after 5,25,45,60 minutes successively and amasingly the maximum number of bubbles that was found in his systems was found in the right heart and he had only 2 bubbles every third beat while his security SCUBA team who dived on air and mixed gases showed tens of silent bubbles up to 1 hour after they surfaced and of course still had no symptoms! So the whole team concluded that Patrick was absolutely at NO risk of DCS following his single deep exposures even down to 200 meters and I even suggested that he stops normobaric oxygen breathing after his trials to avoid the harmfull effect on the lungs even at this minimal dose. Upon arrival to the base, Patrick performed a lung function test and all the functions and capacities of his lungs were found normal.

here's the link: H2O Magazine - Spring 05

now that is why I say it is unlikely to get DCS from freediving. Still possible but unlikely.

 

[trux]

this is for you...

NO risk of DCS following his single deep exposures even down to 200 meters ...

Yet, after his attempt to 209.6 m, he experienced severe DCS symptoms, was transported to hospital, and treated in a hyperbaric chamber. Because of the problems they called off the planned final dive, made just a shallow simulation for the press, and told that the last training dive was the record instead.

 

[trux]

And as for the Doppler measurements of circulating bubbles, Dr. Ralph Potkin, who is an expert on freediving physiology, working at the Beverly Hills Center for Hyperbaric Medicine, Los Angeles, California, also did research using the Doppler method. Just he did it little bit more systematically than Dr. Nassef, and with a bigger group of breath-hold divers. Strangely, he has a quite different opinion than you, or than Dr. Nassef:

Dr. Potkin's three research areas address issues of considerable practical concern for freedivers. DCS used to be thought of as an issue for scuba divers, but Dr. Potkin's Doppler measurements have made it clear that there is a real, though as yet unquantified exposure for apnea divers as well. As performance parameters increase and more freedivers dive deeper and longer this issue will very likely become of greater concern to more people.

 

[jome]

Should be pointed out that Patrick didn't pack...Which potentially makes a huge difference

 

[unobreath]

Yet, after his attempt to 209.6 m, he experienced severe DCS symptoms, was transported to hospital, and treated in a hyperbaric chamber.

Severe DCS is very serious. Usually life threatening and is not resolved in one treatment. Most people that have severe type 2 DCS symptoms end up having a lot of nerve damage and sometimes paralyzed. I do not doubt that he may have gotten a slight type 1 hit or even a little scare, but I doubt it was "severe" as many if not all people do not dive again after a severe case of type 2 DCS. there is not a severe type 1 as type 1 is not life threatening and usually only takes 1 treatment table to clear up with a few HBO's afterward to make sure there are no reoccurring symptoms.

 

[laminar]

Couple of things:

1. I think that the general opinion that freedivers are not at risk of the bends contributes to the lack of reporting of such suspected incidents. I know of examples of local divers having symptoms of the bends. In one case, the diver thought it couldn't possibly be the bends and it went untreated for quite a while. I think if DCS was presented as a very real risk we would have more cases reported and the actual incidence of DCS would fall someone between the two. Also, since most freedivers (my assumption, here) are not necessarily trained scuba divers, they wouldn't immediately recognize DCS symptoms, as often trained scuba divers I imagine would rather not admit that they've been bent, but a dive master probably would take the safe route? I think lack of awareness makes it difficult to make a claim that freedivers don't often get bent.

2. I think we also have to admit that the rules for DCS in freediving may be completely different. Eric has already mentioned that surface interval and lung volume may have had little to do with his DCS, but rather it was ascent rate. We are so far away from having sort of chance of developing deco tables - how many dives are needed to supply the raw data? Probably will never happen. Also, as Trux mentions, a lot of other bizarre things are happening to the body in apnea that could worsen or lessen DCS.

3. I met Dr. Potkin at the 2004 World Championships in Vancouver, BC. He was conducting tear film tests on many competitive freedivers and the safety divers running the comp. Trux, do you know if he's reported those findings officially in a study? I do remember him being surprised that almost all of us had significant microbubbles in our tear film. Several of the safety freedivers made 30-60 dives to 30-15m with approx 7 minutes of interval, whereas the competitive divers made usually only 2-3 dives in a day, with one max dive.

Pete

 

[trux]

Severe DCS is very serious. Usually life threatening and is not resolved in one treatment. Most people that have severe type 2 DCS symptoms end up having a lot of nerve damage and sometimes paralyzed.

Such cases do exist in freediving too. Permanent neurological damage is not uncommon among native professional freedivers (i.e. ama), but we also know it in competitive freediving too. The best known are the cases of Benajmin Franz (Germany), who is paralyzed since his freediving DCS accident in 2002, and the accident of the Venezuelan world recordman Carlos Coste last year, who got severely hit, suffered a brain damage, and despite getting the best available treatment, it took many months before he recovered.

Some of the quoted documents list dozens of DCS cases among amas, freedivers, and spearfishers (for example Decompression Sickness in Breath-Hold Diving by Robert M. Wong - a study of 101 freediving DCS cases). It includes cases of complete paralysis and death.

So please stop spreading and advocating your baseless and false suggestions about low risk of DCS. Backing it with your claim being an expert in the field (that we are unable to verify, because you remain anonymous), you act very dangerously. Spreading such false theories may endanger health and life of freedivers who would rely on your "expertize".

 

[trux]

Eric has already mentioned that surface interval and lung volume may have had little to do with his DCS, but rather it was ascent rate.

I do not think this is the right interpretation. The ascent rate certainly matters a lot, and likely can cause a DCS alone, but the other factors still play an important role too. For example the study of 101 freediving DCS cases made by Wong (included in this document) shows that DCS was the most frequent at freedivers diving below 20m for a period over 3 hours, and with short surface intervals (highest risk at intervals shorter than the apnea). Of course, the ascent rate is very important even in such cases, but not the only factor. It's importance it higher at deep freediving with very few dives - then the influence of the other factors is limited.

The above linked document by Dr. Wong also mentions the work of Dr. Schaefer who observed foam in venous and arterial blood drawn immediately after a BH diver surfaced from a single dive, lasting one and a half min to 27m. Similar measurments using the Doppler method by other researchers did not show any bubble formation after single dives to similar depth. That likely confirms Eric's words - probably in that very case the diver ascended faster than at the other later measurments. Unfortunately, I did not yet see a study where the ascent speed was measured.

He was conducting tear film tests on many competitive freedivers and the safety divers running the comp. Trux, do you know if he's reported those findings officially in a study?

Well, there is another document about tear tests in my database, bu it is by Dr. Sheard. I know about the work of Dr. Potkin, I also know he did Doppler measurments on freedivers. The work is often referred and quoted, but I did not find it published anywhere. If you happen to have a contact to Dr. Potkin, please let him know that we would love to see it. If he does not want publishing it to the wide public, but would agree having it accessible by confirmed freedivers only, I could place it on my server where it could be accessed only by registered members who passed a strict theory test.

 

[unobreath]

So please stop spreading and advocating your baseless and false suggestions about low risk of DCS. Backing it with your claim being an expert in the field (that we are unable to verify, because you remain anonymous), you act very dangerously. Spreading such false theories may endanger health and life of freedivers who would rely on your "expertize".

First, I never told you that you wouldn't get bent and I did say it was possible. You have taken this to the personal level where writing on forums are not suppose to go but usually end up that way. What I say is my OPINION and I am entitled to it. If you don't want to hear it then don't log on and read it. Last time I checked this was a forum and not a medical journal. This is the reason I remain anonymous. You take someone's opinion who happens to be very knowledgeable in the area and you find on the internet a case study that says the exact opposite, I could find hundreds of case studies that support my opinion but what's the point as they are just a doctors interpretation of their findings. The fact of the matter is that getting bent and not getting bent is not written in stone. Some people on their first time diving will get bent, then the guy that has been diving fro 20 years has never gotten bent. If you take the ratio of people who dive to the ones that get bent. The number is very small. Meaning it is possible yet unlikely.You read my post then come back with a completely different take on what I am saying. It is an opinion get over it. I told you I was very knowledgeable in the area of DCS and diagnosing it, I gave you example after example of DCS, types of DCS, other diving related illnesses and even told you some symptoms and so on and so on. I never said I was a doctor or that I am an expert in freediving physiology. And as to false theories, [EDIT(sanso):removed insult] You are relying on googling "DCS in freediving" where I have first hand knowledge of diagnosing it and treating it. At the end of the day You are just some ignorant dude on a forum who doesn't know jack shit about DCS but would rather google it then post your results on here. At the end of the day I am the one who treats [EDIT(sanso): beep] like you in a chamber when you do get bent. I figured you would have been mature and respected my opinion as a fellow freediver but your last post just shows your true character as a person. Dont come to hawaii and get bent, as I will surely lose all my knowledge of diving related illnesses the second you step foot in the chamber. Have a nice day. And oh yeah one more thing just in case you forgot. IT'S MY OPINION! So please stop whining about DCS. You get bent you get bent. Its not an exact science. The sooner you figure that out the better.

 

[trux]

Well, I ignore your invectives, because you are apparently not controlling yourself, but let's speak to the topic:

... The fact of the matter is that getting bent and not getting bent is not written in stone. Some people on their first time diving will get bent, then the guy that has been diving fro 20 years has never gotten bent. ...

That's something I'd agree with, but do not think it is consistent with your claim that "DCS at freediving is unlikely". It is unlikely only if you respect the rules - surface intervals, dive time, ascent rates,... If you do not respect them, you may get hit pretty likely. That's the point I am trying to make since the beginning.

 

[cdavis]

Both of you guys need to chill.

Trux, you have been beating unobreath over the head for 4 pages, point made, enough!

Unobreath, your comments about Trux are obnoxious and have no place in this forum. Go somewhere else if you can't do any better.

Connor

 

[efattah]

You are relying on googling "DCS in freediving" where I have first hand knowledge of diagnosing it and treating it.

Well, YOU are just a third party who treats and diagnoses it. You have never been bent from freediving. So I would say the we who HAVE been bent while freediving are a FAR GREATER authority than your theories and hypotheses.

I accumulated dives profiles from more than 100 of my own personal dive sessions without DCS and 8 personal sessions with DCS, and by correlating them, made some real conclusions which I know for me are far more relevant than some abstract theories put forward by someone who has never even experienced the problem personally.