Can freediving cause DCS?

[unobreath]

Originally Posted by Mullins

So you think it will be fine for me to do 4x80m CW dives in a row with brief intervals? DCS still 'unlikely'?

There are plenty of freedivers around these days who could easily get themselves bent if they were not cautious about surface intervals and # of repetitions. If you haven't come across any DCS incidents, it is probably because you haven't dealt much with this group of freedivers.

What if's are just not practical. I dont know what your body can handle and what it can't. There are super human freaks out there that can omit 2 hours of decompression and not get bent. then you have a normal person who does the same things and they spend the next three weeks in a recompression chamber for serious type 2 DCS.

I asure you I have dealt with a lot more then I care to tell.

[chrismar]

Originally Posted by billieball

I know of cases whereby it would be wise to monitor one's nitrogen loading when freediving and SCUBA diving in the same day. My handy dandy freediving/mixed gas Oceanic Geo dive computer even shows a hypothetical buildup of nitrogen in my tissues after repetitive deep freedives...all to err on the side of caution, I am quite sure. That being said, in my studies it would appear that DCI/DCS is improbable during freediving excursions. Sure, it could happen. It just isn't an issue I would waste too much time worrying about.

It may not be something we all need to stress about, but it*is* something that top spearos and freedivers should worry about, on every trip. Dave's example above is something that he would be physically capable of (probably!), but could never do because of the massive DCS risk. Heck, even the way Dave spearfishes would put some people at DCS risk! He's far from the only one too; plenty of top guys are capable of getting DCS and some have actually done it.

In fact, a little while ago at least a couple of spearos ended up in chambers after a spearing comp. I'm sure someone else has more details on that incident.

[Mullins]

Originally Posted by unobreath

What if's are just not practical. I dont know what your body can handle and what it can't. There are super human freaks out there that can omit 2 hours of decompression and not get bent. then you have a normal person who does the same things and they spend the next three weeks in a recompression chamber for serious type 2 DCS.

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.

[unobreath]

Originally Posted by chrismar

It may not be something we all need to stress about, but it*is* something that top spearos and freedivers should worry about, on every trip. Dave's example above is something that he would be physically capable of (probably!), but could never do because of the massive DCS risk. Heck, even the way Dave spearfishes would put some people at DCS risk! He's far from the only one too; plenty of top guys are capable of getting DCS and some have actually done it.

In fact, a little while ago at least a couple of spearos ended up in chambers after a spearing comp. I'm sure someone else has more details on that incident.

DCS is being used very vaguely. DCS is hard to diagnosed by someone who doesn't know what they are doing.

DCS is treated by a re compression chamber.

Other related injuries not associated with DCS could happen while freediving, but they are not DCS.

Such as pneumothorax, Mediastinal Emphysema, or subcutaneous emphysema

It is very possible to get DCS from freediving after scuba diving even if you scuba dived the day before. But just freediving alone is still not likely.

Many people may say they got bent but until someone of a somewhat professional diganosises them with DCS or a.g.e or any other diving related injury I would not take their word for it. becuase like I said before DCS is being used very vaguely, where as DCS is a type of illness and not a synonym for "bent"

[unobreath]

Originally Posted by Mullins

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.

I give up with you guys. I dont know and I don't care is more accurate.

IN MY PROFESSIONAL DEEP SEA DIVER OPINION WITH MANY YEARS OF EXPERIERENCE WITH DCS, A.G.E., AND ALL OTHER DIVING RELATED INJURIES I WOULD STILL SAY THAT DCS TYPE 1 AND TYPE 2 ARE UNLIKELY UNDER NORMAL FREEDIVING CONDITIONS, OR EVEN NOT SO NORMAL FREEDIVING CONDITIONS. BUT THEN AGAIN WHAT THE HELL DO I KNOW.

[Mullins]

That's more like it. This is an important issue for us. You can expect us to demand a bit of clarity when people with medical experience offer their input. Not because we don't respect that experience, but because we take it seriously and make use of it when we decide how we are going to dive.

One thing, assuming you haven't stormed off already - you'd consider competitive freedive training to be outside the bounds of what is normal?

[unobreath]

Originally Posted by Mullins

That's more like it. This is an important issue for us. You can expect us to demand a bit of clarity when people with medical experience offer their input. Not because we don't respect that experience, but because we take it seriously and make use of it when we decide how we are going to dive.

One thing, assuming you haven't stormed off already - you'd consider competitive freedive training to be outside the bounds of what is normal?

There has been a study on freediving and DCS.

It is possible I dont deny you that. But they were diving for 5 hours to 130-150ft with small SI. So after making 40-60 dives some did get DCS. But I dont see 40-60 dives as normal in one day.

My training is well outside the bounds of normal but I would more than likely use the term above average, as i train hard and long just like any professional athlete. Your normal may be different from my normal. As I enjoy living on the edge of my fingertips and like the fact that the ocean can swallow me whole whenever she wants. I have a dangerous job but I like it that way. Now if I were standing from the outside looking in I am sure everyone thinks we are crazy. Especially when we can hold our breath for 6, 7, or 8 minutes and dive 100m underwater. That is not normal for most but for us it is.

For me I would worry more about shallow water black out then DCS. I have had guys come in like two weeks after a dive complaining of pain or loss of sensation, or whatever, and make a full recovery after a few treatments.

Every person I have know to get shallow water black out I have either attented their funeral or heard the story of how their buddy saved their life.

I try not to worry about any thing, if it happens it happens and then I will worry about it.

[chrismar]

Originally Posted by unobreath

There has been a study on freediving and DCS.

It is possible I dont deny you that. But they were diving for 5 hours to 130-150ft with small SI. So after making 40-60 dives some did get DCS. But I dont see 40-60 dives as normal in one day.

Sounds a bit like your spearfishing profile, eh Dave!

Nobody is saying that all freedivers are at DCS risk. All we are saying is that it is a serious consideration for some. Agreed? The reason Dave is hot on the issue is that DCS, oxygen toxicity and nitrogen narcossis are the big unknowns in his dives. He may not be a normal case, but he at the very least is quite interested to see what the implications of his training are.

[BennyB]

Unobreath, I don't think anyone is saying that you aren't knowledgeable in your area of expertise, nor are they doubting your experience and credibility, but to come onto a freediving website and say that DCS is unlikely when freediving is a fairly tough sell.

There was a study was published in 2006, "Decompression Sickness in Breath-Hold Diving", by Robert M. Wong, MB, FANZCA, Department of Diving & Hyperbaric Medicine, Fremantle Hospital, Freemantle WA. This study tested a group of spearfishermen and included a table of DCS symptoms and the percentage of subjects who encountered them:

Headache - 50%
Nausea - 50%
Dizziness/Vertigo - 50%
Lacks concentration - 37.5%
Fatigue/lethargy - 37.5%
Visual disturbance - 25%
Lacks coordination - 25%
Disorientation - 12.5%
Speech disturbance - 12.5%
Vomit - 12.5%
Paresthesia - 12.5%
Joint pain - 12.5%

It's an interesting read if you get a chance to look at it.

There may not a great deal of published scientific evidence of DCS in freediving, but it would be pretty unwise for most breath holders to dive thinking it's unlikely to happen to them.

Cheers,
Ben

[Mullins]

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.

[unobreath]

Originally Posted by Mullins

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]

Originally Posted by unobreath

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]

Originally Posted by trux

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]

Originally Posted by unobreath

... 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.