Keep it civil please everyone, if the personal attacks continue i'll close the thread.
Thanks,
Ben
Thanks,
Ben
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Can freediving cause DCS?
- Thread starterfishnchips
- Start date
Thread Status: Hello
, There was no answer in this thread for more than 60 days.
It can take a long time to get an up-to-date response or contact with relevant users.
It can take a long time to get an up-to-date response or contact with relevant users.
Personally, I am quite chilled out and enjoying the discussion very much
And do not tell me that the arguments you heard here from all who participated, and all the links we posted are uninteresting. In contrary, I bet that for many visitors this thread will remain an important reference regarding DCS and freediving - with many personal wisdoms, counter arguments, facts, and links to scientific documents. There is no need trying to stop the flow of information. I do not think it is necessary to ask someone to shut up, or stop discussing as long as his/her posts stay on-topic, informative, factual, based with solid arguments, and polite. We are not obliged to agree with each other, or with a common consensus, and we should have the right to support our opinion by arguments. That pays for both sides of any dispute.
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My apologies, I take my job seriously and to be called out on it because my opinion is different from someone else's is uncalled for.
people get bent all the time following the "procedures". I understand that this is a concern for you due to the diving you participate in. The only thing that most of the people in this forum do not understand is that you may think you have a type 1 hit, but more than likely it is hypoxia or some other illness that can have the same symptoms as DCS. As someone posted earlier that many cases are not properly reported, well the door swings both ways as many may thing they took a DCS hit just because they have a headache or pain, when is actuality they do not know what DCS really is. They assume DCS because DCS is associated with diving and getting bent when they are actually many ways to get bent, DCS is just one of them. As a neurological examination is one of the tests that can be done to determine DCS. Most doctors do not even know how to do a neuro let alone someone else. My point is that although you may think it is DCS it in fact could be something else, as the stated earlier DCS is serious. hypoxia is not. The other way to diagnose DCS would be a doppler. I don't know how many of you have access to one but my guess would be very few if none. My point is that DCS is hard to diagnose if you do not know what you are doing. And still even if you do know what you are doing it is still hard to pinpoint whether it is DCS or something else, as dive profile and many other things are considered when determining the type of diving related illness you have. I think it is very possible to get bent while freediving. Especially diving beyond 80m. The likely hood of it happening is possible but undetermined. This is why I think it is unlikely. Just my thoughts on the topic. being bent does not mean DCS, and many confuse the two. DCS usually involves omitting decompression. hence decompression sickness. Just food for thought.
And let me explain why I am so vehemently "beating unobreath over the head for 4 pages" - the problem is that DB forum posts rank very well in search engines when you look up any freediving topics. So you can be pretty sure that many people who research information about the risk of DCS in freediving will find this thread. What they would see is a post from the only "hyperbaric expert" in this thread who tells that DCS is practically a non-issue at freediving.
I would mind much less if any other DB member posted such opinion, because it would be considered as such - a personal opinion. In the moment you start claiming you are professional and expert in this specific topic, visitors who do not know who is who, will tend to trust the one that proclaims himself to be expert. Unless we questrion it, they would not know that Unobreath is (probably) a technician in hyperbaric center, has no experience with the research of freediving physiology, has no experience with competitive freediving, and did no scientific research in this field. They might not know that other participants like Eric Fattah or Dave Mullins are freediving world record holders, and together with other freedivers who posted here have the first-hand experience with the DCS risk.
So I think it was indeed necessary to post all those arguments, and all those links to outweigh the claim of the self-proclaimed expert. It might have gotten more interesting if he supported his claims with counterarguments, so the discussion might show another turnout, but unfortunately he preferred resorting into vulgar personal invectives. Frankly told, it was something I anticipated - some people tend to be agressive when they miss arguments and try to stop the discussion in such way.
I would mind much less if any other DB member posted such opinion, because it would be considered as such - a personal opinion. In the moment you start claiming you are professional and expert in this specific topic, visitors who do not know who is who, will tend to trust the one that proclaims himself to be expert. Unless we questrion it, they would not know that Unobreath is (probably) a technician in hyperbaric center, has no experience with the research of freediving physiology, has no experience with competitive freediving, and did no scientific research in this field. They might not know that other participants like Eric Fattah or Dave Mullins are freediving world record holders, and together with other freedivers who posted here have the first-hand experience with the DCS risk.
So I think it was indeed necessary to post all those arguments, and all those links to outweigh the claim of the self-proclaimed expert. It might have gotten more interesting if he supported his claims with counterarguments, so the discussion might show another turnout, but unfortunately he preferred resorting into vulgar personal invectives. Frankly told, it was something I anticipated - some people tend to be agressive when they miss arguments and try to stop the discussion in such way.
Because you have gotten bent that makes you the far greater authority? WOW. That's funny. Do you know anything about getting bent besides getting bent yourself?
Yes, this sounds better. Thank you for the apology, and sorry if you felt offended by my arguing.
I agree that DCS may get misdiagnosed (in both ways). However, as you could see in the documents I listed, there are numerous cases that were closely examined by the best experts in the field of hyperbaric medicine. Tear bubble test, Doppler measurement, and direct drawing of venous and arterial blood were performed to collect reliable evidence. And bubbles were often detected even in cases being quite far from any extreme freediving. Unfortunately I think that you did not read any of the documents I suggested.
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why the need for articles to support my opinion. The facts I am telling you about DCS are written in every diving manual know to man. If you knew anything about this you would know that. As our opinions are coming from two different sides of the spectrum. I am the professional diver, you are the competitive free diver. I freedive for fun and enjoy spearfishing. you dive for competitions and whatever else. My opinion was based on my back ground in professional hard hat diving, along with rebreathers and everything that falls between the two. I am not a hyperbaric tech. My services are asked for when serious cases are in question as many of my co works do the same thing I do. We are knowledgeable in the field and therefore are asked to help. diving related illnesses happen the same way, whether freediving or on scuba or any other form of breathing compressed gas. my "theories" are backed by common knowledge that you can find in any commercial diving manual, navy diving manual, and many advanced courses on diving. You can read my so called theories and hypothesis in any of those manuals as diving related illnesses and symptoms are there in black and white. I assumed since you knew I was a professional diver that my knowledge would come from my training which comes from the NAVY DIVING MANUAL. I dont know to many people who would disagree with that manual, as it is the FAR GREATER AUTHORITY on diving related illnesses then any other source in the world. As they perform many tests over and over again to find better and safer ways or diving. What you assume about me is your own fault. I said I was a professional diver with extensive knowledge in diving related illnesses. NOT A DOCTOR OR FREEDIVING EXPERT or whatever else you assumed. take it for whats it worth. it was an opinion based on my knowledge of DCS not freediving. You were so eager to say I was wrong that you missed many points about where this info was coming from. I wasn;t pulling it out of my ass. It was coming from a dive manual. I never said I was an expert, those are your words. Assuming that I was is your fault. professional and expert are two totally different things.
I agree, but for the ones who assume it is DCS with out proper diagnosing like many who have posted in this thread can not be considered. The gray area in this matter is very large. And if to narrow it down by saying that competitive freedivers who dive deeper than 200' multiple times are at risk for DCS then I would have agreed, but the thread started out with can freediving cause DCS, which it can but is unlikely due to the physics that cause DCS. Which is why I disagreed and most of my co-works who I have showed this to also dis agreed. but they are divers with a very good understanding of diving related illnesses.
I did read some of the links you posted. some were back dated to the 70s I think, and even early pearl divers but science has come a long way since then. for the links that were current with proper testing I couldn't disagree, but in relation to the topic if you take all the dives on which they were bent and put them next to all the dives in the same time period that no one got bent the ratio fom bent to not bent is very vast. this is why I said it is unlikely. example. for one competition 10 divers competing. 1 gets bent 9 didn't yet all where to around the same depth. It was unlikely to get bent as 1 out of nine did. now do that for every freediving competition in the past year that the freedivers went to about the same depth? the ratio will be alot did't get bent and only a few did. see where I am coming from. it is possible yes, but not likely, on that point of view.
Thank you for clearing up your profession. It was not quite clear from your initial posts. And since your post in this thread was the very first post in DB, we did not know you at all in that time. You wrote:
It is probably my own fault, but I interpreted it so that you hyperbaric doctor - when I'd get bent, I'd go to see a doctor, not a professional diver. And I am afraid others may have misunderstand your claim in similar way.
As for manuals - most of us know them very well. From my experience, big part of freedivers are certified scuba divers as well, and many of them have military scuba training too (including myself). We all know scuba related DCS theory, and we know what it tells about freediving. The problem is that those theories and those claims are simply not consistent with the experience we have as freedivers, and are exposed as false by studies made specifically on freedivers. From those studies it is clear that DCS is a considerable risk, but more research is still needed to quantify the risks, and to find out how the different physiology during freediving influences decompression and recompression.
It is probably my own fault, but I interpreted it so that you hyperbaric doctor - when I'd get bent, I'd go to see a doctor, not a professional diver. And I am afraid others may have misunderstand your claim in similar way.
As for manuals - most of us know them very well. From my experience, big part of freedivers are certified scuba divers as well, and many of them have military scuba training too (including myself). We all know scuba related DCS theory, and we know what it tells about freediving. The problem is that those theories and those claims are simply not consistent with the experience we have as freedivers, and are exposed as false by studies made specifically on freedivers. From those studies it is clear that DCS is a considerable risk, but more research is still needed to quantify the risks, and to find out how the different physiology during freediving influences decompression and recompression.
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Good info is being put out. There is no reason to be offended. we are just coming from two different areas and the points we bring to the table are valid yet they are oil in vinegar so to say. The gray area (who gets bent and who doesn't) will always be in controversy because we just dont know. genetics plays a big role in diving medicine.
I live on an island and as to many other people who live on islands military divers are the ones they come see because well we usually the most qualified to do treatment tables and we can pull from a wide variety of resources. Civilian chambers are either to far away or aren't used for diving related illnesses, even in the states a chamber ride involves taking a helicopter to it some times hundreds of miles away. we take our chambers everywhere we go. which make us very vital to the civilian divers and freedivers. yet still to this day haven't had a freediver come to one of our chambers.
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"Personally, I am quite chilled out and enjoying the discussion very much"
Trux, that's the problem, you are enjoying it very much, at least, so it appears from here. Beating the guy up is still counter productive.
I have very much enjoyed this thread. You are right that strong arguments are very useful and often bring things to light that need discussing; I completely agree. Polite, strong argument works better than beating people up. In this case, I find it hard to imagine that anyone reading the thread would conclude that there is no chance of DCS being a potential threat. Again, IMHO, it has the appearance of a replay of what we have seen many times in freediving, the "expert" on something that appears to be relevant to freediving makes what look like flat statements that latter proved wrong. Of course, I could be wrong.
Trux, that's the problem, you are enjoying it very much, at least, so it appears from here. Beating the guy up is still counter productive.
I have very much enjoyed this thread. You are right that strong arguments are very useful and often bring things to light that need discussing; I completely agree. Polite, strong argument works better than beating people up. In this case, I find it hard to imagine that anyone reading the thread would conclude that there is no chance of DCS being a potential threat. Again, IMHO, it has the appearance of a replay of what we have seen many times in freediving, the "expert" on something that appears to be relevant to freediving makes what look like flat statements that latter proved wrong. Of course, I could be wrong.
I have a friend, who I still work with, who also worked at a civilian chamber on the island. To my surprise the doctors they had working the chamber where just regular MD's. My friend was the one who diagnosed most of the patients and recommended which treatments to use. later to be confirmed by a neurologist who specialized in dive medicine.(only one on island) the only problem was the"neurologist" is very expensive and usually not there. Doctors specialized in diving medicine as usually military (as we have 5 or 6 on island) and there are very few. which is why I can see why not much research is put into freediving and DCS.
I would read the results differently - the conclusion I drew from the documents is, that bents are getting rather "likely" at freediving when certain conditions are met. It especially means when you do not respect surface intervals and ascend velocity, dive for several hours, and dive deeper than 20m in the same time.
And here we are in the same situation as in scuba - if you respect the rules, bents are indeed unlikely - both in freediving and scuba. When you disrespect them, the likeliness quickly raises. The only difference is that at scuba sufficient empiric data is available, and the mechanism well studied, so we know pretty well when the risk is unacceptable. At freediving, there are still far too many unknown factors (especially very different cardiovascular responses, extreme blood pressure changes, vasoconstriction, anaerobic metabolism, strong hypercapnia, ...) so we cannot reliably estimate the risk. Calling it "unlikely" is definitely not the right word, on my mind, though, because the likeliness only depends how much you violate the safety rules (and on the tolerance of your organism of course too).
This is why freedivers must be educated about the risk, and why it should not be dismissed outright as improbable.
I would agree. I wasn't dismissing the fact that it can not happen. As we all know it can and will happen. Unlikely may have been bad word choice but still got the point across. maybe if I said the percent of freedivers that dive to a certain depth and get bent in far less than the divers who dive to the same depth and dont get bent. As we push the limits of our bodies the unlikely/likely hood of getting bent with fluctuate greatly due to the study not being wide enough. As we know some people get bent much easier than others and some super human freaks just can't get bent all at. understanding the human body is the key to freediving as there is no man made devices involved in the mechanics that let you hold your breath for long periods of time.
Took us 5 pages to reach a civilized discussion. :duh
onebreath, before you ridicule efattah for getting the DCS, tell me what diving table should he have followed to avoid getting the DCS?
I think you also stated that some people get DCS, some don't even when they follow the same table. Would you laugh at those DCS stricken people, too?
Have a look around the forum for posts by efattah and other active members and you'll find active minds, searching for answers, ready to consider ideas that haven't been fully explored yet. I think you'll also find that freediving is an undiscovered country, despite the great collection of studies, articles and documents that trux has been collecting.
Also, your presence here will be much more appreciated if you ask questions first, rather than making assumptions and that goes for everyone.
I have a question for you: please explain the distinction in technical/medical terms between the bends and DCS. I think most people use the terms interchangeably, so illumination from you would be appreciated.
onebreath, before you ridicule efattah for getting the DCS, tell me what diving table should he have followed to avoid getting the DCS?
I think you also stated that some people get DCS, some don't even when they follow the same table. Would you laugh at those DCS stricken people, too?
Have a look around the forum for posts by efattah and other active members and you'll find active minds, searching for answers, ready to consider ideas that haven't been fully explored yet. I think you'll also find that freediving is an undiscovered country, despite the great collection of studies, articles and documents that trux has been collecting.
Also, your presence here will be much more appreciated if you ask questions first, rather than making assumptions and that goes for everyone.
I have a question for you: please explain the distinction in technical/medical terms between the bends and DCS. I think most people use the terms interchangeably, so illumination from you would be appreciated.
I was being sarcastic. I would never laugh at someone with DCS as it is very serious matter. And it takes alot more to come forward and say you have gotten bent especially in my profession because we all think we are "untouchable"
To answer the bends DCS question:
The bends is DCS but many use the bends as a vague term to mean "I was diving and I dont feel right after wards." And many people say they got a DCS hit when in actuality they don't really know what the hell happened, all they know is they feel different after diving. People will swear they got DCS but many of the symptoms are the same for a few illnesses but treatment is different, so unless you really know the difference it is hard to diagnose without proper training. A lot of people on this forum use DCS improperly and I have seen it alot in other forums as well that are specifically for scuba diving. Mostly because they don;t know better. Most certified scuba divers dont really know the difference because it is not taught in basic or advance classes. Some instructors I have worked for and talked to don't even know much about DCS and A.G.E. as I have treated a few. This is why I had a bit of a problem with this thread and random people saying they got DCS when it really could be something else.
DCS(type 1 and type 2), A.G.E., P.O.I.S. (pulmonary over inflation syndrome) that includes pneumothorax (tension and simple) mediastinal emphysema, subcutaneous emphysema, CNS 02 toxicity, hypoxia, hypercapnia, CO poisoning just to name some of the serious ones.
Site I googled: Occupational Medicine this really doesnt go in todepth but it is basic info. reading this will put you way ahead of most people when talking about diving related illnesses.
The most common type of diving disorder that would seem logical with freediving would be the P.O.I.S. As many freedivers "pack" which fills the lung cavity to capacity if not over capacity. Now with that being said on ascent is where this would be a concern due to boyle's law. although you are not breathing gas at depth the lungs are still filled over capacity on the surface along with a rapid ascent, the expanding gas can possibly cause a pneumothorax tension or simple (simple would be a one time leak thru the pleural cavity and tension would be a continuous leak that you would surely notice on inhalation) it would feel like trying to breathe with a broken rib on one side of the body. mediastinal emphysema could also be of a concern for freedivers which also occurs with rapid ascent and holding your breath. if you have ever heard of someone getting rice crispy's on their neck that is subcutaneous emphysema. a lot of things are possible while freediving, knowing what they are and how they happen may minimize the risk but in the end there are a lot more factors that contribute to diving disorders, and even more that unknown in freediving.
i am somewhat opposed to the idea that whoever is posting here has a greater obligation to the "freediving community". people post their opinions, based on whatever, and that's it. if i, or someone else, believe or adopt content into diving practise that is entirely our own responsibility.
well, i'd say the ascent rate is the primary and only factor that leads to DCS. if a diver doesn't ascend exceeding a certain ascent rate there won't be any bubbles. no bubbles, no DCS. everything else (predisposing factors, exposure time, pressure, etc...) just explain the quantity of bubbles and the degree of a possible incident. no?
everything freedivers are doing are just procedures to minimize the DCS risk. bubbles are forming, they just don't cause symptoms.
roland
The ascent rate is important, but certainly not the only factor. It is true that it depends on your ascent speed whether you get bent or not. That's correct for both freediving and scuba. However, there are other factors that determine the maximal ascent rate; and that's especially the maximal achieved pressure and the level of nitrogen saturation. Those are then dependent on the depth, the duration and profile of each dive, the number of dives, surface intervals, the total time of the diving session, and then of course on many other physiological factors which may be quite individual.
So you are right that the ascent rate is decisive for the creation of the bubbles, but the quantity and the size of the bubbles (and hence the maximal possible ascent rate) will be greatly dependent on the other factors. At a single deep dive, it will be especially the depth - you certainly agree you are not in the same risk when ascending from 5m (even if it is quite fast) and when coming from 100m. But at repetitive dives, the studies clearly show that the risk raises, besides the depth, also with short surface intervals, and with the time of diving / number of dives. That proves that the nitrogen saturation exists and plays an important role in freediving too.
The next question, which I did not see addressed in the documents I studied, is whether extremely high CO2 level in depth (common in freediving but not in scuba) does not pose decompression problem itself, or as an additional factor to nitrogen decompression.
EDIT: alone it is probably not a too big problem, because CO2 bubbles would get rather quickly eliminated by hemoglobin once you start breathing, but I imagine it could aggravate and accelerate the creation of nitrogen bubbles during the ascent.
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