Does "shallow water blackout" really exist?

[Cliff Etzel]

I think I wasn't too clear on my responses - the heat of the moment thing ya know...

To play devils advocate for a moment: Why would I need to be liberal in my POV? Aren't my actions (or yours) capable of potentially affecting those around us? By being involved in personal relationships, aren't we therefore affecting those who choose to care for us? And if those who care for us - aren't we therefore affecting their emotional well being by practicing poor judgement?

I am not saying that I am responsible for others happiness - they need to be secure in themselves - but it is a fine line drawn between pushing the envelope and going over the edge in terms of good decision making - especially in an activity such as ours. My wife understands that what I do in freediving has an inherant risk - she also knows that I care about her more than the sport and that I would not do anything that would jeopordize my life.

That is making a good decision about what I do. That doesn't make me any better - far from it. But I do feel that freedivers who take the time to understand more about what they are doing, make informed decisions, and then deal with the ramifications of their actions are far more likely to dive safely than those who do just enough to let them say "I did this" or "I did that".

The sport of diving is a male dominated sport statistically (something like 85 - 90%) and as such will more than likely have guys who are thinking more with their "manhood" than with thier brains.

I can understand your tone regarding how I answered many of my posts - but unless an advocate (unofficial) at least puts the idea out there - no matter how much it will ruffle a few feathers, then we will just "coast along" as we have already, without forcing us to "think more deeply" about the sport, how we participate, etc. - and end up with more divers who die due to poor decision making.

I think rather than try to restrict the freedom of people, we should be personally responsible as freedivers, meaning that we should do our best to disseminate accurate information in a reliable way. Perhaps our organizations could collect reliable information, agree upon it by consensus of members and "experts," and then offer it as the view of that organization (keeping in mind the liability issues). Folks would then know that that information has some weight behind it.

- I absolutely agree 110% with you on this - and I think my mind was racing faster than I could type and missed this in my responses.

I specificially would NOT recommend that someone educate himself by simply punching up terms on an internet search engine. I think that is actually an irresponsible way of finding good information. I rely on electronic information finding for my scientific consulting business and hire professionals to assist me - believe me, the internet is NOT the way to go here. There is no way to determine what is good versus bad information on the internet. People have to remember that the internet is a free-for-all in terms of ideas - bad ideas do not come with a label. There is no "truth-in-information policy" on the internet.

- again I agree - My intent was more about getting the basic information and then doing the necessary followup to get actual, accredited information that could be backed up or refuted.

So, I think there is a role here for certification and for freediving organizations to really help the sport. I would be the first in line for a good course if it were affordable and I had some assurance it provided information I don't already have, and I would volunteer time to help organize these things and become a certified instructor. BUT, moving toward restrictions on people is something I would fight tooth and nail. It would be bad for freedivers and ultimately bad for the very sport you are trying to promote.

- EXACTLY! - Kirk Krack is offering through his Performance Freedive Clinics a new beginners freediving class that allows those interested in the sport to get first hand instruction in the basics, while also giving the necessary academics needed to make better informed decisions about freediving.

I wasn't trying to sound elitist - far from it. I think much of the intent get's lost in the sterile tone of text on the screen. I, for one, enjoy seeing newcomers to the sport - to see them react the way I did the first times I went freediving and to see the excitement on their faces. To know that they will be participating in a sport that is simplicity in appearance, yet complex underneath.

I still get a kick out of hearing tank divers rant about the size of my fins when I go diving - I think of it as "Fin Envy"

Well - a good night's sleep has helped me to re-examine my position and how I responded. I hope that this response clarified those concern's you have. Let me know if you are still unclear on some of these issues.

 

[cjborgert]

Cliff,

It sounds as if we actually agree on the concerns and the approach to addressing them. We should urge one another to continue progress toward better education and training for those who want to learn to freedive safely, and more enjoyably. I support this and would like to get more involved myself. So let's make sure we don't coast along, as you warn.

Just one quick point, not in rebuttal, but in explanation. By "a liberal view" I meant that your view of what imperils others would have to be very expansive, with few limits, to include freediving, not that your view coincides with those of political liberals.
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To play devils advocate for a moment: Why would I need to be liberal in my POV? Aren't my actions (or yours) capable of potentially affecting those around us? By being involved in personal relationships, aren't we therefore affecting those who choose to care for us? And if those who care for us - aren't we therefore affecting their emotional well being by practicing poor judgement?
——————————————End Quotation————————————————>
I certainly agree with you that everything I do affects others in some way, my family more than others. I certainly refrain from doing things I believe present an unacceptable risk because my family depends on me and I have a responsibility not to let them down. Being dependable for them is more "manly" than how deep I dive, how fast I run, or how much beer I can drink. But I'm not sure that everything I do directly imperils them, even freediving. More importantly, I don't feel I can draw that line for others.

So we agree. Let's keep pushing to make more information available, and let's test that information against experience, science, and reason so that people understand the level of reliability of that information.

[As a plug, please see my post on safety training for overhead environments. Perhaps you have suggestions. I am really trying to dig up information here to help myself and others. In its absence, I am trying to reason out safety "rules" for myself. If those with experience can help, perhaps this could be the start of helping people understand the risks and precautions that can be employed in diving overhead environments.]

 

[Cliff Etzel]

First day of deep breathiong exercises...

I know that if I had done these over the weekend before responding like I did to the various posts, I would have been more clear minded and more thoughtful in what I had to say.

But I am pleased to hear that we are both on the same wave length regarding these issues...

Now off to do my PowerLung Exercises (ugghh) :head

 

[snorklebum]

Screw "certification". Though fortunately without the need to buy air, it wouldn't be an inforceable ban like in SCUBA diving. I think scuba divers need to be told what to do, and there are plenty of people glad to get paid to do so...and happy to require more and more people to have to pay. Hey, you've got your heavy principles...I've got mine.

I like your list of rules to avoid SWB. That makes a lot of sense, and does tend to get away from the "random wrath of God" idea that I was also picking up on, and reacting to. Can we assume that those who suffer blackouts are violating these guidelines?

Frankly, I think having free-diving schools and classes would be great, we end up learning things piecemeal. I would especially like to see somebody have classes for cave and night diving, for instance.
But any move to try to regulate free diving (make it less free, if you get my drift) sucks.

 

[Crispin]

SnorkelBum,

I am one of Howard Jones safety divers for the courses he runs at HMS Dolphin (100ft deep tank). I have studied with Umberto Pelizzari, and have observed divers in competitions and in other situations many times. I have been diving in this tank for my third year now and this is what happens....

I have been instructed by Howard to watch certain people at the tank based on breathing patterns and length of dive, because of his awareness I have observed and assisted in the recovery of SWB victims more times than I care to remember... every time 100% successfully I might add.

I have watched all types of blackout SnorkelBum, and I assure you that it exists completely. It has also happened to me, and I can testify first hand to it's symptoms.

When you are diving in a crystal clear 100ft tank and you follow someone up from 80ft and watch them all the way only to see them encounter SWB at 15ft you can truly see what is going on.

Pipin simulated SWB dry I believe* by giving someone a deprived mixture and watching lose conciousness (DRY NOT WET!!!)

*As far as I am aware - but cannot verify %100

Read all the evidence before you cross examine....Don't just question for the sake of it or on a whim....

 

[crazyfrenchmen]

DAN Study

Try this link to DAN. They need people for a study on the subject.
http://www.diversalertnetwork.org/medical/research/breathhold/overview.asp

 

[shaneshac]

SWB

One of my very close friends blacked out at the bottom while practising a "wait" spearfishing, He died. His brother also blacke dout and died trying to lift him up to the surface. So don't tell me SWB does not exist. They were both extremely experienced.

 

[M-2]

DAN Study

...sounded interesting until I got to the part about 'setting up an arterial line'. Kinda lost interest at that point. :naughty

-Mike

 

[Pekka]

Be careful there fellas, all those stories and experiences people have had with SWB and BO leading to critical situations and death make me sad.. I am not saying that wouldn't happen to me...oh that's the worst kinda thinking I think.. But Just a note for all you who have started the sport just this summer or are beginning to think about it.. be careful!

 

[orca]

Thank you so much, this thread has been really interesting. I regularly dive as deep as I can go, and always alone for lack of buddies. I had no idea there was such a thing as shallow water blackout, luckily I've never experienced it although I have felt extremely dizzy and faint at depth before. So thanks again, this will definitely change the way I dive.
Cheers,
Abbie

P.S. What does samba mean? I've seen it mentioned many times, but can't find a definition.

 

[Abriapnea]

Hi Orca , I am sure others here can provide you with a more concise and accurate definition , but a samba is what you experience just prior to a blackout ; mainly ocurring with competitive freediving when depleting your O2 to such an extent that your central nervous system is on the verge of shutting down and pulling the plugs ... Physiological causes will vary depending on wether you are doing statics or returning to the surface from a dive .
It can happen to spearo's as well although we normally don't push our limits to the same extent .
When someone sambas they start shaking uncontrolably , hence the name . They will also have no recollection of the event .
Hope I didn't confuse the issue even more ... ,am sure our experts will put me right if so .
BTW , pucker your lips and spit ...

 

[orca]

Hi Abri

Thanx for the perfect explanation. Scary!
Is there any sure way to avoid it other than being careful and not hyperventilating as mentioned in the previous posts about SWB? Knowing you limits makes sense, but how do you find out what your limit is?

Safe diving,
Abbie

P.S. I know I ask too many questions, and this is completely off subject, but does anyone know how whales drink? It's been bugging me all day...

 

[donmoore]

samba

Orca and Abriapnea,
I just took my first freediving class and the instructor gave a slightly different samba definition. He called it any loss of motor control, such as inability to raise one arms, involuntary shaking, legs, etc.. He said, like with SWB, there is usually denial and anger, and just as with SWB the diver should quit for the day.
Don

 

[M-2]

Hey Abbie! I couldn't help but chuckle at your question about whales. It's one of those things we don't really think about very often. In most cases I think you'll find that whales and other marine animals get the water that they need from their food. Also their physiologies are different than ours so they deal with the water that they need differently.

In all animals, including people, there is a balance that must be reached between salts and water. In talking about these processes in whales, sharks, or other critters it's called osmoregulation. The trick for marine animals is that they have to be able to retain water in a salty environment. Remember that salt robs the body of water. That's why you get thirsty when eating salty foods. Many marine animals have a special salt gland that helps them compensate for the saltwater environment that they live in. I'm not sure if most whales have such a gland or not. When you see sea turtles 'crying' as they lay their eggs, what you're actually seeing is the affects of the salt gland at work.

Hope this helps.

Now to all you DBers that are wondering how we got from shallow water blackout to whales drinking, keep in mind that dehydration may make you more susceptible to SWB (although I'm not sure that's been proven).

Tada! Back to the original thread........

M-2

 

[orca]

Hey M-2! Awesome explanation, now I can sleep...
I liked the sea turtle fact.
Also, good tip on dehydration making you more susceptible to SWB, it made me thirsty.
Cheers,
Abbie

 

[DeepThought]

keep in mind that dehydration may make you more susceptible to SWB (although I'm not sure that's been proven).

I don't think that there's much to prove about this, among other nasty effects, dehydration cause low blood pressure, which will cause less O2 arriving the brain. And dehydration is known to affct the nerve system and reduce alertness. So I don't think it's a 'maybe'.

 

[charcaradon]

"For those who haven't noticed, NAUI WAUI and such have a history of inventing problems and creating weird rituals, probably to protect themselves from any conceivable lawsuit."

Hi there snorkelbum...

As a NAUI Instructor, I feel compelled to leap to the defence of this organisation. NAUI does not "invent problems" or "create weird rituals..." - wow! What a statement! Quite contrary to your allegations, the NAUI (and PADI) curriculums pay particular attention to issues which might endanger the safety of divers. The heavy emphasis placed on issues such as shallow water blackout (and other physiological) hazards are necessary to properly socialize new divers into the diving environment - a diver who is aware of potential problems and understands them is (or at least has no excuse not to be) a much safer diver.

My association with NAUI dates back more than twelve years, and it is my decided opinion that the organisation is certainly not intent on "creating weird rituals to protect... from lawsuits". NAUI's concern, and the primary concern of its Divemasters and Instructors should, by their commission, be to qaulify divers who are capable to deal safely with any conceivable scenario underwater. This is, in my experience, best achieved through training drills (mask clearing, combo retrievals etc), as prescribed by NAUI training guidelines (perhaps the rituals you were referring to?).

Divers who are aware of the physiological and environmental factors that are consequent of being underwater are able to govern their behaviour with due deference to their (and their buddy's) safety.

I encourage you to research NAUI policies and procedures. Perhaps even sign on for a course or two - I'd be more than happy to acqaint you with the NAUI way of doing things!

Safe diving!

 

[gerard]

snorklebum here it goes my opinion

that might change definitively your mind:


Deep diving contrarily to shallow diving increases hydrostatic pressure, which has its effects on human physiology, mainly a reducton of the thorax volume due to the increase of air in the lungs, and you know air is a gas and as such it can be compressed. Therefore a decrease in volume will produce an automatic pressure of the air contained within the lungs and a partial increase of O2. This means that according to Henry's Law more O2 will be shifted to the blood and as a result you'll be able to stay longer under the H20 than if you were at surface level (in other words, at athmospheric pressure)

****************************************************
Henry's Law states the following (basic Chemistry):

Pgas = k Cgas

Pgas = pressure of the gas above the solution

k = constant for a particular gas at a particular temperature

Cgas= concentration of dissolved gas

The solubility (that does not react completely with the solvent, i.e. O2 and blood) increases with increasing pressure of the gas above the solution.

****************************************************

Therefore, increased time on depth depends on the availability of O2 hat can be used.

However, there is a trade-off and as such we must give back what we took on surface, when our thorax recovers its original volume with the result that there will be fall in air presure and partial O2 contained in the lungs. This will produce a sudden fall of the O2 required for a normal functioning of the body, and as a result "shallow water black-out" will occur. This "disequilibrium" will sometimes shut the O2 required for a maintenance of the nervous system because it quickly travelled to the lungs, especially in the last meters of the ascent. And sometimes it also happened that the freediver, spearo or whatever blacked-out with the head out of the H20 when they were going to exhale as they "broke" that equilibrium in pressure in that critical point (exhaling). This shows how precious is diving with a competent buddy.

IMO freediving is a crazy activity for crazy people like us fellows of the RT.