Underwater Swim Training- Shallow Water Blackout

[John C. Ratliff]

DD, you realize that the second dive you showed in your video, as well as the first dive, the free diver descended further than you could see, and so was out of sight for a period of time. The second dive was about 1:15, and to a depth somewhere around 100 feet. I hope that you had sufficient surface time (unrecorded) to assess that he had recovered fully from that first dive shown. In my opinion, the second dive should not have been done; a speargun and fish are not worth a life. Repeated diving after an incident increases the risk of SWB.

adfitzer, the decrease in arterial blood oxygen levels is not only due to the decrease in pressure, but also to the reverse osmotic gradient whereby the oxygen flows from the blood back into the lungs because of this decreasing pp in the lungs with the decreasing pressure.

I am going to introduce you two to the Shallow Water Blackout Prevention website.
http://www.shallowwaterblackoutprevention.org

Apparently, we just lost two competitive swimmers and two U.S. Navy Seals to SWB. That is why it is called "The Expert's Disease." What I'm trying to break through is your acceptance of SWB as unpreventable. Here is what they state about that:

SeaRat

THE PROBLEM OF BREATH-HOLDING ACCEPTANCE IN OUR CULTURE

• Underwater breath-holding and underwater swimming have been practiced for decades.
• Coaches and military trainers teach hypoxic training and breath-holding, which can be deadly without professional, one-on-one monitoring.
• Lifeguards typically do not have training to monitor breath-holding.
• Lifeguards and parents routinely accept and encourage breath-holding drills conducted in swimming pools.

 

[dmaziuk]

I think we all understand that drowning is 100% preventable: just don't get anywhere near water. For those of us who chose to get in the water, the risk of drowning is by definition non-zero and the drownings are therefore not entirely avoidable.

 

[TONY CHANEY]

Just a few thoughts:
There is only one way to avoid SWBL...never go below the surface of the water.

Breath hold swimming can cause SWBO and it is dependent on lack of oxygen or increased in CO2.

Hypoxia almost always leaves the victim with permanent damage to include death.

Hypercapnia seldom has permanent effects if death does not occur. (We are not talking about chronic CO2 retension)

Adfitzer has very good points but simply lacks the understanding that breath hold swimming can cause SWBO. From Adfitzer, "I, like DD, really don't think of breath hold swimming as having the potential for SWBO. However, SeaRat and Chaney do". In review, we are all talking about SWBO but from two different points of view. Please go back to the OP, Rooster59's, which was about a young man dying in a swimming pool at the YMCA with family members at pool side. SeaRat and I are talking about this situation and not about free diving which DD has tried his best to change it to. Now if either of you really want to express what can go wrong in free diving, then start a new thread and stop downplaying what can happen in a pool.

 

[dumpsterDiver]

This is getting ridiculous. If you are going to go underwater while holding your breath, then you need to have proper support. It is ridiculous to think that BO can be prevented in all situations.

For a while DAN was promoting the idea that all breath hold dives should be less than 60 seconds... and then i think they assumed all would be good. I'm not sure if they are still promoting that, but it made little sense and people are not going to listen to it anyway. Not so different than saying... don't scuba dive deeper than 30 feet .. so you won't get the bends.

Also, as for the definition of shallow water black out. It has a very specific meaning in the freedive community. Application of this term to swimmers in a pool is not consistent with the common usage. That was my original point.

If the pool safety Nazi's want to hijack the term for their own use...and dilute the meaning of the word.. well not much we can do to stop them i guess.

One of the values in using the term shallow water blackout is to help hammer home the idea to new freedivers that.. they may well feel really good at depth... since the PP of oxygen is high, but as you come to the surface the reduced ambient pressure in shallow depth, causes the brain to "go to sleep" due to low oxygen partial pressure.

How many newspaper articles have we read reference to a diver's oxygen tank?

 

[dmaziuk]

How many newspaper articles have we read reference to a diver's oxygen tank?

Where I grew up to "cut off oxygen" was fairly common slang usage for removing someone's support in general.

 

[TONY CHANEY]

Damn, DD the thread is about swimmers having SWBO in pools. You are the one trying to either downplay it or trying to hijack the thread to a free diving event. SeaRat and I have stayed the coarse and trying to help save some lives. You are the only one trying to add to a thread to either downplay what is actually going on or trying to trump up to what you are doing as bad ass and only for the elite. Your video showed nothing! The diver came up, you touched his hand and all was well. No rescue breaths, no assistance, no time off prior to the second dive (as you stated earlier was the norm), no additional oxygen, etc. You would do better by saying, "damn, I did not know that swimmers die in pools trying to do breath hold events but we see similar accidents happen in free diving." Then start a new thread and I will support you on your stance.

 

[dumpsterDiver]

Damn, DD the thread is about swimmers having SWBO in pools. You are the one trying to either downplay it or trying to hijack the thread to a free diving event. SeaRat and I have stayed the coarse and trying to help save some lives. You are the only one trying to add to a thread to either downplay what is actually going on or trying to trump up to what you are doing as bad ass and only for the elite. Your video showed nothing! The diver came up, you touched his hand and all was well. No rescue breaths, no assistance, no time off prior to the second dive (as you stated earlier was the norm), no additional oxygen, etc. You would do better by saying, "damn, I did not know that swimmers die in pools trying to do breath hold events but we see similar accidents happen in free diving." Then start a new thread and I will support you on your stance.

This is what my first post was.... I reinforced the danger of pool diving where a true expert died alone. You are the one who is providing incorrect information. A black out almost never ever causes death (or brain damage). You should admit that your assertion is wrong. My video was posted to show the way I try to dive and to be available for assistance...I am old and fat and never was a good freediver... If you think my video represents "elite" you are just reinforcing the idea that you are unfamiliar with the topic.

This was my initial comment. I was not the one who confused the bends with SWBO.

Technically, shallow water BO does not result from breathhold swimming in shallow water.

Shallow water BO is a loss of consciousness which results from a drop in oxygen pressure in the brain as a breathold diver ascends from deeper water into shallow water (or more commonly actually reaches the surface).

However, breathold practice in water should never be done without adequate supervision - even if the water is shallow. A few years ago a world record holder died in a shallow pool alone- presumably while training alone.

 

[Bob DBF]

Also, as for the definition of shallow water black out. It has a very specific meaning in the freedive community. Application of this term to swimmers in a pool is not consistent with the common usage. That was my original point.

When I started diving scuba, freediving included SCUBA diving. The freediving I do now is probably not even considered freediving by the freediving community. What they use for their common usage does mean it is the actual definition of the term, and from what I read from you they only use one of the two mechanisms for SWB.

As for damage caused, I've killed my share of brain cells and I've never had a SWB. Some people say they can notice it, others can't.


Bob

 

[TONY CHANEY]

No DD, your first post was, "Technically, shallow water BO does not result from breathhold swimming in shallow water." Now you are trying to change what you have said.

 

[dumpsterDiver]

No DD, your first post was, "Technically, shallow water BO does not result from breathhold swimming in shallow water." Now you are trying to change what you have said.

LOL.. I copied my entire post for the reading challenged and you still don't get it. LOL