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Old 08-14-2006, 04:26 PM   #31
Dignan
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Re: Deep water black out question.

I've seen stars a couple of times at the end of dives, everytime i was out of the water for at least a couple of hours afterwards.

Then i blacked out in the pool at a PFD clinic doing a static, very scary how quickly it happens, i didn't even know i had done it until afterwards they asked about how it felt. very scary....
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Old 08-14-2006, 05:12 PM   #32
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Re: Deep water black out question.

My understanding of it is that to black out on the bottom (no SWB) you have to stay well past the time you could still make it back to the surface. Like a multiple of times. This is because of the increase in particle pressure at depth.

I have passed out twice doing statics in a pool and once doing dynamics. To throw some numbers out as an example, if a person is capable of doing a 2:00 minute dive to 66 feet. They probably take about 20 seconds on descend. That means they need to leave the bottom at 1:40 from the time they started their dive: 20 seconds down, 1:20 on the bottom and 20 more seconds to make it back to the surface.

A person capable of doing this dive, should be able to do about a 4 minute static, give or take a minute. The difference between a static at the surface and laying on the bottom in this example is two. First the diver exerted himself for 20 seconds and thus had less O2 and more CO2 when he started his non-active phase, second the particle pressure at 66’ is 3 times what it is at the surface, so even though the diver burned more O2 before starting the dive, his lungs would be able to extract more O2 than at the surface.

I believe the 3 x increase in particle pressure would more than make up for the 20 seconds of descent, especially when you consider the dive reflex that is invoked with added water pressure, but for this example lets just say it broke even. Therefore the diver should be able to hold his breath at the bottom for 3:40 seconds before he would pass out. Notice this is well beyond the time he needed to leave to make it back safely to the surface. So instead of leaving at 1:20 into the dive, he stayed an additional 2:20 for a total of 3:40? Is it possible to distract your mind so much that you stayed almost 3 times down longer than usual? I and others have searched long and hard for such mind over matter methods to use in statics.

CO2 is an interesting theory, but I don’t believe it is the reason for divers blacking out on the bottom lying motionless. CO2 is created by the use of muscles. The 20 second descent in the example would increase CO2, but nothing like doing a dynamic for the whole dive. CO2 blackout and all this stuff have been studied extensively. CO2 blackout can occur, but it is when CO2 is taken to the extreme. Another name for CO2 is pain! Accumulation of CO2 is the main cause for the urge to breath. The point at which a person can blackout from CO2 is beyond most people’s ability to bear. Breathing off excess CO2 before holding the breath can help a person make it to the point of blacking out from low O2, but it cannot help a person reach the point of blacking out from CO2.

Kirk Krack knows what he is talking about. He has worked with many researchers and witnesses many blackouts. In all of apnea there is NO proven deep water blackout. No camera and usually no people to witness it. Yet in freediving events and research 1,000’s of blackouts have been observed and documented. Kirk hit the nail on the head. It’s silly what us spearos do, all in the name of freedom and tradition. We should be ashamed that our sport has more fatalities than any other more major organized sport!

Sorry if I offended anyone. Just felt I needed to say it like I saw it.
don

Last edited by donmoore; 08-14-2006 at 08:04 PM.
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Old 08-21-2006, 09:51 PM   #33
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Re: Deep water black out question.

Don, were these just numbers you picked or do you actually make it to 66 feet in 20 seconds? Thanks,
Derek
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Old 08-22-2006, 12:55 PM   #34
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Re: Deep water black out question.

Derek,
Yes 20 seconds is about what it takes to do 66 feet one direction. That is 1 meter per second.
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Old 08-22-2006, 01:45 PM   #35
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Re: Deep water black out question.

hey guys this info on SWB is very eye catching.. i just started freediving so any advise that you guys can give me will be very helpfull..ty...BULLSHARK!!!!
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Old 08-23-2006, 02:51 PM   #36
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Re: Deep water black out question.

I had always heard that for some reason 1 meter per second was supposed to be the ideal speed, but I rarely reach it. Maybe at the very end of my descent or ascent. What kind of fins do you use? 40 feet usually takes about 17-18 seconds, and 100 takes a little over 40 seconds for me. I'm sure I could do 1 m/sec, but I would really have to exert myself. And I didn't get in to freediving to put forth effort (just kidding)!
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Old 08-24-2006, 02:34 PM   #37
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Re: Deep water black out question.

I think you guys are discusing 2 diferent things.
We as freedivers vs we as spearos, and BO are very serious , Pure freedivers
have taken the step of not diving alone, and it has been very succesfull, also, they use less lead on their belts, wich xplains why some can go down faster than others.
I will be short here, for a fact, some divers have died from statics in pools, no need for pressure changes like in SWB, recent memory a guy in a Florida pool, training for
the USA freediving team, he died siting in less than 5 feet of water, weight belt on.

We as spearos , spend a lot of time in the water, but on less depth, its the fact that we are alone what kill us.
In blue water for example, a 2 minute dive for me, is a deep dive, I go down, wait , go up, and do it over and over again, for hours and sometimes days at a time.
In a freediving class, I can go down so much deeper, just a few times, with someone with me, and just be so much safer.
I read a lot of people asking how deep you can go, well, you should ask, how long you can stay down, this is even more dangerous, just because every dive is diferent, and is also diferent every day, and for every one.
Is not the 02 , CO2 , the pressure, or the black out what will kill us, but the fact that we are diving alone.
I have seen my share of black outs, is just a switch, turns off the brain, no big deal, but underwater, alone, it leads to death.
To freedive safely, you cant be lazy, you need a buddy, and to know a few things, why cant we just spearfish the same way, I have dome it many times, and most times, i dont have a buddy who knows whats going on, so actually am diving ALONE, with someone near by, not the same thing.
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Old 08-29-2006, 12:45 AM   #38
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Re: Deep water black out question.

This is just my 2 cents, I had a shallow water black out for the simple fact of chaseing a fish, luckly me and my dive partner dive one up, one down and a shoulder width apart. So no one else makes the mistake, I had gotten up that morning and run a 15k race feeling tired and having the rest of the day off my buddy said how would you like to go diving. I said sure and we made a 1 1/4 mile swim out to our spot, still feeling the excertion from 5 hours before i made a couple dives to about 70ft we continued this for about an hour, but i could not get good bottom times on my computer. As i grew more relaxed in the water we decided to head out to the ledge as planned, we made about 5 dives to 95ft and then i saw i nice coral trout at the bottom of a large coral head and made the dive, as i hit the bottom i saw the grouper but it went to the other side of the coral head, i followed it and as i got to the other side he scooted again playing cat and mouse, finnaly i saw him though a gap and took the shot, as i swam over to him i tried to get the shaft unstuck finnally i start for the surface, and that is when i realized it was a long way back up. The catch is this, on the way up i got a thigh cramp or charlie horse. this was at about 40ft, my buddy said he said i stopped kicking at about 15ft from the surface and my momentum carried me to the surface due also to my weight being adjusted to float at 25ft lucky, for me my trusty dive buddy was and did catch me at the surface. i do not remember anything but getting the cramp on the way up and wondering why my buddy was trying to keep me afloat. the dive registered 2:36 seconds at 108ft and 3:57 seconds total dive time. I belive that this occured from being dehydrated and haveing phsically exerted myself earlyier in the day. Hope you all take a note from this and remember that no fish is worth dying for because you wont live to brag about it! and that you should be properly hydrated before every dive !
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Old 08-29-2006, 07:29 AM   #39
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Re: Deep water black out question.

Glad to hear you are OK.

Due to your bad experience, I have promised my wife that I will not do a 15 k run in the morning and then follow it up with a hunting dive to 108 for over 2 and a half minutes..
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Old 08-29-2006, 07:51 AM   #40
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Re: Deep water black out question.

its not the time that matters its the excertion that truely matters and every one is susceptable if you lose track
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Old 08-29-2006, 08:04 AM   #41
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Re: Deep water black out question.

A quick addition/correction...

SWB is caused by a drop in O2 *partial* pressure on ascent into the hypoxic range which is thought to be below .12 or so, depending on the individual.

CO2 increase causes the urge to breathe but O2 sustains life and consciousness. The reason SWB occurs is because an O2 partial pressure of .21 (the same as air at one atmosphere) at 33' becomes .105 at sea level and will cause black out due to hypoxia, or not enough O2.

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Old 08-29-2006, 12:02 PM   #42
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Re: Deep water black out question.

[quote=DABEER. the dive registered 2:36 seconds at 108ft and 3:57 seconds total dive time. [/QUOTE]

So you're saying you were at 108ft for 2:36 and the dive was 3:57??
Are you sure you're not just adding a couple minutes on that dive for dramtic effect?

At what point in that dive did you black out?

That sounds RIDICULOUS to me, I've never heard of anyone who does dives like that......, no even GR, ALBERTO March, NOBODY...That actually sounds pretty stupid to me, chasing fish around and exerting yourself that much for THAT LONG at that depth.

If what you're saying is true, then you need to pay a LOT more attention to your watch on those dives. 2 and a half minutes at that depth is PLENTY of time to spear ANY fish, and if you dont have the skills to get whatever fish you want on that dive, just go up and drop again. A dive like that is just plain stupid to do trying to get some dumb coral trout, and regardless of if you actually did stay down THAT long, you risked your life for that fish, a CORAL TROUT....come on.

Us freedive spearos need to be smarter divers as a whole, this is one of many stories I have been hearing lately that makes me think some people shold not be in this sport. Chasing a little grouper around at 108 ft for 2 and a half minutes, Dios Mio brighten up and grow a brain.

Sorry if that sounded a little harsh, but it needs to be.
Deaths from SWB are very detrimental to our sport, and we dont need any idiots running around chasing grouper at 108 ft for 2 minutes

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Old 08-29-2006, 12:16 PM   #43
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Re: Deep water black out question.

Quote:
Originally Posted by wreckchick
A quick addition/correction...

SWB is caused by a drop in O2 *partial* pressure on ascent into the hypoxic range which is thought to be below .12 or so, depending on the individual.

CO2 increase causes the urge to breathe but O2 sustains life and consciousness. The reason SWB occurs is because an O2 partial pressure of .21 (the same as air at one atmosphere) at 33' becomes .105 at sea level and will cause black out due to hypoxia, or not enough O2.

Rachel
Whoa, lightbulb. That's the first explanation of SWB that makes total sense to me. O2 starts at .21 at the surface, then increases in partial pressure as you descend. You use some, and PO2 drops. You don't blackout at depth because you maintain higher than .105 (or .16, or .14, or whatever your personal BO tolerance is). Then you ascend, and the PO2 in your lungs drops rapidly. When the PO2 crosses your threshold while ascending, bam, you're done.

Sorry if that was redundant, just sort of thought through it "out loud".
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Old 08-29-2006, 12:27 PM   #44
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Re: Deep water black out question.

That pretty much sums it up although it's not the PP in the lungs, it's in the tissues.

R
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Old 08-29-2006, 05:30 PM   #45
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Re: Deep water black out question.

Dude,
That same sh*t happened to me diving the Corey and Chris off of Pampano Beach FL.The day before I had brought the entire Fl Gators cheerleading team to climax so I was quite tired.
We decided to go diving so I leveled out just above the wreck at 200 feet.Just then a 180lb AJ swam up and I shot it right in the ass.After 5 mins on the bottom I subdued the fish and started up.At 100 ft my left nut started to tingle? I guessed it was from yesterdays activites.At 50 ft I saw boobs and the next thing I know I was on the surface coughing up a pair of thongs.


[quote=DABEER]:. the dive registered 2:36 seconds at 108ft and 3:57 seconds total dive time. I belive that this occured from being dehydrated and haveing phsically exerted myself earlyier in the day.
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