Have you experienced a Shallow Water Blackout?

I have an beginner story from a few years back in Canaries islands.

I was diving with a friend, at something like 13m deep, quite soft fins (beutchat gold or something like), when I clearly step over my own boundaries... This little hole in there: may be a fish and is just a couple meters away!

Once I try to turn over to get to the surface I get a cramp on the back of my leg, that instantly kill any kind of self control I had... and I start to lurk desperate at the surface while trying to force my way up with a cramp and gutless fins... you can see the picture!

At two meters of the surface I start to feel myself all warm and well feeling, like a soft and comfortable slide away with blur visions of my loved girlfriend... Nothing painful or scary, more like a full state of relaxation on a hot bath and all my builds payed!

My friend report to see me come up like an arrow surrounded by a cloud of bubbles, to pierce the surface with an open mouth and start to sink straight down by my own weight. He then grab my arm to pull me back to the surface before thinks get to nasty.

I just remember his face and fell something burning down my lungs before the cuffing nearly kill me.

Once over and after a relax I resume fishing a more suitable depths, and see the only albacore school I never encounter under water.

The over all time of the dive was well on my marks, no contractions or discomfort. But from my feelings and the accumulation of other experiences (I'm not a bad samba dancer now) the over consumption and the fast descend of the partial O2 pressure get me in trouble by starving my brain. But is a lot to say from the lack of concentration and self control about the primary causes...

For a time after that I adopt a 3kg drop weight connected to the floating line that make the ascent much safer: until I get better fins! The experience teach me the hard way a boundary to be careful with... and I learn a lot from it.

In most cases, diving with someone else means that each is after a different fish, and only fishing with one gun is a warranty that someone is ready to act in this few seconds that can save your live. Because that is not always possible, I take much care on have a huge margin of air and control when hunting, and let stomach dancing or over complicate preparations for the training when I get more concentration and attention.

In contrast my lasts dives are a gentle glide to the depth of the day (depending of my condition), with a relax ascent with no loss of bubbles or unnecessary efforts... all in the rhythm!!!
If anything is not feeling right, or well before the first sign of contraction back to the surface, but slow and if needed I breath the air in the mask in and out a couple of times to help. In the surface just deep slow breaths, but I'm going to try some M1 technique (forced breaths) to recover faster.

Is anybody else using the same technique to breath in and out the air on the mask during the ascent? Nobody seems to use it over here! any contraindication from the gurus I've seen along the threads?

Thanks to every one is sharing his experiences and knowledge along the treads!

I was told by a trainer at a pool that SWB is also to be avoided as if you BO once your body becomes less tolerant to CO2 the next time. Anyone know anything about this?

Always dive with a buddy - unless you want to take the V out of dive.

Just last week I had my first (and hopefully last) SWB. Fortunately, the lifeguards knew what I was doing and I signaled before diving I was going to try my max.

Normally I can do 55 meters with no fins. But i had already been swimming 2 hours (with a 20 minute break) on an empty stomach. So I must have burnt out most of my anaerobic reserves.

First, there is absolutely no warning whatsoever. I did not get tunnel vision. I did not get loss of color vision. I did not get contractions (I never do, I don't know why). I remember reaching 40 meters, thinking "I'm out of air, but can make it on my anaerobics!" - swimming as fast as possible. Next, I remember felling someone touching me, seeing the corner of the pool and the two other lifeguards and knowing "I'd made it":

I do not remember attempting to ascend but I did. The pool is 4 m deep. I swim close to the bottom to max 02 pressurization. But, like I said, I don't remember trying to surface.

Midway on ascent I stop ascending, start sinking, and then lay on the bottom for like a moment. The lifeguard jumped right in and got me right out. I started breathing on my own. They would have let me keep swimming but I decided to call it a day.

The next day I had a massive headache and my legs were very sore. The headache lasted 1 day. The sore legs 2 days. I took a day or 2 off.

I expected either tingling skin (nope) or that everything would go red (nope).

The thing that pisses me off is that its shot my confidence. My training partner is teaching free diving in Egypt now and wont be back for at least another month. So for the next month I am just doing 35 meter underwater sprints and aerobic bike training.

One thing I do differently now is to keep my head more horizontal so that my corotid artery has no resistence (bend your neck back check out corotid to see what I mean). I am also really conscious about my ascents. I am also not pushing myself as hard as before at least not till my partner gets back.

He also had an SWB. When he gets back the first thing I intend to do is to compare notes - and then to knock out 60 meters. This is really pissing me off...

Also I have had a couple sambas. That was the odd bit though - I did not get any muscle spasm underwater, at least not as I remember.

So, yeah, I would REALLY like to compare notes with ANY SWB survivors to figure out how to spot this insidious killer. My rule used to be "blow air and anaerobics for 5 meters". Now its "blow air and surface": at least when not with partner.

Hypoxiajunkie,
I have had two blackouts while training statics, which I have described on other threads, and both times I didn't get any warning.

I agree with you that it is hard to get your confidence back after something like that.

The first time it happened, I don't remember feeling anything before BO except a strange relaxed feeling, and it was impossible for my buddy to know exactly when I blacked out because there were no obvious signs that anything was wrong. The second time, I had a strong urge to breathe, but no contractions. I decided to stay a little longer, but ended up passing out and having a major samba. I also had a samba and nearly blacked out when someone (not a buddy!!!) held me under for some time after I ran out of air. Fortunately this time I managed to rescue myself.

In all these instances, and in the three times I have been the buddy to someone who has had LMC, there was a (usually failed) attempt to get to the surface. However this decision is usually made too late - once I tried to do this after being unconscious for about 40 seconds!

From my experience, and from what other freedivers have told me, there is no reliable way to predict LMC/BO.

I'm sure you will get your confidence back - I felt the same, and now it doesn't affect my performance at all.

Best wishes,

Lucia

I talked with the lifeguard who fished me out. I was literally AT the surface at the time of the black out so my memory of seeing the lifeguard and them helping me may actually be from when surfacing - and not from when being fished out. This is very good to know. Its restored some of my confidence.

I literally had one hand out of the water! I was literally inches from 02 when I blacked out. ARGH!

Anyway my biggest mistake was blowing all my 02 - every last reserve - with still 10 or even 15 m to go. That and apparently exhaustion of anaerobic reserves.

Till my partner gets back I am focusing on improving my technique. For example I did 40 meters today with no breathe up. Just plunged in and did it to see how my c02 reaction was. I did several sets of 45 to 35 meters during two hours. The lifeguad confirmed my worst fear. I have a lousy kick technique, at least without fins.

Anway my rule stands: once I've blown all air its time to surface. However I am going to become a lot more conservative about blowing 02 and relying on anaerobics. If I had not blown the 02 I would have made it. I think that and watching my sufacing and eating some salt will prevent this in the future.

Blowing air out is a sure-fire way to blackout. A primary rule is to never exhale until your head is out of the water. (or, upon ascending in a constant weight dive, I would exhale no more than 1 or 2m below the surface).


Eric Fattah
BC, Canada

Couple of things.

Hypoxia, what do you mean by blowing your O2? Do you mean you empty your lungs before you surface? I'm not really understanding you.

Lucia, the person that held you underwater would have been knocked out if they did that to me!

Lastly, I experienced three, yes three (3) slight Sambas on Saturday's dive. My partner was close by and when we got to shore he didn't even realized I had them. Symptoms were eratic breathing, slight twitching of my feet and spasm of my left hand. Dives weren't that deep or long, I guess I'm really out of shape.

Brad

Originally posted by w3ac
Couple of things.

Hypoxia, what do you mean by blowing your O2? Do you mean you empty your lungs before you surface? I'm not really understanding you.

Lucia, the person that held you underwater would have been knocked out if they did that to me!

Brad

Click to expand...

Yes; Basically, I slowly blow out my 02 as the urge to breathe grows. However at the end of this dive I was basically "reverse packed" with at least 5 maybe even 10 meters to go.

So I am altering my diving style. No longer am I going to blow out any of my 02. And when I do I will immediately surface. I may try the "j hook" breathing. I'm also eating salt again. Speaking of which: salt and garlic. Are either bad or good for freediving?

Oddly, while coming up from a 25 meter once at the pool I noticed there was someone was where I wanted to surface just hanging around not swimming (I really hate that; people that want to sauna should go to the sauna). So I adjust my surfacing appropriatey so as not to surface in the middle of him.

As I am coming up I notice something odd - I seem to actually be surfacing where he is - have I miscalculated?
So I try to move out of the way.

Then the mother6u3k5r actually puts his hands on my head and pushes me down! B1$turd! Thank god I was not trying to surface after a 50m run (I use no fins and my kick technique needs a lot of improvement...).

So when I come up surface my fist is clenched and my arm is cocked. He came within 1 second of a broken nose. I was in the military. Um, I'm not unfit either.

Turns out the idiot thought I was someone else. He was shocked and horrified. I explained to the kid (he must have been at least 18 so he should have known better) exactly how dangerous what he did was and how close he came to getting his clock cleaned. I think the look on my face and the clenched cocked fist said it all. But I explained it to him in no uncertain terms twice just to be sure he got the message. There is one less idiot on the earth today, the nice way.

If someone like that gets me killed some day i intend to reincarnate and return the favor. Anyway I was livid , and rightly so.

Oh, today at the lake I did a couple 5 meter dives. I know that is nothing but I have been doing mostly dynamic, i.e. I am a beginner diver. I do know not to go deeper than 20m without being cautious (I'm so far from that right now anyway its not really relevant). And before I do 10m I intend to get an underwater watch so that I can time myself.

Maybe we need to learn underwater martial arts to keep safe in public pools!

Seriously, I am very careful now and avoid surfacing anywhere near anyone in a public pool. It is really difficult not to be scared after something like that - I was two or three seconds away from a very serious accident, as unfortunately I had empty lungs at the time and was already at the limit. I was also upset that although there were many other people in the pool, and lifeguards nearby, nobody made the slightest attempt to help me, so I had to get myself to the surface alone with LMC.

Maybe we should start a poll: Have you had an underwater fight?

Lucia

That all sounds pretty scary... and probably leaves quite an impression on the brain (such as being over-carefull in the next times)...

It sounds like in some pools you better dive with a quick-release knife and a speargun. A knife will clear the way, and with the gun you can shoot the ceiling and reel yourself to that relieving air...
Though explaning 'freediving/LMC/SWB' to the average cop afterwards might not do it.:hmm

Originally posted by elementalphotos
Ok, first of all, I'm not saying SWB doesn't exsit like in this thread:
http://forums.deeperblue.net/showthread.php?threadid=16379&perpage=15&pagenumber=2

Quite the opposite, I just had a SWB a couple weeks ago, and I'm just looking for people with similar experiences to share.

How did the SWB affect you, psychologically or physically? How did it affect your friends and family? Did you change the way you dive after the incident?

I was diving with a buddy when I blacked out, that's what kept me alive today. I haven't dove since, because I lost my mask in the rescue and haven't replaced it. But I don't think I'll have any trouble getting back in the water, we will see once I get a new mask. On the other hand, I scared the hell out of my buddies, not to mention my family. They'll probably think twice about going freediving now. How did you cope with the emotional scars on your family and friends?

Click to expand...

Hey Boer, it's been about two years, but this is Matt, one of the guys who was with you when you BO'd! I was actually thinking about you the other day and tried to use your page to get in touch with you. PM me if you read this post.

And FWIW, you did scare the hell out of me and I didn't stop diving but I started going to only half of my limit (i.e. I had done 60 ft dives even solo but would only do 30 ft dives for a long time). But I'm mostly recovered from my emotional scars now and did a 70 ft dive last week with some spotters (though I still was nowhere near my limit) and do a lot of solo diving again too, not pushing my limits...

Wow.
This underwater fighting stories sound soooo scary! I've never been trough these things...
but sound like a nightmare. OK, It could be funny if it happens at the beginning of your breathhold so that you can freak out the guy holding you, but at the end of the breathold... ugggggghhh

Thanks for sharing this, It'll make me have special care next time I'll go to the pool

Does anyone else have my experience of blackout resulting from muscular exhaustion and or/exhalation?

Recall, I was well and truly tired from 1 hour or more of previous diving.

Was that any other survivors experience?
Or do other SWB survivors had a BO with full lungs and fresh muscles?

My experience was: no major warning signs like "everything goes red" or "everything goes blue" or "panic" or "_Massive pounding in the solar plexus (contractions)". Is this other persons experience or does anyone know of a warning sign?

I'd like to make a few comments based on personal experience and very little else. Divers have always claimed to do way better after a long dive day. There is some truth in the claims, but the reasons are often faulty. IMHO, when you are physically tired you tend to relax more and if you're diving deep or long, you become less cautious or careful about operating close to max. Worked with me.
My second comment is on the 'experience' of blackout. In suffering knockout/blackout six times, loss of memory is a common factor. Once, at the scene of the accident, eye witnesses reported the crash 7-8 seconds later than my last memory. Two very good doctors explained the mechanics and I believe this happens anytime you lose consciousness, maybe even when you fall asleep.
My point is, if you B/O you don't know what happened in those last seconds and some warning signals may have been there. You'll get far better information from the safety than the diver.
Aloha
Bill

My buddy Don when he blacked out doing statics in Kirk's Miami Clinic was very tired afterwards. It seems that your body uses alot of energy to recover from the BO.

In terms of warning signs, one of the girls at the clinic was blacking out, but while her safety buddy was telling her to breath, she was thinking "Now who are they saying that to?" she thought that someone else had blacked out! Which means that not only you may not percieve any warning signs, but that you may think you are OK while in a strange dreamlike state bordering on unconsciousness.

Adrian

Originally posted by hypoxiajunkie

My experience was: no major warning signs like "everything goes red" or "everything goes blue" or "panic" or "_Massive pounding in the solar plexus (contractions)". Is this other persons experience or does anyone know of a warning sign?

Click to expand...

I think there is no reliable warning. By the time I noticed that something was not right, I was too semiconscious to care. As for contractions...not even one.

Strangely, I feel more energetic after a blackout, instead of feeling tired!

The lesson from all this is to ALWAYS have a buddy VERY CLOSE when you are doing anything near the limit, and it must be someone who knows what to do. Also, be VERY careful in public pools during non-freediving sessions, as there are jokers around who might cause a serious accident to someone who would never have got into trouble on their own.

Lucia

just getting back into it

I've really been unable to dive much for quite a few years. Mostly the tremendous time consumed raising kids. etc. This summer has really been the first time I've focused on it in years.
I used to spearfish a great deal in my teens - mostly carp since they are the biggest and most warey fish around here. (learned to listen for them in cloudy waters along rock breakwalls - their scales make sort of a 'crunch' when they spook out of the rocks)
I've never blacked out. The deepest I've been was probably 60 or 80 feet - I'm guessing - visibility was supposed to be 80 and I could see no surface detail - ocean dive obviously - not the great lakes.

The closest I probably came was in the great lakes though. I was cruising along at about 15 feet and shot at a large carp. I missed - picked up my spear, reloaded and continued cruising. I then realized I felt absolutely no need to breathe and surfaced. Way too long a dive for that.

Now I don't even try to push it. I love cruising in about 20 feet of water - just hanging with the fishies. When you chill down there they all gather around. The big, warey bass like to shadow you but if you make yourself small on the bottom and catch their eye they'll come in to look at themselves in your mask - they are also very attracted to wiggling pinky fingers. I love hunting underwater but the laws are pretty limiting here - and most gamefish you can damn near get with a good pair of gloves.

Fascinating reading - I need to learn more to make sure I don't get near it.