Blackout Feeling...

[Polorutz]

Ok here's the deal, I train alone usually... I've got these great days when I can get the chances to train with Carlos Coste and other Apnea stars but most days I can train by myself alone.

I have just entered this sport and Im' relatively new, Im' reaching 25m+- CW (Didn't have a depth meter but Im sure it was at least 6 meters after 16m due to bottom landmarks, I knew that a given rock was at 16 and went way past it.)

I reach 50m DWF very easily (no hook breath needed, only a wee bit tired on the legs), I haven't found the strength to turn and go for another 25 or 50 because I don't have a spotter and didn't want to take a chance.

I've started packing and I know from other experiences what a BO feels like, however, when you pack the BO feeling comes rather slowly... like a closing screen or something, I've found that I can most of the time do a short hooklike (as in hook breath) effort and the BO does not occur.

My question is the following, does an underwater BO feel the same? do you have that sort of "reaction time"?

 

[Bill]

"does an underwater BO feel the same? do you have that sort of "reaction time"?"

It is not possible to answer your question because no one can remember the last 8 seconds before blackout. If it happens to you, you will have to accept the account of an observer. That is why some divers say that there is no warning and the safety diver reports an obvious struggle before the blackout.
Aloha
Bill

 

[efattah]

After having many blackouts, I can say that in my case I can remember everything that happened until the blackout, unless the blackout was severe. This was not always the case. Perhaps my brain has adapted to avoid the memory loss which used to always occur.

For me, my vision always starts fading before I black out, but by the time this happens, it is already too late and there is nothing I can do. In that case, my last thought is often, 'shoot, I'm going to black out in 2 seconds and there is nothing I can do...'

I often have blackouts when I have blood tests (blood + me = fainting).

It doesn't always happen though. However if it is going to happen, I feel my vision fading, and I tell the nurse, 'I'm going to black out in 2 seconds', and then I do.

 

[shaneshac]

Hey Eric,

DO you get that buzzing feeling while your vision is fading??

I always feel a whirrrring sound in my head, my peripheral vision closes in, everything gets white and then i'm on the floor.

Blood also does it for me - only my blood though. A big bong did it once too rofl

 

[naiad]

After having many blackouts, I can say that in my case I can remember everything that happened until the blackout, unless the blackout was severe. This was not always the case. Perhaps my brain has adapted to avoid the memory loss which used to always occur.

I have also remembered what happened up to the point of blackout. There is no reliable warning. For me there is a strange, confused and pleasant feeling just before it happens, but by this point I can't make the decision to stop. There has never been anything like vision fading, whirring sound etc for me. The blackout itself is instantaneous.

If you are going anywhere near the limit, always dive with a buddy who knows about rescue procedures.

Lucia

 

[samdive]

I've only had a couple of blackouts but have come close a few times and definitely notice warning signs that include:

visual disturbances - tunnel vision, blurred vision
ear ringing - and one time a definite tollling chuch bell

and most obviously and most weirdly...

I get a very strong metallic taste in my mouth when I am near blackout or samba - like biting down on silver foil... not sure if anyone else has ever mentioned that!

Hope that helps

Sam

 

[naiad]

I get a very strong metallic taste in my mouth when I am near blackout or samba - like biting down on silver foil... not sure if anyone else has ever mentioned that!

I noticed this when coming round from a blackout! A bit late for a warning... :duh

Lucia

 

[Reynard]

How can one know how long one can hold ones breath for? Other than to do it till the point of unconsciousness. Which does not seem sensible. In the words of Clint Eastwood: "A man's gotta know his limits."

 

[Polorutz]

Reynard, the best way is not to go all the way into your limits but sensibly into them, listen to your body and learn to feel comfortable with its messages.

My personal experience is as follows, I started holding my breath until I got my first contraction, that first contraction usd to happen very fast and usually I would get scared and stop the hold. I learned with time that I could set a limit using the contractions, for example instead of holding my breath wating for time I wait for contractions, I set my watch and just wait until I pass a certain number of contractions, 10, 15 whichever and just increment that.

I am nowhere near the limit of my breathhold and I really don't want to be because the limit between a BO and a healthy rise is thin...

 

[X-Fins]

Well i was only one time in BO, in the CASA UCV pool by the way. My experience tell that you will experiencie air hungry but the last seconds will not be remembered. My last remind it's in the bootom of the pool (+- 5 mts). The follow remind it's in the floor receiving the help of the medical personal. No memory about how i get the surface. I tried to get the surface by itself but i can't remember.

I hope that help you, it's similar that the previous answers gived to you.

Best regards, Luis (i'll PM you as soon as posibble)

 

[jome]

How can one know how long one can hold ones breath for?

You can't really, except by going to the limit, but what you can do is sensibly increase the time and if you didn't have problems, be happy!

If you don't try huge leaps, but increase it just by a few seconds at a time, you will find your "samba limit" before your "BO" limit, that's a good sign to slow down.

Just remember that even if you can hold your breath x-minutes without problems, does not mean it is safe to dive solo x-minutes. It may vary from day to day.

Also take into consideration that even if you find your limit, a year from now, it may be totally different. You may samba in 4 minutes now, but with training, a year from now you may not even get a breathing reflex in 4 minutes...

I think the contractions thing Poloruz mentioned is good (if you get them). It's an easy way to learn your self push a bit further. Add 1 contraction every session if the last one felt good and easy...It can also serve as a crude measure of your "limit". You may, for example, know that 10 contractions are safe. However it should not be used to replace proper safety measures, as it is not entirely reliable. One day the contractions are different, come later, are less frequent etc...And of course contractions are completely different for staying still (static) or moving (dynamic), or depth (increases contractions) and depend greatly on the preparation for the dive.

For example on a normal dive you might think that 10 contractions are ok. Let's say these start at 1:00 and end at 1:45.

Then one day, you take a longer surface time and without realizing it, you hyperventilate slightly. You 1st contraction will come at 1:30 and you try to push to 10, but it's 2:30 and you BO.

 

[pat fish]

be aware also about blackouts caused by other factors than hypoxia in general, like a sudden drop of blood pressure due to a sideways movement of head for example (nervus vagus stimulation). there is always a risk when diving alone, even when doing shorter dives.
yours
pat