Feeling the OOA

[dumpsterDiver]

The question is not what mechanism stimulates the urge to breath, most everyone knows that it is a build up of CO2 not depletion of oxygen. That is one reason why hyperventilation prior to freediving is dangerous.

However, do we really think that hemoglobin saturation values will not drop after SEVERAL minutes for a swimming and active diver without any air in their lungs?

I seem to recall some data from DAN on freediving and as I recall, the hemoglobin saturation levels began a noticable drop in freediver at approximately one minute of apnea and I can only assume this was done with full lungs (as before, I suspect that empty lungs would shorten the time). Maybe my recollection is wrong?

 

[HenrikBP]

The question is not what mechanism stimulates the urge to breath, most everyone knows that it is a build up of CO2 not depletion of oxygen.

From your previous post (#21) it looked to me to be exactly what you were questioning. Maybe I misunderstood?

Henrik

 

[dumpsterDiver]

From your previous post (#21) it looked to me to be exactly what you were questioning. Maybe I misunderstood?

Henrik

Originally Posted by TSandM
In fact, to your body, it matters very little whether you stop breathing with your lungs empty or full. What determines the length of time you can hold your breath is the CO2 buildup in your blood, and that occurs regardless of the volume in your lungs.

Yeah the topic kinda drifted, but my primary issue was the statement about lung volume being inconsequential. As I said before people pass out from low oxygen not CO2, yes??? Exactly how this relates to the original topic is not too clear to me anymore.

 

[HenrikBP]

Exactly how this relates to the original topic is not too clear to me anymore.

Good point

I guess I interpreted Lynne's comments to indicate, that when the CO2 in the blood reaches a level that forces you to breathe (or try to at least) by pure reflex, you will still be a - relatively - long way from reaching a critically low level of O2. Even if you start out with "empty" lungs (you will always have residual volume of air in the lungs, even after a "complete" exhale: Residual Volume).

If that were indeed what Lynne meant, I still agree with her

Henrik

 

[CamG]

Greetings Thanshin and welcome to SB! Great post with even better information in the following posts. I think you have received some great advice. A true OOA situation can be a very revealing event. My experience was at about 60+ dives at a inland lake @ 40fsw. I had double checked all my gear maintained a vigil on my spg so I knew it was a mechanical failure. Just so happened a fellow diver slipped up behind me and shut my air off. This was not a training dive nor any communication of this event was given. Not cool and was a interesting debrief. Upon drawing my last half breath I gave the OOA signal and share air as I was trained. I then proceeded to reach for his alternate but soon discovered it was either tangled or hose was to short. I had to breath from the second stage from his chest strap. Not really comfortable but it was working. I also learned to breath around water. When he handed me my regulator and turned my air back on I figured what had happened. We had a long surface conversation and I love him like a brother. True story as I told it. I would never recommend doing this to anyone. Since then I have trained to do S drills and OOA share air and stage / pony bottle switches. OOA does not just happen if YOU the diver are being vigilant and prepared for your dive by planning. GAS MANAGEMENT! Great skills that will keep you out of trouble with enough gas!
CamG keep diving....keep training....keep learning!

 

[Thanshin]

Greetings Thanshin and welcome to SB! Great post with even better information in the following posts. I think you have received some great advice.

Indeed. The threads drift but always to some interesting topic.

Actually I'm starting to worry about the fantastic signal to noise ratio in this forum. My theory is that Darwinian forces are strong in the diving community.

We had a long surface conversation and I love him like a brother.

You must've had pretty dangerous brothers.