First Static Warm-up time

Tyler,
I haven’t tried slow breaths at the end of the fire breaths. One of my opinions that has changed from using a pulse-oximeter is exactly that “sense of lightness and well-being” being useful. When I took the performance clinic I told Martin Stepanek that I was addicted to that feeling. He said that some people like to use it to help them get in the relaxed state, but he preferred not to.

With the pulse-oximeter I have found that my heart rate goes up instead of down and my O2 doesn’t stay as high for as long. It will be interesting to see what your results are.

I also don’t believe CO2 causes black out, at least not the majority of the time. The body shuts down from lack of oxygen. Even with poisons gases it usually the oxygen starvation effect that kills. Even in the situation of blackout from hyperventilation, and O2 is high in the blood stream, its still O2 starvation to the brain that causes blackout. This is because the low CO2 tells the body to contract the blood vessels in the brain, which decreases the blood flow and thus decreases total amount of O2 making it there.

CO2 is just the main trigger in telling the body to breath. High CO2 is very painful, and can cause muscle spasms, etc. which will also burn O2 quicker, but it’s low O2 that will eventually cause blackout. Juro, I’m more than willing to change my mind and learn more, if you can give us some documentation of blackouts caused my high CO2.
don

donmoore: I think you mistook what I was meaning slightly. I was not meaning that intense hyperventilation followed immediately by a breath-hold would lower the heart-rate. I was refering to hyperventilation followed by "breathing" relaxation. Which is exactly what you did. You stated you purged for 20 secs and then performed slow breathe-up for another 1:30. This is what I would say is similar to a breathing relaxation. The benefit being a significantly lower heart-rate during the last relaxation phase of the breathe-up, induced by the prior hyperventilation. With a lower heart-rate leading up to the breath-hold I think we have a better chance returning to the heart-rate once the breath-hold begins.

The relaxation phase may be essential depending on the person since performing physical activity affects us all quite differently from a mental perspective. Some people can have their heart-rate increase dramatically at the idea of preparing and/or performing a physical activity.

As far as the lightness and feeling of well-being, I have experienced this for all the past breathholds over 6min that I can remember. Whether doing the standard slow-preparation or the fire-breathing. Definately the degree is different dependent on the amount of ventilation but nonetheless it is always there if I am going to get contractions after 3:30. I also find that when I am having a good breath-hold, I lose sense of time. What seems like 30 seconds ends up being 1:30 or something.

Regarding CO2 blackout: I as well have heard a few references to CO2 blackout being a danger at depth and do believe it is possible. I think I came across some references to it recently. However, I do not think there are many references to actual experiences of such. I will try to find what I can when I get a chance.

Cheers

what I read about CO2 BO

hi don,
I am neither an expert in this field nor have I any personal experience with CO2 black out or narcolepsy.
I just read what was posted on DB forums about this issue.
here are some quotes from posts written by Eric Fattah (whom I'd like to thank for sharing his experience and the info with us):

"On land, the highest etCO2 I have ever managed was 8.8% (after more than 7 minutes of apnea), just short of the 9% required to enter CO2 narcosis. However, doing a pure oxygen breath-hold on land, most freedivers can get etCO2 > 9% and enter narcosis, and some can black out from CO2 narcosis, even when they have tons of O2 left (see for example the study at Duke university).
I bet that Martin Stepanek goes over 9% etCO2 (PaCO2 68.4mmHg) during his 8+ minute statics...maybe he becomes the first person ever to get CO2 narcosis from an atmospheric air breath-hold..."

"CO2 buildup can also cause a blackout, but it is far less common than a low O2 blackout, because CO2 blackouts cannot occur during breath-holds at atmospheric pressure--if you want to experience a CO2 blackout, you either need to do apnea at extreme depth (and stay there), or you need to inhale pure O2 at the surface, and neither are recommended!"

"As far as I know, CO2 itself can cause you to blackout. As the PaCO2 goes over 90mmHg, you enter CO2 narcosis; once you enter CO2 narcosis, you have around 2 minutes before you suffer from 'narcolepsy', or spontaneous falling asleep/loss of consciousness.
The most striking example of this was during the Duke study when subjects would inhale pure oxygen, then hold their breath and bike on a stationary bike. Their oxygen levels were monitored during the test. Some subjects couldn't resist the urge to breathe, but those who could first entered CO2 narcosis, then blacked out, despite having totally safe levels of oxygen dure to the inhalation of pure oxygen."

"The question this brings up is one that me and my friends have been struggling with for ages: is CO2 narcosis caused by low blood acidity in general, or is it the CO2 itself? i.e. could lactic acidosis cause narcosis?
This is very important for me since I nearly blacked out from CO2 narcosis during a deep dive last year"

"CO2 narcosis can only occur when there is unusual amounts of oxygen available. This occurs either during pure O2 inhalation at atmospheric pressure, or during hyperbaric conditions, for example deep diving.
It is well known among variable-ballast divers that hyperventilating before the deep dive reduces the narcosis. I have confirmed that with my own experiments.
It is known that CO2 amplifies nitrogen narcosis, and it was previously assumed that by hyperventilating, you simply reduced the 'CO2-N2 amplification effect.'
But now, after the Duke study, we see for sure that there is such thing as narcosis induced only by CO2. If you do the math on the CO2 level of a deep constant ballast or variable weight diver, you will find a PaCO2 way over 90mmHg during the worst phase of the dive (around 1/3 the way up the ascent)."

"A freediver who blacks out from CO2 toxicity will likely be diving in physical discipline such as variable, constant, or free immersion. The blackout will likely happen around 1/3 of the way up, when he is the most negative, producing tons of CO2, and yet the pressure is so high that his lungs are still completely collapsed, so the CO2 has nowhere to go except the blood."

"Only deep freedivers get CO2 narcosis (i.e. 80m+), ordinary scuba divers cannot tolerate enough CO2 to allow their CO2 levels to go over 70mmHg, with a couple of exceptions--I heard a couple of people with very high CO2 tolerance blacked out from CO2 narcosis while scuba diving at 40m and 69m on air dives (or so the medic claim after examination). I'm not sure how the medic discovered that the 69m blackout was from CO2 syncope and not O2 toxicity."

"My calculations show that the highest CO2 ever encountered will on the ascent of an 80+m constant weight dive, and, that same dangerous CO2 level will start around 70m and peak between 50m and 40m, and it definitely goes WAY over the critical 70mmHg, but there is the question of time. It seems on my 'accident' dive I was truly approaching that time limit and just about fell asleep at 53m. Come to think of it, it feels like I'm on the edge of falling asleep during the entire ascent on the 80+m dives, a classic symptom of CO2 narcosis/narcolepsy."

Thanks Juro. That is very interesting.
Don

CO2 blackout on a cw or f.i dive has always been at the back of my mind. i hope there's more discussion about it on this thread or another. i'm experimenting with extremely gentle breathups, long divetimes and no scuba support, and i'm wondering if i should be worried for dives to say 70(limited by the bottom to depths a bit shy of that for the moment).
related to this, is high CO2 tolerence a help or a hinderance? am i less likely to feel the onset on CO2 narcosis(bad?), or will i be more resistant to it's effects(good?)?? thanks
bevan