Hypoxia Experiment

[Chuck_Northrup]

Ok, this thread is to correct the misinformation regarding the hypoxia experiment and carry on the topics of hypoxia and hypercapnia. 8)

Here is an overview of the experiment (as it actually happend) :

At zero hour loop PO2 was .56/ 97% saturation/pulse 114

1:15 PO2 .28/ 99% saturation/pulse 108

3:00 PO2 .21/ 98% saturation/ pulse 113

3:30 PO2 .17/ 93% saturation/pulse 120

4:00 PO2 .11/ 85% saturation/pulse 122

4:45 PO2 .05/ 75% saturation/pulse 132

5:00 Black Out

I hope this clears things up.

CN3

[Freedive WI]

That makes more sense. I have heard of people blacking out at a range of 37%-70% sa02, depending upon their level of adaptation.

Here is a graph from one of the better freedivers from Canada. You can see the lowering sa02 as time goes on. He never black's out during this hold.

Pluse oximiters can give very different readings depending upon which kind they are. The ones that attach to the finger tips can have a 20 second lag time on what they display. The ones that attach to the ear, or forehead, are suppossed to be more accurate. Some units will never go above 98% saturation on a full breath- since 100% isn't really possible from what I have read. Some of the newer units are said to be much more accurate than the older ones.

I know of freedivers who have bought their own units, off of Ebay, for training pruposes. I still haven't found the need to throw down the $300+ for my own unit yet.

What kind of exercises did the RB instructors recommend for hypoxia/hypercapnia training?

Jon

[Freedive WI]

I found this quote from Eric Fattah, former constant ballast world record holder and "hypoxia geek" who studies all of this stuff at a level I would never care to- since I like to have a social life.

"I have measured SaO2 at blackout for different ph levels via different breathe-ups (and different CO2 levels). There is no doubt that you black out at a higher SaO2 if you hyperventilate."

I am wondering if the higher level of sao2 at time of black out was because the RB diver started out with a higher 02 breathing mix-.56?

Just a thought...... ???

Jon

[Inspirationdiver]

Hey Chuck,

In your data, you show that the breathing loop PO2 dropped from .56 to .28 in the first 1 min 15 sec. During the rest of the test, the drop averaged between .04-.07 per 1:30. Can you explain this? Why did the PO2 drop so quickly right away. When I've done out of oxygen drills on my kit the PO2 drops pretty consistantly until I turn it back on.

[ghosch]

Is it possible that the "subject" started with a full breath, and exhaled that 17% into the loop, so in essence it dropped significantly the first breath, and then leveled out?

When I start my pre-breath, and the unit is maintaining at .7, I'll often see it drop to .5-.55 as it catches up.

[Chuck_Northrup]

ID,

I would not try to read too much into the scientific value of this experiment

I think ghosch is on the right track, we put the "subject" on the loop (with no flushes) right away. The first minute consisted mostly of the loop reaching homeostasis. Obviously there was more disolved nitrogen in the divers body than the loop.

Jon,

We were using the finger type oximiter, I can see why an oximiter closer to the brain would be more accurate.

With regards to the black out, the "subject" in the experiment was about as "average" a test sample as you could have. I think a person who trained under hypoxic situations (free divers/Lance Armstrong) would have a better tolerance for that phenomenon. ???