Is it possible to determine one's capability to hold his/her breath by any measuremen

[growingupninja]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

But that is probably 85% in the fingertip right? Fingertip oxymeters are not showing the proper low because of vasoconstriction.

How low does it drop after you breath again?

Btw I noticed in the seven sambas text that he seems to get sambas at a higher and higher percentage... I think it is wise to stay clear of sambas, some people say the body will be more prone to samba if it happens often...

I will look at those links. To my understanding it drops after you start to breathe again because of the Bohr shift and that together with sudden drop in blood pressure can cause BO. This is one of the more sobering things I discovered when I started to train with a meter. Also why people black out after surfacing and why you should watch your buddy for a good 30 secs after they surface.

The drop tends to be larger with longer holds and between 10-15% for ones near limit at least for me. For me that drop happens very fast, lasts a second or two then starts to climb. I have nothing to back this up, but a strong cardiovascular system seems like a good thing to keep a diver safe in this period.

 

[Apneaddict]

It was fingertip. It dropped to 82 or 81 after I started breathing again.

 

[baiyoke]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

To my understanding it drops after you start to breathe again because of the Bohr shift and that together with sudden drop in blood pressure can cause BO. This is one of the more sobering things I discovered when I started to train with a meter. Also why people black out after surfacing and why you should watch your buddy for a good 30 secs after they surface.

I saw your thread on the fingertip oxymeters. I think the biggest reason is the simple mechanisms behind the vasoconstriction: If it is strong, the blood in the small bloodvessels in the fingers perhaps pretty much just stay there, and oxygen consumption is really low. In the core, lungs-heart-brain, oxygen is way lower... After breathing again, vasoconstriction realeses, and low O2 blood flows to the finger within 10-30 seconds... Seems likely to me anyway..

That said, the other things mentioned is also at effect of course... I think it's important to watch your buddy for 30+ seconds, but the low O2 is a mechanical false reading to my understanding... By the time it drops down, the brain-O2 is on it's way up...

The drop tends to be larger with longer holds and between 10-15% for ones near limit at least for me. For me that drop happens very fast, lasts a second or two then starts to climb. I have nothing to back this up, but a strong cardiovascular system seems like a good thing to keep a diver safe in this period.

Re-oxygenation of the blood going to brain should take only few seconds... I don't think it matters much what shape your in... But have nothing to back it up either... I'd say that technique, correct hook breathing, would be a more important factor if that close to your limit... But who knows... In general I just don't think being in good shape matters much in this sport (except for helping you cope with training)...

 

[growingupninja]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

Re: fingertip meter. An actual doctor could answer the question, but I think the fingertip reading is for the most part correct although delayed from what O2 is in the core and brain, and of course there is the accuracy/sensitivity of the device itself. Many consumer models are not rated to be accurate at extremely low O2 saturations and HR; what competitive freedivers consider 'not particularly hypoxic' would be cause for hospitalization, tests, and observation in any non-freediving context.

As far as vasoconstruction in the fingertip, most medical grade ones now have a pulse graph--in a state of vasoconstriction the graph is very flat. Some consumer models have a crude graph as well (mine does). I can see vasoconstriction happening and for me it releases in the first few seconds after I start to breathe (on dry statics at least). Cold water facial immersion tests I have done on myself the DR tapers off just a little more slowly. Empty lung it tapers off slower still.

A $70 fingertip meter is not word of god but I consider it a good training tool and trust the consistency of the reading if not the accuracy, at least for values which I train to.

 

[baiyoke]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

An ear oximeter would be better according to some people...

Incindentally there is an excellent video clip I saw once of an air force pilot undergoing hypoxia testing

Sounds very similar to this... My friend watched a documentary that said, that there were more flight gun-men dying from failure in oxygen supply than from battle...!

[ame=http://youtu.be/WTNX6mr753w]hypoxia - YouTube[/ame]

 

[baiyoke]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

Damn!!! I just can't believe that a doctor, supposedly knowledgable about freediving, can generate this amount of complete BS... (about the O2 curve flattening at 80, and about being unique) :-( Start at 8:55

[ame=http://youtu.be/5-0gSmgkkxo?t=8m55s]Superhuman Freediver - YouTube[/ame]

 

[growingupninja]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

Damn!!! I just can't believe that a doctor, supposedly knowledgable about freediving, can generate this amount of complete BS... (about the O2 curve flattening at 80, and about being unique) :-( Start at 8:55

Superhuman Freediver - YouTube

Yes, that is the other video I was referring to. The commentary seems a little goofy but the graph response during his static was interesting when it held very steady for a while at 80%. I suppose some kind of MRI or medical imagery could show in real time when splenic contraction is happening but I wonder if for this diver (and the video of Goran shows similar) the blood O2 is leveling off there for a while because his spleen is dumping red blood cells at that point.

 

[baiyoke]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

I don't think that's the main reason. After reading other threads on the subject, I'm quite sure the main reason is simply strong vasoconstriction... Depending on how tight that vasoconstriction is, I guess spleen contraction could reduce the speed of O2% falling, good point... But in a survival/evolutionary perspective it would make more sense if spleenic contraction comes late and after strong vasoconstriction... I think the rate at wich fingers use oxygen is really low and slow... So unless blood is actually still pumping around, I could imagine the blood just more or less being there in the finger, and mostly general metabolism just slowly uses oxygen. A bit speculative, but seems likely as far as I can tell from different threads on DB.

In general an ear oximeter would be better most likely, and top notch would be a bloodvessel oximeter - preferably in or near the brain I tried putting my tongue in a fingertip oximeter I borrowed, but can't actually remember if I got a reading or not...

 

[Apneaddict]

i tried putting my tongue in a fingertip oximeter i borrowed, but can't actually remember if i got a reading or not...

lol!!!

:d

 

[Stephan Whelan]

Re: Is it possible to determine one's capability to hold his/her breath by any measur

Moved to General Freediving forum