Pulse Oximeter

WJ100, watching the video, I'd tell that you could do much better if you stopped moving all the time, moving your hands, and head, watching the timer and oximeter, and turning to the sides. You apparently spent quite a bit of energy there with all that activity. You may do much better if you stay quiet, concentrating on relaxation, eyes shut, and ignoring the watch and oximeter (just let it recording, or point a camera on it if it has no logging function). You can also ask a friend to give you signals at certain times, or program it on a PC. That will allow you avoiding all that moving and help with the relaxation.

Also using a nose clip may help, especially if you want to pack. When you have no nose clip, you may involuntary or subconsciously inhale some extra air time to time, especially when you move around a lot. And some O2 gets absorbed by the sinus anyway, so if you train for wet apnea, it is better avoiding it. It can then result in false results, and can be frustrating if you cannot replicate them in water. In water you should actually have better results - it is easier to completely relax there, and also the diving response usually kicks in better.

Thanks for the input. I am aware I need to stop moving. It is much easier to stay still in the water I think. Fewer distractions there. I have started using the camera to record things like oximeter readings so I don't have to look at it so much when I am training. I am not too worried about inadvertantly breathing in. My lungs are pretty full already anyway. I figure that is a negligible effect given the small amount of air that might be involved. Good idea on the nose clip though. I need to get used to wearing that or a mask anyway. I am limited a little bit in that I am training alone, so everything that I would normally have a partner to do, I have to do myself. Also I cannot train in the water for the same reason. Last year when I went to AIDA training. I did 5:30 in the water easy enough, but I didn't get to do my breathe up, so I am not sure what I could have done. At the time I was doing 6:00 holds pretty easily dry. I have had alot of recent improvement, but I have not had a chance to see what I can do in the water.

Today I did a demonstration hold to test the effect of using a nose clip and also demonstrated pulse oximeter use. I posted a video on YouTube:

Been doing more holds with a pulse oximeter. Did a recent personal best of 7:18 although without using the oximeter. The oximeter did provide useful information in working up to the attempt. I find that my SAO2 is consistently in the 78-80% range at 6:00, and at 7:00 in the 73-75% range. My pulse ends up in the high 30s or low 40s at the end of a 6-7 minute hold. Usually SAO2 doesn't go below 90% until about 5 minutes. The lowest I have ever seen SAO2 was 73% at 7:00.

[ame=http://www.youtube.com/watch?v=VRFqfduOulM&feature=channel_page]YouTube - 7:18 Hold with Discussion[/ame]

Seems to be very good values.
Compare with me year 2004
http://www.freediving.biz/features/breathhold.html

And some recent values:
Freedive tests

I average 85% at 5 min.
You are 5% "ahead" at 5 min.

Sebastian

PS.
Why all these breathing Walt?
When do you get contractions?
How much food in your stomach?

Try this and tell us the result:

Rest 5 minutes. Tidal.

6 minutes with 4 breaths a minute (you do about 6 breaths now).
Go below FRC, nearly to RV on at least 12 of these 24 breaths.
With the others use the "pressurazation technique" you use now.

Very interesting tests, Sebastian. Wow I have so far been able to get down below 72% SAO2, certainly not even close to your 42%. How did you feel at that level? I haven't pushed my holds out far enough yet in my current training cycle. My recent improvement has just recently pushed my ability to go past 7:00 consistently, so I have not gone much beyond that. I tape every hold longer than about 6:15 that I do and I have never had a BO or LOMC on my tapes. You can see in my YouTube videos that I am still in pretty good shape at 6:30-7:00. I saw on your test page that you use a fingertip oximeter just as I do. I have seen alot of commentary about the use of different types of oximeters, most of it negative regarding fingertip oximeters, but I feel I am getting good results with it. Thanks for the feedback.

Walt

wjohnson100 said:

Very interesting tests, Sebastian. Wow I have so far been able to get down below 72% SAO2, certainly not even close to your 42%. How did you feel at that level? Walt

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Feel? Nothing. Mind is at some unknown place, only routine can make you do SP and/or recovery breathing at that level. I can not swear by the number, but the oximeter costs more than my car.
And frankly I havent gone lower than 60% in years.

wjohnson100 said:

You can see in my YouTube videos that I am still in pretty good shape at 6:30-7:00. Walt

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Yes , will be intresting where you will end up, specially since you have many things to try before getting you most efficient style, I believe.

wjohnson100 said:

I saw on your test page that you use a fingertip oximeter just as I do. Walt

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Find it adequate for my needs. Dont really agree with the disrespect fingeroximeters have recieved in this thread ;-)
I dont believe vasoconstriction is that great out of water (that gives pressure and temperature change that have a big impact on vasoconstriction).

And my intrest is mainly in the end result, which will appear on the oximeter sooner or later, its the same O2 levels in all the blood I think and it will get to the fingertip eventually. Usually some 25 secs after start breathing.

Sebastian

Sebastian,

I agree with your opinion on fingertip oximeters. I think that with all oximeters there is a lag time, and as long as you take that into account, you will be ok. Like you I find that my lowest SAO2 is about 25-30 seconds after the end of a hold.

Walt

cebaztian said:

I dont believe vasoconstriction is that great out of water (that gives pressure and temperature change that have a big impact on vasoconstriction).

And my intrest is mainly in the end result, which will appear on the oximeter sooner or later, its the same O2 levels in all the blood I think and it will get to the fingertip eventually. Usually some 25 secs after start breathing.

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Vasoconstriction is definitely present and well documented also at dry apnea (or even at sleep apnea), and you will find many studies confirming it. I do not remember any study comparing vasoconstriction at dry and wet apnea, so do not know whether there is any difference (likely indeed yes), and how big it is, but even if the vasoconstriction was only minor at dry apnea, it would influence the measurement. The level of saturation is namely not equal in all body. There are gradients. If you have an area with restricted circulation, the tissue there oxygenates slower and blood desaturates of course faster (that's why it works so well for us), hence there are lower saturation values than in the core. You would need to measure on arteries (and closer to the heart would be better), to avoid that effect.

Additionally to the direct effect of the vasoconstriction, cheap and/or less sensitive devices may amplify the effect, because they may falsely interpret the loss of signal at low blood flow. Sensitive device will still show the correct values of the local desaturation, but those with limited sensitivity may be wildly incorrect.

EDIT: some more expensive devices are able to pick up two signals (for the arterial, and for venous saturation) from the measured area, so those may be more informative. Though, I am afraid the saturation in the small finger arterial capillaries is already influenced by the slow blood flow due to the vasoconstriction anyway.

Get some good deals here: https://www.healthcaredeliveries.com/diagnostics/pulse-oximeters