Blood oxygen question

[TNdiver]

I reciently borrowed a finger clip style blood oxygen meter. For the record a little less than a year ago i had regular access to one (before i started any training) and mine was always 97-99 so i dont think what im noticing is from any type of medical problem. anyway, I've been using it for a while now during holds to see how low my oxygen level is getting. During the breathe up before the holds its just about always 98-99. the last few days ive checked it several times just at random and ive noticed its been some what lower, often 92-93 range. As soon as i take a few deep, not really fast, but faster than just relaxed breathing, breaths it is right back up at 98-99.
I was wondering if theres a chance that doing hypoxic training would increase the hemocrit levels enough that the amount of oxygen actually available in my system would be the same, but that the saturation percentage would be lower because my blood is capable of holding more than it needs for me to be able to function comfortably. I've read on several medical sites, that at levels around or below 90 people should go on oxygen treatment. I know that when my grandpa's oxygen level would get that low he would feel really weak and be really tired feeling. I feel fine, and im not noticing any signs of low oxygen levels. Ive had a few other people (non-divers) try the tester and they all got a reading 98-99, so i dont think its just the tester reading funny. Has anyone else noticed similar readings at rest. Maybe eric could shed a little light on if the hemocrit idea is right or not?

 

[Bill]

I have similar readings that I only noticed after training for apnea. Nurses do not like to see numbers below 95. Now when I am anesthetized, even very mildly, they feed me O2 in the recovery room. I figured it must have something to do with all the trouble I'm having getting to eight minutes or maybe it's just old age.
Aloha
Bill
P.S. Don't experiment with their O2 machine when they connect you to it in an hospital. You'll get in trouble.

 

[BennyB]

P.S. Don't experiment with their O2 machine when they connect you to it in an hospital. You'll get in trouble.

If only I had discovered freediving when my mum used to run a hospital...

I recall as a teenager a couple of us did work experience at Mum's hospital and the nurse hooked us up to an oximeter and she said that it would be able to tell if we were smokers or not. Needless to say a couple of us (ie. me) were pretty nervous, i'm sure mum put the nurse up to it.

Cheers,
Ben

 

[naiad]

P.S. Don't experiment with their O2 machine when they connect you to it in an hospital. You'll get in trouble.

But it's just about the only fun thing to do in a hospital! rofl

 

[cebaztian]

I use to hold my breath in secrecy during the EKG tests (that cardio meter thing). Messes up bloodpressure and pulse. Very funny indeed.

Sebastian
Sweden

 

[TNdiver]

rofl Thanks for the hint Bill, id say that could get one in quite a bit of troublerofl Anyone else have a similar experience after starting training?

 

[naiad]

Maybe it has something to do with breathing less.
http://forums.deeperblue.net/showthread.php?t=66811&page=5

 

[TNdiver]

i havent read all of that thread yet, but from what i read on the last page of it that seems to be kinda along the lines of what i was thinking. I assume by breathing less our oxygen sat. would be somewhat lower. Looks like this may be one of those thats a little hard to explain

 

[Lammy]

Just found this background..could be any of these

In the following situations the pulse oximeter readings may not be accurate:


A reduction in peripheral pulsatile blood flow produced by peripheral vasoconstriction (hypovolaemia, severe hypotension, cold, cardiac failure, some cardiac arrhythmias) or peripheral vascular disease. These result in an inadequate signal for analysis.

Venous congestion, particularly when caused by tricuspid regurgitation, may produce venous pulsations which may produce low readings with ear probes. Venous congestion of the limb may affect readings as can a badly positioned probe. When readings are lower than expected it is worth repositioning the probe. In general, however, if the waveform on the flow trace is good, then the reading will be accurate.

Bright overhead lights in theatre may cause the oximeter to be inaccurate, and the signal may be interrupted by surgical diathermy. Shivering may cause difficulties in picking up an adequate signal.

Pulse oximetry cannot distinguish between different forms of haemoglobin. Carbo-xyhaemoglobin (haemoglobin combined with carbon monoxide) is registered as 90% oxygenated haemoglobin and 10% desaturated haemoglobin - therefore the oximeter will overestimate the saturation. The presence of methaemoglobin will prevent the oximeter working accurately and the readings will tend towards 85%, regardless of the true saturation.

When methylene blue is used in surgery to the parathyroids or to treat methaemoglobinaemia a shortlived reduction in saturation estimations is registered.

Nail varnish may cause falsely low readings. However the units are not affected by jaundice, dark skin or anaemia.

 

[TNdiver]

Nail varnish is not the problem (dont use it, im a guy)
methylene blue isnt an issue (havent had it used)
i doubt that carbon monoxide is an issue, because i dont think ive been in any situations to have been around any
bright lights, shivering etc. arent the problem.

Ive tried different fingers (and toes for that matter) so i doubt it being any limb blockages

Ive had my heart checked out pretty good not all that long ago because my pulse tends to run high and they wanted to make sure nothin was wrong. They didnt find anything, other than its fast.

My blood pressure is ok (i dont remember exact numbers, but well within "normal" range)

the one thing there that might fit is the low blood volume. That kinda makes sense because ive noticed that if i stand up really quickly from being down in the floor i get a little light headed some times (seems low blood volume would have somewhat of the same affect as low BP so maybe?) I guess i may have to have that looked into. Thanks for the input. Ill keep this updated if i find anything out. Any one elses input is still welcome. (especially if you've noticed the same affect)

 

[BennyB]

Do you smoke?

 

[TNdiver]

Nope, and I never have. No one in my house has for probably 8 or 9 years. Before i got in to freediving I more or less always got readings of 98-99.