lowest level of SpO2 level

[pikapika]

Hi, I recently bought a oxymeter to monitor my SpO2 level and pulse rate during sleep. The lowest SpO2 level is about 92%. I did an experiment to see how low I can push the SpO2 level, by holding my breath for about 30 seconds. SpO2 level dropped from 98% to about 96%. So I am questioning the oxymeter's accuracy. If you have a oxymeter, can you please do the same experiment and report the SpO2 drop? Thank you very much.

[RicaLynn]

Was that with or without your cpap? Other members here have experienced drops much more dramatic than 92%, and you will not be able to replicate an Sp02 drop by holding your breath while awake.

[Julie]

Doesn't work that way and you're wasting your time.

[SleepyToo2]

Do you have sleep apnea? Why are you concerned about your oxygen level? The only way you can test an oximeter is to compare the reading on your meter with that from another meter that is known to be good - both recording at the same time. Because you are controlling your breathing while you are awake, the test that you did doesn't mean very much compared with when you are asleep. Also, a difference of a few % in the oxygen saturation is not going to make much of a difference: some people with sleep apnea do not have significant decreases, while others have big falls. My level dropped to 74% during my first sleep study, but that is not the biggest drop that has been reported on this forum.

[HoseCrusher]

30 seconds isn't long enough.

Sit down and relax. Once your breathing is normal and your pulse rate has reduced to something stable, breathe out and then hold your breath for a minute or two. You should see a drop below 90.

Think of yourself diving in a swimming pool and swimming underwater to the other end.

Note that holding your breath while awake is not the same as having your airway blocked during sleep.

[sleepy1235]

The oximeter usually works by having a sleeve attached to a finder.

I am not sure what the time delay would be your lungs through your heart and out to your finger.

Additionally, there is oxygen in your lungs even as you hold your breath. Exhaling is done to expel CO2 as well as to inhale fresh air with oxygen. I am not sure what the oxygen percentage of exhaled air, but it probably isn't that low.

Additionally, the equilibrium is driven by the binding constant of oxygen to the hemoglobin. Given a chemical reaction as follows:

A + B <--> AB, there is a constant [AB]/[A] = K If K is a large number for oxygenation of hemoglobin, the hemoglobin would be nearly saturated even with depleted oxygen in your lungs.

So on multiple levels this experimentation doesn't prove anything.

Also, don't breath N2 or Argon to test the device. You have an excellent chance to see SpO2 to drop, but also a really good chance of losing consciousness and dying without warning or knowing that it was about to happen.

N2 or Argon isn't toxic, but can painlessly asphixyate you if you are breathing a 100% concentration.