O2 sat

[ozark]

Why would someone's O2 sat be in the low 90's at rest either sitting or lying down? I have at times mucous that when I cough my sat would rise to 97% then go back down to 92-94. I have tested my O2 with stairs and it will go up to 95-96%.  What does that mean?  I know it's good that it goes up with activity, but I'm confused as to why it does and why at rest it's lower.  At times when lying down, I have checked it and it may even go to 88-89% .  If I cough it will rise but for the most part it's in the low 90's. Unfortunately, I am a smoker.
Thank you

[crud]

wow---I have sever Emphysema and my saturation level stays higher than yours.  Im thinking its time for you to see a Pulmonologist!

[xxbowiexx]

my hunch is that you tend to breath deeper during activity than when lying at rest.  The deeper you breathe, the more oxygen introduce to your bloodstream. I would suggest for you to monitor your O2 sat as you take several deep breaths (in through your nose, out from your mouth) while lying down and see if your sat would rise.

If you are diagnosed with COPD then your normal sat would probably be around 90%