Hi @bsi15. You know, that's an interesting one. If I follow what you're asking, I think your O2 saturation levels can be a good data point to help you determine if you have a breathing issue. Low O2 can mean many things so it's good to get checked out when oxygen measured by a pulse oximeter is lower than what it should be. In my case, when my air hunger first started, my O2 saturation was always at 100% which was not normal for me. My normal range was 93-95%. The high value indicated to me that I was possibly hyperventilating over time, expelling CO2 and causing O2 to climb. When I did breathing exercises to regulate my breathing, my O2 levels dropped to normal. So it's definitely something to think about how it can tell you something about your health.