Hi. I'm 29. I smoke. It seems like i have a bit of dyspnea. I noticed almost everytime i stand up quickly i have dizziness. I'm on sertraline, idk if it can be that. My oxygen saturation at rest is 99%, even when i feel this shortness of breathing. My theory is that I'm starting to have copd and my CO2 levels are rising. Last time i went running 1.8 miles and i became all red in face and it lasted a lot, more than 40 min maybe. Is this consistent with copd? Did you have the same symptoms at the beginning, standing up dizziness?