I was told I have early Emphysema I don't feel nor look like a person with Emphysema. I'm 60, smoked on and off for 30 years. My symptoms were shortness of breath, especially with activity as little as walking across a room. My 02 sats would drop as low as low 80's. I was put on oxygen. My question is, I've been having good sats , low to mid 90's and on room air ( been trying not to use 02) . Why am I still short of breath with reasonable O2 sats? Can someone please explain this to me? Thank