I'm sorry, we must have been posting at the same time and I didn't see your question re: SE. Exercise is good because fit muscle uses oxygen more efficiently. I take D3 which is supposed to be good for your lungs. there was some research with probiotics and rats that looked promising but was not replicated or something, I think its good to take them anyhow, it won't hurt and may help in some way they haven't discovered.

99% )2 saturation is normal, they prescribe oxygen if you drop below 88% consistantly but you really want to try to stay at least 92-94% .

judi