@Jebbn - Sorry this is so long, but wanted to explain my own experience with my COPD diagnosis and vaping.
After I'd been smoking 1 - 1.5 PAD for 30 years, I was diagnosed with the beginning stages of COPD (emphysema). The diagnosis was based on changes in yearly chest x-rays I'd always had while smoking and on changes my doctor could detect when listening to my lungs during exams. I still smoked for another 12 years, while trying numerous things to quit during that time. However, nothing worked until I tried vaping in Nov. 2013. That did it, and I had my last smoke 2 months later, in Jan. 2014. Have never wanted 1 since then.
I
will say that even with that diagnosis years ago, I'd never needed to be on meds for it, and it didn't restrict what activities I took part in. My doctor said it was most likely due to how good my overall health was and how active I've always been.
Anyway...after not smoking for 2 years, and still vaping as much as I wanted to, my doctor had me do a spirometer test and get a chest x-ray. He was
so amazed at how good my spirometer results were...that he double-checked with me that I'd honestly smoked as much as I did, and for 42+ years! My chest x-ray actually looked
better than it
ever had! My lungs sounded
totally clear to him during the exam, too. He said that it
might be possible, that vaping had actually helped my lungs (and in turn my breathing) get so much better...because of the warm, moist vapor they were exposed to. He also commented that PG
is the carrier used in medical inhalers, so there might be a correlation there with the PG in eliquid being helpful when vaped. He gave me a thumbs up and a high-5 at my great results and to my continuing to vape and not smoke. He still does one or the other when I see him every 6 months for check-ups and tell him I'm still vaping.
As far as how, and what, I've been vaping since Nov. 2013:
1) Always low wattage and
never subohm - I'm a Tootle Puffer
2) Not DTL, nor even MTL - I inhale vapor only as far as down the back of my throat, hold it there a second or so, then exhale it through my mouth and/or nose. Since nicotine in vapor is absorbed better in the cheek linings, sinuses, and nasal passages...I've
never had a problem getting my "nic fix". I've been perfectly satisfied for more than 4 years doing it that way.
3) Started with 50VG/50PG eliquids, but after 6 months changed to 60VG/40PG (found that the slightly higher PG was causing headaches)
I hope some of the above was the kind of info. you were looking for.
ETA: Info I'd forgotten before