I remember seeing this a few years back in this thread. From what I recall, most people did find an overall improvement in lung function however I think it also depended on what you vaped too. Some people get a "heavy lung" feeling with higher VG ratios (or at 100% VG), and/or if you vape alot. Its quite easy to become a chain vaper. Flavorings can play a part too.
While I had quit smoking for 4 years and would vape on and off, I had recently starting smoking again last year in September. (bad I know) I started a new Job in Jan of this year, and I have to climb 2 sets of stairs to get to my desk. I was noticing, some panting in beginning of March which pretty much made me say to myself ...! (I mean I had been saying that to myself all winter going out for a smoke, but this was starting to upset me). So I stopped and switched to vape and have been every since. (going on 9 weeks now) I dont pant anymore coming up those stairs! I mean it took a few weeks but its all good now.
Im very selective on what I vape. I stay away from exotic and dark colored flavors and tend to stick with light natural-ish flavors like apple or spearmint. Im also trying to treat the vape like I would with a cigarette. While I was on it hard when I first stopped smoking (again) and would do it heavy during the day at my desk, and I dont do it at home with my kid in the room I wait for him to go to bed. But now that the weather is getting a bit warmer here, Im going outside to do it and spreading it out more.
Probably not a good idea to vape just before a run anyway, just from a common sense point of view - not that I'm implying you lack it
