I do a lot of Scuba diving, the benefit I got was on identical dives 3 months apart (depth, conditions, time underwater etc etc) my air consumption dropped from 14.5 litres per minute from when I was on 30 a day to 11.5 litres per minute 3 months after giving up smoking totally and using vaping........... So huge difference I thought, don't know what the scientifically proves properly but im guessing my body can handle and process oxygen more efficiently and as such I don't need to use as much.
Okay the downside is that I try to get max VG but obviously a lot of 70/30 out there and ive noticed the PG gives me "dry mouth", a lot of divers suffer with it but I never did. Basically it is exactly that only extremely dry, so much so you cant secrete any saliva until you down a bottle of water........ not possible underwater ! Its a nasty feeling, ive tried squirting mint freshener and other things before diving but it doesn't work so I have to reserve max VG juice for when I dive.
Definitely dehydrate quicker with PG, shame as its an awesome flavour carrier. The only other thing is that the windows in the house get a film on them and have to be cleaned all the time (I didn't smoke in the house before vaping)