I used an e cig to stop smoking around 7 years ago and i still use them now.
I once did a lung function test at my docs when i was in my 30’s when i thought i was fit,but i smoked and had done since my early teens – the results were poor.
I did another test last year in my late 50’s and the Doctor said the results were fantastic and i had the lung power of a 30 year old non smoker.
He did also point out that having good lung function doesn’t necessarily mean you’re not going to get something horrible!
As an aside,i like to try and be discreet whilst using my e-cig, i can’t be doing with those people who have an uber stealth model e-cig powered by a car battery and who seem to delight in pluming massive clouds everywhere – even indoors!