Smokers don't magically undo the damage they did to their lungs after they stop smoking. Stunned might be hyperbole, but it is at least a little bit surprising.
They absolutely do! Not all the way, but if you'd have smoked a pack a day for 15 years and then have given up for the last 15, there's absolutely no way you'd be saying this!
Hey here is something for you to stun on:
https://old.reddit.com/r/OldSchoolCool/comments/1v73w9s/hydr...
"Stunned" isn't really a scientific term. It's the sort of editorializing you should expect to come from people who aren't the scientists themselves. More than hyperbole, it is classic click bait.
Also, quitting smoking definitely eases a number of symptoms, especially if you're not at the point of chronic emphysema. The reduction of inflammation triggers alone after a bit of time is fairly significant. Less coughing, less mucus buildup, etc.
> “ Smokers don't magically undo the damage they did to their lungs after they stop smoking”
Except that they do undo the damage.
“ After 15 years, your chances of getting lung cancer are almost the same as someone who has never smoked.”
https://www.nhs.uk/conditions/lung-cancer/prevention/