My FIL is a resp. therapist, and when he was doing my asthma testing I asked him about it

He says when I cough and get phlemgy after running or being outside for a long time in the winter it has to do with the body trying to moisten up the air from outside to make it easier to use, since it's harder to "breathe in" when it's so dry - so you produce more phlegm, and afterwards, cough that phlegm up.


He used a lot of elaborate terms and explained it wayyy better - but that was the jist of it...