Bare with me while I try to relate this if I can remember it correctly.
In Chinese medicine the flow of energy chi is key.
When the chi is not flowing and is obstructed is when our bodies don't work well.
That is when you get blocked channels.
Alot of that chinese medicine stuff is either blocking certain channels or clearing channels in order to help the body to cure itself.
When the chi is not flowing it is stagnant and it festers in certain parts of our bodies.
Like a shallow pond full of algae and fungus rather than like a clear flowing river or ocean.
And this is what asthmatics lungs are like.
An asthmatics lungs are not functioning optimally and there is alot of blockage and things are not flowing and clear and beautiful.
When you add moisture into an asthmatics lungs it will fester and be a breeding ground for disease, sickness, infections, etc.
Of course we all need moisture to a certain degree.
Being a asthmatic whom has suffered severely in the past I have learned a little.
I have been hospitalized a few times in the past, once near death.
I have had a few bouts of pneumonia.
I have been put under sleep observation for dangerously low blood oxygen levels during sleep because of asthma, lung blockage, and shallow breathing.
It has been nearly 10 years since I have really kicking asthmas ass.
I wish I could fight in muay thai but sometimes I feel like I have already been through too many wars and I didn't even get to get into the ring.
My point is that maybe you can believe what I am saying and don't simply shrug this advice off or let it go in one ear and out the other.