Salt inhalation is well proven to work....perhaps Andrew would know how...I am thinking it affects the density of the blood in the lungs as well. People go into salt caves and their respiratory issues are resolved.
Interesting thing about salt is that a small quantity placed under the tongue of a dying person can extend their life significantly--this would indeed increase the density of not only the blood but the lymph and cerebro spinal fluid right at the top of the circulation trees.
Inhaling through salt will serve to remove water from the air we breath in, this in turn will increase the evaporation from the lungs, working much the same as a dehumidifier. If we leave dry salt exposed to the atmosphere it quickly absorbs moisture from the air. I doubt there will be salt inhaled and absorbed into the lungs from these caves.
I think you are spot on Sir! That's exactly what the salt does....and people use the therapy for skin issues as well as respiratory. Quite interesting. Back home and just got my bed to full 5 degrees by putting another inch.