Thats right but it shows you what you said could not happen can...

Thats right but it shows you what you said could not happen can and does happen.

It all depends upon the persons standing oxygen blood count togethe with standing blood sugar levels.

@ramAustralia the degree of damage to the lungs before exposure and during exposure determine to what extent recovery can occur along with the age of the person. People over 65 have a far lesser ability to recover than the young, Those with prior lung damage due to pneumonia start at a standing blood oxygen measure disadvantage regardless of age. Any lung tissue that goes fibrotic won't recover.