It isn’t medical story but what I felt things.
The amount of oxygen contained in atmosphere doesn’t change. If your bronchial tube becomes thin, you can increase repetition of your breath to solve the insufficient oxygen. But, this problem doesn’t solve. The increasing repetition of breath can’t increase your body-needed oxygen.
I have been said by the student of Faculty of Nursing in old times, " The color of your fingernail shows the symptom of the cyanosis".