from my late teens 40 years ago l have had instances of being stopped in my tracks because l cannot breath. lt would happen if l came out of a warm atmosphere into the cold air, l learned to stay calm and cover my mouth until l could breath again and move on. lt has become worse in middle age. Often l would awake at night to find l had floated up to the ceiling (l now realise it must be caused by lack of oxygen). lt occurs if l am lying on my back 'l try not to' or if the temperature in the room has dropped. I was diagnosed as suffering from 'Silent Asthma' when l got into my 50's.l now use a Nebulising machine..l put one 2.5 Ventolin Nebule intiothe chamber of the mask, switch on the machine and breath in the mist of the Nebule Liquid for about 15 minutes, before l go to sleep and during the night if needed. and during the day if needed. It helps me tremendously.Kindest regards.