Matt. Very important fella. I'm borderline asthmatic in so far I only need an inhaler on a really heavy cold couple of times a year were my capacity goes down to a third... I mean a third... So it makes me aware of a change etc, so when I first turned without a mask - knackered 12 hrs later. Those b and q type rubbish btw.
Couple of chaos here with some real horror stories. You wouldn't ride a motorbike without a helmet, I thinks is the same tbh.