I only ever had one of them and for the life of me I didn't know what it was when it happened but because of that, I found out I had asthma and COPD.
Going back to 2003 when I was not working and had been made redundant AGAIN and was down in the dumps, got up early to nip up the shops and this was during wintertime and the hall lights in the stairway had gone off (the timings were fucked up) as I was approaching my flat door I was suddenly gasping for breath, I was fumbling around with the keys trying to open the flat door, couldn't find the keyhole slit so I just banged at the door for the wife to let me in.
In short, she panicked when I said I could not breathe and thought I was having a bloody heart attack, started crying whatnot, called the doc out and he gave me some oxygen and said I think you have had an asthma attack which made you panic, make an appointment with your doc and get checked out which I did confirmed I had asthma and COPD and that's me on my pumps now forevermore until I depart to the wild blue yonder.