I am one of those that gets a lot of phlegm, especially after I eat, and I have to cough it up. Once in a while it causes a blank spot in my brain (brain almost feels like it is stopping) because I coughed so hard trying to get the phlegm up. One of my doctors explained that there could be "back pressure" on the blood flow to the brain when we put pressure from muscles around the lungs and heart, and that affects the brain for a second or two.

A couple times when I have had a grain of rice stuck in my throat , scary, but nothing other that that.

I cough that hard sometimes. Ive almost passed out a few times also
Its certainly not fun!! 😺😺