At the end of an Olympic weightlifting circuit, I fainted and coughed up blood. Is that intense enough? Personally, I think it's utterly silly and unnecessary. But then again, that was a one off episode in a span of 30 years of lifting...not bad!
The reason for fainting: heart rate went overboard and oxygen could not get to the brain fully, hence the falling down, (which is a good thing as far as the brain is concerned where now gravity is working in its favour).
Fadi.