Can you pass out while exercising?
Oh yes you can, it's awful.
I played pro tennis and trained with the olympic team in Poland.
This included everyone from swimmers to track runners.
We did this exercise called the 100-50.
You run 100 meter as fast as you can, then you jog back, and run 50 meters all out, jog back and repeat for 7 minutes. After a few minutes you breathe faster than you're exhaling and you're body can't physically catch up. So it goes into preservation mode and shuts down. Long story short you pass out if it's too much. It hasn't happened to me, but i've seen it.