What the title reads. Well, actually I had stopped at a red light, and before I could react I fainted. I had barely run for 1 km and at a low pace of around 6:30 min/km. I had eaten like 3.5h hours earlier —a chicken and vegetables sandwich and a pastry. There was nothing unusual. I simply stopped at the red light, started feeling hot, a couple of seconds later everything went gray and fuzzy and I fell to the ground. I hit the back of my head on the sidewalk —I can even remember I felt it and I heard the noise, but it was like distant. In the meantime I was having a pleasant dream while the music kept playing. I woke up a few second later as an elderly man was softly slapping me. I'm still trying to figure out what could happen. I went to the doctor and got an electrocardiogram, but everything was ok. No headache, no chest pain, just a bruise in the back of my head. The arterial tension was a bit high but within normal limits; they thought it could just be the stress of the situation. Does any of you have gone through something like this?