I passed out in a grocery store once. I hadn't eaten all day, it was 100F outside, i hadn't drank anything, no a/c in the car. It was sunday so there was ALOT of people in there and I was incredibly blown.

IMPORTANT INFORMATION
IF you or someone you know begins to freak out, give them a dark soda. (dr pepper/coke/pepsi) Heartrate will fall. You will feel ok after a few seconds.