I coached HS football for years. We're talking a handful of kids per year with most of it from heat exhaustion. Being dehydrated and going into heat stroke does give you a heart attack. It does happen though, one kid from the jv level after our game almost died. He fell on the football on his chest with some fat linemen on top and he was out after that. Not sure if that did it or not. I coached a kid with tachycardia and needed surgery. Nothing like this though, the numbers will go up too.