As a kid I watched a lot of wrestling. Mainly in the 90's when it was the best. Sometimes I watch old matches like Hogan vs Ultimate Warrior, matches of Mr Perfect (I disliked him but now I see that he was the most skilled of all), story of NWO...the huge and extremely powerful wrestlers of that era.
I often watch this as a sport. They do things what common people would die immediatelly. It's a profession and for them learning how to do these fights takes a lot of time and practice.
Unfortunatelly many of them died. Mainly the reason is steroid abuse like Fvendal said. Their hearts gets big over the years and they get fatal heart attack (Ultimate Warrior, Randy Savage, Brittish Bulldog, Big Boss Man and many more...).
Some of them died by drug overdose and suicide.
I still dont know why Ms Elisabeth got this fate (drug overdose). She was beautiful and I'm sure half of USA's men would have married her happily.