Michael Phelps vs. The Energy Drink?

Question

I drink probably around a red bull or two a day. And i exercise..a lot. Coming with a barrage of info from people, i'm a bit afraid of collapsing with a heart attack from an energy drink. But is that really fair?

Michael Phelps allegedly ingests crazy amounts of caffiene a day..from coffee in the morning to energy drinks at lunch and dinner. Being that he's an insane athlete pushing his body to the limit..why hasnt caffiene or anything affected him dangerously?

It makes me think that it is NOT the energy drinks we should be concerned with (as all the scientific studies would report), but rather each persons individual heart/body and whether it can handle the energy drink intake.

Any thoughts? Thanks