Hulk Hogan was battling leukemia at the time of his death, according to medical records obtained by PEOPLE on Thursday, July 31. His cause of death was also shared, revealing he died of a heart attack.

Hulk Hogan's cause of death has been ruled natural. The 71-year-old had a secret battle happening behind the scenes.

The cause of death for legendary professional wrestler Hulk Hogan was a heart attack, according to the Pinellas County Medical Examiner in Florida. The superstar wrestler and reality star, who had a controversial legacy died at 71 on July 24 after emergency responders treated him at his home in Clearwater and took him to a local hospital,