LOUISVILLE, Ky. (WDRB) -- The Jefferson County Coroner's Office has determined the cause of death for an amateur fighter who died in July after a Mixed Martial Arts fight in Louisville.

According to the coroner's office, 37-year-old Donshay White died of "hypertensive / athrosclerotic cardiovascular disease" -- a form of heart disease classified as natural causes.

White, a U.S. Army veteran from Radcliff, had no illegal or prescribed drugs in his system, according to the autopsy report. The report indicates that White suffered from high blood pressure and did not take his medication.

White fought on the night of Saturday, July 15, at Expo Five on Seventh Street Road during the Hardrock MMA 90 fights. A witness said White was having trouble defending himself, but wouldn't submit, so the referee stopped the bout about two minutes and 20 seconds into the second round. White's opponent, Ricky Muse, was declared the winner in his first amateur fight. 

The Kentucky Boxing and Wrestling Commission said White passed a physical the day of the fight. 

"He looked exhausted," BJ Ferguson, another fighter who witnessed the fight, said of White.

Officials with Bluegrass MMA said White, who was from Radcliff, Kentucky, collapsed backstage after the contest. A doctor and medics were already on scene at Expo Five, but they could not revive him. He was pronounced dead at 9:02 p.m.

"Absolutely the worst possible fear as a promoter of Mixed Martial Arts is somebody would, one, get injured or hurt severely and, two, lose their life," said Gary Thomas with Hardrock MMA, shortly after White's death. "So every emotion of sadness, fear and remorse just overwhelms you."

The Kentucky Boxing and Wrestling Commission is doing its own autopsy, examining policies, procedures and rules for MMA. Last year, the agency overseeing combat sports in Kentucky re-wrote all of its bylaws, adding more medical provisions for amateur fighters. 

"I just hope the sport can continue," Ferguson said. "I don't want to see them try to shut it down because this happened."

White passed two physicals prior to the fight, including one an hour before the fight. White's former trainer, Billy Smith, was not in his corner that night, but he said the 37-year-old fighter was not in great shape. Smith believes the fallout from his death will bring more regulation from the state.

"You're going to have to take it seriously, and I think it will bring some new kind of  rules and laws," Smith said. "You are going to have to have a better resume to step in that cage from now on."

A second fighter also received medical attention that night and eventually recovered, but at that point, all remaining fights were canceled.

"This was a guy who had goals and had dreams and was fighting for those dreams and died for them," Smith said. "I mean, that's powerful in my mind."

White was only on his second amateur bout that Saturday night. The first he won in November of 2015. 

Whether professional or amateur, any MMA fighter dying in the cage or right after a fight is unusual. In the United States, it's only happened about five times in the history of the sport.

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