Ric Flair is one limousine ridin', jet flyin' tough son of a gun ... but even he admits that he's worried about his health failing him in the final wrestling match of his historic career later this summer.

The WWE legend was speaking to reporters in Nashville on Thursday while promoting his much-anticipated "Last Match" bout ... and he revealed he does have some concerns about previous health issues popping up during the tilt.

Specifically, the 73-year-old said he's worried about his pacemaker ... as well as some inner ear problems he's had in the past.

Flair also hinted blood thinners could have an impact on his body as well.

The Hall of Famer, though, did say he's not horribly concerned about any of it, saying if his pacemaker becomes unplugged, he'll just "plug it back in." He added that he also won't take his blood thinner medication that day as well.

Flair said expects to put on a great show at the event -- one in which he's been training for nonstop with former TNA superstar Jay Lethal since its announcement -- explaining if the crowd is big and rowdy, he'll push way beyond his limits.

"Now that I know I can do it," Flair said, "I'll be flying around if there's 7,000 people."

TMZ Sports spoke to the 73-year-old Hall of Famer wrestling icon recently, and he told us his doctors medically cleared him to compete ... paving the way for the "Nature Boy" to take one final walk down the aisle.