"After having a weak heart for such a long time, I forgot that I couldn't feel my heart beating," said Garlett. "And all of a sudden, there is just this loud thumping going on in my chest. Just dum, dum, dum."

This weekend he will put every beat of that new heart to work - running more than 26 miles, swimming 2.4 miles, and riding 112 miles in the Ironman Triathlon World Championships in Hawaii.

"I asked my doctor if I could do an Ironman," said Garlett. "And his first response was, 'are you crazy?' And-- and I responded, 'well, maybe. But can I do it?'"

"I thought about it for awhile and thought 'hmmmm, this may be very interesting,'" said Dr. Jon Kobashagawa, a transplant cardiologist.

Particularly interesting because no heart transplant recipient has ever before attempted an Ironman triathlon. But Kyle figures it'll be easy - compared to the other things he's survived.

Garlett said, "In my early 20s, I was convinced that I would never live to be 30. I just knew that the cancer was gonna take me."

By the time he was 25 he had been diagnosed with cancer four times. Once with leukemia, three times with Hodgkins lymphoma. He underwent years of chemotherapy radiation, and a bone marrow transplant.

"During my bone marrow transplant, you know, there were nights where I was afraid to fall asleep because I really didn't think I had the strength in my body to wake up the next morning," he said.

He needed the heart transplant because the side effects of chemotherapy ruined his heart - damaged his joints too.

"I have an artificial hip. I have an artificial shoulder. I've got a series of wires that were put in my sternum post heart transplant," said Garlett.

"Are you the luckiest guy on earth or the unluckiest guy on earth," asked Blackstone.

Garlett replied, "I'm for sure the luckiest guy on earth. It's been 20 years since I was first diagnosed with cancer. And here i am alive."

More than alive, he's thriving. And while it's his own courage that is carrying him into the Ironman competition. He never forgets that another man's heart is making it possible.

"I don't know him or his family," Garlett said. "I just know that they gave me the greatest gift I could possibly ask for."

He's determined to use that gift to its fullest.