10/03/2013 07:58 am ET Updated Oct 03, 2013

Diana Nyad Tells Oprah How Her Mother's Death Inspired Her Historic Swim (VIDEO)

At age 64, Diana Nyad became the first person to swim from Cuba to Florida without a shark cage, am incredible feat she completed in just under 53 hours. On "Super Soul Sunday," Nyad tells Oprah she decided to take on this challenge after her 82-year-old mother passed away -- and her reasons had nothing to do with swimming.

"So I started thinking, my mom died at 82," Nyad says in the above video. "Does that mean, really, I have 22 years left? And maybe those last two or three or four aren't going to be too vital, I don't know." she says. "But the clock is, like, choking me now. And it wasn't so much what did I want to do. It was who I want to be."

"Whoa," Oprah says.

"That's what it was," Nyad says. "There's a Henry David Thoreau quote that really grips me hard, and it says when you achieve your goals in life, it's not what that gets you, it's who I am," she paraphrases.

Nyad says forget about the fame or the money. "I don't care about that anymore," she tells Oprah. "As you know, those things -- as you get older, who cares?"

She explains what's truly important to her: "Am I living the life that I can admire? Am I going to leave this earth, maybe as you do, leaving it a place where it's a little more just than it was, and human rights have been fulfilled more?

"Those are my values," she says. "And never giving up. And finding a way through your obstacles, and finding your grit and your will. ... At [age] 60, it wasn't about swimming, and this swim for me has never been about swimming. And I don't think to anybody out there it's been about swimming. It's about those values," she says.

"And you know what? I am that person. Swimming or not. And I proved it to myself and that's why I did this swim," Nyad says.

"What you showed us all," Oprah says, "is what a real warrior looks like."

Oprah's interview with Nyad on "Super Soul Sunday" airs Sunday, Oct. 6 at 11 a.m. ET on OWN.



PHOTOS: Diana Nyad's Swim