At 31, Michael Phelps has been to five Olympic games. He won 23 gold medals, three silver medals and two bronze medals. His total of 28 makes Phelps the most decorated Olympian in history.
At 6 feet 4 inches tall, Phelps has a physique that is naturally predisposed to race through water, but he still had to learn how to optimize his body. For one, he slept — a lot. Early on in his career, Phelps learned that to be able to swim seven days a week, covering between 70,000 and 100,000 yards each week, he had to get a lot of shut-eye.
"I really can't say it enough. I don't think people really pay enough attention to how important sleep is," says Phelps, speaking to CNBC from the New York City showroom of direct-to-consumer mattress brand Leesa. The Olympian has recently entered into a four-year brand partnership with the company.
When he was training, Phelps slept eight hours a night and took a two- to three-hour nap each afternoon.
While Phelps spent the majority of his days in either the pool or his bed, here are five habits he follows outside the water that made him a powerhouse.
HE WRITES DOWN GOALS AND KEEPS THEM ON HIS NIGHTSTAND
Phelps has found it helps to put his goals down on paper and to frequently look them over, especially after a tough day.
The swimmer still tracks his long-term goals. At the recommendation of his agent, Phelps sets goals for five, 10 and even 20 years from now.
It's been an adjustment to think that far ahead. "I never thought like that. I was always thinking of the next race or the next practice," says Phelps.
HE NEVER USES THE WORD "CAN'T"
Phelps' coach, Bob Bowman, worked to take the word "can't" out of Phelps' vocabulary.
That allowed Phelps to "broaden my mind and believe that I could do whatever I wanted to, and I think that was a big key of us being so successful," the swimmer says.
"I was always a kid or a young man that would think as big as I could possibly think. And dream as big as I could possibly dream."
HE IS WILLING TO GIVE UP A LOT
Swimming seven days a week and taking care of an Olympic-tuned body means there isn't much time for much else.
"A lot of it is the work you do every day and the sacrifices that you make. I think that's a really big word, a big key word," says Phelps.
HE USES OTHER PEOPLE'S TRASH TALK AS FUEL
Phelps won't talk about his business goals, other than to admit they are ambitious. At the pool, Phelps was known to keep quiet, too. He says there's "no point" in trash talking.
But if other swimmers taunted Phelps, he listened and used the competition as motivation.
"I welcome the trash talking. I love when people do it. I love when they do certain things to just fire me up," says Phelps.
HE FOCUSES ON HIMSELF
"I am staying in my lane," says Phelps. "I am doing what I have to do, what I want to do to try to be the best. For me, at the end of the day, when I was training, as long as I figured out what I needed to do in order to accomplish my goals and dreams, then that was all that mattered. Nothing else mattered. Everything else would just play out."
Rather than get distracted by other swimmers, Phelps learned what he needed to do to be successful and focused squarely on that.
"I can't control what other people do, so for me, I was always worried about myself and worried about what I needed to do. And, it worked."