Like many people, Michael Phelps' routine has been thrown off during the Covid pandemic. The 23-time Olympic gold medalist says 2020 has been "a year of ups and downs."

"Being somebody who's traveled so much throughout my career and has been on a strict, scheduled routine for 20 to 25 years, [the pandemic] threw a big wrench into the to the equation," Phelps tells CNBC Make It.

As a professional athlete, Phelps, 35, was accustomed to working around the clock, 365 days a year to fine-tune details of his swimming performance in order to win races.

"Throughout my career, I controlled everything that I could [to be] pretty damn perfect," says Phelps, who retired from swimming in 2016.

"Through the mental health struggles that I've had this year, I've been forced to learn, and for lack of a better term, like 'sit in my own s---.'"

The most decorated Olympian of all time has been vocal about dealing with depression and perfectionism, and says the past year has been a learning experience.

"I feel like I've learned so much about myself" during the pandemic, Phelps says.

For example, he is trying to find ways to slow down during the day, take deep breaths in moments that feel stressful. (He encourages his young children — Boomer, 4, Beckett, 2, and Maverick, 1 — to take a deep breath, which they call a "lion's breath," when they're frustrated.)

On Phelps' desk at home in Arizona, he keeps a photo of himself from the 2008 Olympics, in which he won a gold medal by one-hundredth of a second.

"I spent 20 years trying to get a hundredth of a second faster, or win a race by the smallest margin of victory," he says. "And now I have to try and slow time down."

After retiring from his swimming career, Phelps says he was working 100 days a year, doing advocacy work and partnerships. But in 2020, due to the pandemic, he estimates he only worked 30 days, mostly doing photo shoots and virtual gigs. (Phelps recently partnered with Silk Ultra, a plant-based protein drink.)

"A lot of it was pretty much just sitting here at the house, and it was a big change for me," he says.

Despite the drastic change, Phelps has turned to familiar tools that he's learned throughout his career to manage his mental health, like reaching out to people when he needs support, he says.

"I'm talking to my therapist and talking to my friends more, calling family members more, all of these little things because I want to try and feel as normal as I can," he says.

Being able to spend more time at home with his kids is another blessing, he says.

Another habit from his swimming days that Phelps says will never change? "I work out and eat right."

Although he is no longer competing, Phelps' wellness routine involves exercising six or seven days a week: He lifts weights three days a week for 70 to 90 minutes with his wife, Nicole, and does cardio three to four days a week.

"It's almost like greasing the chain up a little bit on a bike," Phelps says. "It's not hard, I just have to get back into the rhythm and figure it out."

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