On a hot morning in early August, Heather MacLean put on her sneakers and did what she usually does: she went for a run. Her time at the Tokyo Olympics was coming to an end after she failed to qualify for the women’s 1,500 meters final, and as she started jogging she found herself doing in the face of this harsh reality – toe to toe.

“My legs had never felt so heavy in my life,” she said.

For many athletes, competing in the Olympics is a dream, the fruit of years of hard work. But there is no real roadmap for the future, in the days and weeks following the Games. MacLean had heard others describe some kind of post-Olympic accident.

“But I don’t think there was any way for me to prepare to actually experience it,” she said in an interview this week.

On Saturday, MacLean will compete in the Wanamaker Mile at the Millrose Games, the prestigious indoor competition held annually at The Armory in Washington Heights. The women’s mile field also includes Elle Purrier St. Pierre, who set a national record for the event in 2020, and Athing Mu, the reigning Olympic 800-meter champion.

This will be MacLean’s first track meet since the Olympics. Mark Coogan, MacLean’s coach with the New Balance Boston team, had advised him to be methodical in his approach to returning to competition.

“Just because I kind of went through it myself,” said Coogan, a former Olympic marathon runner. “I know there can be huge disappointment after the Olympics, and I think it was important to just be in solidarity: ‘What an amazing year. No one but us thought you were going to be part of the Olympic team, and now you’re an Olympian. And once you charge up, we’ll get back to it.”

MacLean, 26, has had a meteoric rise. She didn’t start running until her junior year of high school in Peabody, Mass., outside of Boston. At the time, she was working in a grocery store with one of her best friends.

“She was my commute to work,” MacLean said. “So when she joined the track team, I thought I might as well join her, so we could carpool to work and train together.”

MacLean quickly proved to be a natural talent who embraced hard work. After breaking a host of records at Peabody Veterans Memorial High School, she battled injury and adversity at the University of Massachusetts to become an All-American. But it wasn’t until she was five years old that she considered racing professionally.

Armed with a master’s degree and freed from academic demands, she joined the New Balance Boston team and made steady progress. At the United States Olympic Track and Field Trials last June, she made her first national team placing third in the 1,500 meters behind Purrier St. Pierre and Cory McGee.

MacLean was still at the height of that experience when, on a flight home from a pre-Olympic meet in Monaco, she watched “The Weight of Gold,” an HBO Sports documentary that details the mental health issues facing some olympic athletes face: their sacrifices, the inflated expectations they internalize and the inevitable uncertainties they face after the olympics: what now?

She recalled facing “tremendous pressure” even before arriving in Tokyo.

“I was trying to keep my routine for life,” she said, “because I’m obviously incredibly excited and so excited about everything that’s going on, and I want to talk to everyone. But at the same time, I want to protect my own energy and I definitely let a lot of people into my space, so it was hard to navigate.

At the Olympics, she completed her first run in 4 minutes 2.4 seconds, just short of her personal best, before fading to a 12th-place finish in the semis.

She had planned to run a few more races after returning home, she said, but felt exhausted. She had to remember that she had nothing to prove.

“I made the best decision for myself,” she said.

Before officially ending her season, however, she took a trip to Cape Cod to compete in the Falmouth road race with Molly Seidel, who had won bronze in the women’s marathon at the Olympics, and Dana Giordano, a close friend and fellow professional runner. Seidel had entered the race for charity: she would start at the back of the field and collect $1 for every runner she passed.

Seidel had assured MacLean that she was going to jog the seven-mile course, so MacLean took the liberty of meeting friends the day before the race. She didn’t feel particularly sharp on the starting line.

“I run on three hours of sleep or whatever and then they just started sprinting,” MacLean said. “And I’m like, ‘Why are we going so fast?’ But it was so funny.”

Seidel and his crew passed nearly 5,000 runners. For MacLean, Falmouth was a fitting way to end an extraordinary year. She couldn’t imagine boarding another plane. She also had nagging wounds that she needed to heal.

“I hadn’t felt fluid in a while,” she said. “So I just wanted to be able to go out for a run and have my body feel good and mentally, and it just took a little while for that to happen.”

During her self-imposed hiatus, MacLean moved into a new apartment in the Boston area. She celebrated her birthday. She took long walks and listened to podcasts. She did rollerblading. She joined the Peloton craze. She has become a regular at the Breakfast Club, her favorite restaurant. (She loves breakfast.) She made coffee for her brother Shawn. And she was the guest of honor on “Heather MacLean Day,” when the mayor of Peabody presented her with a key to the city.

At the beginning of December, she resumed her journey with a few slow jogs. She has spent the past few weeks training with her teammates at altitude in Arizona.

“She looks really good,” Coogan said.

MacLean learned to prioritize her mental health, she said, which only helped her as an athlete. She reads books on mindfulness. She practices yoga. She does a guided meditation before bed. She worked to detach herself from her phone and limit her time on social media. His friends know about his various routines.

“I think people think I’m sitting in bed with all these crystals around me,” she said. “Which, OK, I have crystals.” But it’s not like that!”

Now, ahead of her first track meet in months, she feels like herself again, she said. She is ready to run.