Despite running rival fast-casual empires, the two millionaire bosses start most mornings in the gym together, debating trends like AI, protein-packed menus, and getting fresh perspectives on each other’s business ideas, like Chipotle’s guacamole-making robots.

“I was actually in the gym with [Niccol] just this morning, talking about what’s going on at Starbucks, sharing some thoughts around what’s happening at Chipotle,” Boatwright recently revealed at Fortune’s COO summit. Although the CEOs didn’t reveal their preferred workout routine, Niccol has previously told Fortune that he alternates between strength training, weight lifting, and a “run-slash-walk.”

Of course, the two gym-going executives weren’t always competing for consumers’ dining budgets: Their relationship first blossomed in 2018 when Niccol was tapped to serve as chief executive of the burrito brand, with Boatwright serving as his right-hand man as chief operating officer. 

“Brian and I made a great tag team because I was effectively running the business,” Boatwright added. “I think I ran a pretty good business, and I know that Brian really managed a great stock.”

Their paths diverged when Niccol was tapped to lead Starbucks and Boatwright was promoted to take his place. “Don’t screw it up,” Boatwright recalled the advice shared by his bench-press spotter.

And it’s a reminder that even at the very top, having a friend you can turn to for career advice still matters. 

Fortune reached out to Niccol and Boatwright for further comment.

Keep your friends close at the top of the corporate ladder

Not many business leaders can say they live in the same neighborhood as Niccol and Boatwright and can network at the treadmill. Executives often face isolation in leadership roles, making close professional connections a practical asset.

No business relationship may be better known than billionaire Warren Buffett’s close connection with Charlie Munger. In fact, the Berkshire Hathaway founder has said that his relationship with the late Munger was critical to both of their success.

“Every time I’m with Charlie, I’ve got at least some new slant on an idea that causes me to rethink certain things,” Buffett said on CNBC. “We’ve had so much fun in the partnership over the years.”

However, maintaining effective relationships is not easy. Brian Chesky, founder and CEO of Airbnb, recently revealed he sought out the advice from former President Barack Obama on how to better be a more effective leader.

“I think the vast majority of people, if they reach out to someone, someone will want to help them,” he said on Michelle Obama’s podcast IMO. “They reach out to an old friend, the old friend will want to reach back out to them, and that is the path for reconnection. It’s a path for relationships, and it’s a path for purpose.”

Exercise: CEOs’ key to maintaining health at the top

Beyond having friendships, free time is one of the things many leaders would likely say they wish they had more of. But for leaders like Niccol and Boatwright, carving out time to exercise is essential—not just for health, but as a key driver of their success.

For Airbnb’s Chesky, two workouts are sometimes part of his routine. The former competitive bodybuilder begins each morning around 8:30 a.m. with light cardio—either on the StairMaster or walking his dog through his hilly neighborhood—before starting work, he told Fortune. 

Then, around 7:30 p.m., he works out again with a personal trainer. But above all, he said, getting sleep is the biggest health practice he prioritizes.

“[A] non-negotiable is I want to try to get at least seven hours of sleep,” he said. “I know there are people that go off four, five, even six hours of sleep, but the extra hour you save by not sleeping probably makes every hour the next day a little less productive.”

Despite being in his seventies, Disney CEO Bob Iger starts his day early—at 4 a.m. He uses the time to get in a workout, something he said helps maintain the energy to run one of the largest entertainment companies in the world.

“Staying in shape and having stamina is critical for me—that’s eating well and exercising,” Iger told the In Good Company podcast last year. “Just taking care of my body and my mind is really important, I could not do this job if I were not in some form of physical and mental health.”