Rebel Wilson Is 'Locked In' to Her Workout Routine Says Trainer Gunnar Peterson: 'She's on Her Game'

Shutterstock Rebel Wilson

Plenty of people have to be pushed to get in a workout, but not Rebel Wilson.

The Pitch Perfect star, 41, has been on a mission to improve her health over the last two years, and her longtime trainer Gunnar Peterson says she's a star student.

"She got really serious about her workouts," the celebrity trainer tells PEOPLE. "And when she went to do her last three projects, she was with me for a few months and then she'd be gone for a couple months, and I don't worry about her. It's not like you go, 'I'm turning you out of the nest, and oh gosh, I hope it doesn't all fall apart.' She has locked in. It's the best."

Peterson says that "it doesn't matter where she is. It doesn't matter what her call time is. It doesn't matter what foods they have or don't have available. She's eating right. She's recovering right. She's managing her stress levels and she's staying up to date and she's staying up to speed with her training."

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With clients that are independently motivated like Wilson, it pushes Peterson to be better.

"She's the kind of person that makes the trainer look good," he says. "She's the kind of person that makes you feel like what you're doing is worthwhile and important. And she's also the kind of person that makes me want to be better. I know she's putting the effort in, so I want to match that and exceed it."

Sanofi and Regeneron Gunnar Peterson

Wilson's goal now is to "maintain," Peterson says, which he helps her achieve through regular interval- or cardio-based workouts.

"With Rebel, it's going to be intervals until we're done or it's going to be whatever cardio plan we laid out. And if she's not in the gym and needs me to send something, I will. But if not, I know she's going to knock it out because she's on her game," he says.

Along with working with top celebs — Peterson also counts Charlize Theron and Lindsey Vonn among his roster of athletes — the trainer helps anyone searching for that push in the gym, which currently includes plenty of people trying to get back into working out after pausing during the pandemic.

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Peterson is also on a mission to encourage people who may think that it's too risky for them to exercise to try — particularly people with asthma. He teamed up with Sanofi and Regeneron to provide workout tips at JoinLungZone.com to help people get moving.

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"Asthma is a serious disease. And some people feel like, 'Oh, if I have that, I can't exercise. I gotta be careful. I don't want to have an asthma attack.' And then they start stressing, which we know triggers asthma," Peterson says. "So you can put them at ease and say, 'Here's a way to get started, progress it from here, regress it as needed and find what works for you.' I like being the doorman to that club."

Peterson says that anyone — whether they have asthma or not — can benefit from doing deep breathing exercises to build up the lungs.

"You want to strengthen your lungs. You want to strengthen your heart. You want to strengthen your muscles and all this is part and parcel to a comprehensive program," he says. "You're going to be a better athlete, and you're going to get more out of your workouts."