Imagine being a professional athlete who is used to performing at sea level, and traveling to the Mile High City for a competition—only to be faced with shortness of breath. (That’s why so many ultra-athletes and Olympians train in Colorado: to condition their lungs.) Now imagine being a professional opera singer, a livelihood that depends on managing and releasing breath, and performing at the renowned Crested Butte Music Festival (CBMF), which takes place at a whopping 8,900 feet above sea level.

“It’s very hard to sing up here,” says Mark Moorman, CBMF’s director of artistic administration. “One of our previous artistic directors, who was a football player and then became an opera singer, was aware of the fact that there are similarities between the kind of training you need as a professional athlete and a singer, basically because your body is your instrument. We realized that if we brought some physical fitness to the program, we’d maybe see some results.”

That’s why the 12 opera vocalists chosen for the festival each year participate in exercise sessions three times a week while they’re training for and performing in CBMF. (The multi-week extravaganza runs through August 3 this year.) The singers work with two Gunnison fitness gurus: triathlete Jenny Hopkinson Smith on cardio and weight training and yoga instructor Sherrill Stenson on flexibility and breath awareness.

Many opera programs incorporate yoga classes because “that’s kind of natural,” Moorman says, but it’s rare for strength conditioning to have an equal emphasis. And according to soprano Caitlin Gotimer, who’s in her second year of performing at CBMF, that component is crucial. “Now that we’re in the 21st century, we have to jump on tables and do stage combat, which requires a tremendous amount of strength,” she says. “We really have to think about it all.”

The one-hour workouts range from hiking to spinning to circuit training and can be modified for different fitness levels, a benefit considering the singers come from across the country with wide-ranging backgrounds. Even Gotimer, who identifies as health-conscious, says the jump to altitude is tough, and no one’s in better shape than anyone else at the outset of the program. Plus, so much of singing depends on confidence, and the training sessions boost the vocalists’ belief in themselves as much as their fitness levels.

“You want to get up there and feel like you have a steady ground beneath you, and a lot of that comes from having a connection with your body through physical fitness,” she says. “I will never not work out before a performance ever again.”