Former Broadway dancer creates high-altitude yoga and fitness experience in Riverdale

Editor's note: A previous version of this story incorrectly spelled A.J. Fisher's last name.  It also stated she moved to Riverdale from Inwood. She moved from Brooklyn.

In Riverdale, athletes and yogis are stepping into a backyard studio to breathe air that more closely resembles Colorado’s Rocky Mountains than the Bronx.

A.J. Fisher, a former Broadway performer turned personal trainer, built the space outside her home to bring together ideas she had been developing for years. Inside, oxygen levels are deliberately lowered to replicate conditions at roughly 10,000 feet above sea level, creating an environment where the body must adjust while remaining within a safe range.

She pairs that setting with a structured breathing method she developed through years of training clients and graduate study in exercise science.

The space, which she calls the Hypoxix Institute, serves as both a studio and a testing ground. Inside the sleek, shed-sized room, she leads small, closely monitored classes that combine hypoxic exposure with a structured breathing method designed to regulate how the body responds to physical and mental stress.

“We’re almost at 10,000 feet,” Fisher said, gesturing toward a series of narrow pipes lining the floor. “These pipes on the floor are what are supplying the room with the nitrogen and the oxygen change that has us at almost 10,000 feet.”

When Fisher and her family purchased their home, the space had been used by the previous owner, a 95-year-old former dancer, as a personal studio. Before moving in last year, Fisher brought in engineers from Hypoxico Altitude Systems to install equipment that creates a hypoxic system, artificially diluting oxygen concentration.

At the center of that system is an altitude generator, housed just outside the space. The device filters and concentrates nitrogen from the surrounding air, then feeds it into the space through pipes running along the floor. As nitrogen levels rise, the proportion of oxygen drops, creating the effect of higher elevation without changing air pressure.

“The generator is doing all the work,” Fisher said. “It’s taking normal air and adjusting the ratio so that you’re breathing less oxygen with every inhale. This is really about changing the environment just enough that your body has to respond.”

Oxygen levels can be adjusted, and Fisher monitors each session using pulse oximeters to ensure clients remain within a safe range. She typically keeps participants between 82 and 93 percent blood oxygen saturation, explaining that it is low enough to prompt physiological adaptation without causing distress.

“Your body is adapting,” she said. “You don’t even have to be working out when you’re in here. Your body is adapting, and your brain is adapting,” she said.

In class, that adaptation is carefully paced. Movements unfold slowly — a shift into position, a pause, a controlled inhale, then a long, measured exhale. The class soundtrack mirrors that pattern, embedding breath cues directly into the music so participants can follow even when Fisher’s voice fades into the background.

At the start of each session, Fisher tells students to listen for that rhythm. If they lose their place, the breath is there to bring them back.

“You don’t need to rush anything in here,” she said. “If you stay with the breath, everything else starts to fall into place.”

Intensity builds gradually, she added. She designed the method for those who may not be able to tolerate traditional high-impact cardio workouts but still want comparable results.

“I designed this training method for those who can’t do high-impact, high-intensity exercise in a normal way, but want to use the combination of altitude and breath control to get high-intensity results without the extra stress and impact on the body,” Fisher told The Press.

Her path to her current work is rooted in dance. Raised in Massachusetts, Fisher trained intensively from childhood before moving to New York to pursue a career in theater. After years of auditions and regional productions, she achieved her goal of performing professionally, including a multi-year run on Broadway.

Alongside performing, she worked as a personal trainer, building a client base that included performers and high-profile clients such as comedian Amy Schumer.

Over time, her focus shifted toward the science behind training, leading her to earn both a bachelor’s and master’s degree in exercise science. Her research focused on how breathing patterns influence oxygen use, muscle activation and the nervous system, forming the basis of the method she now teaches.

The altitude component developed gradually, beginning with her interest in breathwork, and expanding into hypoxic environments before the two approaches were combined.

“I became really interested in what was happening inside the body,” she said. “Not just the movement, but how breath and oxygen were actually driving performance and recovery.”

Fisher wanted a space where she could put those ideas into practice, pushing her and her husband to move to Riverdale with their two children last year from a one-bedroom Brooklyn apartment.

But her altitude room is used for more than workouts. A Murphy bed built into the wall allows clients to remain in the chamber for extended periods, gradually acclimating to lower oxygen levels while resting and sleeping. Some use the space to prepare for high-altitude hiking and travel, alternating between light activity and passive exposure.

Gregory Taylor, a Riverdale resident and class regular, discovered Fisher’s high-altitude yoga class after sustaining a severe injury, seeking a way to push himself physically without relying on high-impact exercise.

“I need high intensity, but without the weight bearing,” he said. “I’m not going to run, I’m not going to do that kind of exercise anymore, so this felt like a way to push myself without putting that stress on my body.”

What he found was a different kind of effort, one that required attention as much as exertion. The class demanded constant focus on breath and timing, layering cognitive awareness onto physical movement.

In the weeks after starting, Taylor said he began to notice clear changes. After years of struggling with sleep, he was now sleeping through the night, and his meditation practice, which he tracks with a biofeedback device, showed measurable improvement.

He also noticed changes in his breathing. A longtime harmonica player, he found he could sustain notes with greater ease.

“I don’t know if it’s lung capacity or if I’m better at controlling it,” he said.

Fisher said that while many of her clients are elite athletes, others are just drawn to the method as an alternative to traditional training, particularly those managing injury, stress or physical limitations.

Now, she is preparing to take that work a step further.

Fisher is set to lead a yearlong research study in Riverdale focused on menopausal women, examining how hypoxic training and controlled breathing affect cognition. It will be her third grant in this area and her first focused specifically on cognitive outcomes.