Casie Griffin exercises almost every day and is OK with the hefty price tag: $300 a month for intimate classes in the boutique studios she enjoys.

Most days, the 31-year-old goes to Unite Fitness near Rittenhouse Square where top-rated fitness instructor Leroy Mapp acts as both a DJ and motivator, yelling instructions as he switches up the beats in the club-like atmosphere. Within walking distance, similar scenes play out daily at chains such as Flywheel, Solidcore, SoulCycle, and others for exercise including yoga, cycling, and Pilates. Single classes typically cost about $20 to $30.

This popularity shows how a boutique fitness studio — typically a smaller space with group classes and a specialization — can be more than a place to burn calories. It's often a sign of a wealthy or a now-gentrified neighborhood with a crop of residents seeking these workouts.

"Health is the new wealth," said Josh Leve, the founder and CEO of the Association of Fitness Studios. "As the fit get fitter, ultimately, people are looking to spend more of their discretionary income on these classes."

Philadelphia-area boutique studios, including those in the Pennsylvania and New Jersey suburbs, cluster in affluent communities, according to an Inquirer analysis of the fitness subscription service ClassPass' member studios in the region. ClassPass offers a monthly membership from $35 to $100 for two to 12 classes at various studios, enabling users to try multiple studios without having to join each one.

The participating gyms — mostly studios — listed on the ClassPass website as of Aug. 1 are in 89 zip codes out of 228 in the eight-county region. People living in those 89 zip codes have a higher median income and are more likely to have a college degree, the analysis found.

Though each studio may attract a different population — Unite Fitness founder and president Gavin McKay is proud of the diverse instructors and clientele at his gym — the zip codes with ClassPass locations are almost 80 percent white, compared with 57 percent in those without a participating gym.

"We only have so much control over where these studios and gyms are popping up so we are trying to think past that," ClassPass spokesperson Lauren Craft said, adding that the subscription service recently launched a free app, ClassPass Go, to "expand our total addressable market."

"We're trying to target everyone. We think about it holistically," she said. "Everyone should be incorporating health and wellness into their lifestyle."

The 16 boutique fitness studios in Center City five years ago jumped to 36 this year, according to an analysis by Casandra Domínguez, the Center City District's director of business attraction and retention.

The classes "cater to a very specific, specialized, and passionate segment who are very willing to pay more for being part of a 'tribe,'" Shannon Vogler, a spokesperson for the International Health, Racquet & Sportsclub Association, wrote in an email. "It's the sense of belonging where everyone is 'like them' vs. a traditional club, which caters to many different types of exercisers."

Studios hope to attract Philadelphia's quickly growing millennial population with clublike lighting, popular dance music, and group workouts multiple times a day. The city's millennial population rose more than other major cities when looking at the group's percentage of the overall population, according to the 2014 Pew report, "Millennials in Philadelphia," which considered people aged 20 to 34 as of 2012.

Noah Neiman, cofounder of the Rumble Boxing studio, which plans to open a facility on Walnut Street this year, described today's fitness scene as "like the new happy hour."

His team identified Philadelphia "as one of the fastest growing fitness-centric cities," when choosing to expand his business from New York and California.

In the last nine months, OpenBox Athletics, a CrossFit gym with a yoga studio, opened in the Graduate Hospital area — which the 2016 Pew report, "Philadelphia's Changing Neighborhoods," shows is the city's most gentrified neighborhood — while an Orangetheory Fitness, a chain boutique studio, opened in Northern Liberties.

Yet, the emerging fitness consciousness isn't necessarily accessible to everyone. Philadelphia still has the highest poverty rate of the 10 most populous cities, at nearly 26 percent.

In less affluent parts of the city, residents rely on government services, some of which may be rundown, or more-affordable classes. There are also gyms such as Planet Fitness, City Fitness, and the YMCA that offer lower-cost membership fees.

Philadelphia also remains one of the least fit cities in the country. The city was listed 82 out of 100 cities across the country for its fitness, according to the American College of Sports Medicine 2018 ranking. The survey considered health behaviors, chronic disease, and community infrastructure.

Mapp, the instructor at Unite Fitness, also teaches Flywheel classes in the city and is aware of how he can introduce boutique fitness to people who may not have thought this sector was for them. He praised Unite Fitness for having diverse instructors and events, such as the company's LGBT pride workouts, and thinks showcasing this is a way to attract a broader audience.

"I'm a heterosexual black male that's a cycling instructor. That's a rarity," Mapp said. "Me being myself, I draw in a lot of people, people of color into Unite."

Kelli McIntyre, the physical activity coordinator in the city's Department of Public Health, said those frequenting boutique studios are not as likely to be suffering from chronic diseases at the highest rates or hurting from lack of access to care or healthy foods.

McIntyre turns her attention to the other zip codes, where residents can't afford $20 or more a class, with the city's fitness initiative Philly Powered.

"Wouldn't it be great if you could try different things and you didn't have to sacrifice groceries?" McIntyre said. "If you try five $12 classes this month, that's a lot of people's PECO bill."

Studio 34 in West Philly is a yoga studio that aims to provide an inclusive environment with affordable classes. A class could be as low as $6 and there's a work-exchange program for unlimited free classes. Other low-cost studios include Watts Fitness Studio in Fairhill, which offers $5 classes in one of the poorest neighborhoods in the city.

In yoga classes, "it's very apparent when you are the only person of color in a room vs. here when you practice, you see people who look like you, you see people who live like you," said Anisha Chirmule, 29, who is Indian and an instructor and participant at Studio 34 in West Philadelphia. "There's like instant kinship and solidarity."

There have always been exclusive country clubs that are inaccessible to most residents and where people play sports, said Emily Dowdall, the chief of policy implementation at Reinvestment Fund. Still, she said, it's important to have accessible fitness options as wealthy residents drive demand for more expensive workouts.

"The story of Rocky is obviously based on the real boxer Joe Frazier, a tradition of having boxing gyms in neighborhoods," Dowdall said. "Fitness is not just a province of young millennials, so I think it's important there continue to be diverse options for fitness, for food, for clothing, for all Philadelphians."