“When you walk in, you shouldn’t feel like you’re in a gym,” says Esther Gauthier, founder of the new Aqua fitness studio on Franklin Street. “I want it to be homey and cozy—like you’re visiting a friend’s house, and your friend happens to have a pool, and you decide to do an aquacycling class.” I could use a friend like that….

Aquacycling is riding a stationery bike while waist-deep in water. (Ten benefits are listed on Aqua’s website.) “I love swimming and I love riding a bike, and this made sense when I tried it in Europe,” says Gauthier, who is from France; she was previously a producer of fashion photo shoots.

Classes are 45 minutes long, with 15 participants max, and you can book online. All you need to bring is a swimsuit—perhaps a one-piece or mini shorts and a sports bra—and when you check in at the ground-floor front desk, you’re given a towel and special shoes and led to the locker room downstairs (Classes are women-only for now.) Further down, in a dramatic, tall-ceilinged space with two big windows in the back, is the pool. Basically, Aqua lowered the basement level; there’s a sub-basement level below the pool. (Note how the old wooden beams have been repurposed throughout the space.) You rinse off in the poolside showers, then choose a bike. The instructor spends time on bikes in the pool and on the deck, the better to demonstrate certain moves. He or she starts by explaining the correct posture: Because the body floats, you don’t lean forward on the handlebars; instead, you engage your core to maintain the right posture. And unlike traditional spin classes, you set the resistance at the start—there are three levels, and the default is the middle one—and leave it there.

The workout is intervals of sprints and climbs, incorporating arm exercises, with water supplying the resistance instead of weights. The water is 84 degrees. “Some people think it’s too cold, but not once they get going,” says Gauthier. There’s position you can do in aquacycling and not on land, where you sort of hover off the back of the bike: “It’s so refreshing to be in the water!” I asked whether the atmosphere is as motivational as SoulCycle’s is said to be. “There’s music, but it’s more relaxed, more chill than land classes. It’s still intense, but it’s not party time.” As anyone who works out in water knows, there’s something about it that simultaneously relaxes and enlivens you. “We call it blissfully energizing!” says Gauthier.

Once Aqua has settled in, Gauthier has plans for the ground floor—a juice bar, retail, adding a Tribeca-style skylight in the rear. “There’s a phrase in French, espace de vie.” Life space? We agreed it doesn’t translate. “I’d like it to be somewhere you can just hang out, read a magazine, and chat.”

Aqua is at 78 Franklin (between Church and Broadway), 212-966-6784; aquastudiony.com.

Recent New Kid on the Block/First Impressions articles:
• Mulberry & Vine
• Gloria Jewel
• Los Americanos
• Hotel Particulier
• The Hummus & Pita Co.
• Haus Alkire
• My Little Sunshine
• Le Restaurant
• Steven Alan Home Shop
• Crave Espresso Bar