On a Friday afternoon in July, the temperature was around 35°Celsius. But inside Brrrn, the cool fitness studio in the Flatiron district of New York where the temperature is kept cool, it felt like a brisk November morning. “Fifty minutes, 50 degrees, 100 per cent,” is one of its mottos, and the thermostat in the workout studio where the 50-minute classes are held is set at 50°Fahrenheit (10°Celsius).

Every boutique fitness studio these days has an origin story, and Brrrn is no exception. In 2013, Jimmy Martin, a personal trainer (and aspiring comic), had a client who, on one hot July morning, talked about her preference for working out in the cold. Martin was intrigued by the idea of cold workouts and eventually met Johnny Adamic, who became his partner in the venture. In 2018 they founded Brrrn, the spelling representing the sound of your teeth chattering.

People love debating the benefits of temperature on the efficacy of workouts. Bikram yoga has brought hot yoga to the masses, and Tracy Anderson keeps her studios around 95°F (35°C) with 75 per cent humidity. The idea is that heat allows the muscles to be more pliable and that sweating a lot is good for you.

Heated yoga, particularly in the winter months, can be addictive and sweating to the point of being completely soaked can feel cathartic. But sometimes I have headaches from dehydration by the time I get home, no matter how much water I drink before and after class.

Adherents for cold workouts say they can reduce dehydration and inflammation, and boost metabolism, so you burn more calories. And they believe the cold room helps improve endurance.

As with most wellness fads, both sides like to trot out evidence that their method is best. More-conservative sports medicine practitioners have said that extremes of hot or cold basically make your body feel as if it’s doing more work.

For my purposes, I was trying out these workouts not as some science-based test but purely for the experience. In other words, I was hot, and the best way I could get myself to exercise was to do it somewhere that promised a little relief.

The Brrrn website suggests “dressing in light layers as if it were a crisp fall morning.” I went in wearing leggings, a sports bra, a tank and a

long-sleeve cotton shirt that I immediately ditched, as did the dozen other people in the class that Friday afternoon. In fact, the 50-degree studio felt pretty comfortable.

Besides, once an instructor named Caitlyn started leading us through side stretches and jumping jacks in the warm-up, I was already starting to sweat. The class was HIIT (high-intensity interval training), and alternated between battle ropes and weights. We did variations of squats and lunges with our choice of dumbbells and slammed the heavy ropes down like a demonic version of double Dutch.

Each exercise was 30 seconds long, so nothing felt interminable or impossible, but there was also no break in movement for the 50 minutes of class. It was difficult, but easily modifiable. I took my friend Rich, who is in much better shape than I am, and he was challenged as much as I was.

Brrrn also has an infrared sauna that is kept at 140 and 158 degrees. It seats eight, and Rich and I booked a 40-minute session afterward, which may be a good incentive for going in the colder months. (And at $28 for a session, the infrared sauna is much cheaper than any others I’ve seen in New York.)

Rich and I returned a few days later to try Slide, Brrrn’s other signature class. For this class, the studio is covered in panels the size of yoga mats but slippery. Covers are provided for your shoes, and you glide from one end to the other, sort of like speedskating.

Lateral movements always feel awkward, and being accident prone, I feared slipping and falling. I didn’t, and the sliding got easier as class went on. When we weren’t sliding on our feet, we did weighted exercises with SandBells and did variations of plank poses that resembled Pilates.

Like the HIT class, we did everything in short intervals with no breaks. It was a difficult 50 minutes, but it went by quickly.

The day after the slide class, I was surprised not to feel sore since I had used some long-dormant inner thigh muscles. Maybe it was science, or maybe it was just my own comfort level, but it turns out I loved working out in the cold. At the very least, I have found a more productive way to avoid the heat than movie theaters.