Of all the fitness crazes that seem to pop up each week, cold gyms are really bringing something new to the game. “Out of the 36,000 fitness concepts currently in the United States, we are the first to focus on exercising below 68ºF,” says Johnny Adamic, co-founder of Brrrn, the freezing fitness space that he opened in New York City earlier this year, promoting a brand-new “coldture” around exercise. “It’s an abundance of heat, even in ambient temperatures, that gets in the way of a great workout,” says co-founder Jimmy T. Martin. Turns out heat makes you fatigue faster and you’ll burn more calories and fat as your body tries to warm itself. So the next time you want to work up a sweat, turn the thermostat down.