The instructors at Supernova Yoga encourage students considering hot yoga to think about the body as two very different things: a tough metal and a sponge. This is because heat makes everything more pliable, even the toughest metals, and, like a sponge, people absorb toxins that can be squeezed out by compressing (or "wringing out") their sweat-drenched bodies. In each of the studio's classes, practitioners flow through a traditional series of 26 postures and two breathing exercises, which some students have found can ease conditions as varied as insomnia, depression, arthritis, back pain, and currently not doing yoga.