Hot air swirls around Bikram Yoga’s studio, heating limbs and relaxing tense muscles as students sink deeply into their practice’s 26 postures. During 90-minute sessions, a Bikram-certified instructor leads classes through a consistent routine of standing and seated poses mixed with two breathing exercises. In the space’s equatorial temperatures, students of all fitness levels burn calories, strengthen muscles, and eject perspirable toxins as instructors offer encouragement and personalized modifications. In addition to bringing a yoga mat and towel from home, students should prepare for class by drinking enough water to float a flock of rubber duckies.