Bikram Yoga studio's suggestion that you bring a towel to class is not to be taken lightly. In fact, you might want to bring two, just in case. Bikram is a form of Hatha yoga (what we know as physical yoga) practiced in a room heated to 105 degrees with 40 percent humidity. The instructor guides you through 26 stretching postures and breathing exercises while you bend, contort and sweat -- a lot.