People wonder about the appeal of doing yoga in a hot room. Reasons for the popularity of hot yoga are individual, but also broad and deeply rooted. Mircea Eliade, former professor of religion and philosophy at the University of Chicago, wrote in his authoritative work, Yoga: Immortality and Freedom, that the Indians, in the Rg-Veda, called the practice of using heat and ardour in ascetic effort a tapas.
Tapas, he wrote, cleanses the yogi and prepares them for another dimension. One reason yoga devotees searched for this other dimension was to reach the state of samadhi, a union or absorption into the Godhead or Brahmin.