Tumo (or Tummo) is a Tibetan term for a type of religious practice that causes
an intense sensation of body heat to arise. Stories and eyewitness accounts abound
of yogi practitioners being able to generate sufficient heat to dry wet
sheets draped around their naked bodies while sitting outside in the
freezing cold, not just once, but multiple times.
Perhaps the most famous practioner was the Tibetan Buddhist saint, Milarepa [1],
The biography of Milarepa is one of the most popular among
the Tibetan people (for an example translation, see 'Tibet's Great Yogi Milarepa',
translated by W.Y. Evans-Wentz ISBN 0766167240).
Modern western witnesses of this practice include the adventurer Alexandra David-Neel ('Magic and Mystery in Tibet ' ISBN 0486226824 ), and Lama Anagarika Govinda ('Way of the White Clouds ' ISBN 0877730075).
While the practice could be said to have some practical benefit in the frigid
climate of Tibet, it cannot be said to be cultivated merely for the
sake of keeping warm, but is rather a side-effect of a religiously oriented
intensive meditation practice, and is the outward manifestation of an
inward state of religious ecstasy or divine union .
Similar experiences of a mystic fire have been described among practitioners
of other religions, such as the Sufi Irina Tweedie
('Daughter of Fire ' ISBN 0963457454), and among those who practice Kundalini
Yoga.