Eventually, a Harvard Medical School researcher named Herbert Benson thought it might be time to put Tummo to the test. Benson flew to the Himalayas in 1981, recruited three monks, hooked them up to sensors that measured the temperature in their fingers and toes, and then asked them to practice Tummo breathing. During the practice, the temperature in the monks’ extremities went up by as much as 17 degrees Fahrenheit and stayed there.
