While health care professionals have long accepted the health benefits of yoga, researchers continue to explore its precise effects on both the mind and body. In a recent issue of the Journal of Alternative and Complementary Medicine, the authors looked closely at an Eastern Virginia Medical School study that examined Tibetan yogis engaged in Tumo, an extreme form of yogic practice. Through the practice, yogis maintain a normal body temperature in extraordinarily cold conditions without any resultant physical harm.
A film created by cardiologist Dr. Herbert Benson shows yogis wearing only loincloths while sitting on the freezing ground. Iced sheets wrapped around their bodies melted. Meanwhile, the film crew wore mountaineering gear to bear the cold.
The new study focused on various cardiovascular factors among yogis and non-yogis in subzero temperatures. The non-yogis required warming to maintain a healthy body temperature, whereas Tumo practitioners did not even shiver without the benefit of such warming. By monitoring heart rate, blood pressure, and other factors, researchers concluded that the yogis activated brown fat and generated heat to increase blood flow significantly and decrease peripheral vascular resistance. In these individuals, yoga practice has effected substantial physiological changes.