The monks were doing g Tum-mo, a yoga method that allowed them to achieve a profound state of concentration and greatly increase their body heat, some by as much as 17 degrees Fahrenheit in their fingers and toes. Today, Buddhist monks across Tibet still practice g Tum-mo, raising their body temperature before prayers to feel the effects of their minds on their bodies. Monks in the Himalayan region of Nepal also use this technique, but instead of focusing on their breathing, they think about the harm they can do with their hands during prayer times (because violence is not part of Buddhism). Body heating exercises date back at least as far as 535 AD, when Indian monks developed a series of movements they called "aparigraha" (non-possessiveness) to help release anger and improve mental focus. These exercises are still performed today by Hindu priests who aim to purify their mind and body before important rituals. In America, Tibetan Buddhists use a similar exercise to calm their minds before meditation sessions. They call it "gong-tum." Gong-tum means "heat meditation" in Tibetan language.