Qigong, yoga and acupuncture are ancient practices that derive from medical systems originating thousands of years ago in China and India. While wildly divergent in their details, the Chinese and Indian systems rest on certain premises about the human body, one of which is that the body is fundamentally an energy system. Energy - called “prana” in Indian ayurvedic medicine or “qi” in Chinese medicine - moves throughout the body but can become blocked or misdirected resulting in disease or symptoms of sickness. Practices like acupuncture, structured breathing, various movements and postures, and meditative techniques are designed to restore the energy’s proper movement, thus restoring health and wellness
http://www.chron.com/health/article/Qigong-may-ease-cancer-patients-stress-4543570.php