Qi-gong is a qi (vital energy) management practice, which is used to integrate and cleanse the body, mind and spirit. Through the use of specific postures, proper breathing and mental reframing, qi (vital energy) can flow freely throughout the entire body. Constant practice helps to promote health, prevent disease and develop personal potential. During this self cleansing process, certain physical or mental reactions can occur. The phenomena are called "qi-gong reactions".

When qi-gong reactions appear, it means certain stage is achieved. They can be classified into two categories:

Sensational effects
When a practitioner conducts qi-gong exercises, his body tends to have various sensations, such as the phenomena of "eight touches" stated in Tong Meng Zhi Guan (Acme of Children Enlightenment, a Buddhist spiritual cultivation book completed in the Sui Dynasty). The eight touches listed in this book included pain, itching, cold, warmth, lightness, heaviness, astringency and slipperiness. Modern interpretation of these are large, small, light, heavy, cold, heat, itching and tingling sensations. Less often, a practitioner may also experience phenomena, such as spontaneous jerks and a flashing sensation. These various manifestations only appear in well-trained practitioners, when qi flows freely in the meridians, and all levels of functional activities become active. For example, after the practitioner enters a qi-gong state, the genuine qi flows freely making the peripheral blood vessels expand. Parts of the body may have filling and expanding sensations. Then the practitioner may experience the body becoming taller and larger. These are usually temporary and localized phenomena, they result from a tranquilized brain that stimulates various perception abilities.

   
Physical effects
Qi-gong may alter someone's physiological activities, due to brisk qi activities and primordial qi accumulation. Practitioners may experience a hot sensation all over the body, slight perspiration, freshness, a vigorous spirit, good appetite, increased gastrointestinal peristalsis (wavelike muscular contractions of the alimentary canal by which food contents are forced onward), skin itching, muscular jerks, excessive saliva, tearing, a runny nose and belching or passing gas.

Without an adequate understanding of why these effects are occurring; practitioners may fear or worry that something is wrong with their qigong practice; or some may lose their focus in pursuit of these curious reactions. Instead, practitioners should carry on peacefully and calmly, the reactions will disappear spontaneously in a period of time.

On the other hand, some extreme phenomena will occur when the training methods are inappropriate, such as dizziness, Headache, distended forehead, Vertigo, Tinnitus, discomfort in the chest and abdomen, weakness and soreness in the back, irritability, annoyance, palpitations and limb numbness, or overheating or coldness in the limbs. These are called qi-gong deviations. Practitioners should stop immediately if these occur, the reactions are harmful and they should be mended in time.