The following is an excerpt from pages 74 – 78 of Qi Gong Therapy: The Chinese Art of Healing With Energy by Shih, Tzu Kuo ISBN 0882681389
Jing (essence), Qi (vital energy), and Shen (spirit) exist in every living thing. They are the substantial basis for vital activity and are the foundation for the formation and maintenance of life in the human body. Together with Yin/Yang, the five elements, the Zang Fu and meridians, they form part of the core of TCM and serve as a guide to clinical Qi Gong. But Qi Gong, in particular, stresses the direct exercise of Jing, Qi, and Shen in order to eliminate disease, strengthen the body, promote intelligence, and prolong life.
[The five elements are the energies of earth, metal, water, wood, and fire; transforming, contracting, sinking, expanding, and rising respectively. The Zang Fu are the organ pairs that have correspondence to the five elements: stomach/spleen, lung/large intestine, kidney/urinary bladder, liver/gall bladder, heart/small intestine, and additionally the "organ" pair of the pericardium/triple-heater which is not an organ as recognized in Western medicine. The meridians are the energy pathways throughout the body, usually accessed through acupuncture. TCM stands for Traditional Chinese Medicine, the broadest term for the practice that includes Qi Gong, Herbal Medicine, and Acupuncture.]
What are Jing, Qi, and Shen?
Jing (essence): Jing is an essential component of the human body and serves as a basis for vital activity. Types of Jing are distinguished according to their source and function: there is congenital Jing, acquired Jing, Jing of the Zang Fu organs, and the Jing of reproduction. The types of Jing do not exist as four separate substances, but interact with, with, support, and transform into one another. Congenital Jing is inherited from the Jing and blood of one's parents and forms one of the prime substances of vital activity in the human body. Congenital Jing is involved in the support and transformation of other types of Jing.
Acquired Jing comes from the nutrients in food. Jing is extracted from food by digestion and absorption under the auspices of the spleen and stomach. Through the function of the lung, it is transported to all the Zang Fu organs where it becomes Zang Fu Jing.
Both Jing and Qi are stored in the two kidneys. The kidney also dominates the bone and produces marrow. The Kidney is the root of Qi. Qi Gong exercise stresses exercising Jing, nourishing Jing, and reserving Jing, particularly stressing exercise of the vital energy stored between the two kidneys.
In the practice of Qi Gong, attention is paid to increasing one's intake of nutrients in order to reinforce acquired Jing, and to keeping sexual activity at a moderate level in order to preserve congenital Jing.
Qi (vital energy): The meaning of the term "Qi" is very broad. Ancient Chinese philosophers, doctors, and scholars considered every vital activity in the world to be a function of Qi. Qi was considered to be the essential substance out of which the world is composed. The transformations of Yin and Yang Qi produce the various things existing in the world. "The body receives Qi and thus can live." "Life is due to the coming together of Qi and death is due to the dispersion of Qi." The body is within Qi and Qi is within the body. Thus all life depends on Qi. With Qi, beings live; without it, they die. It is a dynamic power promoting the activity of the human body. Qi coexists with Jing. Where there is Qi, there is Jing. Where there is Jing, there must be Qi. For this reason, ancient scholars often referred to Jing and Qi together as "Jing Qi." In TCM, the circulation and transformation of Qi within the body is thought to operate according to its own law, undergoing processes of ascending, descending, going out, and transforming.
The Qi in the body, the Zheng Qi [called true or healthy Qi], has three sources:
1. The Qi inherited from one's parents. This is known as Congenital Qi.
2. The Qi derived from the air. This is mainly connected to the oxygen we breathe from the air.
3. The Qi acquired from food.
Both air-Qi and food-Qi are Acquired Qi. All three forms of Qi are indispensable for life.
Both Acquired Qi and Congenital Qi are stored in the kidneys. Through the respiratory action of the lung, the circulatory activity of the heart, the digestive and absorptive processes associated with the spleen and stomach, Acquired Qi and Congenital Qi are transported throughout the body.
Shen: "Shen" means different things in different contexts. Most frequently it means spirit, mind, sense, or expression. Here it mainly means spirit or mind. Shen is also a general name for the vital activity of the body. It is the result of the highly concentrated activity of the brain and manifests outwardly as an expression of the Zang Fu, meridians, Qi, blood, Jing, and body fluids. It is derived from Jing and Qi, and like them it has a substantial basis. It may be said that Shen is the outward manifestation of the cooperating action of Jing and Qi. Where Qi is strong, there will be Shen, where Qi is absent, Shen will weaken. Shen moves along with Qi and Jing is its interior. The substance of Shen manifests in bodily appearance, while at the same time, Shen is a function of bodily appearance.
In Qi Gong practice, we pay a great deal of attention to preserving and training Shen. The exercise methods of nourishing the Heart/Mind (Xin) and calming, regulating, and preserving Shen are therefore developed. By the three forms of regulation [regulating the body, regulating the breath, and regulating the Heart/Mind (Xin)], the brain activity is inhibited and the body feels comfortable. This is the state known as "Inner Quiet." In the Qi Gong state of Inner Quiet, the brain cells are rested and their function is regulated because of the reduction of disturbance to the brain. The body metabolism is generally reduced and oxygen consumption decreases while the storage of energy increases. Through these means, the functioning of all the systems of the body are directly influenced and strengthened, and imbalance tends toward a relative dynamic equilibrium.
Among the functions of the Qi Gong state of Inner Quiet are the build-up, transfer, and strengthening of Zheng Qi. How can Qi Gong prevent and treat disease, promote intelligence, prolong life, and develop human potentialities? By regulating and nourishing the heart and the mind through bringing the brain to a quiet state and thus promoting a condition of active regulation.
As we have been stressing throughout, Jing, Qi, and Shen play important roles in vital activity. Thus, the ancient practitioners of Chinese medicine and scholars specializing in methods of preserving health paid particular attention to the preservation and exercise of these three fundamental substances. Jing, Qi, and Shen do not exist in isolation. They coexist in the same body and cannot be separated. The Ancient doctors pointed out that Shen moves along with Qi and that Jing exists in the interior of the Shen. The longevity of the body depends upon the care and preservation of Jing, Qi, and Shen.
Through the regulation of body, breath, and heart/mind, the various forms of information coming from the inner and external environments – information that stimulates and disturbs the brain – can be responded to effectively, thus protecting and strengthening the self-stabilizing, dynamic equilibrium of the body's control system. [I.e., protecting and strengthening the body's ability to maintain health!]