• Origins of Qi
• Functions of Qi
• Movements of Qi
• Types of Qi

Western medicine places strong emphasis on the physical structures of the body, which are made up of different organic and inorganic components, such as proteins, cells and tissues. These substances form the physiological basis of human. Traditional Chinese medicine (TCM), on the other hand, views life a little differently. Instead of emphasizing discrete body components with cells being the basic building blocks, the body is seen as a whole entity with connecting parts that work together to sustain life. Some parts have more energetic properties while others have more material characteristics. It is the interactions between the different parts that are vital for normal activities of life.

In TCM, the body is primarily constituted by qi (pronounced chee), blood and body fluids, and they are also the substances that interact with different body parts. Therefore, the qi, blood and body fluids are referred to the fundamental substances necessary for life.

The ancient Chinese people believed qi was the most fundamental entity making up the world. They thought everything in the universe resulted from the movement and change of qi. The Chinese character for “qi” is the same word used for air or gas, and it is thought to have the same properties as these substances. Qi can be interpreted as the “life energy” or “life force,” which flows within us. Sometimes, it is known as the “vital energy” of the body. In TCM, qi is a widely used term. Qi is the vital substance constituting the human body. Physicians also refer it to the disease factors, medicinal properties, organ functions, pathological conditions and products, food nutrition or inherited factors sometimes. In fact, it may be difficult to find one equivalent English word or phrase that completely describes the nature of qi. Most often, qi is best defined according to its functions and properties.

Origins of Qi

Human qi comes from three main sources. The first source of qi is inherited from our parents at conception, known as the “innate essential qi.” Other sources are nutrient essential qi derived from food and drinks, and the air we breathe. Both the inherited and the acquired parts are further processed and transformed by the organs, to form the useful qi for the body.

Kidneys first sends the innate essential qi upwards where it combines with food essential qi derived from the spleen. It further mixes with the fresh air from the lungs where it finally forms into qi of the body.

By understanding how qi is formed, TCM has identified two important factors necessary for maintaining health. Through eating a healthy diet and breathing fresh air, the body extracts their most valuable essences and uses them to help form the qi. Following these simple principles are the first steps towards creating a healthy balance in the body.

Functions of Qi

Qi works in many ways inside the body. Physiological functions of organs, meridians, limbs and bones, or sense organs can be viewed as its effects.

1. Promoting functions of qi
Just as wind (highly active air) provides energy to push the sails of a boat or turn the turbine of a windmill, qi provides the active, vital energy necessary for the growth and development of the human body and to activate the physiological functions of the organs, meridians and tissues. In addition, qi promotes the formation and circulation of blood and supports the metabolism of body fluids. If there is a deficiency of qi, its promoting functions are weakened. As a result, growth and development can be affected or delayed, the organs and meridians cannot function properly and blood formation is hampered, leading to a series of health problems. For blood stasis or fluid retention conditions, TCM physicians may add some qi herbs in the remedies, which is aimed to relieve the sluggish flow of blood or fluid.

2. Warming functions 
In a gaseous state, air contains more kinetic heat energy than in its liquid state. Like air, qi also contains heat energy for the body. Being a heat source, qi warms the body and keeps it at a constant temperature, so normal physiological functions can take place. Deficiency of qi that fails to product body heat, individuals may develop a lowered body temperature, intolerance of coldness, limb coldness, declined organ functioning, and even sluggish flowing of blood and body fluids.

3. Defending functions 
In TCM, one of the main causes of disease is the invasion of “evils,” pathogenic factors that lead to illness. They are classified as wind, summer heat, dampness, dryness, cold and fire. By resisting the entry of pathogenic factors into the body, qi defends against their attack and maintains healthy physiological functions. Clinically, individuals who catch cold and flu frequently, or tend to develop infections and fever, are usually associated with a qi deficiency, especially lung qi deficiency. In western terms, this qi defending function acts like the immune system.

4. Consolidation and retention functions 
Qi consolidates and retains the body’s liquid substances and organs by holding everything in its proper place. First, qi keeps the blood flowing within the vessels and prevents it leaking out into the tissues. Secondly, qi controls and adjusts the secretion and excretion of sweat, urine, and saliva, and keeps body fluids from escaping the body. Thirdly, qi consolidates and stores sperm to prevent premature ejaculation. Lastly, qi consolidates the organs and stops them from descending into a position where they cannot function properly. If qi is deficient, or its consolidating function is weakened, it will lead to various kinds of health problems such as bleeding; frequent urination, premature ejaculation and stomach or kidney prolapses (where the organ sinks).

The promoting and consolidating functions of qi work in a complementary manner. For example, qi promotes blood circulation and the distribution of body fluids, but it also controls and adjusts the secretion of fluid substances. The balance between these two functions is essential for maintaining a healthy blood circulation and fluid metabolism inside the body.

5. Transforming functions
Qi also possesses transformation functions, which are important for the metabolism of fundamental substances. The activities of qi may change substances in the body and transform them into other essential substances. For example, certain actions of qi allow food to be changed into nutrient essence, which is in turn transformed into different types of qi and blood. Indigestible food and waste are also transformed by qi into urine and stools for excretion.

6. Nutritive functions
Qi is a fundamental substance that derived from nutrient essence and fresh air. It is constantly consumed by organs and tissues, as a supply of energy and nutrient for their functioning. Physical activities like heart beats and muscle power are determined by the state of qi supply.

Movements of Qi

TCM calls qi activities as movements of qi, which interpreted them in four directions. The qi movements are up, down, outward and inward. These movements are so important that once qi can no longer travel in these directions, life will come to an end.

Each organ has different specialized movements. For example, spleen qi ascends the pure part of digested food from the stomach for transformation into nutrient essence. Stomach qi, on the other hand, pushes food downwards in order to remove its impurities. Some organs, like the lungs, perform movements in all four directions. Lung qi moves in and out during breathing. However, when disseminating nutrient essence to the body, lung qi ascends and then descends when liquefying waste to be sent to the kidneys.

The different movements of qi work in a coordinated manner to maintain a harmonious balance. The ascending balances the descending movement while the outward balances the inward movement. Balanced movement is important for promoting the physiological functions of different tissues, organs and meridians. Disharmonious qi movements like sluggish flow, stagnated flow, inverse flow, qi sinking, qi collapse lead to health problems. For example, insufficient downward movement of lung qi causes a cough. When stomach qi cannot descend nausea and vomiting occurs.

Types of Qi

Qi is further classified according to its functions or locations. There are inborn qi, pectoral qi, middle qi, nutritive qi and protective qi.

1. Inborn qi
Inborn qi also named as “primordial qi” or “genuine qi” is the most original, essential and vital type found in the human body. Inborn qi is derived from “congenital essence” stored in the kidneys, it is further nourished by “acquired essence” (food essence derived from digestion) of the spleen and stomach. After this process is complete, inborn qi is ready to travel to the entire body to exert its effects. Starting from the portion between the two kidneys, known as the “vital gate”, the qi moves through the triple burner and circulates through the organs, muscles, skin and meridians providing the power source for all of life activities.

2. Pectoral qi
Pectoral qi is stored in the chest. It is formed by combining fresh air inhaled by the lungs and food essence derived from the spleen and the stomach. Because pectoral qi concentrates in the chest, it promotes the heart and lung functioning. By flowing through the respiratory tract, pectoral qi supports the breathing function of the lungs and affects voice and speech. Its ability to flow through the blood vessels and the heart is important in regulating the heartbeat and supporting the circulation of other types of qi and blood. Pectoral qi also plays a role in keeping the limbs warm and influences the activities of the limbs. It is also associated with hearing and vision abilities.

3. Middle qi
This refers to qi gathered in middle burner, the body region where suites the spleen and stomach, thus middle qi is mainly associated with functions of the spleen and stomach. Middle qi is formed by a combination of inborn qi and nutrient essence; it distributes throughout the spleen, stomach and intestines, regulates the whole digestive track and ensures the smoothness of digestive processes. Besides, middle qi also keeps the body structures and organs in right places, if this function is weakened, there will be distention and heaviness feelings in the gastric and abdominal regions, chronic diarrhea leading to anal protruding, or internal organ prolapse.

4. Nutritive qi
Nutritive qi, as its name suggests, supplies nourishment to the body. It mainly circulates through the blood vessels with the blood. Sometimes this combination of nutritive qi and blood is referred to collectively as “nutritive blood” or “nutritive yin”. Nutritive qi mainly comes from food essence derived by the spleen and stomach. Starting from the middle burner, nutritive qi goes to the lungs where it enters the main circulation. Nutritive qi has a yin property, so it can form into materials needed by other parts of the body. For example, its close relationship with blood allows it to provide some of the necessary substances needed to produce new blood. Nutritive qi also provides the needed nutrients to support the physiological functions of the organs.

5. Protective qi
Protective qi protects against evils, the body relies on it to adapt external environmental changes. As previously mentioned, evils are pathogenic factors that lead to illness. In western terms, protective qi functions like the immune system, which helps prevent disease from occurring or spreading. In comparing with nutritive qi, protective qi has a yang property, because it has more functional characteristics, and is known as “protective yang” sometimes.

Protective qi comes from the food essence derived by the spleen and stomach. This type of qi is characterized by forceful and rapid flowing, it moves outside of blood vessels, distributes to the diaphragm and scattered around the chest and abdominal cavities. Externally, it moves between the skin and muscles that act as the first line of protection for the body. Protective qi not only guards against disease, it also nourishes and warms the organs, muscles, skin and hair. It regulates the sweat glands and skin pores to keep the body temperature within range.

Although nutritive and protective qi share the same origin, their flow directions are opposite to one another. By balancing the nutritive (yin) and protective (yang) qi flowing, healthy sweating, temperature control and defense functions are maintained. In case if external evils attack the body, that leads to a disharmony between the nutritive qi and protective qi, individuals may develop chills, fever, and sweating problem.