The common cold and influenza are frequently recurring disorders caused by attacks of exterior pathogenic factors, especially when combined with Wind. The underlying cause of illness is a failure of Lung Qi to disperse fluids and regulate the Protective Qi and the inability of Protective Qi to mount a strong defense at the surface of the body.
From the moment Qi enters our bodies, by eating, drinking and breathing, it goes through a thorough process of separation and refinement. Food and drink are broken down and the dense or turbid parts are sent for further processing and eventual elimination. Meanwhile, the clear, clean Qi is extracted and sent up to the chest where it combines with the Qi of the Lungs and Heart to become what is know as Zhen Qi or True Qi. As is the way with Chinese medicine, this True Qi has both yin and yang aspects. The Yin aspect is called Ying Qi or Nutritive Qi. This, Nutritive Qi circulates in the channels of the body as well as in the blood vessels. It is closely related to Blood, and it nourishes our internal organs.
The Yang Aspect of True Qi or Wei Qi
The Yang aspect of True Qi is called Wei Qi or Protective Qi. It circulates close to the surface of the body, between the skin and the muscles as well as on the surface of the skin. It is dynamic, fast moving and easily activated. It is our Wei Qi that provides a barrier against external pathogenic factors.
Chapter 18 of the ‘Spiritual Axis’ says:
“The human being receives Qi from food: this enters the stomach, is transported to the Lungs. It is transformed into Qi, the refined part becomes Nutritive Qi, the coarse part becomes Defensive Qi. Nutritive Qi flows in the blood vessels and channels, Defensive Qi flows outside the channels”.
Chapter 43 of the ‘Simple Questions’ says:
“Defensive Qi is derived from the coarse part of food and water, it is slippery in nature, hence it cannot enter the channels. It therefore circulates under the skin, in between the muscles, it vaporizes in between membranes and diffuses over the chest and abdomen”.
Chapter 47 of the ‘Spiritual Axis’ says:
“Defensive Qi warms the muscles, fills up the skin, enters the space between skin and muscles, opens the pores”.
The Lungs regulate and control the circulation of Wei Qi over the surface of the body. The functions of Wei Qi are often attributed to the lung for that reason, and deficient Lung Qi is often the cause of weak Protective Qi. Wei Qi plays a critical role in protecting us from harm and regulating certain bodily functions. It warms and nourishes our skin and muscles and regulates the opening and closing of the pores of the skin. In this way, Wei Qi is also responsible for regulating sweating and body temperature. Some key signs that someone’s Protective Qi is weak might be that they easily feel cold or are prone to spontaneous sweating. Wei Qi protects us from attacks of external pathogenic factors such as Wind, Cold, Damp and Heat. It is these external pathogenic factors, especially combinations like Wind-Cold or Wind-Heat that are responsible for the majority of cases of cold and flu. A weak Wei Qi will make you more prone to catching colds.
Exterior Pathogenic Influences
There are six external pathogenic factors (they are sometimes referred to as the Six Pernicious Influences); Wind, Cold, Damp, Heat, Summer-Heat and Dryness. Each of these influences are capable of causing common cold and it is especially common to see them in combinations such as Wind-Cold, Wind-Heat or Summer Wind-Dampness.
If a decline in our general health and vitality (sometimes called Righteous Qi) allows our Lungs to become deficient and they fail to disperse fluids, warm the skin and circulate the Wei Qi, we become susceptible to an invasion of one or more of these factors. In some cases there may be a pre-existing condition with the Lungs, for example an accumulation of Phlegm-Dampness (which can be generated internally through poor diet, organ imbalance or emotional imbalance), and the Lungs will not be able to regulate the Wei Qi and a combination of internal and external pathogens occur. Therefore, the state of our general health can determine, which pathogens we are most susceptible to. Yang deficient people are more susceptible to wind-cold, while Yin deficient people tend to catch wind-heat or Dry-Heat. People with accumulated Phlegm-Dampness will be more prone to invasion by Dampness.
The Common Cold
The common cold can be divided into two categories; Mild cold and severe cold. There is also epidemic cold to consider. Mild cold occurs when an exterior pathogen invades in the corresponding season, such as Wind-Cold in winter or spring. Severe cold is caused when pathogens invade outside of their normal season, for example wind-cold in summer and summer heat in winter. Epidemic cold is caused by epidemic pathogenic factors. It is typically highly contagious and is more like influenza as opposed to the common cold.
In Chinese medicine, influenza is considered to be an epidemic cold disease. It is more severe in it’s presentation than a common cold and is highly contagious. Depending on the season and clinical manifestations, it may be categorised as wind-warm febrile disease, summer-warm febrile disease or fall dryness.
Influenza is caused by exterior wind attacking a person with deficient Righteous Qi (a term used to denote general good health and vitality) and deficient Wei Qi. Pathogenic Wind invades through the skin and lodges in the Cou-Li space (between the skin and muscles). This kind of epidemic invasion is more common mid-season with an uncharacteristic change in the weather.
Influenza has a sudden and rapid onset, and is accompanied by high fever. Even though Influenza can be caused by wind-cold and wind-heat, it is most often caused by warm-febrile pathogens. The treatment principle is similar to that for common cold, but requires extra attention to clearing heat and relieving toxicity.
Constitutional strength is an important factor in the occurrence influenza. A weak constitution coupled with poor Protective Qi increases the risk of invasion of epidemic wind. Once influenza has succeeded in penetrating the bodies defences, a weak constitution will allow the pathogen to move quickly to deeper levels in the body. This is why the symptoms of influenza are so much more severe than the symptoms of a common cold.
Regular acupuncture to strengthen the Wei Qi and support the Righteous Qi during winter and around the change of season is an excellent way to both reduce the chances of getting a cold or the flu, and also serves to reduce the severity, in the event that you do catch a cold. Acupuncture is also a very effective treatment to speed recovery time and reduce the impact of symptoms when you are sick.