Gu Qi is the first stage in the transformation of food. Food is first "Rotted and Ripened" by the stomach and then sent to the Spleen to make Gu Qi, still in unusable form.
Gu Qi is sent from the Middle Burner (housing the Spleen and Stomach) to the Upper Burner (housing the Lungs and Heart), where it combines with air to form Zong Qi.
Part of the Gu Qi from the Middle Burner is also sent to the Lungs, then passes to the Heart, where (with the help of Yuan Qi and Kidney Qi), it is transformed into Blood.
Also called "Normal" Qi. Zong Qi is transformed into Zhen Qi with the help of Yuan Qi. Zhen Qi is the final stage in the transformation and refinement of Qi. It is the Qi that circulates in the channels and nourishes the organs.
Zhen Qi has two different forms, Ying Qi and Wei Qi.
Ying Qi (Nutritive Qi)
Ying Qi nourishes the internal organs and the whole body. It is closely related to Blood, and flows with Blood in the vessels as well in the channels.
It is the Qi that is activated by insertion of an acupuncture needle.
Ying Qi spends two hours in each channel, moving through all twelve channels in a twenty four hour period. During these periods, the specific organs are nourished and maintained by the Ying Qi.
Wei Qi (Protective Qi)
Wei Qi is more Yang than Nutritive Qi. Fast moving, "slippery" and easily motivated.
Primarily on the Exterior (skin and muscles). Travels both inside and outside the channels. Flows primarily in the superficial layers of the body, especially in the Tendino-Muscular meridians.
Wei Qi Functions:
- To protect the body from attack by exogenous (coming from outside) pathogenic influences e.g., Wind, Cold, Heat, Dampness).
- To warm, moisten and aid in nourishing skin and muscles.
To adjust opening and closing of pores (thus regulating sweating and regulating the body temperature).
- Wei Qi is controlled by the Lungs, which regulates its circulation to the skin. Lungs also disseminate fluids to moisten the skin and muscles. These fluids mix with Wei Qi. (Perspiration function depends on the Lungs ability to circulate Wei Qi and fluids to the exterior).
Deficient Wei Qi can lead to spontaneous sweating (pores not correctly opened and closed, so that the fluids escape).
When an exogenous pathogen (e.g., Wind-Cold) invades the Exterior, the pathogen can block the pores, inhibiting the function of the Wei Qi, and blocking sweating. The treatment is to restore the Lungs' function of dispersing, strengthen the Wei Qi and produce sweating, to expel the pathogen. Sweating therapy is often used in the early stages of a Wind-Cold pathogenic invasion.
Circulation: Wei Qi has a complex circulation pattern, of 50 cycles during a 24 hour period, 25 times in the day and 25 at night.
In the daytime, Wei Qi circulates in the Exterior, but at night it goes into the Interior and circulates in the Yin Organs.
From midnight to noon, the Wei Qi is exteriorizing, and is at its maximum strength on the Exterior at noon.
From noon to midnight, the Wei Qi gradually withdraws into the Interior, to protect the Yin Organs.
This is why one is more apt to catch cold at night rather than in the daytime, since the Wei Qi has withdrawn to the Interior at night. Sleeping under an open window at night, for example, gives exogenous pathogens a better chance for attack than during the daytime, since the Exterior of the body is less well protected.