"According to Chinese medical theory, the Qi or energy body is considered Yin, while the physical body is considered Yang. The Yin aspect of your body is related to your thinking, soul, and spirit, while the Yang aspect executes and experiences the decisions of the Yin. They must balance and coordinate with each other so that life can exist. Qi is the source of life and the actions of the physical body are the manifestations of life. When the Yin is strong the manifestation of Yang can also be strong. When Yin is weak or too strong, the Yin and Yang may lose balance and sickness can result. For this reason, Chinese medicine and Qigong are primarily concerned with how to maintain the correct balance of Yin and Yang.
"According to Chinese Qigong and medicine, the Qi in your body is divided into two categories: Managing Qi and Guardian Qi. The Managing Qi is the energy which is sent to the organs so that they can function. The Guardian Qi is the energy which is sent to the surface of the body to form a shield to protect you from negative outside influences such as cold. In order to keep yourself healthy, you must learn how to mange these two Qi efficiently so they can serve you well.
"Chinese doctors discovered long ago that the human body has twelve major channels and eight vessels through which the Qi circulates. The twelve channels are like rivers which distribute Qi throughout the body, and also connect the extremities (fingers and toes) to the internal organs. I would like to point out here that the “internal organs” of Chinese medicine do not necessarily correspond to the physical organs as understood in the West, but rather to a set of clinical functions similar to each other, and related to the organ system. The eight vessels, which are often referred to as the extraordinary vessels, function like reservoirs and regulate the distribution and circulation of Qi in your body.
"When the Qi in the eight reservoirs is full and string, the Qi in the rivers is strong and will be regulated efficiently. When there is stagnation in any of these twelve channels or rivers, the Qi which flows to the body’s extremities and to the internal organs will be abnormal, and illness may develop. You should understand that every channel has its particular Qi flow strength, and every channel is different. All of these different levels of Qi strength are affected by your mind, the weather, the time of day, the food you have eaten, and even your mood. The Qi strength in the different channels varies throughout the day in a regular cycle, and at any particular time one channel is strongest. For example, between 11:00 AM and 1:00 PM the Qi flow in the heart channel is the strongest. Furthermore, the Qi level of the same organ can be different from one person to another. When the Qi flow in the twelve rivers or channels is not normal, the eight reservoirs [help to] regulate the Qi flow and bring it back to normal.
"When a person is sick because of an injury, his Qi level tends to be either too positive (excessive, Yang) or too negative (deficient, Yin). A Chinese physician would either use a prescription of herbs to adjust the Qi, or else he would insert acupuncture needles at various spots on the channels to inhibit the flow in some channels and stimulate the flow in others, so that balance can be restored. However, there is another alternative, and that is to use certain physical and mental exercises to adjust the Qi. In other words, to use Qigong.
"There are two main purposes of Qigong training: first, to maintain the smooth circulation of Qi (bioelectricity), and second, to fill up the Qi vessels (Qi reservoirs) with Qi. In order to have smooth circulation of Qi we must regulate the electric potential difference which controls the Qi flow, and also remove all sources of resistance in the path of the circulation. In order to fill up the Qi vessels, we need to know how to increase the charge in our “battery.”
"At this point you may ask, “If we keep increasing the EMF of the battery (Qi reservoirs), won’t the excess Qi flow overheat the circuit (make it too Yang)?” The answer is yes, this can happen. However, your body is different from a regular electric circuit in that it is alive and can change. When the Qi flow becomes stronger, your body will react and build itself up so that, as you build up the Qi stored in your channels, your body has time to readjust itself. All of this also makes your body stronger and healthier.
"You can see that the key to Qigong practice is, in addition to removing resistance from the Qi channels, maintaining or increasing the Qi level (EMF) in the Qi reservoirs (battery). What are the energy sources in our daily life which supply energy to our body, or, expressed differently, what are the sources by which the EMF can be increased in the body’s bio-electric circuit, which would increase the flow of bio-electricity? There are four major sources:" *