Chinese medicine is applied philosophy. Perhaps the most basic thing at the root of that philosophy is the theory of Yin and Yang. This theory describes two entities that are the part of the same whole, separated into the Yin and the Yang. Each corresponds to certain directions and qualities
Yin and Yang are relative terms. So West is Yang in comparison to East, and Heaven is Yang in its relationship to the Earth. Humans bridge the gap between Heaven and Earth, and have qualities of both Yin and Yang. Our Yin substances include the tissues of the body, the organs, the bones, and the fluids. Our more Yang substances include the mind, the spirit, and the energy of life known as Qi. In acupuncture theory, we are often trying to balance Yin and Yang in a person. Consider this: activities can be qualified as Yin or Yang. For example, work is Yang, and rest is Yin. In our society, people have an abundance of Yang, but lose the Yin. They exhaust their Yin - Yin is consumed to allow for the expenditure of Yang, this is one of the laws of Yin and Yang.
Many of my treatments aim to nourish and support Yin, and I may coach my patients to build some time into their day that is more Yin. Maybe it’s taking a nap, or meditating, or at least doing a breathing exercise. I find my patients have much more energy to do all the Yang things they want to do when they spend just ten minutes a day doing something Yin to re-charge.