The Kidney's Relationship With The Heart
According to the five elements theory, the heart belongs to fire and the kidneys belong to water, they coordinate with each other as possessing yang and yin properties. The heart and the kidneys are closely related, with a mutually dependent and restrictive relationship. If this functional relationship is abnormal, that is to say, if a dynamic balance is disrupted between the body's yin and yang, or water and fire elements, the morbid condition is termed as "non-coordinated between the heart and kidney." The relationship between the heart and kidneys can be showed in below:
Water and fire coordinate with each other mutually
According to TCM theory, the heart is located in the upper part of the body; it belongs to yang and fire element, and has a dynamic tendency. While the kidneys are situated in the lower part of the body, they belong to yin and water element, and has a static tendency. Under normal physiological conditions, the heart fire will descend to the kidneys and joins with the kidney yang to warm and propel kidney yin. On the other hand, kidney water will ascend together with heart yin to nourish heart yang and prevent it from becoming overactive. There are Chinese medicine sayings such as "when the kidneys lack heart fire, then it turns cold; when the heart lacks kidney water, then its fire blazes." When the heart (fire) and kidneys (water) are working in harmony, a dynamic balance between the yang above and the yin below is maintained, ensuring a healthy body and long life.
Coordination between the heart and the kidneys is necessary for each organ to work properly.
Once the functional relationship is disrupted between heart (fire) and kidney (water), pathological conditions will occur. For example, when kidney yin is exhausted, the kidney water fails to ascend and restrict the heart fire, there will be heart fire blazing in above; or when heart fire blazes alone and does not descend to warm the kidney water, the kidneys will become cold. Therefore, the upper part of body is suffering from overactive heart fire, whereas the lower part of body is suffering from coldness and coagulated of kidney water, leading to problems like insomnia, involuntary semen emissions at night and in severe cases, mental confusion such as delirium.
Essence and blood transform each other mutually
The main function of the heart is to rule blood and its flowing, and the main function of the kidneys is to store essence. Blood and essence are the fundamental substances for maintaining life activities. The kidney essence can transform into blood, and the blood can transform into essence too. The interchanging and mutually nourished actions of them provide the material basis for the functional coordination of the heart and kidneys.Essence (jing) and spirit (shen) employ each other mutually
According to TCM, the heart houses the spirit (shen), which dominates all life activities and also help replenish the essence. The kidneys store the essence (jing), which can transform into bone marrow and then gathers and fills up the brain (sea of marrow). That is why TCM believes the kidneys also shelter memory, willpower, emotions or sentiments. There are Chinese sayings such as: "essence is the material basis of the spirit; while spirit is the outer manifestation of essence." Accumulating essence can make the spirit full and complete so that it can be on guard internally, and be sharp in mental responses. That is to say, our mental activities are not only controlled by the heart, but also are influenced by the kidneys intensively. A well-established close relationship between the kidneys and heart ensures that the kidney essence (represents yin) ascends and soothes the heart's spirit. On the other hand, it also ensures that the heart qi (represents yang) descends and supports the kidneys' effect on the brain. When there is a disruption of the dynamic balance, for example, kidney yin deficiency and heart fire blazing, that lead to the heart fails to house the spirit, and also kidney essence fails to support brain functioning, conditions such as mania, depression and dementia can occur.
