The main functions of the Kidney are storing the Essence of Life, regulating water metabolism, controlling inhalation, and sexual activity.
– Storing the Essence of Life
There are two components of the Essence of Life. The first is known as the Prenatal Essence of Life, or Prenatal Qi. It is given at conception. It can be somewhat strengthened through food and nutrition, and is, or can be, transformed to the Qi of the Kidney. The Qi of the Kidney contributes to the growth, development, and replacement of the body, for example, the growth of teeth. The body grows as the Qi increases. When the body reaches puberty, the Qi of the Kidney is at its peak. It then initiates the production of sperm in boys and eggs and menstruation in girls. As the body ages, the Qi of the Kidney weakens, also diminishing reproductive capabilities.
The second component or type of Essence of Life is known as the acquired, or Postnatal, Qi. It is derived from food. The Spleen and the Stomach transform food into Postnatal Qi, which is then transported to the five viscera and six bowels. When there is not enough Postnatal Qi for body function, the Kidney will supply it from its reservoir; conversely, when there is surplus , the Kidney stores it. So, when any organ is not functioning correctly, the Kidney needs to be nourished because it will be relied upon to supply any deficiencies.
The Kidney’s Essence of Life can aid in making bone marrow, which nourishes the bones. When the Kidney is functioning well, bones and teeth are strong. Conversely, when the Kidney is weak, both bones and teeth are weak also. The Essence of Life also turns into blood, which nourishes the hair. When the Kidney is functioning well, the hair is strong and shiny. Withered, balding, or gray hair can be a sign of a weak Kidney. Finally, the Kidneys also influence brain function; when Kidney Qi is strong, thinking and memory will also be strong and clear.
– Regulating water metabolism
The Kidney maintains balance of the fluid in the body. Fluid in the body is responsible for transporting nutrients to organs and tissues, and for carrying waste out of the tissues. The Kidney plays an important part in both functions. The Kidney either releases water or retains needed water. When the Kidney is functioning well, urination is normal. When it doesn’t function well, the Kidney could release too much, causing diseases like polyuria (excess urination) and frequent urination. When the Kidney does not release enough, it can lead to oliguria (scant urination) and edema (swelling, excess water collecting in body tissues).
– Controlling and promoting respiration
According to Chinese medicine, the Kidney, along with the Lungs, aids in inhaling air. When the Kidney is not functioning well, exhaling will occur more than inhaling, which can result in dyspnea (difficult or labored breathing) and severe panting.
In Chinese medical theory, Kidney Essence is like the battery power that runs your life. You can never have too much, but you can use it up. Thus, all Kidney disease patterns involve deficiency of some sort. Sources of potential deficiencies—that is, ways your Kidney Essence can become exhausted– fall into six categories: Hereditary, emotional, sexual, chronic illness, aging, and overwork.
– Hereditary weakness
Prenatal Qi or Life Essence is formed at conception; its quality is determined by the quality of the parents’ Essences, Heavenly Qi, and the environment. If the parents’ Essences are weak, which means they had weak constitutions, then the child will also be weak and may have such symptoms as poor bone development, poor teeth, enuresis (inability to hold urine), thin or weak hair, and in extreme cases some mental retardation. Since a person’s vital energy naturally declines with age, conceiving late in life can weaken the constitution of the child. When Prenatal Qi is weak, the person must pay particular attention to the other factors in order not to put a stress, or drain, on this irreplaceable vital force.
Fear, fright, shock, and anxiety makes the Qi descend, especially in children. It can happen to anybody; something that happens to you or something that you witness can cause shock, and deplete your Kidney Qi. In adults such depletion may be the root cause for insomnia and mental restlessness.
– Sexual activity
Excess of sexual orgasms weakens the Kidneys because orgasms are directly related to the Kidney Essence. This also includes masturbation. Since the Heart and Kidneys are closely related, during an orgasm one can often experience palpitations. Conversely, Heart deficiency caused by sadness and anxiety can weaken the Kidneys and cause impotence or lack of sex drive, as well as coldness in the limbs and enuresis (involuntary urination).
– Chronic illness
Any long-lasting, chronic condition will create a deficiency of Kidney Yang and/or Kidney Yin.
Kidney Essence naturally declines with age. In fact, in Chinese medicine the process of aging is defined as the manifestation of a decrease of the Kidney Essence. Hence, as a person ages, they experience decline in all the functions controlled by Kidney Essence, namely, decreases in hearing, bone density, sexual function, memory, and hair.
This means mental and physical work for long periods of time or burning the candles at both ends. In modern society, this is the most common cause of depleted Kidney Yin. Long work hours, particularly mental work, in poor environments, emotional stress, lack of relaxation, lack of exercise, improper and irregular meals, poor sleep, lack of exercise, etc. draws directly on Yang energy. When Yang energy normally used for these functions is exhausted, the body starts using the Yin Essence. Yin Essence is generally harder to restore, and its depletion leads to problems that are more difficult to treat. In all of these cases, eliminating the drain on Yang Essence is the first step to recovery.