TCM Views on the Natural Aging Process
The ancient Chinese already described human physiological stages 2,000 years ago, in the Yellow Emperor’s Classic of Internal Medicine, the Bible of traditional Chinese medicine (TCM). 
In the 1st chapter of The Plain Questions, it states below:
In the 1st chapter of The Plain Questions, it states below:
For women lifestage changes every 7 years
- When a girl is 7 years old, she has abundant kidney qi for the growth of permanent teeth as well as body hair;
- At 14, tian gui begins to be produced which ensures active functioning of the Conception Vessel and the Thoroughfare Vessel; thus she starts to menstruate and is able to conceive;
- At 21, the level of kidney qi attains its peak and her body's development stops and her wisdom teeth grow;
- At 28, her body reaches its peak with strongest muscles and bones, and thick and luxurious hair;
- At 35, her body starts to decline, initial aging signs such as a sallow face, wrinkles and hair loss are usually due to the degeneration of the Yang Ming Meridian.
- At 42, the three yang meridians in the upper body begin to decline, which leads to facial sagging, and graying hair which eventually turns white.
- At 49, due to declining tian gui production, the Conception Vessel and Thoroughfare Vessel become empty and collapse, her body will then deteriorate generally, and her ability to menstruate and give birth will cease.
For men lifestage changes every 8 year
- When a boy is 8 years old, his kidney qi has consolidated properly and he grows permanent teeth as well as body hair;
- At 16, his kidney qi is abundant and tian gui starts to be produced; as a result, kidney essence will transform into sperm, and if he has sex, he can make a girl pregnant.
- At 24, the level of kidney qi attains its peak, his body development stops, the wisdom teeth grow and his limbs are strong.
- At 32, his body reaches its peak and it will be sturdy with powerful bones and tendons.
- At 40, the kidney starts to decline that usually shows signs like hair loss or loose teeth.
- At 48, the body's yang qi starts depleting from the upper body, and there will be facial sagging, gray hair and beard.
- At 56, the liver degenerates leading to joint and tendon problems; declining tian-gui production and less essence storage in the kidney, leading to both his vitality and body wane greatly.
- At 64, he will lose his hair and teeth.
The book further specifies: "The kidney forms the foundation for the body's reproduction and development; it receives and stores essence from the other organs. Only if all five zang organs are in good conditions, can the body develops and reproduces. As the zang organs decline with age, essence stored in the kidney will be depleted and no more tian-gui is produced; the bones and tendons become weak, and body hair turns gray; there will be clumsiness and loss of fertility."
In TCM understanding, aging is mainly due to congenital essence being used up while the ability to supply acquired essence declines. The two essences are what make up human vitality. We inherit a fixed amount of congenital essence from our parents and obtain acquired essence constantly from ingested foods and drinks. They are stored in the kidneys and form the material basis for all kinds of functional activities. When kidney essence is exhausted, our physiological activities will stop and one's natural life span soon ends.
Basically, TCM claims that the five zang organs play the key roles in body’s development and degeneration. Chapter 51 of the Vital Gate summarizes their changes throughout life:
- At age ten, the five zang organs grow and develop properly, blood and qi flow smoothly, and kidney functions are efficient enough, therefore child is active.
- People in their twenties, blood and qi start flourishing, muscles are fully grown, body motions are quicker and can walk very fast.
- People in their thirties, the five zang organs are fully developed, muscles are firm and strong, blood and qi flow briskly, and so the youth person like to walk in steady pace.
- People in their forties, all the five zang organs, six fu organs and twelve regular meridians reach their peaks and can no longer grow and develop, the body’s striae begins to loosen, the face looks less bright, the hair turns gray, vitality declines and so individuals prefer sitting rather walking.
- People in their fifties, the liver functions begin degenerating, liver body thinning and bile secretion reducing, and thus vision begins blurred.
- People in their sixties, the heart functions begin degenerating, individuals may feel sad and worry more easily, and since blood and qi activities become sluggish, they prefer lying down rather then moving.
- People in their seventies, the spleen functions become weak, and the skin thinning.
- People in their eighties, the lung functions degenerated, that can no longer ensuring a sound spirit, which leads to speech error frequently.
- People in their nineties, the kidney functions exhausted, blood and qi in all other four zang organs and the meridians are depleted.
- When people reach one hundred years old, all the organ functions are exhausted, vitality disappears, the body will be died.
The above are the earliest records about divisions of life cycle in human, which form the foundation for later Life Nourishment and Gerontology in TCM.
