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Huangdi asked, saying: May I inquire about the flourishing and declining states of Qi? Qibo replied: At ten years of age (in another version, sixteen), the Zang organs begin to stabilize, Blood and Qi are already flowing through the meridians, and its Qi is located in the lower part; therefore, one enjoys running. At twenty years of age, Blood and Qi begin to flourish, muscles are growing, therefore one enjoys walking quickly. At thirty years of age, the Zang organs are fully stabilized, muscles are firm, and blood vessels are full; therefore, one enjoys walking steadily. At forty years of age, the Qi of the Zang and Fu organs and the twelve regular meridians reaches a peak and stabilizes, the interstices (Couli) begin to open, luster fades, and the hair on the temples turns gray; although abundant, it does not fluctuate wildly, therefore one enjoys sitting. At fifty years of age, Liver Qi begins to decline, the liver tissue becomes thinner, bile secretion decreases, and vision begins to blur. At sixty years of age, Heart Qi begins to decline, leading to frequent sorrow and grief; Blood and Qi become slack and lax, therefore one enjoys lying down. At seventy years of age, Spleen Qi is deficient, the skin begins to wither, therefore the four limbs cannot be lifted. At eighty years of age, Lung Qi declines, the Hun and Po spirits scatter, therefore speech is prone to errors. At ninety years of age, Kidney Qi is exhausted, the Zang organs wither and dry up, and the meridians become empty. Upon reaching one hundred years of age, all five Zang organs are deficient, Shen Qi departs, and only the physical form remains alone until death.

For females, at seven years of age, Kidney Qi flourishes, teeth change, and hair grows. At fourteen years of age (referred to as Tian Gui arriving in *Suwen*), the Ren Mai (Conception Vessel) becomes unobstructed, and the Chong Mai (Penetrating Vessel) flourishes; menstruation arrives on time, therefore conception is possible. At twenty-one years of age, Kidney Qi is balanced and even, wisdom teeth emerge, and the body reaches its maximum height. At twenty-eight years of age, sinews and bones are strong, hair reaches its maximum length, and the body is in its prime. At thirty-five years of age, the Yangming meridians decline, the face becomes sallow, and hair begins to turn white. At forty-nine years of age, the Ren Mai becomes deficient, the Chong Mai (or Ren Mai in some versions) declines, Tian Gui is exhausted, and the menstrual pathway is blocked; therefore, the body deteriorates and fertility ceases.

For males, at eight years of age, Kidney Qi is substantial, hair grows, and teeth change. At sixteen years of age, Kidney Qi flourishes, Tian Gui arrives, essence overflows and is discharged; Yin and Yang harmonize, therefore conception is possible. At twenty-four years of age, Kidney Qi is balanced and even, sinews and bones are vigorous, wisdom teeth emerge, and the body reaches its maximum height. At thirty-two years of age, sinews and bones are robust, and muscles are full and strong. At forty years of age, Kidney Qi begins to decline, hair falls out, and teeth become brittle. At forty-eight years of age, Yang Qi declines in the upper body, the face becomes sallow, and the hair on the temples turns gray. At fifty-six years of age, Liver Qi declines, sinews cannot move freely, Tian Gui is exhausted, essence is scant, Kidney Qi weakens, and the physical form reaches extreme fatigue. At sixty-four years of age, teeth and hair fall out. The Kidneys govern water metabolism and receive and store the essence of the five Zang and six Fu organs; therefore, only when the five Zang organs are flourishing can they excrete reproductive essence. Now that all five Zang organs have declined, sinews are lax, bones are weak, and Tian Gui is exhausted. Thus, there is graying of the hair and beard, heaviness of the body, unsteady gait, and infertility.