For those who were wondering, here are the men’s Jing (vitaliy) Cycles:
From the Yellow Emperor’s Inner Canon
8 (1×8)- A man’s Kidney energy is prosperous, his hair develops and his teeth emerge at the age of eight.
丈夫八岁，肾气实，发长齿更；
16 (2×8)- His Kidney energy grows and is filled with vital energy, and he is able to let his sperm out at the age of 16.
二八，肾气盛，天癸至，精气溢写，阴阳和，故能有子；
24 (3×8)- His Kidney energy is developed, his extremities are strong, and all of his teeth are developed by the age of 24.
三八，肾气平均，筋骨劲强，故真牙生而长极；
32 (4×8)- His body has developed to its best condition, and his extremities and muscles are very strong at the age of 32.
四八，筋骨隆盛，肌肉满壮；
40 (5×8)- His Kidney energy begins to decline, his hair falls out and his teeth begin to whither at the age of 40.
五八，肾气衰，发堕齿槁；
48 (6×8)- His Kidney energy declines more, the yang energy of the entire body declines, his complexion becomes withered and his hair turns white at the age of 48.
六八，阳气衰竭于上，面焦，发鬓颁白；
56 (7×8)- His Liver energy declines as a result of Kidney deficiency; the tendons become rigid and fail to be nimble at the age of 56.
七八，肝气衰，筋不能动，天癸竭，精少，肾藏衰，形体皆极；
64 (8×8)- His essence and vital energy is weak, as are his bones and tendons. His teeth fall out and his body becomes decrepit at the age of 64.
八八，则齿发去。
What This Means in Practical Terms
The Jing Cycles serve as a guide for how we can care for ourselves to extend our vitality. They describe a general trend. Some individuals are born with a strong constitution and can get away with misbehaving longer, while others must always exercise caution with their health. The natural peak of vitality for most men is between the ages of 24-40. Before age 24 the body is vulnerable because it has not reached full maturity. Protective measures should be taken, particularly in early childhood, to strengthen digestion and immunity. After age 40, surplus vitality begins to wane, the sex hormones begin to drop, and rejuvenative measures should be employed.
The care of boys prior to age 8 is the same as for girls under age 7 that I describe in 7 Times a Woman. Into adulthood, the diet and lifestyle recommendations are similar to women, and vary more based on individual imbalances (disease pattern differentiation). Where maintaining vitality diverges from women is in the area of procreation.
Longterm Vitality Means Conserving Jing
We pass on the best of ourselves to our offspring through the genetic material via the egg and sperm. Our egg and sperm can be viewed as a physical manifestation of our Jing. Our bodies do not differentiate between when we actually want to produce a child or not, so there will be some Jing loss for every menstruation (or gestation) and ejaculation. For this reason women must take extra care of themselves during menses and during the first month postpartum, to recuperate the loss. Men must learn to limit ejaculation based on their levels of vitality. Both men and women need to practice rejuvenation and boost their hormone levels during menopause and andropause, when sex hormones decline.
