Cherish your vitality and plan ahead. Su Wen's theory of ancient naivety holds that people can "live to be a hundred years old" when they are alive. It can be seen that the natural life expectancy of people at that time was over 100 years old. According to Shang Shu Hong Fan, "once lived 120 years old." It is more clearly pointed out that the limit of life is 120 years. Zhang also thinks that people are over 100 years old in Zhongxing Lun. Even if the individual life span of people is different due to genetic differences, although it is impossible to be a hundred years old in the spring and autumn, most people should be over 90 to 100 years old. However, in fact, most people are half-baked, and their actions are all failures. As for the reasons, they should be responsible for the loss of nutrients and vitality. As Su Wen's "Ancient Naivety" said: "Take wine as the pulp, be reckless, get drunk, try your best to exhaust its essence, dissipate its truth, never know its feet, always resist God, speed up its heart, go against its fate, and stop its impermanence, so it can fail in half a hundred." Zhang also holds this view, arguing that apart from objective reasons such as natural disasters and man-made disasters, it is "self-loathing" (On Zhongxing). Since it is "injured by people", it is "the way to recovery, whether it is still up to people" (On Zhongxing). Vitality is the foundation of the human body, and it can't exist in the body forever. When people reach middle age, their vitality will gradually decline from the peak, so we should cherish it more. But there are always people who don't understand this truth. "I have lost it, but I don't know why." All day long, I am still addicted to wine, sex, wealth, gas and fame, and even "missed the opportunity, life suddenly changed", and my vitality is premature. Therefore, Zhang experienced the loss of yuan and life, and put forward the method of cherishing yuan and avoiding harm, saying: drinking can avoid killing, and I can't get drunk; Sex can be avoided, but we can't be fascinated: money can be avoided, but we can't be greedy; Gas killing can be avoided, and I can see through it without being serious; The killing of fame can be avoided, but I can hide it. "(Jing Yue Quan Shu Zhong Chuan Lu Tian Nian Lun) Zhang not only faces up to people's physiological needs and social needs, but also advocates controlling these needs. Compared with the thought of doing nothing blindly and suppressing people's legitimate needs, Zhang has made great progress in understanding and practice. This not only enriches and develops the theory of health preservation in China, but also provides a correct way of thinking for middle-aged people at the forefront of fierce social competition to cherish and protect their own money, enter a healthy old age smoothly, and study psychosomatic medicine for middle-aged people.