Huangdi Neijing, the most authoritative classic of traditional Chinese medicine, discusses the natural life span of human beings-days and years. Su Wen on Ancient Naivety said: "Ancient people were 100 years old in the Spring and Autumn Period, but their actions never failed. ..... At the end of his life, he is going to be a hundred years old. " The "natural year" here refers to the natural life span of human beings. According to historical records: "Long life is 120 years old", it can be known that the natural life span of human beings should be 120 years old. Neijing holds that as long as we master and correctly use the way of keeping in good health, we will hopefully live a healthy and disease-free life. According to modern scientific research, the (1) sexual maturity calculation algorithm holds that the natural life span of an organism is about 8~ 10 times of its sexual maturity, while the sexual maturity of human beings is 14~ 15 years. According to this method, the natural life span of human beings should be 165438. (2) According to the growth period calculation algorithm, the natural life span of mammals is about 5-7 times of its growth period, and the growth period of human beings is 20-25 years (based on the age of human wisdom teeth). According to this method, the natural life span of human beings should be 100~ 175 years. (3) The calculation method of cell division and division cycle thinks that human cells can no longer divide and reproduce after 50 generations in vitro, and the average division cycle is about 2.5~3.0 years. According to this method, the natural life span of human beings should be 125~ 150 years. (4) According to the theory of the Earth's biological clock put forward by volkov, director of the Rhythm Research Office of the Russian National Institute of Health, the natural life span of human beings is 280 years. (5) Some people think that the gestation period of human beings is 266 days, and the natural life span of human beings should be 167 years, which is based on the variation time of structure or organization during the development of nature. Although there is no accurate method to calculate people's natural life span, according to the above calculation, it is certain that people's natural life span exceeds 100 years. In fact, the actual life expectancy of people over 100 is still very small, which is caused by some factors that affect life expectancy, such as people's ignorance of health care and neglect of health care. Health-keeping activities are an important guarantee for individuals to improve their health, reduce diseases and prolong their lives. For a nation, it is conducive to improving the health level of the whole nation and promoting the prosperity of the country; For all mankind, it can help promote the development of human health and improve human health level and quality of life. Therefore, it is of great significance to correctly understand the ideas and methods of health preservation in Neijing, scientifically guide people to carry out health care and realize human health and longevity. Zhang undertakes the important task of preaching the idea of health care in Huangdi Neijing, introducing authentic Chinese medicine theories to everyone, establishing people's awareness of health care and mastering some common sense of Chinese medicine health care. At the same time, let everyone witness what real Chinese medicine is like! Ha ha!