Why is the life span of people always between 65438 and 000?

How long can a person live? This is a very complicated problem. For thousands of years, this attractive question has played a joke on thousands of people in Qian Qian, such as divination, fortune telling, seeking immortals and asking God ... There are many tricks outside.

The so-called life span refers to the time from birth to development, growth, maturity, aging and death, and age is usually used as the measure of life span. Because there are some differences in life span between people, the average life span is usually used when comparing the life span of human beings in a certain period, a certain region or a certain society. Life expectancy is often used to reflect the medical development level of a country or a society, and it can also indicate the economic and cultural development level of a society.

The length of life is influenced by many factors, such as innate endowment, acquired supply, living conditions, social system, economic situation, medical and health conditions, environment, climate, manual labor, personal hygiene and other factors. Since birth, everyone has experienced the tempering of social factors, the interference of biological factors, and the special unexpected encounter of congenital genetic factors, thus making the life span different. Does this mean that people's life is unfathomable? No, man is the master of all things in the universe and the creator of all material and spiritual civilizations. Through continuous efforts, people can always explore the law of longevity and accurately calculate the length of life.

There is a certain limit to human life. The so-called limit refers to the age at which natural life can live, which is called "natural year" by Chinese medicine. So, how old should people live? Huangdi Neijing thinks it is a hundred years old. For example, when talking about ancient naivety, Su Wen said, "To live to a hundred years old is the end of a person's life." The Book of Rites calls centenarians "Yi". Shangshu also puts forward that "one life is 120 years old", that is, one can live to 120 years old. The great philosopher Wang Chong said: "A hundred years old is a positive number of years. Things still die in autumn, and things are in the right period. " Ji Kang, a famous health expert in Jin Dynasty, thinks that "longevity" can reach 120, which is "the same at all times". According to the above, Chinese medicine believes that people's life span should be around 100 ~ 120 years old. But social reality tells us that most people can't reach their natural life span, and some reasons haven't been recognized yet. Although the road of history is tortuous, human society will always make continuous progress. The ancients said that "life is seventy years old and rare", but today it seems obviously out of date. A large number of statistical data prove that the average life expectancy of modern people has greatly exceeded that of ancient people. How does modern science understand "Gregorian calendar year"?

For a long time, according to the careful observation of scientists, it has been found that all kinds of animals have a relatively fixed life span, that is, each has a different natural life span. This life span is related to the growth or maturity time of various animals. For example, in mammals, the life span of dogs is 10 ~ 15 years. Its growth period is two years. The life span of cats is 8 ~ 10 years, and the growth period is one and a half years. The life span of cattle is 20 ~ 30 years, and the growing period is 4 years. The life span of a horse is 30 ~ 40 years, and the growing period is 5 years. The life span of a camel is 40 years, and the growing period is 8 years. After a lot of statistical research, scientists found that the average natural life span is 5 ~ 7 times that of the growing period. According to this law, the growth period of human beings is 20 ~ 25 years, and its natural life span should be 100 ~ 170 years. Aristotle, the representative of ancient Greece, holds the above view, who put forward: "Animals with long growth periods also have long life spans." On this basis, scientist Feng Ba put forward a "life coefficient", that is, the life span of mammals should be 5 ~ 7 times that of their growing period. The above is the first method to calculate life.

The second view was put forward by American scholar Hai Foley in 196 1. According to his own experimental research, he found that the number of times of division of animal embryonic cells in the growth process is regular, and aging and death will occur at a certain stage. This is related to the number and cycle of cell division. Multiplying the two is its natural life. Helfley's specific experiment is like this: he put fetal cells in the culture medium to divide again and again and reproduce from generation to generation, but when the cells divide to 50 generations, all cells will age and die. On the basis of a large number of experimental data, he proposed to calculate the life span of people according to the number of cell divisions, and the division cycle was about 2.4 years. Life expectancy should be 120 years. The number of cell divisions in chickens is 25, with an average cycle of two months a year and a life span of 30 years. The cell division number of mice is 12, the division cycle is 3 months and the life span is 3 years.

There is also a view that life expectancy is calculated according to the sexual maturity of mammals. According to the biological law, the maximum life span of human is 8 ~ 10 times of sexual maturity, while the sexual maturity of human is 13 ~ 15 years. According to this, the natural life expectancy of human beings should be 1 10 ~ 150 years old.

The above three calculation methods are different, but no matter which calculation method, the results show that people's life span should be above 100 years old. In fact, there are many records of long-lived elderly people living to 100 years old, and even those living to 150 years old are not uncommon. China Tang Dynasty physicians Quan Zhen, Sun Simiao and Wang Bing all lived to be over 100, and they could still study and practice medicine. Luo Mingshan, an old Chinese doctor in Mianzhu County, Sichuan Province 1980 May. When he was 1 13 years old, he still saw the clinic for 6 hours every day and could treat more than 40 patients. There was a movie in the Soviet Union that recorded Muslimov, once known as the "father of the earth", energetically renovating gardens, boating and riding bicycles when he was 167 years old. A large number of modern data show that the average life expectancy of human beings is gradually approaching the next year. It used to be said that "seventy years old is rare", but now it is said that "eighty is not old, seventy is rare, sixty is in the prime of life, and fifty brothers".