A person's life goes through different life processes such as birth, growth, maturity and aging. Aging is an irresistible natural law of life activities, but the time of aging and the length of life are different for everyone. The reasons are mostly related to health care.
Aging is a very complicated biological evolution process, including a series of degenerative changes such as body shape, physiological functions of tissues and organs, coordinated control between tissues and organs, and adaptability of the body to the environment. Aging can be divided into physiological aging and pathological aging. Physiological aging refers to the physiological degradation of the body after it grows and matures with age, which is a universal law of all living things. Pathological aging is a pathological change of human body due to internal or external reasons, which leads to premature aging. Of course, absolute physiological aging does not exist, and the two often interact.
Aging is a stage of life development. Usually, 40-59 years old is called pre-senility or decline period, 60-80 years old is senility period, and over 80 years old is old age period, which is quite consistent with the signs of women's "May 7th" and men's "May 8th" in Neijing. However, because the aging process of human body is gradual, there are great differences among individuals. It should also be determined in combination with the characteristics of aging. The obvious characteristics of aging include: flabby skin, lack of elasticity, pigmentation due to the increase of wrinkles, sparse and shedding white hair, slow response, slow action, decreased vision, hearing loss, loss of appetite, restless sleep, memory loss, decreased sexual function, decreased adaptability and resistance, and possibly senile diseases such as hypertension, cardiovascular diseases, chronic bronchitis, diabetes, and prostatic hypertrophy.
As for the causes of aging, Chinese medicine believes that kidney is the root of vitality, the foundation of life, and spleen is the source of qi and blood biochemistry, so the weakness of spleen and stomach, deficiency of essence and qi, and imbalance of yin and yang are the most fundamental reasons. In addition, viscera deficiency, qi-blood imbalance, qi deficiency and blood stasis are also related to aging. Modern scientists have made unremitting efforts to explore the mechanism of aging, and so far there have been dozens of theories and hypotheses, which can be roughly summarized as follows.
One is genetic theory.
It is believed that the aging process is determined by heredity, and the growth, development, maturity, aging and death of organisms are the inevitable results of their own genetic programs. For example, the biological clock theory holds that there is a "biological clock-like regulation mechanism" in the hypothalamus of human body, which controls the speed and times of cell division. A middle-aged person is composed of about 50-60 trillion cells, which will not divide after 46-50 times from the embryo.
The second is environmental theory.
Its main point is that although heredity plays a certain role, environmental factors are also very important, such as pollution, drugs, diseases, radiation and other unfavorable factors will cause cell damage and lead to aging. For example, according to the poisoning theory, aging is caused by the accumulation of various metabolites in the body, leading to cell poisoning and death. According to the cross-linking theory, as long as a little cross-linking interference occurs in the biochemical reaction in vivo, the abnormal cross-linking of colloids in human cells and tissues will increase with age, so the cell function will be affected, which will lead to aging. According to the free radical theory, some free radicals will inevitably be produced in the process of life activities, which can react with some components in the body, causing damage to the body and leading to aging. According to the theory of cell mutation, the genetic material in biological cells suddenly mutates under the action of some chemical factors, physical factors and biological factors.
The third is comprehensive theory.
It synthesizes the related contents of various aging theories, and it is an aging theory formed from the perspectives of metabolic disorder or cell information damage. For example, according to the error disaster theory, if the human body makes mistakes in synthesizing protein, it may synthesize a large number of defective protein, and the accumulation of these protein in cells to a certain extent will cause cell aging and death. According to the theory of aging pigment, lipofuscin is widely distributed in human tissues. It increases with age, and once it appears in large quantities, it will make cells shrink or die. Therefore, some people call lipofuscin "aging pigment", as well as endocrine dysfunction and central nervous system decline. Although these theories are inconclusive, they reflect some aspects or some mechanisms of aging, a complex life phenomenon, from different angles and depths.