What are the factors that affect life span?

From the subjective and objective conditions, it can be divided into objective factors and subjective factors.

Objective factors 1? Gender. Compared with women, which side has a higher life expectancy? Some people say that men are stronger than women and naturally live longer. However, the statistical results of scientists are just the opposite. The average life expectancy of women is longer than that of men. The average life expectancy of men in China is 67 years, and that of women is about 70 years. The average life expectancy of men in the United States is about 69 years, and that of women is about 77 years. Japanese men are about 74 years old and women are about 79 years old. It is a common phenomenon that women live longer than men. Different age groups have different mortality rates for men and women. It is estimated that the ratio of male to female fetus during pregnancy is 120: 100, and the ratio of male to female at birth is reduced to 105: 100. The ratio of male to female in adolescence is 103: 100. When young and middle-aged people get married and have children, the ratio of male to female is almost the same, and it drops to 75: 100 in old age. The reason for the difference in life expectancy between men and women is related to the social division of labor between men and women. Men are labor-intensive, nervous, adventurous and have poor working conditions. Men also have many bad living habits. Internally, women have twice as many genes to produce immune antibodies as men.

Why do women live longer than men? American geneticists explain the physiological advantages of women from the perspective of genetics. They believe that there are 23 pairs of chromosomes in the nucleus of human tissue cells, and the last pair is called "sex chromosome". Men are composed of one X chromosome and one Y chromosome, and women are composed of two X chromosomes. Immune genes that can regulate the immune system in the body exist in the X chromosome. Women's two X chromosomes determine that women's physiological immune substances are twice that of men, so women's antibodies are stronger and their ability to resist diseases is stronger. In addition, women are easy to establish conditioned reflex and have strong adaptability to the environment. Estrogen secreted in the body, menstrual cramps and blood loss during childbirth can promote the metabolism of women's bodies and delay the aging process.

In addition to physiological factors, there are social factors that cannot be ignored. People's life span is closely related to economy, occupation and environment. In modern society, men are engaged in many dangerous occupations such as space, high temperature, underground and seabed, which are easy to cause accidental death and affect the average life expectancy of men. However, women's living environment and lifestyle are better than men's, and their life and work are more regular, relatively safe and less threatened by death. The age of arteriosclerosis in men is earlier than that in women. Atherosclerosis may occur in men aged 30-40, while it mostly occurs in women after menopause.

In terms of lifestyle, men's habit of smoking and drinking is generally higher than that of women, which leads to many diseases, such as bronchitis, lung cancer, cardiovascular disease and liver cancer.

Women live longer than men and psychological factors are also very important. After retirement, the elderly often weaken their enterprising spirit and sense of accomplishment with the decline of social status and economic income, and become idle, unhappy and depressed. Female elderly people are different. Most of them take on the burden of housework after retirement, and still maintain abundant energy and a strong sense of responsibility. Take care of husbands and children, and help the younger generation to succeed in life and career. Even if the elderly are widowed, it is easier for them to quickly adjust their adaptability to life because of the diversity and complexity of life.

Although the average life expectancy of men is lower than that of women, its objective factors can be self-regulated except physiological factors. Developing good living habits and maintaining an optimistic mood can all achieve the purpose of prolonging life.

2? Natural environment. Environment is closely related to life span. Man is a warm-blooded animal. Constant temperature is most suitable for human survival, and life expectancy will be shortened at extreme temperatures. Most scholars have proved that air pollution is a cause that cannot be ignored. High noise is like an invisible killer, and water pollution and radiation pose a great threat to human health.

3? War. In the era of slavery and feudalism, war has always been an important cause of population death, and the two world wars at the beginning of this century have also brought great destructive power.

4? Hunger and lack of nutrition. The lower the ability of human beings to conquer nature, the greater the threat this factor poses to human life. In today's world, many developing countries are still plagued by hunger and malnutrition due to economic backwardness.

5? Medical treatment and sanitation. Disease has always been an important cause of death. In the process of social development, with the progress of medical technology and the development of health care, people's life expectancy is generally extended, and more and more people live longer. A major breakthrough in medical science in Shanghai will obviously improve the life span of the whole population.

6? Heredity. The influence of genetic factors on human longevity is often prominently reflected in those who live long. The genetic factor of longevity given by parents is only the innate condition of longevity, and the acquired condition also has an important influence on longevity.

1At midnight on May 4, 975, an air force pilot of a certain country suffered a heart attack and died after being rescued. At the same time, the pilot's twin brother also died of the same disease. Geneticists have found that there is not only one case in which twins get sick and die at the same time. After careful investigation, they found that the life span of twins is very close: the average difference between identical twins is only 3 years, and the difference between fraternal twins is 6 years. And the causes of death are mostly similar. It seems that every pair of twins are equipped with the same "biological clock" at birth, and at a certain age, the "biological clock" stops swinging. It is called "biological clock" in medicine.

As early as 196 1, the medical scientist Kalman reported his investigation conclusion: the life span difference between identical twins is smaller than that between identical twins. Parents live long, offspring live long, parents live short, and offspring live short. Twins often die for similar reasons. This shows that the biological clock of life has genetic characteristics. Dr Gillette of the University of Rome came to the conclusion after summarizing the genes of more than 5,000 pairs of twins. Each gene acts as a clock of life activities and determines when these genetic characteristics appear and disappear in a person's life.

Since the biological clock is determined by heredity, is life predestined? That's not true. Someone once compared the relationship between human life span and genetic and environmental factors to a triangle.

The bottom of the triangle represents genetic factors, and the other two adjacent sides are environmental factors, including personal lifestyle, spiritual factors, social factors and natural factors. The area of a triangle with three sides is the life span. The longer the three sides, the larger the area, that is, the longer the life. From the metaphor of this image, we can see that the bottom-genetic factor is important, but the influence of two adjacent aspects-acquired environmental factors can never be ignored. If the genetic factors are good, the base of the life triangle will be long, and the acquired environmental factors such as food, clothing, housing, mood, marriage, climate and geography will make the area of the life triangle bigger.

How to prolong life is a subject that needs long-term research. We believe; The mystery of "biological clock" will be solved one day, and human life will certainly continue to be extended to approach or reach the limit of human normal life.

Subjective factors 1? Living habits. The extension of life requires reasonable nutrition and proper diet supply. Diet does not lie in abundance, but in the complete ingredients in food, reasonable collocation and moderate quantity, and the content and quantity of diet should be suitable for age and environment.

2? The pace of life. The rhythm of life is the rhythm of life metabolism. Proper labor intensity is beneficial to health, and most of the long-lived old people around the world insist on working in their later years. Active physical and mental exercise is not only the way to health, but also the treasure of longevity.

3? Mental and psychological. Modern medicine reminds people that the influence of psychological aging on aging sometimes exceeds that of natural aging, and sound psychology is also the guarantee of health. Optimistic attitude towards life, strong will and perseverance to difficulties, cheerful and optimistic personality and spiritual sustenance are all conducive to good health. Cultivating good living habits, maintaining an appropriate pace of life and paying attention to mental health will all prolong the life span of individuals more or less.