Aging (senescence) refers to the state of morphological changes, functional decline, metabolic disorders, etc. that occur with the growth of the body, leading to a decrease in the body's adaptability to the external environment. Aging refers to the dynamic process of aging. With the development of society and economy, the improvement of medical and health care levels, the decline in fertility rates, and the extension of average life expectancy, the world's population is aging. According to statistics from the World Health Organization, there are 112.5 billion people over the age of 80 in the world. By 2050, people over the age of 60 will account for 22% of the total population. The problem of population aging is developing faster than ever before, and the health problems accompanying the aging population have also received increasing attention.
Core test points: What is health? What is aging? How to maintain healthy aging?
1. Characteristic changes of aging
Aging is an inevitable process that occurs spontaneously as organisms age. It manifests as structural degeneration and functional decline, body adaptability and resistance decline. Aging is the natural law of ontogeny , and it is a natural phenomenon in which the body gradually tends to die. From the perspective of biology , aging is due to the accumulation of damage to molecules and cells over time, which causes the gradual failure of the functions of various tissues and organs of the body, mental decline, reduced resistance to disease, and ultimately leads to the death of the body.
(-) Human body structure Aging
As the human body ages, the body's water content decreases and fat increases. The normal body water content of adult men accounts for about 60% of body weight, and that of adult women accounts for about 50%; the body water content of men over 60 years old drops to about 51% of body weight, and that of women is 42% to 45%. The main reason is the decrease in intracellular fluid water content. In addition, the body's metabolism slows down with age, more of the ingested heat energy is converted into fat storage, and the distribution of fat also changes with age.
(2) Reduction in the number of cells
After the body matures, the number of cells in various tissues and organs begins to decrease with age; cells age, atrophy, and die; due to the reduction in cell number, the weight of tissues and organs decreases, body weight decreases, and organ function decreases.
(3) Reduced tissue and organ functions
As age increases, human skin gradually becomes loose, dry, and wrinkles appear. Vision and hearing decline, loose teeth , bone marrow hematopoietic function decreases, red blood cells and white blood cells decrease, hematopoietic cells are gradually replaced by fat cells and connective tissue . The energy metabolism of myocardial cells is reduced, and myocardial contractile function is reduced. Blood vessel calcification increases, elasticity decreases, and blood pressure increases. vital capacity decreased, pulmonary fibrosis increased. The sensitivity of the nervous system is reduced, and the functions of the digestive system, , and reproductive systems are reduced.
(4) The body's adaptability to the internal and external environment decreases
The body's basal metabolic rate, energy metabolism and material metabolism all decline with age; the ability to regulate hormone levels in the body decreases, the sensitivity to insulin decreases, water and sodium regulation and calcium regulation are abnormal; the body's motor function decreases, and the responsiveness to environmental changes decreases.
2. Physiological aging
Aging can be divided into physiological and pathological aging. Physiological aging mainly refers to the physiological degeneration process that naturally occurs with age; pathological aging refers to the age-related changes in the body caused by various reasons, including diseases.
The general manifestations of aging include decreased mobility, lack of energy, hearing loss, refractive error , cognitive decline, arthritis, chronic obstructive pulmonary disease , diabetes , etc., and they gradually worsen with age. These changes in body structure and function, as well as the decrease in adaptability and resistance that occur with age, are not linearly and continuously related to age, but are loosely related.
For example, some 70-year-olds have good body function and health, while others are frail and unable to take care of themselves. In addition to the biological changes of the body itself, social and environmental factors also affect the aging process. For example, retirement, changes in living environment, and the departure of peers around them will all have an impact on the physiological state of the elderly.
Healthy life expectancy refers to the number of years that an individual is expected to live in good health at a certain age, unaffected by disease, death and functional impairment. The China Elderly Health Research Report (2018) shows that my country’s life expectancy in 2016 was 76.4 years, with men at 75.0 years and women at 77.9 years. It is expected that by 2030, the life expectancy of Chinese men will reach 76 years and that of women will be 79 years. The gap between healthy life expectancy and average life expectancy increases with age.
3. Pathological aging
Pathological aging is non-physiological premature aging or aging changes in the body caused by various reasons including diseases. There is no absolute boundary between physiological aging and pathological aging. Due to the overall decline in the functions of various systems and organs in the elderly body. The elderly have reduced resistance to noxious stimuli and increased susceptibility to multiracial diseases. They often suffer from health problems caused by various non-specific reasons, such as weakness, urinary incontinence , falls, delirium, etc., also known as geriatric syndrome.
The prevalence of most chronic diseases increases with age. As the aging of the population intensifies, age-related diseases such as cardiovascular disease, cancer, Alzheimer's disease, and other chronic diseases continue to increase. Most diseases are caused by environmental factors, including family, community, personal lifestyle habits, etc. These factors may come into play earlier, thus affecting health in old age.
For example, nutrition and environmental factors in children and even in the fetus, as well as living habits developed in early life, will have a long-term impact on a person's life, directly or indirectly causing rural diseases in old age. Maintaining good living habits such as a reasonable diet, regular exercise, and work and rest schedules can effectively reduce the process of physical failure and mental decline in the elderly.
With the aging of China's social population, the disease spectrum in our country is also changing, from mainly infectious diseases to chronic non-communicable diseases such as hypertension , heart disease , stroke , and cancer. According to the "Elderly Health Blue Book China Elderly Health Research Report (2020~2022)" report citing a nationally and provincially representative Chinese chronic disease and risk factor monitoring data, the prevalence rates of hypertension, diabetes, and hypercholesterolemia among residents aged 60 and above in my country are 58.3%, 19.4%, and 10.5% respectively. More than three-quarters of residents have co-existing conditions. As age increases, the prevalence of chronic diseases increases.
In the composition of disability-adjusted life years for residents aged 70 and above, cardiocerebrovascular diseases (39.11%), cancer (15.40%), and COPD (10.48%) account for the top three . As the aging of the population intensifies, the absolute number of people affected by chronic diseases such as hypertension, diabetes, cancer, stroke, and arthritis and the burden of related diseases will continue to increase.
4. Healthy Aging
In the World Report on Aging and Health, the World Health Organization defines the process of developing and maintaining the intact functional status of the elderly as healthy aging. In order to achieve healthy aging, the World Health Organization proposed a global strategic plan for healthy aging in 2016, striving to cover healthy aging actions in all countries by 2030. Actions mainly include establishing a social environment friendly to the elderly, providing continuous family, community, and medical service guarantees for the elderly, and strengthening monitoring and research on healthy aging.
In China, the main risk factors for health problems among the elderly are poor eating habits, high blood pressure, smoking, air pollution, and lack of effective exercise. More than 50% of deaths among people over 60 years old in China are attributed to poor eating habits and high blood pressure. Risk factors for chronic diseases are unevenly distributed among older Chinese men and women. About half of men aged 60 and over smoke, and 38% drink alcohol regularly. The proportion of lack of exercise, insufficient intake of dietary fiber and high body fat index is higher among older women.
Eliminating the above risk factors through health promotion and disease prevention strategies can prevent and alleviate many chronic diseases that plague the elderly. Including about 80% of heart disease, stroke and type 2 diabetes , and more than 40% of cancers. Therefore, to achieve healthy aging, we must carry out life-long health promotion work. In addition, health promotion needs to be based on social value systems, families and individuals. Our country has begun to take preventive measures to promote health, and has successfully tried them in some areas. For example, our country's smoking rate has been declining since 1980. The country is currently formulating a new tobacco control policy, with the goal of reducing the tobacco use rate to 5% by 2050.
Since China entered an aging society at the end of the 20th century, the number of elderly people and their proportion in the total population have continued to grow. By 2018, the population aged 60 and above had reached 249 million, accounting for 17.9% of the total population. In the future, the degree of aging will continue to deepen, and it is expected that the elderly population will account for 28% of the population by 2040. To achieve healthy aging, it is urgent to incorporate non-biomedical methods to improve the health of the elderly into the national development agenda, such as increasing educational opportunities, ensuring that everyone has access to health care services, including long-term care, and creating behaviors that promote lifelong health, such as good diet and exercise.
Article References
[1] Introduction to Medicine Second Edition-Zheng Ming-Peking University
[2] China Elderly Health Research Report (2020~2022)
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