With the increase of the average life expectancy of the global population and the aggravation of aging, WHO has redefined the age stage, stipulating that young people are under 44 years old, middle-aged people are 45-59 years old (prime of life), young people are 60-74 years old, real old people are 75-89 years old, long-lived people are over 90 years old, and centenarians are over 0/00 years old.
According to developmental psychology, it is divided into: lactation 0- 1 year-old infant 1-2-year-old preschool 3-6, 7- 1 1, 662-year-old adolescence.
Extended data:
Physical and mental characteristics of middle-aged people:
1, cardiovascular system, from the age of 50, the blood transfusion volume decreased by 6-8% every 10 year, but the blood pressure increased by 5-6% in the same period. With the gradual hardening of the artery, the elasticity of the blood vessel wall decreases, and the motor function of the blood vessel and the ability to regulate blood pressure weaken. Blood cholesterol levels also increase with age. Atherosclerosis can occur in coronary arteries and cerebral arteries of the heart.
2. The respiratory function is also declining year by year. The diameters of alveoli and capillaries increase with age. The elasticity of lung tissue gradually decreases. The expansion and contraction ability of the lung is reduced, and the vital capacity is also reduced accordingly. Due to alveolar interstitial fiber hyperplasia, capillary wall thickening, lung ventilation function is also declining year by year.
At the same time, lung respiratory function and disease resistance decreased. The incidence of chronic respiratory diseases such as chronic bronchitis increases with age.
3, digestive function decline, the most significant is the gradual decline in gastric juice secretion. The acidity and pepsinogen content of gastric juice decreased, and the functions of other digestive glands also decreased. This is because the growth and development of human body has stopped, and it is no longer necessary to meet the positive metabolic balance of nutritional needs.
At the same time, the function of the human body is declining, the metabolism is slowing down, the basal metabolic rate is slowly decreasing year by year, the nutritional demand of the body is also decreasing, and the required nutrition is also reduced accordingly.
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