The physiological characteristics of the elderly are as follows: 1. Multi-disease coexistence, the elderly are prone to a variety of chronic diseases, such as hypertension, diabetes, coronary heart disease, cerebral infarction, emphysema, tumors, osteoporosis, prostate enlargement, malnutrition and so on, due to the declining physiological function and aging of tissues and organs. 2. These diseases often coexist, resulting in reduced quality of life and increased mortality in the elderly.2. The metabolic rate of the elderly slows down, resulting in easy accumulation of drugs in the body. Therefore, the elderly should minimize the use of drugs or reduce the dosage of drugs.3. Due to the decline of digestive function, the elderly often have a reduced appetite, reduced food intake, and are prone to malnutrition and reduced immune function. As a result, they are more likely to suffer from various infections, mostly serious infections, which are difficult to control.4. Older people also often suffer from insomnia, anxiety and other physiological phenomena, which are related to their declining social skills and reduced activity level.