The cause of hypertension is unknown, and the factors associated with its development are (1) Age The incidence tends to increase with age, with a high incidence in people over 40 years of age. (2) Salt The incidence of hypertension is high in those who consume a lot of salt, and it is believed that hypertension hardly occurs in those who consume <2g/day of salt; 3-4g/day, the incidence of hypertension is 3%, 4-15g/day, the incidence is 15%, and >20g/day, the incidence is 30%. (3) Weight The incidence is high in obese people. (4) Genetics About half of the hypertensive patients have a family history, which may be related to hereditary renal sodium excretion defects. (5) Environment and occupation Noisy working environment, overstressed mental work are prone to hypertension, and the incidence of hypertension is higher in urban than in rural areas. The pathogenesis of hypertension is unknown, but the main theories are: a. sympathetic adrenergic system hyperfunction theory. The nephrogenic theory. Cardiac natriuretic theory Plasma cardiac natriuretic factor is significantly lower in patients with hypertension. Fourth, the ion theory.