The increase in blood flow resistance is mainly influenced by the viscosity of blood. It is known from Poiseuille’s law that the resistance to blood flow is proportional to the viscosity of blood. Any factor that increases blood viscosity may increase peripheral resistance, increase blood pressure, and increase the burden on the heart. Blood pressure can be reduced by taking appropriate medications and foods that lower blood pressure. Causes of increased resistance to blood flow: Smaller internal diameter of blood vessels, increased blood viscosity. Blood lipid stasis and increased blood viscosity lead to smaller inner diameter of blood vessels and increased resistance! The resistance encountered by the flow of fluid in the blood vessels is called blood flow resistance. Blood flow resistance is caused by the consumption of energy due to friction during blood flow, which is generally expressed as heat energy. This thermal energy cannot be converted into potential or kinetic energy of the blood, so the pressure of the blood gradually decreases as it flows through the blood vessels. In the case of turbulent flow, the various masses in the blood constantly change the direction of flow, so more energy is consumed than in laminar flow, and the resistance to blood flow is greater. Pediatric hypertension: The normal value of blood pressure in pediatric patients varies with age, and the younger the age, the lower the blood pressure. It is currently considered that blood pressure is 20 mm Hg above systolic (high pressure) or diastolic (low pressure) in the same age group, or >110/70 mm Hg in preschool children and >120/80 mm Hg in school-age children should be considered hypertensive. Primary hypertension is rare in pediatric patients, accounting for about 20% to 30%, but there is an increasing trend in recent years; secondary hypertension is more common, accounting for about 65% to 80%. In pediatric secondary hypertension, renal disease accounts for 79%, followed by cardiovascular disease, endocrine disease, neurological disease and poisoning. Cardiomyopathy: It is a lesion of progressive heart dysfunction caused by structural changes in the lower chambers of the heart and impaired function of the myocardial wall. Cardiomyopathy can lead to gradual weakening of the heart, irregular heart rhythm and eventually heart failure, but the coronary arteries are mostly normal. People of any age have the opportunity to develop this disease.