There are many reasons for insufficient blood supply to the heart and brain, mainly in the following aspects: 1) atherosclerosis causes narrowing of the lumen of the blood vessels, or vascular spasm causes a decrease in blood flow, resulting in insufficient blood supply to the area supplied with blood.2) microthrombosis, atherosclerosis formed by the detachment of lipid plaques caused by the blockage of the blood vessels, which causes an insufficient supply of blood to the area supplied by the blood vessels.3) some causes cause the blood to be viscous and the blood flow rate to be slowed down, which also causes insufficient blood supply. Slow down, which also causes insufficient blood supply. 4, hemodynamic disorders, certain causes of low blood pressure or reduced cardiac output, can also cause insufficient blood supply. The above are the main pathological and physiological factors that cause insufficient blood supply to cardiovascular and cerebrovascular vessels, and bad habits in life can also be caused, such as smoking, alcoholism, staying up all night, mental stress and other factors, which can also accelerate the process of cardiovascular and cerebrovascular atherosclerosis.