Slow blood flow during physical examination is mainly related to two factors: firstly, slow blood flow indicates high blood viscosity, which is usually due to insufficient water intake if there is no pathologic disease; secondly, it is necessary to be highly alert to the fact that high blood viscosity is pathologic, which is usually due to lipid viscosity, including triglyceride, cholesterol, and low-density lipoprotein (LDL). Further biochemical examination, if the blood lipid is too high, in mild cases, it can be relieved or even returned to normal by low-fat diet and strengthening exercise; if it still cannot be returned to normal after conservative treatment, it is usually necessary to use lipid-lowering drugs to avoid atherosclerosis caused by high blood lipid.