Standing for a long time will be dizzy is caused by the following situations: first, belong to the normal physiological phenomenon, because when people stand for a long time will cause the lower limbs bruises, that is, the venous return of blood to reduce the amount of blood, resulting in a decline in blood volume of body circulation. When the volume of blood in the body after the decline in blood circulation, it will lead to a relative lack of blood circulation, thus the emergence of postural hypotension, when the blood pressure can be caused by a drop in blood pressure in the brain, resulting in insufficient blood supply to the brain, ultimately resulting in cerebral ischemia and hypoxia, resulting in energy metabolism disorders of the brain cells, thus affecting the function of the brain, dizziness will occur. Secondly, it may be due to pathological factors, such as increased vagus nerve excitability, because after standing for a long time, a part of the people will stimulate the vagus nerve thus causing increased vagus nerve tone, causing vasodilation and increased vascular volume, thus causing a decrease in the volume of return blood, and ultimately resulting in a decrease in blood pressure in the body circulation. It can also cause cerebral ischemia, hypoxia, energy metabolism disorders, and ultimately the phenomenon of dizziness.