The total blood volume of healthy people accounts for about 8% of body weight, and the metabolic activity of blood is very vigorous. The total blood volume of an adult is about 4000-5000 ml, and the blood donation of a healthy adult is 200-400 ml, accounting for only 4% of the total blood volume of the whole body. After blood donation, the body will automatically adjust, so that the blood flow can quickly return to normal, and at the same time stimulate the hematopoietic function of the body. Usually, 80% of the blood circulates in the heart and blood vessels to maintain the normal physiological function of the human body and donate blood without compensation; Another 20% of the blood is stored in the liver, spleen and other organs. Once blood loss or strenuous exercise occurs, blood will enter the blood circulation system. After donating blood, the blood stored in the body will be replenished immediately without reducing the circulating blood volume in the body. Water and inorganic substances lost after blood donation will be replenished within 1-2 hours; Plasma protein, synthesized by liver, can be supplemented in a day or two; Platelets, white blood cells and red blood cells also quickly recovered to their original levels. The blood of human body is constantly metabolized. Many blood cells are aging and dying all the time, and at the same time, a large number of new cells are generated to maintain the balance of human metabolism.
After blood donation, the lost blood cells are quickly replenished because of stimulating hematopoietic function. Therefore, a healthy person who donates blood according to relevant national laws and regulations will not have a significant impact on his health.