How much blood does the human body have?

According to scientific determination, the total weight of a normal human body accounts for about 8% of the body weight. A person weighing 60 kilograms has about 4800 ml of blood. Under normal circumstances, these blood do not participate in blood circulation, and 1/5-2/5 blood is stored in liver, spleen, lung and subcutaneous capillaries for later use. People habitually call this a "small blood bank" of the human body. When the human body is engaged in strenuous activities and can lose a little blood, the blood in the blood bank will be released after cooling to participate in blood circulation and maintain the normal physiological function of the human body.

Blood itself has a strong metabolic ability, and a large number of blood cells are aging and dying all the time. After blood donation, it will stimulate the hematopoietic function of human body to be more vigorous, accelerate the production of blood cells, promote blood metabolism and meet the needs of the body.

The human body has a strong self-regulation ability, and the blood volume changes frequently within a certain range, which is not harmful to health. After blood loss, firstly, the water and inorganic salts in plasma can be recovered in a short time of 1-2, which is the result of the accelerated synthesis of protein by the liver. Red blood cells recover slowly, and it takes about two weeks to make up for the lost red blood cells. Therefore, donating 200-400 ml of blood within the specified time interval is harmless to health.

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