The blood volume in the human body is relatively stable, and the blood volume of adults is 7% ~ 8% of body weight. Medical research has proved that if the blood loss is less than 400ml at a time, plasma and blood cells can return to normal levels in a short time through self-regulation. A healthy adult who donates 200 ~ 300ml of blood each time will not only affect his health, but also help to improve the hematopoietic function of his own hematopoietic organs.
So the answer is: √.