The total blood volume of healthy people accounts for about 8% of body weight, and that of adults is about 4000 ~ 5000 ml. Usually, 80% blood circulates in the heart and blood vessels to maintain normal physiological functions; 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. A person donating 200 ~ 400 ml of blood at a time only accounts for 5% ~ 10% of the total blood volume, and the blood stored after blood donation will be replenished immediately without reducing the circulating blood volume. 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, due to the enhancement of hematopoietic function, the lost blood cells were quickly replenished. Therefore, a healthy person who donates blood according to the regulations will not have any influence on his body, let alone "hurt his vitality", but will be beneficial to his body.

Donating blood according to the regulations can promote human metabolism, enhance immunity and disease resistance, stimulate human bone marrow hematopoietic organs, and keep them in the same vigorous hematopoietic state as when they were young, so as to achieve the effect of prolonging life and prevent cardiovascular and cerebrovascular diseases such as arteriosclerosis. It is reported that 332 former blood donors over 66 years old were compared with 399 non-blood donors under the same conditions. As a result, the survival rate of former blood donors was significantly higher than that of non-blood donors, and those who donated more blood lived longer. Donating blood has many benefits. A lot of scientific research has proved that blood donation is good for health.

First, it can prevent and relieve hyperviscosity.

Scientists have studied the relationship between blood and blood donation by using hemorheology and hemodynamics, and found that adhering to long-term moderate blood donation, especially donating tangible components such as red blood cells and platelets, can obviously reduce blood viscosity, speed up blood flow and increase cerebral blood flow, thus alleviating or preventing hyperviscosity, making people relaxed, clear-headed and energetic.

Second, it can prevent and reduce the occurrence of cardiovascular and cerebrovascular diseases.

An expert in Qingdao made a comparative study on hemorheology of 127 repeated blood donors, 87 hypertensive patients and 60 ischemic stroke patients. The results show that blood donors have a positive effect on reducing the occurrence of cardiovascular and cerebrovascular diseases. A research team in Finland investigated 278 men aged 42-60 years. Five years later, the proportion of blood donors suffering from coronary heart disease was 86% less than that of non-blood donors. Another study followed up 1532 people who donated blood L-2 times. Results Only one person had acute myocardial infarction, and the incidence rate was 0.043%. Among 2306 people who didn't donate blood in the same period, 226 people developed acute myocardial infarction, the incidence rate was 9.8%, which was significantly higher than that of the blood donation group. A study by a cardiovascular disease research group in the United States also shows that within three years, the risk of cardiovascular disease of blood donors (men) is only 1/2 of that of non-blood donors.

Third, male blood donation can reduce the incidence of cancer.

Too low iron content in the body is prone to iron deficiency anemia and bradykinesia, while too high iron content is counterproductive. International Cancer once reported that if the iron content in the body exceeds 10% of the normal value, the probability of cancer will increase, and proper blood donation can prevent cancer. The article also mentioned that women lose a certain amount of iron due to blood loss during menstrual cycle, so there is no obvious relationship between iron content in women and cancer.

Fourthly, it can promote and improve mental health.

A large number of studies show that healthy emotions can communicate with the brain and other tissues and organs through the nervous system, body fluids and endocrine system, so that they are in a good state, which is conducive to the enhancement of human immunity and resistance. Blood donation is a noble character to save lives. While helping others and being kind to others, it also purifies one's spirit, soothes one's soul and enriches one's work and life. Doing good by virtue actually helps others and yourself, which is an important element of health and longevity.

Fifth, it can prolong life.

Foreign scholars also made a prospective comparative study of 332 people over 66 (blood donors) and 399 people of the same age and sex (non-blood donors). The results show that:

The average life expectancy of blood donors is 70. 1 year, which is higher than that of non-blood donors (67.5 years).

The survival rate of blood donation group was 67%, which was higher than that of non-blood donation group (40%).

The mortality rate of blood donation group was 33%, which was lower than that of non-blood donation group (60%).