How much blood is there in the human body

Blood is an essential substance in the human body. If a person lacks blood, he may go into shock and die. If a person has too little blood in his body, he will develop anemia, which is very harmful to a person's health. However, the human body should not have too much blood. There is a certain amount of blood in a person's body. So how much blood does a person have in his body?

1. How much blood does a person have?

The total amount of blood in the human body is called blood volume, which is the sum of plasma volume and blood cells. However, except for red blood cells, the number of other blood cells is very small and often negligible. The amount of blood in each person's body is determined by their weight. The total blood volume of a normal person is approximately 7%-8% of body weight, or 70-80ML per kilogram of body weight, of which the plasma volume is 40-50ML. There are 4-5 million red blood cells, 4,000-11,000 white blood cells, and 150,000-400,000 platelets per cubic millimeter of blood.

In addition, for people of the same weight, thin people have slightly more blood than obese people, and men have slightly more blood than women. Under normal circumstances, the total blood volume in a person's body is about 8% of body weight. If the body weight is 100 catties, the blood volume is 8 catties. That is 4 kilograms. The total volume is 4000 ml, of which plasma accounts for more than half.

2. Will donating blood harm your health?

When donating blood, a person donates 200 to 400 ml of blood at a time, which only accounts for 5% to 10% of the total blood volume. Donating blood according to regulations will not have any effect on the body, nor will it "hurt your vitality". On the contrary, it will be beneficial to your health.

3. Safe range of blood donation

Anyone who has donated blood knows that the average blood donation is between 300 and 400 ml. If it exceeds this amount, people will feel dizzy. A healthy adult has approximately 3.8 to 5.6 liters of blood in his body. Losing 15% of your blood volume won't make you feel uncomfortable immediately, but once it exceeds this standard, your pulse will speed up and you may feel dizzy and cold. If 40% of the blood volume is lost, this will affect the blood flow back to the atrium, causing symptoms of tachycardia.