A healthy person loses a lot of blood, how much can he faint?

A healthy person generally begins to experience dizziness, fatigue, sweating and other symptoms when the blood loss reaches 800 ml, and hemorrhagic shock will occur when it reaches 1500 ml.

In addition, the blood of adults accounts for about 8% of their own weight, and the blood of a person weighing 50 kilograms is about 4000ml. When traumatic bleeding occurs, when the blood loss reaches more than 20% of the total blood volume (800ml), obvious shock symptoms appear, such as pale face, cold limbs, purple limbs, accelerated pulse, decreased urine volume, mental retardation, and decreased blood pressure. When the blood loss reaches 40% of the total blood volume (1600 ml), it is life-threatening.