Why did the Roman legions take young men who blushed in a state of fear?

Most likely it concerned not scared fighters. During a fright, most people turn pale, since blood flows into more important organs than the facial capillaries. The blood simply goes down and fainting may occur. When a person blushes, the blood rushes to the head due to stress. This is the body’s reaction to danger. Therefore, most likely it concerned a person’s performance in stressful situations. If a person blushes, then he will not lose consciousness and he is ready to defend himself and attack, since the body does everything for this.