Why Do People Turn White When They Are Frightened?

It is because of a simple scientific reason as to why the facial skin turns stark white whilst one is experiencing the emotion of fear or apprehension or shock.  The reason is that the blood rushes away from the face, the main source of giving the face its rubicund glow.  This happens because the blood is diverted towards a more urgent task than to give the face its rosy colour.  Another change that occurs physically while one is frightened is the expedited heartbeat and an erratic and more fast-paced rate of breathing.  For all these reasons, the supply of blood is needed in the body to cater to these physical changes.  The message of more demand of blood is conveyed by the automatic nervous system, which automatically, in harmony with its name, detects the need as it is in charge of the internal body functions of organs like the heart, the lungs and the digestive system.  When the message is given to the brain, the blood is sent to satisfy these sudden changes, its main job carrying oxygen to different parts of the body and distributing food and nourishment to organs, which require it.