Fight-or-flight Response

The fight-or-flight response (also called the fight-or-flight-or-freeze response, hyperarousal, or the acute stress response) was first described by Walter Bradford Cannon.

His theory states that animals react to threats with a general discharge of the sympathetic nervous system, priming the animal for fighting or fleeing. This response was later recognized as the first stage of a general adaptation syndrome that regulates stress responses among vertebrates and other organisms.