Fight-or-Flight response refers to physiological changes in the human body that occur in response to a perceived threat, including the secretion of glucose, endorphins, and hormones as well as the elevation of heart rate, metabolism, blood pressure, breathing, and muscle tension. It is a physiological reaction to threat that mobilizes an organism for attacking (fight) or fleeing (flight) an enemy. Moreover, Fight-or-Flight response is a response to threat in which the body is rapidly aroused and motivated via the sympathetic nervous system and the endocrine system to attack or flee a threatening stimulus; the response was first described by Walter Cannon in 1932.