fight-or-flight response

/ fīt′ôr-flīt′ /

1. A physiological reaction in response to stress, characterized by an increase in heart rate and blood pressure, elevation of glucose levels in the blood, and redistribution of blood from the digestive tract to the muscles. These changes are caused by activation of the sympathetic nervous system by epinephrine (adrenaline), which prepares the body to challenge or flee from a perceived threat.

Example Sentences

The BUD/S instructors had a fast way of testing our fight-or-flight response.

From The Daily Beast