fight-or-flight reaction

[fahyt-awr-flahyt]

noun

Physiology, Psychology.

1. the response of the sympathetic nervous system to a stressful event, preparing the body to fight or flee, associated with the adrenal secretion of epinephrine and characterized by increased heart rate, increased blood flow to the brain and muscles, raised sugar levels, sweaty palms and soles, dilated pupils, and erect hairs.

fight or flight reaction

1. The set of processes that occur in the body when it is confronted with some form of physical or mental stress. For example, if a person is faced with danger (as from a vicious animal about to attack), the nervous system signals for adrenaline and other hormones to be released into the blood. These hormones prepare the body either to confront the attacking animal or to flee to safety (thus, “fight or flight”). Changes in the body include increased heart rate, dilated pupils of the eye (to improve vision), and increased supply of blood to the muscles (to prepare the body for action).

Example Sentences

This condition, Hartman claims, induces her with a very literal “fight or flight” reaction: “I feel the need to get on a plane to go away,” she said.

From The Guardian

Cunningham, the defense psychologist, said Christian spent more than eight years in prison during his early adulthood and may have had a “fight or flight” reaction when the passengers confronted him.

From Washington Times

In a "fight or flight" reaction, he yelled at his classmates to run back into the school, where they sheltered upstairs.

From Los Angeles Times

“You experience this fight or flight reaction.”

From Time

Many illnesses are caused or worsened by stress, which activates our "fight or flight" reaction.

From US News