fight-or-flight response

American  

[fahyt-er-flahyt-ruh-spahns] / ˈfaɪt ərˈflaɪt rəˌspɑns /

noun

fight-or-flight responses plural

1. Physiology. the body's response to stress, involving the release of epinephrine and effects such as increased heart rate, blood pressure, and respiration.

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fight-or-flight response Scientific  

/ 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.

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Example Sentences

That’s our fight-or-flight response at work, and it can cause a lot of problems in a relationship.

From The Wall Street Journal • Dec. 27, 2025

Vd Roest was well aware that the man’s virtually generated image wasn’t real, but that didn’t stop a fight-or-flight response from kicking in upon seeing his face.

From Slate • Dec. 18, 2025

For example, norepinephrine, a chemical involved in the body's "fight-or-flight" response, is often higher than normal in anxiety disorders.

From Science Daily • Dec. 4, 2025

This is part of the body's fight-or-flight response that has evolved to help us react quickly to the sounds like a predator crashing through the bushes.

From BBC • Mar. 15, 2025

I wonder if after a while your body starts to wear down when you don’t listen to that fight-or-flight response.

From "Internment" by Samira Ahmed