The fight-or-flight response, also known as hyperarousal or acute stress response, is a total body reaction to a perceived threat or stressor. In the 1920s, physiologist Walter Cannon first detailed the sensations of fight-or-flight, which were included in general adaptation syndrome (GAS), a stress response theory put forth by endocrinologist Hans Selye in 1936. Fight-or-flight, or the “alarm reaction” as Selye defined it, is followed by resistance (the body evaluates how to respond to the threat), and finally, exhaustion. This survival mechanism is triggered by various stressors, including life-threatening, micro-stressors, [eustress](https://www.masterclass.com/articles/eustress-explained), and general distress.

The fight-or-flight response is a survival mechanism: When faced with a life-threatening situation, the body switches on high alert, ready to respond (fight) or escape (flight) physically. The physiological changes that take place also increase the likelihood of successfully managing the danger; it’s why people have been known to lift cars to free trapped passengers or think clearly and quickly under pressure.

When the stimulus is not life-threatening, but a level of fear or anxiety is perceived, the same signals work to produce a state of heightened awareness and stress. These mild stressors include public speaking, meeting new people, taking a flight, or simply running late.

Fight-or-flight response starts in the brain after we perceive a threat: 

- __The pituitary glands activate the nervous system__. Once a threat is perceived, the amygdala and hypothalamus process the information and trigger the pituitary gland, a small “master” gland located at the base of the brain that controls other endocrine glands. The pituitary gland secretes hormones that activate the sympathetic nervous system, which controls blood pressure, heart rate, digestion, and pupil dilation. 
- __The adrenal glands respond__. The adrenal glands, located at the top of either kidney, respond by flooding the body with neurotransmitters called catecholamines, which include cortisol (the stress hormone), adrenaline (epinephrine), and noradrenaline (norepinephrine). 
- __Physical symptoms begin__. This flood of neurotransmitters produces many physical symptoms through the autonomic nervous system (the body’s automatic, internal regulator) and the parasympathetic nervous system (responsible for increased heart rate, breathing rate, and blood pressure). Muscles may begin to tense enough to tremble or shake visibly. The face may flush or go pale due to redirection of blood flow from the brain to larger muscles. Pupil dilation—a symptom directly correlating to mental effort, as the eyes take in as much light and information about the threat as they can—and tunnel vision (both are caused by adrenaline) may also occur. 
- __Psychological symptoms follow__. Fight-or-flight might feel dominantly physical in the moment, but it can be equally taxing on the mind. Severe reactions, usually stemming from phobias, can escalate into a panic attack if not contained. Constant exposure to the chemical byproducts of the fight-or-flight response—namely adrenaline and cortisol—leads to chronic stress, which can take a toll on mental health. Not only does stress interrupt synapse regulation, making you less inclined to commune with others, but it can also shrink the [prefrontal cortex](https://www.masterclass.com/articles/prefrontal-cortex-explained), the brain’s center of memory.

For instances of acute stress, the fight-or-flight response can be beneficial. However, when everyday triggers and stressors begin to produce the same response, the response presents a significant challenge. For individuals with post-traumatic stress disorder (PTSD), severe phobias, or anxiety, the flight-or-fight response can be especially problematic when triggered by every day, non-life-threatening occurrences. There are a few ways to circumvent the response:

1. __Recognize the signs__. One tactic for containing a recurring fight-or-flight response is to become familiar with the initial signs of its approach. Tuning into your heart rate in a moment of perceived stress or noticing a change in your breathing pace can signal that you may be in the middle of a response. 
2. __Do breathwork__. Deep, slow breathing activates the parasympathetic nervous system, creating a relaxation response that can help curb the physical symptoms of a fight-or-flight response. Learn more about helpful [breathing techniques](https://www.masterclass.com/articles/simone-biless-5-essential-breathing-techniques-for-maintaining-focus-and-concentration) in our complete guide. 
3. __Use stress management techniques__. Stress management techniques, like [meditation](https://www.masterclass.com/articles/types-of-meditation-explained), can be useful ways to offset the continued activation of fight-or-flight responses in the future. Meditating before a known stressor, like a big meeting, can help prime the mind for what’s to come. Repeating a mantra (to dispel a fear of flying, for example) can focus the mind and prevent escalation.

Find something comfortable to sit or lie on, grab a [MasterClass Annual Membership](https://www.masterclass.com), and dial into the present moment with Jon Kabat-Zinn, the father of the Western mindfulness movement. From formal meditation exercises to examinations of the science behind mindfulness, Jon will prepare you for the most important practice of them all: life itself. 
Fight-or-flight is one of the human body’s neater tricks: Time slows to a crawl while the brain and the nervous system slam on the gas. Learn about this acute stress response and how to manage it when dealing with non-life-threatening stressors. 

Fight-or-flight is one of the human body’s neater tricks: Time slows to a crawl while the brain and the nervous system slam on the gas. Learn about this acute stress response and how to manage it when dealing with non-life-threatening stressors. 

How to Manage the Fight-or-Flight Response

The fight-or-flight response, also known as hyperarousal or acute stress response, is a total body reaction to a perceived threat or stressor. In the 1920s, physiologist Walter Cannon first detailed the sensations of fight-or-flight, which were included in general adaptation syndrome (GAS), a stress response theory put forth by endocrinologist Hans Selye in 1936. Fight-or-flight, or the “alarm reaction” as Selye defined it, is followed by resistance (the body evaluates how to respond to the threat), and finally, exhaustion. This survival mechanism is triggered by various stressors, including life-threatening, micro-stressors, <a href='https://www.masterclass.com/articles/eustress-explained' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/eustress-explained","linkCopy":"eustress","category":null}'>eustress</a>, and general distress.

What Is the Fight-or-Flight Response?

The fight-or-flight response is a survival mechanism: When faced with a life-threatening situation, the body switches on high alert, ready to respond (fight) or escape (flight) physically. The physiological changes that take place also increase the likelihood of successfully managing the danger; it’s why people have been known to lift cars to free trapped passengers or think clearly and quickly under pressure.When the stimulus is not life-threatening, but a level of fear or anxiety is perceived, the same signals work to produce a state of heightened awareness and stress. These mild stressors include public speaking, meeting new people, taking a flight, or simply running late.

What Is the Purpose of the Fight-or-Flight Response?

Fight-or-flight response starts in the brain after we perceive a threat: <ul class="mc-m-4"><li class="mc-my-4"> 1. The pituitary glands activate the nervous system. Once a threat is perceived, the amygdala and hypothalamus process the information and trigger the pituitary gland, a small “master” gland located at the base of the brain that controls other endocrine glands. The pituitary gland secretes hormones that activate the sympathetic nervous system, which controls blood pressure, heart rate, digestion, and pupil dilation. </li><li class="mc-my-4"> 2. The adrenal glands respond. The adrenal glands, located at the top of either kidney, respond by flooding the body with neurotransmitters called catecholamines, which include cortisol (the stress hormone), adrenaline (epinephrine), and noradrenaline (norepinephrine). </li><li class="mc-my-4"> 3. Physical symptoms begin. This flood of neurotransmitters produces many physical symptoms through the autonomic nervous system (the body’s automatic, internal regulator) and the parasympathetic nervous system (responsible for increased heart rate, breathing rate, and blood pressure). Muscles may begin to tense enough to tremble or shake visibly. The face may flush or go pale due to redirection of blood flow from the brain to larger muscles. Pupil dilation—a symptom directly correlating to mental effort, as the eyes take in as much light and information about the threat as they can—and tunnel vision (both are caused by adrenaline) may also occur. </li><li class="mc-my-4"> 4. Psychological symptoms follow. Fight-or-flight might feel dominantly physical in the moment, but it can be equally taxing on the mind. Severe reactions, usually stemming from phobias, can escalate into a panic attack if not contained. Constant exposure to the chemical byproducts of the fight-or-flight response—namely adrenaline and cortisol—leads to chronic stress, which can take a toll on mental health. Not only does stress interrupt synapse regulation, making you less inclined to commune with others, but it can also shrink the <a href='https://www.masterclass.com/articles/prefrontal-cortex-explained' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/prefrontal-cortex-explained","linkCopy":"prefrontal cortex","category":null}'>prefrontal cortex</a>, the brain’s center of memory. </li></ul>

What Happens During a Fight-or-Flight Response?

For instances of acute stress, the fight-or-flight response can be beneficial. However, when everyday triggers and stressors begin to produce the same response, the response presents a significant challenge. For individuals with post-traumatic stress disorder (PTSD), severe phobias, or anxiety, the flight-or-fight response can be especially problematic when triggered by every day, non-life-threatening occurrences. There are a few ways to circumvent the response:<ol class="mc-m-4"><li class="mc-my-4"> 1. Recognize the signs. One tactic for containing a recurring fight-or-flight response is to become familiar with the initial signs of its approach. Tuning into your heart rate in a moment of perceived stress or noticing a change in your breathing pace can signal that you may be in the middle of a response. </li><li class="mc-my-4"> 2. Do breathwork. Deep, slow breathing activates the parasympathetic nervous system, creating a relaxation response that can help curb the physical symptoms of a fight-or-flight response. Learn more about helpful <a href='https://www.masterclass.com/articles/simone-biless-5-essential-breathing-techniques-for-maintaining-focus-and-concentration' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/simone-biless-5-essential-breathing-techniques-for-maintaining-focus-and-concentration","linkCopy":"breathing techniques","category":null}'>breathing techniques</a> in our complete guide. </li><li class="mc-my-4"> 3. Use stress management techniques. Stress management techniques, like <a href='https://www.masterclass.com/articles/types-of-meditation-explained' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com/articles/types-of-meditation-explained","linkCopy":"meditation","category":null}'>meditation</a>, can be useful ways to offset the continued activation of fight-or-flight responses in the future. Meditating before a known stressor, like a big meeting, can help prime the mind for what’s to come. Repeating a mantra (to dispel a fear of flying, for example) can focus the mind and prevent escalation. </li></ol>

Find something comfortable to sit or lie on, grab a <a href='https://www.masterclass.com' target='_self' class='mc-text--link' data-mc-segment-trigger='true' data-mc-segment-event-type='Article Page Click' data-event-obj='{"textTag":"p","href":"https://www.masterclass.com","linkCopy":"MasterClass Annual Membership","category":null}'>MasterClass Annual Membership</a>, and dial into the present moment with Jon Kabat-Zinn, the father of the Western mindfulness movement. From formal meditation exercises to examinations of the science behind mindfulness, Jon will prepare you for the most important practice of them all: life itself.

Want to Learn Even More About Cultivating a Mindfulness Practice?

Fight-or-flight is one of the human body’s neater tricks: Time slows to a crawl while the brain and the nervous system slam on the gas. Learn about this acute stress response and how to manage it when dealing with non-life-threatening stressors.

Fight-or-flight is one of the human body’s neater tricks: Time slows to a crawl while the brain and the nervous system slam on the gas. Learn about this acute stress response and how to manage it when dealing with non-life-threatening stressors. 


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