The Fight or Flight Response

What is the Fight or Flight Response?

The fight-or-flight response, or acute stress response, is your body’s automatic, physiological reaction to a stressful situation, which the mind interprets as fear or anxiety.

The  fight-or-flight response  provides your body the resources necessary to stay and fight, or flee a threatening situation.

The fight-or-flight response provides your body the resources necessary to stay and fight, or flee a threatening situation.

First described by Walter Bradford Cannon, the fight-or-flight response represents the options available to our prehistoric ancestors when faced with an immediate danger or threat to their survival - such as a hungry bear wandering into their cave.

Thanks to the fight-or-flight response, the human body can makes available the energy needed to respond to the threatening situation by either staying and fighting, or running away.

This near-instantaneous, chain reaction is identical, whether the danger is real (in the case of fear), perceived or imagined (in the case of anxiety) - and is essential to keeping you safe from harm or danger.

If you are challenged by health anxiety, or any anxiety disorder, your fight or flight response is being activated when no danger is present.

Below, I provide helpful tips on how to restore a healthy fight or flight response - so make sure you read to the end of this post.

But first, let's explore how the fight or flight response works.

How does the Fight or Flight Response work?

When you encounter a threatening situation, the amygdala (which is located deep within the temporal lobes of your brain and helps you interpret information and stimuli), sends a distress signal to the hypothalamus, which coordinates bodily functions like breathing, heart rate and blood pressure.

The hypothalamus communicates with the autonomic nervous system, including the sympathetic nervous system (which activates the fight-or-flight response) and parasympathetic nervous system (which activates rest and digest, calming the body after the threat has passed).

Upon receipt of a distress signal from the amygdala, the hypothalamus releases corticotropin-releasing hormone (CRH), instructing the pituitary gland to secrete adrenocorticotropic hormone (ACTH).

ACTH activates the sympathetic nervous system, resulting in the release of stress hormones from your adrenal glands:

  • Adrenaline (epinephrine): Activates the fight-or-flight response, resulting in immediate physiological reactions, such as faster respiration, heart rate and sweating.

  • Noradrenaline (norepinephrine): Supports adrenaline by making you more aware, focused, and responsive.

  • Cortisol: Inhibits bodily functions not required to deal with a threat to survival - such as digestion, growth, immunity and reproductive (sex) drive.

When the threat has been eliminated, cortisol levels fall, activating the parasympathetic nervous system, and the rest and digest response.

Fight or Flight Symptoms

The Fight or Flight response boosts blood flow to parts of your body necessary for survival, keeps you cool, provides more energy, and makes you more aware and responsive.

The  fight-or-flight response  can cause tunnel vision to boost your focus on what you need to do to survive.

The fight-or-flight response can cause tunnel vision to boost your focus on what you need to do to survive.

The primary symptoms caused by activation of your fight-or-flight system are:

  • Rapid heart rate

  • Rapid breathing

  • Sweating

  • Muscle tension

  • Shaking

  • Indigestion

  • Tingling or cold hands and feet

  • Dilated pupils

  • Tunnel vision

  • Auditory exclusion (hearing loss)

  • Difficulty concentrating

If you think these fight or flight symptoms sound bad, you're right - but it’s important to understand that there’s nothing wrong and no permanent damage is being done to your body.

Over time, however, repeated activation of the fight-or-flight response can lead to health challenges including hypertension (high blood pressure), high cholesterol, obesity, anxiety, depression, and substance abuse.

Problems with the Fight or Flight Response and Health Anxiety

Under normal circumstances, when one encounters an identifiable threat or danger, fight-or-flight symptoms are easily understood, and they fear the threat or danger itself.

With an anxiety disorder such as health anxiety (illness anxiety disorder or somatic symptom disorder), your fight-or-flight response is activated fart too easily and frequently, resulting in physical symptoms with no rational cause, when no danger is present.

No clear and present danger causes you to fear your symptoms instead - often perceiving them as life threatening. The more you interpret symptoms incorrectly, the stronger the association with your physical health becomes, reinforcing health anxiety.

With panic disorder, the absence of an identifiable threat or danger intensifies your fears - resulting in a feeling of absolute terror and impending doom.

How to Restore a Healthy Fight or Flight Response

To prevent long-term health challenges, it's important you take positive steps to restore a healthy fight or flight response.

During my complete health anxiety recovery I combined all of these strategies into a holistic plan to overcome health anxiety and begin the healthy life, free of anxiety, I enjoy today. This is also the approach I teach my students during the 30-Day Anxiety Detox.

1. Lifestyle

Improve your body’s balance of neurotransmitters and stress hormones with a lifestyle supportive of good physical and mental health.


Exercise is job number one when it comes to restoring a healthy fight or flight response, so schedule at least 150 minutes per week and get moving. Exercise consumes adrenaline and cortisol, tires muscles and promotes release of these powerful neurotransmitters:

  • Endorphins: Neurotransmitters that relieve pain and stress.

  • Dopamine: The neurotransmitter responsible for desire, motivation, pleasure and reward, in addition to circulatory, renal, pancreatic, digestive and immune benefits.

  • Serotonin: A neurotransmitter that improves mood and sense of well-being, increases appetite and promotes a healthy sleep cycle.


A healthy diet goes a long way toward maintaining a healthy balance of the hormones and neurotransmitters related to the  fight-or-flight response.

A healthy diet goes a long way toward maintaining a healthy balance of the hormones and neurotransmitters related to the fight-or-flight response.

Maintain good hydration and a heathy, balanced diet, rich in whole, unprocessed foods including anxiety-fighting B vitamins, and low in alcohol, caffeine, sugar and salt.


Consider how stress and anxiety in your career may be contributing to an overactive fight-or-flight response and health anxiety.

Are you applying your unique talents to do meaningful work you enjoy, with people who share your values, and are you appreciated and rewarded fairly for your contribution?

If not, it might be time for a change.


Observe the words you use to communicate with yourself (through self-talk) and others, as well as your breathing, posture and body language. Do they project calm, non-reactive confidence? Or do they project anxious, reactive insecurity?

Consider what changes you can make to ensure your subconscious mind, and others, are receiving the right message about you and your state of mind.


Make sure you take time regularly to do the activities you enjoy most.


A consistent meditation practice will help you develop stronger focus and non-reactivity skills, so you can always be fully engaged in and enjoy the present moment.


Consider the relationships you maintain - romantic, social, professional and otherwise. Take positive steps to deepen supportive ones while reducing exposure to the others.


Get an adequate amount and quality of sleep by practicing healthy sleep habits.

2. Psychotherapy

Psychotherapy, either self-guided or with the support of a practitioner, offers insight into how imagined threats are contributing to health anxiety and impacting your quality of life.

  • Cognitive Behavioural Therapy (CBT) can help you reduce anxiety by transforming irrational, automatic negative thoughts, interpretations and thinking patterns into positive, rational thinking patterns that serve you.

  • Acceptance and Commitment Therapy (ACT) can help you build acceptance and mindfulness skills to boost your psychological flexibility - especially during challenging circumstances - and focus energy on constructive behaviours that move you forward.

I applied strategies of both CBT and ACT during my 60-day health anxiety recovery, and continue to apply their principles daily.

3. Systematic desensitization

Systematic desensitization therapy helps build confidence with gradual and repeated exposure over time to anxiety- and panic- challenging situations.

4. Medications

Meds can be an effective temporary measure, but they come with costs, side effects, and only mask the problem without giving you the opportunity to fully understand and resolve the causes and underlying risk factors that led to health anxiety. 

During my complete health anxiety recovery, I tried medications (which I'm in the process of withdrawing from) and observed mild success in boosting mood and masking anxiety, but learned that addressing the causes and underlying risk factors of health anxiety were the only way to achieve lasting relief and in time, full recovery.

Moreover, a healthy fight-or-flight response is essential to survival - so dependency on long-term medication to inhibit fear or anxiety, and in turn your survival instinct, probably isn’t your best option.


Now, Apply.

📗 If you don't have a journal, get one. Documenting what you learn, and your progress, is critical to your recovery.

💡 Ask yourself: 

  • Self, do I constantly feel on-edge or vigilant?

  • Do I experience multiple fight-or-flight symptoms, even when no clear and present danger exists?

  • How am I interpreting my fight-or-flight symptoms?

  • What aspects of my exercise routine, diet, career, relationships, language, mindfulness practice and sleep habits support or add stress to my over-active fight or flight system?

💬 Talk to your doctor about whether your symptoms can be explained by the fight-or-flight response, and health anxiety.

✏️ Take this 1-minute health anxiety quiz to measure your anxiety, and reveal your exact next steps to toward recovery.

🙏🏼 Share this post - it may help a loved one or friend finally begin a healthy, fearless life, free of anxiety.