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What is the Fight or Flight Response?

illustration of the Fight or Flight Response

Estimated reading time: 10 minutes

You must have heard about the fight-and-flight reaction, a simplified depiction of human beings and other organisms responding to danger and life-threatening situations.

In other words, an adapted evolutionary mechanism for encountering emergencies.

The fight or flight response is characterised by bodily changes, including neurological and endocrine alterations. This prepares a person or an animal to respond or withdraw in the face of an immediate threat to survival.

This article will cover the dangers that cause this phenomenon, the precise neurological and endocrine changes mentioned in this description, and why the notion of “fight or flight” is an oversimplified one.

Imagined and Real Threats

The fight or flight response can be induced by various threats, both imagined and real. For example, wild creatures, natural calamities, and other individuals would be categorized as physical threats. While, on the other hand, extemporaneous speaking, social circumstances, and phobias are examples of psychological threats.

It seems like evolutionary logic to say that we would possess a robust fight-and-flight response. However, reflecting on the early days with inhabitants living in the largely undisturbed wilderness, you will discover that the ancestors were more likely to encounter predators.

For example, our fear response would be an excellent adaptation in a situation where you encounter a cougar ready to attack. You would want your respiration and heart rate to increase circulation and provide your limb muscles with sufficient oxygen to work rapidly. Therefore, aiding you in either defending or fleeing as soon as you can.

What Role Does Freeze Serve in Fight or Flight?

Bearing in mind the previous statement, fight-and-flight is a generalization to our fear response. Still primarily considered an individual stress response, the term was first coined a century ago in 1929 by Walter Cannon, a Harvard physiologist. Some scientists, however, suggest that the underlying concept could be a lot more complicated.

Research conducted presented four responses to danger and stress instead of two. These were listed as freeze, flight, fight, fright, faint.

An organism’s initial reaction to a hazard pertains to the term ‘freeze.’ For example, if an animal encounters a predator, it will suddenly become hypervigilant and will remain motionless. Although many organisms are less prone to being spotted by a predator, this reflex is evolutionary. Several scientists point out freezing as a counterpart of a military person reacting to a crisis by “stopping, looking and listening.”

Fright, on the contrary, is a somewhat less well-known term that encompasses an organism’s penultimate attempt in refuting threats. Also described by the phrases “tonic immobility” and “acting dead,” fright refers to a predator showing reluctance in attacking a creature that has already died.

Hormones and Symptoms of a Fear Response

Rapid short breathing, an accelerated heart rate, nausea, a parched mouth, tense thigh, neck, and shoulder muscles, sweaty palms, trembling, a concentration on unpleasant thoughts, dizziness, visual hallucinations, and others are all cognitive and behavioural indicators of a fight-and-flight response. So, whenever the fear response is triggered, what happens within the body?

When the nervous system recognizes visual or aural danger signs, the amygdala sends messages to the hypothalamus. Amygdala is an area of the human brain usually affiliated with panic, anxiety, and fear whereas, the hypothalamus is typically responsible for regulating the hormones produced in response to fear.

The hypothalamus is also a component of the hypothalamic-pituitary-adrenal (HPA) axis frequently associated with fear.

As outlined in the introduction, the ‘endocrine modification’ concept in the human body is a fundamental component of the fear response. Hormones are defined as chemical messengers that aid in the healthy operation of numerous physiological activities.

For instance, an endocrine hormone that almost everyone is familiar with is insulin. This is because insulin plays a major role as a blood sugar level regulator in the human body. Listed below are the hormones that are involved in a fear response.

Corticotropin-releasing Hormone

The hypothalamus releases CRH for increasing selective attention and stress while suppressing the appetite. It also activates the pituitary gland to secrete ACTH.

Adrenocorticotropic Hormone

ACTH sends signals to the adrenal gland for cortisol secretion. Adrenal glands are located on top of the kidneys.


Cortisol, often termed the ‘stress hormone,’ is responsible for increasing alertness, energy, and immune responses. All of these are deemed useful in responding to immediate dangers.


Released by the adrenal glands, adrenaline is responsible for accelerating heart rate and respiration.

A continual fight, flight, or freeze reaction necessitates the production of hormones. Some of your bodily processes and systems may be affected by this overproduction. Sleep disturbances, weight fluctuations, headaches, cardiovascular issues, gastrointestinal issues, decreased immune system, poor libido, lack of concentration, and memory loss are all possible side effects.

Almost all of the anticipated challenges we face nowadays are psychological rather than literal; several other matters we stress or obsess about do not necessitate a physical flight or struggle. On the other hand, our physiology has adapted to respond to anxiety physically, resulting in most of the typical anxiety symptoms that individuals experience.

You can be anxious if you are about to deliver a speech before a significant number of people. Your pulse and respiratory rates are probably increasing, yet you are not hungry (since your digestive system has slowed working). Even if it is not beneficial in this scenario, your system is prepared to fight or flee if necessary.

You have probably seen that people respond differently to stress in diverse situations. For instance, if you and a colleague are both trekking and come across a grizzly, one of you would remain calm and rational, whereas the other cowers. There are numerous ideas as to why some people’s fear responses are more robust or perhaps more prevalent than others.

One idea suggests that people are genetically inclined towards certain physiological arousal. For example, neuroscientists have discovered that some variants of the gene catechol-O-methyltransferase (COMT) are linked to a higher fear response. Other studies pointed to distressing childhood experiences’ impact on the HPA axis, implicated in the fear response.

Studies with Wim Hof showed that his method created a hormone release, as mentioned above. The amount and type of hormones released were comparable to someone doing a bungee jump for the first time.

The WHM teaches us to use the power of the mind to change our response. But this isn’t easy as our central nervous system is a powerful controller.

What Happens to the Central Nervous System in a Fear Response Situation?

Hormones behave as cues for the autonomic nervous system to behave a certain way. The autonomic nervous system has two bifurcations: the sympathetic nervous system and the parasympathetic nervous system. These branches are responsible for governing involuntary body functions such as the respiratory and pulse rate.

Whenever discussing the fight-and-flight response, we usually start with the sympathetic nervous system. A memory aid to remember the mechanism of the sympathetic nervous system would be to assume that the SNS has a sense of empathy towards you.

Hence, while sympathizing with you, it will stimulate physiological responses that assist you in handling anything troubling you. It will, as mentioned earlier, boost your pulse and respiration rate while suppressing digestion and preparing you for responding to the threat.

After the apparent crisis has passed, the parasympathetic nervous system PNS takes over. The alterations that occur under the influence of PNS are the pulse rate and respiration returning to normal. Thus, the body will gradually return to its resting phase, giving this system the moniker “rest-and-digest” phase.

What Is the Relationship Between Fight-and-Flight and Anxiety?

We have now learned that the SNS stimulates the defensive physiological mechanisms by activating the fight-and-flight response whereas, the PNS brings it back to the resting phase through the rest-and-digest. In an idealistic situation, this process takes place whenever it is beneficial, and it concludes with the system retreating to rest.

However, this might not always be true due to some issues mentioned earlier.

Anxiety can be termed as the subjective experience of a fear response. If your fear responses are frequent and potent, you will develop chronic anxiety and mood disorders.

Individuals with a dysregulated fight-and-flight response can suffer from panic episodes which are fear responses to no discernible risk. In addition, prolonged anxiety and mood disorders dysregulate the fight-and-flight reactions compounding the problem by birthing a vicious cycle.

Professionals have long known that persistent stress has negative physical health implications, including cardiac diseases. In addition, an excessive stress reaction has also been connected to several mental health issues, including chronic anxiety. Here are several examples:

Post-traumatic Disorder Syndrome

PTSD is linked to excessive anxiety symptoms. Following a traumatic occurrence, you may begin to connect daily experiences with that specific event.

If a particular place reminded you of something negative, that place might trigger a stress response every time you visit.

Your imagination can sometimes be the source of the trigger example; you might have flashbacks or dreams, which trigger the stress reaction in your body.

When the individual is constantly being subjected to fight and flight, this is known as chronic stress. Chronic stress sources differ from individual to individual. Coping with a severe condition, abuse, bigotry, and a lack of sleep are just a few examples.

If you already suffer from anxiety disorders, you are more prone to feeling frightened in not normally dangerous settings.

As mentioned earlier, if you already suffer from an anxiety disorder, you are more prone to feeling frightened in not normally dangerous grounds.

It may be anything as simple as being stuck in traffic or conversing with a grocery cashier. You could also suffer from anticipatory anxiety, which causes you to be nervous about being concerned. These unwanted thoughts may trigger a stress reaction. This could indicate that you have greater heart palpitations, dyspnea, and hypervigilance than individuals who do not have anxiousness.

Strategies for Calming Your Fear Response

Our survival instinct is a natural defence mechanism that has been designed to keep us protected from harm.

Despite the potential advantages of possessing one such reflex, most of us suffer from an exaggerated fight-and-flight response, leading to psychological and physical issues.

You can improve your emotional and physical wellness by knowing why you have such a reaction and how to control it. Listed below are some suggestions to help calm a fight-and-flight response.

Remember, the Wim Hof Method exposes us to controlled danger. Indeed, cold exposure can be dangerous but controlled precisely during our Wim Hof Method workshops allows you to trigger our fear response. Analyse-it. Get comfortable with it. Then we can manage and control it.

Deep Breathing

Rebutting the fight-and-flight reaction usually entails performing the absolute reverse of what the SNS is triggered to do. For example, in stressful situations, the SNS raises the heartbeat, and breathing turns shallower. Still, research has shown that we may actively prevent the fight or flight reaction by taking calm, deep abdominal breaths.

Take Note of your Behaviors

Paying attention to the times when your fight-and-flight response is more prominent can prove beneficial. For example, after observing for some time, an individual discovers that they become agitated and jittery if they consume too much coffee. They could change their behaviour after noticing this pattern and restrict themselves from consuming a lot of coffee to calm their fight-and-flight responses.


Panicking and worrying about your fear response while it is still active could end up lengthening the response. As it sends more threat signals to the brain hence, worsening the situation. A widespread demonstration is an individual undergoing a panic attack.

They would start assuming that their panic attack would harm them more, resulting in the episode’s continuance. Embracing the symptoms of a fight-and-flight response as normal, contrary to popular belief, has a long road ahead towards lessening them.

Physical Activity

Researchers have identified a correlation between workouts and anxiety reduction. Although the explanations for this link are still being investigated, one hypothesis is that moderate stress due to training enhances stress tolerance overall—other ideas centre on exercise’s potential to reduce sympathetic nervous system activation.

Cognitive-behavioural Techniques

After analyzing this article, you should recognize why the fear response is not always suitable or beneficial. Understanding when the fight-and-flight reaction activates and contemplating whether it is valid or not can help you lessen your startle response in situations where it is not.

For instance, if you are feeling highly nervous before a meeting and debating on cancelling it, consider that you are attempting to “avoid” an imagined “danger” via this fight-and-flight reaction. Although your system is prepping you against this, you are not actually in any significant danger. Calm your SNS by reframing how you would interpret the issue and your physiological responses.

Consult a Specialist

Medical concerns may be contributing to a hyperactive fight or flight reaction, in addition to possible psychological problems that an expert may be ready to assist you with. A cardiac arrhythmia, for instance, can make you feel anxious. Beta-agonist medications, commonly recommended for asthma, can also stimulate the HPA axis and cause fear.

Wim Hof Method

The Wim Hof Method has been shown to increase the tolerance to daily stress. Thus, some refer to it as inoculating us from stress.

Regular WHM breathing and cold exposure via ice baths can be fundamental in giving you the ability to withstand more daily stress and recover from that stress.

Face your fears; no fighting or flying is required. But freezing is definitely on the menu.


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