What Is the Fight-or-Flight Response and How Does It Work?

People experience stress on a daily basis. You may feel stressed out because of urgent tasks at work, traffic jams, negative conversations, etc. Whenever you are stressed out, you may feel various psychological and physiological stress symptoms, such as muscle tension, racing heartbeat, or sweating.

The way our body and mind react to stress is called the fight-or-flight (also known as fight, flight, freeze) response. This mechanism had evolved long before people’s psychology became as complex as it is now. The fight or flight response helped our ancestors survive and quickly react to dangerous situations.

When facing life-threatening situations, any animal can either try to fight the source of danger or escape it. The fight-or-flight response can be very helpful, but unlike our ancestors, we may experience stress not only in dangerous situations.

For instance, many people deal with chronic stress, which can negatively affect both their emotions and physical health, and it’s one of the most common reasons why people decide to try therapy.

If you suffer from chronic stress, you may wonder, why is your nervous system stuck in fight-or-flight? What happens to your body when you’re feeling stressed out? Let’s take a closer look at the fight-or-flight response and figure out how it works.

What the Fight-or-Flight Response Is

The term “fight-or-flight” was coined by American physiologist Walter Cannon back in the 1920s. In his book Bodily Changes in Pain, Hunger, Fear and Rage, Cannon noted that, when animals face a threat, their bodies release stress hormones, which in turn cause a number of bodily changes, including increased respiration and heart rate.

Later, Cannon’s interpretation of the psychological and physiological response to a threat was elaborated. Modern psychologists refer to this response as the “defense cascade,” which features such stages as freeze, flight, fight, fright, flag, and faint. This is a complex process that involves both hormonal and neurological reactions to stress, which happen incredibly fast, so you may not even realize that your body has entered survival mode.

Here is what the fight-or-flight response may feel like.

Flushed skin or paleness

Your body increases the blood flow to muscles and other areas that are crucial for your survival. So your face may appear flushed or pale, while your feet and hands might feel cold.

Increased blood pressure and heart rate

When your body prepares to fight or escape the threat, it needs more oxygen and nutrients to feed your muscles. As a result, you start to breathe quicker, and your heart rate also increases because an increased blood flow means more nutrients for muscles.

Suppressed pain response

When your body enters the fight-or-flight mode, you may not feel pain until you return to safety and your nervous system calms down. For instance, people often don’t feel pain when they get into car accidents until they are taken to the hospital.

Tension and trembling

Given that physiological response to stress includes a quick release of stress hormones, you may feel trembling and muscle tension.

Dilated pupils

Dilated pupils help your eyes receive more light so that you can see better and react to any visual signs of danger.

Altered memories

Stressful experiences may also alter your memories. For instance, you may not be able to remember the details of some events, or your memories may suddenly become very clear and vivid.

Awareness and focus

You become more aware of what’s happening around you, and your senses become more acute so that you can quickly notice anything dangerous.

How Does the Fight-or-Flight Response Work?

Now that you know the general information about the fight-or-flight, the meaning of this term, and the effects of stress response, let’s figure out how it works.

When a person encounters a threat or experiences a stressful event, the amygdala, which is an area of the brain responsible for emotions, sends a signal to the hypothalamus. The hypothalamus communicates with the entire body through the autonomic nervous system. It controls numerous body functions, including heartbeat, blood pressure, and breathing.

There are two types of autonomic nervous systems involved in the stress response: sympathetic and parasympathetic. The sympathetic nervous system triggers the fight-or-flight response, and the parasympathetic system slows down the body once the danger has passed.

When the amygdala sends the stress signal to the hypothalamus, it activates the sympathetic nervous system and transfers the signal to the adrenal glands. These glands start to produce adrenaline, which boosts the blood flow and increases a person’s blood pressure.

The lungs start to consume more oxygen, so the brain becomes more alert, and all the senses become sharper. Because of adrenaline, temporary storage areas in the body release blood sugar and fats so that the body gets more energy.

This physiological response happens so quickly that the person cannot even realize it. The neurological connection is extremely efficient, so the amygdala and hypothalamus launch the fight-or-flight response even before the visual centers of the brain process the situation. This is a reason why people can react to a fast oncoming car and move aside without even thinking about it.

After the initial surge of adrenaline, the hypothalamus activates the HPA axis. The HPA axis includes the hypothalamus, adrenal glands, and pituitary gland. It sends hormonal signals to keep the sympathetic nervous system activated.

If the person is still in danger, the pituitary gland releases adrenocorticotropic hormone (ACTH), which in turn makes adrenal glands release cortisol. When the brain no longer perceives danger, the parasympathetic nervous system stops the physiological stress response, and the levels of adrenaline and cortisol fall.

Problems Associated With the Fight-or-Flight Response

While your body’s response to stress happens completely automatically, that doesn’t mean that this system is always precise and accurate. Sometimes, the fight-or-flight response can be triggered even without any real threats.

For instance, people with various phobias may experience the fight-or-flight response when seeing something that terrifies them, even if this thing isn’t actually dangerous.

For example, when a person who is afraid of heights goes to the top floor of a building, their body may initiate the stress response, and in some cases, a severe stress response may lead to a panic attack.

People with anxiety may also experience the effects of the fight-or-flight response on a daily basis. For example, social anxiety may trigger the fight-or-flight response when a person needs to deliver a speech in front of a big audience. When the physiological response to danger is falsely activated, a person may suffer from chronic stress.

Chronic stress has a negative impact on one’s health. Frequent surges of adrenaline can damage arteries and blood vessels, increasing the risk of a heart attack and stroke. High levels of cortisol push the body to replenish the energy stores that were used during the stress response, so the person starts to gain weight.

Besides, chronic stress alone can lead to various mental health problems. So it’s important to know how to manage stress and be ready to ask for professional help if you realize that your fight-or-flight response works against you.

Therapy can help you deal with anxiety and other emotional health factors that might interfere with your fight-or-flight response and lead to chronic stress.

A licensed therapist can help you figure out what triggers your stress response, provide the necessary emotional support, and help you cope with chronic stress. While in-person therapy might not be a comfortable solution for people with tight work schedules, online therapy platforms like Calmerry enable you to talk to a therapist with no need to commute to their office.

Wrapping Up

The fight-or-flight response is an important survival mechanism that can protect you when you’re facing a threat. When the fight-or-flight response is activated, it affects different systems of your body by initiating the release of stress hormones and activating your sympathetic nervous system.

While the physiological response to stress can help you quickly react to threats and escape life-threatening situations, it’s not always activated by real threats. For instance, people with anxiety and phobias may experience the fight-or-flight response even when nothing threatens them.

If a person’s fight-or-flight response is activated too frequently, they may suffer from chronic stress, which can negatively affect both one’s mental and physical health.

If you suffer from chronic stress and want to figure out why your nervous system is stuck in fight or flight, the best solution is to go to therapy. If you’ve never visited a therapist before, you can learn more about the treatment process to know what to expect from your first conversation with a therapist.