The fight-flight-freeze response is your body’s natural reaction to danger. It happens through hormonal and physiological changes that allow you to act quickly so you can protect yourself.

The fight-flight-freeze response is a type of stress response that helps you react to perceived threats, like an oncoming car or a growling dog. It’s a survival instinct that our ancient ancestors developed many years ago.

Specifically, fight-or-flight is an active defense response where you fight or flee. Your heart rate gets faster, which increases oxygen flow to your major muscles. Your pain perception drops, and your hearing sharpens. These changes help you act appropriately and rapidly.

Freezing is fight-or-flight on hold, where you further prepare to protect yourself. It’s also called reactive immobility or attentive immobility. It involves similar physiological changes, but instead, you stay completely still and get ready for the next move.

Fight-flight-freeze isn’t a conscious decision. It’s an automatic reaction, so you can’t control it. In this article, we’ll further explore what this response entails, along with examples.

During a fight-flight-freeze response, many physiological changes occur.

The reaction begins in your amygdala, the part of your brain responsible for perceived fear. The amygdala responds by sending signals to the hypothalamus, which stimulates the autonomic nervous system (ANS).

The ANS consists of the sympathetic and parasympathetic nervous systems. The sympathetic nervous system drives the fight-or-flight response, while the parasympathetic nervous system drives freezing. How you react depends on which system dominates the response at the time.

In general, when your ANS is stimulated, your body releases adrenaline and cortisol, the stress hormone. These hormones are released very quickly, which can affect your:

  • Heart rate. Your heart beats faster to bring oxygen to your major muscles. During freezing, your heart rate might increase or decrease.
  • Lungs. Your breathing speeds up to deliver more oxygen to your blood. In the freeze response, you might hold your breath or restrict breathing.
  • Eyes. Your peripheral vision increases so you can notice your surroundings. Your pupils dilate and let in more light, which helps you see better.
  • Ears. Your ears “perk up” and your hearing becomes sharper.
  • Blood. Blood thickens, which increases clotting factors. This prepares your body for injury.
  • Skin. Your skin might produce more sweat or get cold. You may look pale or have goosebumps.
  • Hands and feet. As blood flow increases to your major muscles, your hands and feet might get cold.
  • Pain perception. Fight-or-flight temporarily reduces your perception of pain.

Your specific physiological reactions depend on how you usually respond to stress. You might also shift between fight-or-flight and freezing, but this is very difficult to control.

Usually, your body will return to its natural state after 20 to 30 minutes.

While the fight-flight-freeze response causes physiological reactions, it’s triggered by a psychological fear.

The fear is conditioned, which means you’ve associated a situation or thing with negative experiences. This psychological response is initiated when you’re first exposed to the situation and develops over time.

The thing that you’re scared of is called a perceived threat, or something you consider to be dangerous. Perceived threats are different for each person.

When you’re faced with a perceived threat, your brain thinks you’re in danger. That’s because it already considers the situation to be life threatening. As a result, your body automatically reacts with the fight-flight-freeze response to keep you safe.

The fight-flight-freeze response can show up in many life situations, including:

  • slamming on the brakes when the car in front of you suddenly stops
  • encountering a growling dog while walking outside
  • jumping out of the way of an oncoming vehicle
  • getting spooked by someone jumping out of a room
  • feeling unsafe while walking down a street

Sometimes, the fight-flight-freeze response is overactive. This happens when nonthreatening situations trigger the reaction.

Overactive responses are more common in people who have experienced:


After a traumatic event, you may develop an exaggerated stress response. It involves a recurrent pattern of reactions related to the initial event.

This is more likely if you have a history of:

In this case, your brain reacts to related triggers to prepare you for future traumatic situations. The result is an overactive response.

An example if you’ve experienced trauma from a car accident. If the sound of a car horn reminds you of the event, you might have a stress response when you hear a car honking.


Anxiety is when you feel scared or nervous about a situation. It’s a natural response that helps you react appropriately. If you have an anxiety disorder, you’re more likely to feel threatened by nonthreatening stressors.

This could spark an exaggerated stress response to daily activities, like riding the bus or sitting in traffic.

There are ways to cope with an overactive stress response. This includes various strategies and treatments, such as:

Relaxation techniques

By doing activities that promote relaxation, you can counteract the stress response with the relaxation response.

Examples of relaxation techniques include:

  • deep abdominal breathing
  • focusing on a calming word
  • visualizing peaceful images
  • meditation
  • repetitive prayer
  • yoga
  • tai chi

When done regularly, these techniques can help improve how you react to stress.

Physical activity

Another strategy is regular exercise. Physical activity reduces the stress response by:

  • decreasing stress hormones, including adrenaline and cortisol
  • increasing endorphins
  • improving calmness
  • promoting better sleep

These benefits can increase your mood and sense of relaxation, which helps you better cope with stressful scenarios.

Social support

It’s also important to nurture healthy social relationships. Social support can minimize your psychological and physiological reactions to perceived threats. It provides a sense of safety and protection, which makes you feel less fearful.

Your social support may include different people, including:

  • friends
  • acquaintances
  • co-workers
  • relatives
  • significant others
  • mentors

If you’re in a constant state of fight-or-flight, consider visiting a mental health professional.

Specifically, you should seek help if you experience the following:

  • always feeling “on edge”
  • persistent worry, nervousness, or fear
  • stress that interferes with daily activities
  • fear of nonthreatening situations
  • inability to relax

A mental health professional can help you determine the underlying cause of these feelings. They can also create a plan to reduce your stress response, depending on your symptoms and mental health history.

Your body’s fight-flight-freeze response is triggered by psychological fears. It’s a built-in defense mechanism that causes physiological changes, like rapid heart rate and reduced perception of pain. This enables you to quickly protect yourself from a perceived threat.

If you have a history of trauma or anxiety, you might overreact to nonthreatening situations. A mental health professional can help you find ways to cope. With their guidance, you can develop the most appropriate strategies for your situation.