Have you noticed how your body reacts when you’re surprised or nervous about something? It’s trying to get you ready to properly react to the perceived threat.

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This is your fight, flight, or freeze response, also known as the stress response. It’s a physiological reaction to something your body has perceived as a threat.

The fight, flight, or freeze response is the body’s built-in way of responding to danger.

It’s activated in response to perceived stressful events. This could be something that seriously threatens your life, such as being chased by a lion. But it can also be activated by the stresses of everyday life, like talking at a work meeting or going on a first date.

When activated, the stress response can make you react in three ways:

  • You fight the threat.
  • You flight from the situation.
  • You freeze and stay in place.

Which response happens depends on the situation and how you were taught to respond according to your upbringing and culture.

Thinking patterns may also play a role. Some cognitive distortions, for example, may increase your stress response.

The fight, flight, or freeze response is crucial for survival. It enables us to respond to life threatening situations quickly.

Without it, our ancestors would have struggled to survive, whether from animal predators or groups at war.

Nowadays, though, many of us live with far fewer life threatening situations than our ancestors. Still, the stress response keeps playing an important role in our survival.

For example, the stress response helps you react quickly to a speeding car coming your way, or to your child tripping and falling.

The fight, flight, or freeze response causes your body to produce a rush of hormones that prepare you to respond to the perceived threat.

What’s happening in the body during this response

When you face a threat, a signal is sent to your amygdala. This is a part of your brain that plays an important role in processing fear and other emotions.

When the amygdala receives the information, it immediately sends it to other organs in the body so they can activate the alarm: the fight, flight, or freeze response.

In short, here’s how your body reacts to the perceived threat:

  1. The amygdala picks up a cue from the environment that signals danger.
  2. It gathers the information and sends it to the sympathetic nervous system, which controls your body’s involuntary responses. In other words, you don’t have to think about it; the body just reacts.
  3. Your adrenal glands receive a signal to pump adrenaline, the fight-or-flight hormone, into your blood.
  4. Adrenaline releases blood sugar and fat from storage sites around your body into your blood, giving you a boost of energy.
  5. Adrenaline also increases your heart rate, pulse, and blood pressure. This blood reaches your vital organs, heart, and muscles. It prepares you in case you need to run, jump, or react in another way.
  6. Small airways in your lungs open wide, and you start to breathe more quickly.
  7. Your brain receives extra oxygen, making it more alert, and your senses become sharper.

What does it feel like for you?

Which stress response you experience will influence how you feel.

In general, you may experience any of these during the stress response:

  • loss of voluntary bladder control
  • sweating, chills, or both
  • hot flashes
  • jumpiness and quick reflexes
  • muscle tension
  • faintness or lightheadedness
  • shock and difficulty moving
  • shortness of breath
  • increased strength, agility, or flexibility
  • racing heart
  • shakiness

After your initial reaction and once the threat has subsided, you may find that you either have no memory of what happened or a crystal clear recollection of the event.

It’s also common to feel less pain while your stress response is triggered. This is why people involved in car accidents usually don’t feel pain from their injuries until later on.

Your body is designed to use the fight, flight, or freeze response once in a while and only when confronted by a life threatening situation. It may find it challenging to face these stimuli constantly.

Activating the stress response too often or all the time may have a direct impact on bodily functions and mental health.

An ongoing fight, flight, or freeze response may require your body to constantly produce hormones like cortisol and adrenaline. This overproduction could affect some of your bodily functions and organs.

You could experience:

  • sleep disruptions
  • weight changes
  • headaches
  • cardiovascular complications
  • digestive problems
  • weakened immune system
  • low sex drive
  • lack of focus
  • loss of memory

There are many reasons why someone may experience an exaggerated or chronic stress response. Sometimes it’s conditioning, genetics, or specific environments.

There are also some mental health conditions that are linked to an exaggerated stress response. These a few examples:

Traumatic stress

Excessively triggering the stress response is related to traumatic stress and post-traumatic stress disorder (PTSD).

After a traumatic event, you may start to associate things in everyday life with the event. For example, if the supermarket reminds you of what happened, your stress response might be triggered each time you go to the supermarket.

Sometimes, your mind may create the trigger. For example, you may experience flashbacks or nightmares that may cause your body to activate the stress response.

Anxiety disorders

If you have an anxiety disorder, you’re more likely to feel threatened by typically nonthreatening situations. These might be everyday situations, like waiting in traffic or talking with a clerk in the supermarket.

You could also have anticipatory anxiety and feel anxious about being anxious. These intrusive thoughts may be enough to trigger the stress response.

This could mean you experience heart palpitations, shortness of breath, and hypervigilance more often than people who don’t live with an anxiety disorder.

Chronic stress

Chronic stress happens when the body is in a constant state of fight or flight.

Triggers for chronic stress vary from person to person. They may include dealing with:

  • a chronic illness
  • abuse
  • racism
  • lack of sleep

The fight, flight, or freeze response is the body’s natural way of getting you out of danger. It can be useful in life threatening situations or when you need an extra push to accomplish something.

When activated too often, though, it can impair your mental and physical health.

A few reasons why you may have a hyperactive stress response include genetics, specific environments, and some mental health conditions.

Stress can be managed, though. For more information, consider these articles: