How Trauma Impacts the Nervous System: An Overview of Survival Responses

Our autonomic nervous system (ANS) is the body's command center, managing everything from heart rate and digestion to how react under stress. While it's designed to keep us safe, trauma can deeply impact how our nervous system functions, sometimes trapping us in survival modes that affect our daily lives.

Trauma isn’t just caused from a life-threatening event. It can also arise from more subtle, chronic experiences, such as feeling abandoned, alienated, or neglected during childhood. When our needs aren’t met, especially in our younger years, it can disrupt the natural development of our nervous system.

Trauma isn’t necessarily about the event itself but rather the impact it has on the nervous system. Unlike regular memories, which have a clear beginning, middle, and end, trauma memories are stored differently. This difference in storage happens because when we experience something traumatic, the amygdala—the part of the brain responsible for detecting danger—takes over. It sends our brain into a high-alert state, inhibiting the areas responsible for neatly organizing memories.

As a result, trauma memories can become fragmented and difficult to process. These unresolved memories don’t just fade away; they linger in the body, influencing our reactions and behaviors, often in ways that we don’t consciously understand. This can leave us trapped in survival responses like fight, flight, freeze, shutdown, fawn, and functional freeze, which I’ll explain in more detail.

Fight Response

The fight response is one of the most recognizable survival strategies. When your nervous system perceives a threat—whether it's a physical danger like an attacker or an emotional trigger like an argument—your body prepares to defend itself. Your heart rate spikes, your jaw tightens, and stress hormones like cortisol and adrenaline flood your system. You might feel a surge of anger or the urge to confront the threat head-on. If we remain stuck in this response, it can lead to chronic stress and difficulty managing anger.  

Flight Response

Flight is another survival response that’s closely related to fight, but instead of confronting the danger, your nervous system urges you to escape. This might look like walking away from a heated conversation or feeling an overwhelming need to avoid a stressful situation. Like the fight response, flight also involves a rush of adrenaline and cortisol, but the focus is on getting away rather than standing your ground. Over time, if this response becomes chronic, it can manifest as anxiety, a need to stay constantly busy, or a pattern of avoidance.

Freeze Response 

When neither fighting nor fleeing seems possible, your body may enter a freeze response. Think of a deer in headlights—tense, unable to move. In this state, your body is flooded with sympathetic nervous system energy (like an increased heart rate) but paired with immobility. You might feel physically stuck, unable to take action, or find yourself holding your breath.

Shutdown Response

If you can’t fight or flee, your body might collapse inward, disconnecting from the overwhelming experience. In this state, your heart rate, blood pressure, and body temperature drop, and you might feel emotionally numb or detached. This is your nervous system’s way of conserving energy and minimizing damage when it perceives no way out of a threatening situation. It can manifest as low energy, slumped posture, a blank stare, or a desire to retreat into isolation, often accompanied by feelings of hopelessness or depression.

Fawn Response

The fawn response is less talked about but just as significant. If you’ve learned as a child that the best way to stay safe is to appease others, you might fall into fawning. This response involves people-pleasing, putting others’ needs before your own, and struggling to set boundaries. It’s a survival strategy where the focus is on avoiding conflict and maintaining connection at any cost, even if it means neglecting your own needs. 

Functional Freeze Response

Functional freeze is a state where you’re still able to function but are emotionally disconnected. You might go through your daily routine, appear calm on the outside, but feel numb inside. It’s a form of autopilot that allows you to carry on with life, even while your nervous system is stuck in a state of freeze. This response can be deceptive because you might seem fine to others, but inside, you’re not ok.

The Importance of Understanding These States

Recognizing your nervous system's role in shaping your responses is a key step in healing. When you understand that your reactions are biological, not personal flaws, it becomes easier to release feelings of shame and approach your healing journey with more compassion.