You Are Not Stuck in Fight or Flight

This is Part 2 of a series on the language of trauma, the science of stress, and what it actually means to be human right now. If you haven’t read Part 1, you might want to start there.

In the trauma and attachment world, we rely heavily on nervous system science to make sense of human behavior. I have utilized it extensively in my practice, and it has shaped how I understand people — including myself. But there has been growing debate about the research we have been leaning on, and it always feels a little threatening when foundational ideas are challenged.

Sometimes I do not realize how attached I am to a piece of research as absolute fact until new data emerges. It serves as a necessary reminder: we are always just approximating what is happening beneath the surface.

So I want to get into the weeds today about what our bodies are actually doing — because the language we use to describe it shapes what we believe is possible for ourselves. And right now, the language we are using is not quite right.

The Myth of the Broken Thermostat

One of the phrases I have used more times than I can count — and that you have likely heard everywhere — is the idea of being “stuck in fight or flight.”

We use it to describe someone who is hypervigilant, anxious, quick to temper, or constantly anticipating disaster. The spirit of the phrase is accurate: there is chronic stress, there is an edge, there is a pervasive feeling that relaxation is not available. But if we consider what being literally stuck in fight or flight would entail, we realize it is biologically unsustainable. The fight or flight response is designed for imminent threats of bodily harm. It involves a massive, time-limited cascade of chemical reactions. It is not a state the body can maintain indefinitely.

The autonomic nervous system does not actually get stuck in any single state. It is incredibly dynamic, constantly shifting between mobilization and recovery, engagement and rest. Even if you have a complicated relationship with rest, your nervous system is not permanently locked in mobilization.

Even in cases of severe trauma, a person does not get stuck in one gear. What actually happens is that the system’s baseline shifts upward, and its threshold for activation lowers. That is a meaningfully different thing — and the distinction changes everything about how we approach it.

The Engine That Runs Hot

This brings us to a physiological concept called allostatic load.

The body has a built-in system for managing stress called allostasis — the process by which the body maintains stability through change. When faced with a stressor, your body is supposed to ramp up: heart rate increases, cortisol spikes, digestion slows. And then, once the stressor has passed, it is supposed to return to baseline. That cycle of ramp-up and recovery is exactly what our bodies are designed to do.

Allostatic load is the physiological debt that accumulates when that cycle fails to complete. When stressors are chronic, unpredictable, or too frequent for the body to fully recover between them, the baseline shifts upward and the system never fully powers down.

Think of it like a car engine that runs hot. A single long drive on a hot day is fine. But if you run the engine hot every single day without an adequate cool-down period, the engine wears differently. The car might not fall apart all at once, but over time, the chronic heat changes how the entire system functions.

In humans, high allostatic load shows up across multiple systems: the cortisol response, immune function, sleep architecture, cardiovascular health. And critically — allostatic load exists on a spectrum. It is not a binary state of traumatized or not traumatized. We all carry some degree of load. Being human is an inherently abrasive experience. The relevant questions are how that stress accumulates, how early in life it began, and what the resulting picture looks like today.

One Spectrum, Not Two Categories

This is where I want to slow down, because it is the piece that ties this essay back to Part 1.

Developmental trauma, complex stress, and everyday human adversity are not categorically different things happening in different bodies. They are all expressions of the same underlying system — the same stress response, the same allostatic mechanism, the same nervous system — operating under different conditions of intensity, duration, and available support.

What distinguishes them is not the presence or absence of a specific event. It is the degree to which the stress was chronic, the degree to which repair was available, and the degree to which the resulting adaptations now significantly disrupt a person’s ability to function. At the far end of the spectrum, where stress was severe, prolonged, and without repair, the adaptations are pervasive. They affect how a person regulates emotion, how they relate to others, how they experience their own body. That end of the spectrum is real, it is serious, and it requires a specific kind of clinical attention.

But most people are not at that end.

Most people are carrying a moderate allostatic load — the accumulated weight of an imperfect childhood, structural stressors, relational friction, and the general difficulty of being alive in this particular moment in history. Their nervous systems adapted, as all nervous systems do. Those adaptations may cause real difficulty in certain areas of life. But that is not the same thing as developmental trauma, and treating it as such does not serve the person. It gives them a story about damage when what they actually need is a framework for change.

The spectrum matters because it tells us something important: all stress is human, and all stress is physiological. But not all stress is trauma. And knowing where you actually sit on that spectrum changes what you need, how you understand yourself, and what becomes possible.

Borrowing a Nervous System

To understand why a baseline shifts upward in the first place, we have to look at how our stress response is formed: through co-regulation.

When a child is born, they have the capacity to experience the world, but they lack the neurological hardware to process it alone. An infant literally borrows the nervous system of their caregiver. We require a regulated adult’s nervous system to learn how to make sense of our own.

If a caregiver carries a high allostatic load — a high baseline and a low threshold for stress — they will have a much harder time regulating a child. This is how physiological patterns are passed down across generations. And it is important to note that this is rarely about a parent failing or having malicious intent. There is a massive difference between a parent who intentionally harms a child, and a parent who is doing their best while battling a harsh economy, working multiple jobs, lacking a support system, and carrying their own unresolved load.

When a child experiences a strong emotion, they do not need a parent to fix it. They need a parent to hold them, breathe deeply, and remain a steady presence. Through that interaction, the child learns: I can have a strong emotion, it will eventually subside, I will be okay, and support is available. That cycle of rupture and repair, repeated thousands of times, is how a human being builds their own regulatory capacity.

But when the environment is chronically stressful, unpredictable, or threatening, the child’s system adapts. It learns that vigilance is required. The baseline goes up. The threshold goes down. This is simply the body doing exactly what it was designed to do: keeping the child safe in a high-stakes environment. Normal stress builds resilience, provided there is repair and support. It tips into something more significant when the stress is chronic, severe, and repair is absent.

The Predictive Brain

This understanding leads us to the predictive brain model, a framework that reframes these adaptations entirely.

Historically, we believed the brain passively waited for something to happen and then reacted to it. An event occurs, the brain processes the sensory input, and an emotion follows. But current neuroscience suggests that the brain is actually a prediction machine. It is constantly guessing what is about to happen based on your past experiences, before it even fully processes the incoming sensory data.

The brain does this to conserve energy. It operates on a model of the world constructed entirely from your history.

If you grew up in an unpredictable home, your brain likely built a predictive model that says: People are unreliable. Keep your guard up. Expect disappointment. Fast forward to adulthood. You are in a safe relationship, and your partner goes a little quiet. Your brain does not wait to gather more information. It immediately predicts rejection or danger based on the old model and triggers a physiological response. You are not reacting to what is actually happening in the present moment; you are experiencing a prediction based on the past.

This is not a flaw. It is an extraordinarily efficient system doing exactly what it was built to do. The problem is simply that the model is running on old data.

Prediction Errors and Digestible Risks

Why does this distinction matter?

If you believe you are stuck in fight or flight, or that trauma is permanently stored in your tissues, the goal becomes purging it. You try to fix the broken machine. You try to get the damage out of you.

But if you understand your experience as accumulated stress and a predictive model running outdated software, the intervention changes entirely. We stop trying to purge and start looking at present-time capacity. We focus on basic needs — sleep, food, movement — which are often the first things to go when allostatic load is high. And most importantly, we begin looking for prediction errors.

If your brain is predicting the future based on the past, the only way to change the model is to give it new data. In therapy, this is sometimes called a corrective experience, but I prefer the term prediction error. “Corrective” implies something is defective. A prediction error simply means: I thought this was going to happen, and instead I experienced this. That was new. That novel experience generates a new physiological response. It registers in the body as true.

Creating these errors requires taking digestible risks — small, tolerable steps into the unfamiliar. We often believe we must resolve everything internally before we can risk vulnerability in relationships. But change actually happens through relationship. It happens by reaching out to a friend when you are upset, even though your brain predicts you will be a burden, and allowing yourself to experience the relief when they actually show up for you.

You are not actually stuck. Your body and mind are in an adaptation — one that made complete sense in the environment that shaped it. And the beautiful thing about being human is that we adapt, and we will continue to change based on what we expose ourselves to.

You have everything you need already. You just have to give yourself the opportunity to experience the surprise of a new outcome, and let the old adaptations unravel.