The Veteran Who Couldn't Sit Still
In the early 1990s, psychiatrist Bessel van der Kolk was working with Vietnam veterans at a VA hospital in Boston when he noticed something that his training hadn't prepared him for.
The veterans could describe their trauma. Many of them had been through years of talk therapy. They could narrate what had happened to them in clinical detail. Some could do it without apparent emotion — detached, factual, almost bored.
But their bodies were a different story.
When van der Kolk measured their physiological responses — heart rate, skin conductance, muscle tension — during these seemingly calm recollections, the numbers told a completely different story. Their bodies were reacting as if the trauma were happening right now. Heart rates spiked. Stress hormones flooded their bloodstreams. Muscles tensed in patterns that looked like bracing for impact.
The mind had processed the memory. The body had not.
This observation — deceptively simple, profoundly disruptive — would eventually become the central thesis of van der Kolk's landmark book The Body Keeps the Score: trauma is not stored as a narrative. It's stored as a physiological state.
Or so the story goes. Recent work in computational neuroscience suggests the picture is more nuanced — and more hopeful — than either van der Kolk or his critics initially imagined.
What Trauma Actually Does to the Nervous System
To understand why trauma lives in the body, you need to understand what happens in the nervous system during an overwhelming event.
Under normal stress, the autonomic nervous system activates a predictable sequence. The sympathetic branch (fight or flight) revs up: heart rate increases, muscles tense, pupils dilate, digestion halts. When the threat passes, the parasympathetic branch (rest and digest) kicks in: the body calms down, relaxes, returns to baseline.
Trauma occurs when this cycle doesn't complete.
When a threat is too overwhelming — too fast, too prolonged, or too inescapable — the nervous system can't discharge the activation. The body mobilizes enormous energy for fight or flight, but the energy has nowhere to go. The person can't run. Can't fight back. Is pinned, trapped, frozen, or too young to do either.
In these moments, the nervous system activates a third response: freeze. The dorsal vagal complex — the most ancient branch of the vagus nerve — slams the brakes. Heart rate drops. Blood pressure falls. Consciousness may narrow or dissociate. The body essentially plays dead.
This is not a conscious choice. It's a survival mechanism hardwired into vertebrate biology, older than the cortex, older than language, older than thought.
The problem is what happens after.
The Incomplete Cycle
In the wild, animals complete the stress cycle. A gazelle that escapes a lion will stop, tremble violently for several minutes, shake off the freeze response, and then resume normal behavior. The trembling discharges the trapped survival energy. The nervous system resets.
Peter Levine, the founder of Somatic Experiencing, spent decades observing this phenomenon. Animals in the wild, he noted, are routinely traumatized — chased, attacked, nearly killed — yet they don't develop PTSD. They complete the cycle.
Humans, by contrast, interrupt the cycle. We override the body's discharge mechanisms with cortical control. We're told to "calm down," "hold it together," "be strong." We clamp down on the trembling because it looks strange. We suppress the tears because they feel embarrassing. We go back to work the next day because we have to.
That survival energy doesn't simply vanish. The nervous system, unable to complete its reset, remains stuck in one of two states:
Hyperarousal — the system stays in fight-or-flight mode. Chronic anxiety, hypervigilance, insomnia, startle responses, irritability. The alarm is still ringing even though the fire is out.
Hypoarousal — the system stays in freeze mode. Numbness, dissociation, fatigue, depression, difficulty feeling emotions or physical sensations. The person is physically present but neurologically checked out.
Many traumatized people cycle between both — wired and exhausted, anxious and numb, swinging between extremes with very little middle ground. Clinicians call this a "narrow window of tolerance." Polyvagal theory frames it as a nervous system that has lost its ability to modulate between activation and rest.
The Body's Memory
Traumatic memories are different from ordinary memories in several critical ways:
They're implicit, not explicit. Ordinary memories are narrative: you remember what happened, when, and where. Traumatic memories often lack narrative structure. Instead, they're stored as fragments — a smell, a sound, a body sensation, a flash of image — without the contextual information that tells the brain "this happened in the past."
They live in the body. The amygdala and the brain's threat-detection circuits encode traumatic experiences as physical states, not stories. This is why a trauma survivor might suddenly feel their throat tighten, their chest constrict, or their legs go numb — not because they're consciously remembering the event, but because their body is reliving it. The trigger might be a tone of voice, a time of day, or a body position that resembles the original event.
They exist outside of time. The hippocampus — responsible for time-stamping memories and filing them as "past" — often goes offline during extreme stress. Without hippocampal encoding, traumatic memories feel perpetually present. This is the defining feature of PTSD flashbacks: not that the person is remembering the event, but that their nervous system is re-experiencing it.
The Emerging Counterpoint: Trauma as Frozen Prediction
In 2026, a paper in Frontiers in Systems Neuroscience by Steven Kotler, Karl Friston, and colleagues offered a rigorous challenge to the "body stores trauma" narrative. Their argument, grounded in the Free Energy Principle and predictive coding, reframes the picture entirely:
The body does not store trauma. The brain dynamically reenacts it through maladaptive inference.
In their model, what endures after trauma is not a memory lodged in tissue but a collapse of metastability — the brain's ability to fluidly switch among semi-stable network states. Trauma overweights the precision of danger priors: the brain assigns excessive confidence to threat predictions, constraining perception around the prior premise of enduring danger.
The "score" the body appears to keep is thus an artifact of circular inference: the brain predicts pain, senses arousal, and takes that arousal as proof that pain persists. The body participates in trauma, but as messenger, not archive.
This distinction matters clinically. Where the storage model leads to metaphors of exorcism — finding and purging what was buried — the inference model leads to training: recalibrating precision, retraining expectations, and expanding the brain's capacity for adaptive variability.
Crucially, the Kotler/Friston framework doesn't invalidate body-based therapies. It explains them differently. SE, EMDR, yoga, and breathwork don't work because they "release" stored energy — they work because they introduce variability, recalibrate sensory precision, and help the nervous system relearn that arousal and safety can coexist.
Van der Kolk summarized it succinctly: "Traumatized people chronically feel unsafe inside their bodies."
The Approaches That Work With the Body
Once you understand that trauma reshapes the nervous system — whether you frame it as stored energy or frozen prediction — the limitations of purely cognitive therapy become apparent. You can talk about trauma for years and still carry its patterns in your physiology. The insight is necessary but not sufficient. The nervous system needs its own process of recalibration.
Several therapeutic approaches have emerged from this understanding:
Somatic Experiencing (SE) — Developed by Peter Levine, SE works with the body's impulses to complete the interrupted defensive responses. Rather than revisiting the traumatic narrative, the therapist guides the client to notice physical sensations — tension, trembling, heat, constriction — and gently allow them to move through. The goal is to discharge the trapped survival energy, one small piece at a time.
EMDR — Eye Movement Desensitization and Reprocessing uses bilateral stimulation (eye movements, tapping, or auditory tones) to help the brain reprocess traumatic memories. The mechanism isn't fully understood, but imaging studies show that EMDR reduces amygdala activation and increases prefrontal engagement during trauma recall. The APA, WHO, and VA all recommend it for PTSD.
Sensorimotor Psychotherapy — Developed by Pat Ogden, this approach combines talk therapy with direct attention to the body's patterns — posture, movement, gesture, and breath. It works with the body's "action tendencies" — the movements that wanted to happen during the trauma but couldn't.
Yoga — Specifically trauma-sensitive yoga, which emphasizes choice, interoception (feeling the body from the inside), and gentle movement. A 2014 study by van der Kolk and colleagues found that 10 weeks of trauma-sensitive yoga significantly reduced PTSD symptoms in women with treatment-resistant PTSD — improvements that rivaled or exceeded those seen with medication.
Breathwork — Slow, controlled breathing activates the vagus nerve and shifts the nervous system from sympathetic to parasympathetic dominance. It doesn't resolve trauma directly, but it widens the window of tolerance — giving the person more capacity to be present with difficult sensations without being overwhelmed.
What This Means for You
You don't need to have a diagnosis of PTSD for this to be relevant. Trauma exists on a spectrum. A car accident, a difficult birth, a childhood marked by emotional neglect, a relationship with someone who made you feel perpetually unsafe — all of these can leave signatures in the nervous system.
If you notice any of the following, your body may be carrying more than you realize:
- Chronic muscle tension that doesn't respond to stretching or massage
- Difficulty taking deep breaths, or a feeling of tightness in your chest
- Hypervigilance — scanning for danger in safe environments
- Difficulty being still, or conversely, difficulty motivating yourself to move
- Emotional numbness or difficulty identifying what you're feeling
- Startle responses that seem disproportionate to the trigger
- Chronic fatigue that isn't explained by sleep or medical conditions
These aren't character flaws. They're nervous system patterns. And nervous system patterns can change — not through willpower, but through the kind of patient, body-based work that teaches the nervous system it's safe to come out of survival mode.
The body reflects what the brain predicts. But with the right conditions — safety, patience, skilled support, and time — the nervous system can learn to update its predictions and recover its flexibility.
Sources: van der Kolk, "The Body Keeps the Score," 2014. Levine, "Waking the Tiger," 1997. Porges, "The Polyvagal Theory," 2011. Ogden et al., "Trauma and the Body," 2006. van der Kolk et al., "Yoga as an Adjunctive Treatment for PTSD," Journal of Clinical Psychiatry, 2014. Kotler, Mannino, Fox & Friston, "The body does not keep the score: trauma, predictive coding, and the restoration of metastability," Frontiers in Systems Neuroscience, 2026.
