Somatic Experiencing: Peter Levine’s Body-Based Trauma Resolution

Category: Somatic Therapy / SE | Level: Serpent (South) — Medicine Wheel

The Animal That Does Not Get PTSD

In the Serengeti, an impala is chased by a cheetah. The impala runs — a full sympathetic nervous system mobilization, muscles flooding with blood, heart rate spiking, adrenal glands dumping cortisol and adrenaline, lungs heaving. The impala is caught. In the cheetah’s jaws, the impala collapses — not dead, but frozen. The dorsal vagal system has taken over: the body goes limp, heart rate plummets, pain is dulled by endogenous opioids. This is tonic immobility — the last-resort defense of the prey animal. Play dead. Maybe the predator will lose interest.

But the cheetah is distracted. Another predator approaches. The cheetah drags its kill toward cover. The impala, momentarily unattended, does something remarkable: it begins to tremble. Its legs shake violently. Its body convulses. Its breathing shifts from shallow to deep. And then — it stands. It runs. It rejoins the herd. Within hours, the impala is grazing normally, showing no signs of traumatic stress.

Peter Levine watched this scene unfold — in nature, in footage, in the ethological literature — and asked the question that became the foundation of Somatic Experiencing: Why don’t animals get PTSD?

The answer, Levine proposed, is that animals complete the defensive response cycle. The impala’s freeze response is not permanent — it is a temporary state that resolves through the involuntary discharge of the accumulated survival energy. The trembling, the shaking, the deep breathing — these are the body’s mechanisms for completing the interrupted defensive response. The sympathetic activation that powered the flight is discharged through the body. The dorsal vagal freeze is released. The nervous system returns to baseline.

Humans, uniquely among animals, interrupt this cycle. Our neocortex — the evolutionary newcomer that gives us language, abstract thought, and social awareness — overrides the body’s discharge impulse. We do not tremble after a car accident because it would be embarrassing. We do not shake and cry after an assault because we must appear strong. We suppress the body’s natural completion response through shame, social expectation, medical intervention (sedation), or simple ignorance of what the body needs to do. The survival energy that was mobilized for defense is never discharged. It remains frozen in the body — a permanently activated survival response with nowhere to go.

This, Levine argued in his landmark 1997 text Waking the Tiger: Healing Trauma, is the essence of trauma. Trauma is not the event. Trauma is the body’s incomplete response to the event — the unfinished defensive action that remains locked in the nervous system, producing the symptoms we call PTSD: hyperarousal, flashbacks, avoidance, emotional numbing, dissociation.

The Felt Sense: Eugene Gendlin’s Foundation

Levine built his model on the work of Eugene Gendlin, the philosopher-psychologist who developed Focusing — a body-centered approach to psychological awareness. Gendlin’s key concept is the “felt sense” — the body’s holistic, pre-verbal knowing about a situation.

The felt sense is not emotion (though it may contain emotion). It is not thought (though it may contain thought). It is not physical sensation (though it is experienced somatically). It is the body’s integrated, implicit understanding of a situation — a meaning that is sensed before it is known.

Gendlin (1978), in his text Focusing, described the felt sense as having six characteristics:

It is experienced in the body, usually in the throat, chest, or abdomen
It is initially vague and unclear — a “something” that is present but not yet articulated
When attended to with patient, open awareness, it unfolds — it “opens” into more specific sensations, emotions, images, and meanings
When the right words or images match the felt sense, there is a “felt shift” — a physical release, a sense of “yes, that’s it”
The felt shift is always accompanied by a change in the body — relaxation, deepening of breath, warmth, a sense of movement
The felt sense contains the body’s wisdom about what needs to happen next

Levine adopted the felt sense as the primary tracking instrument in Somatic Experiencing. SE does not work with thoughts about the trauma (cognitive therapy). It does not work with emotions about the trauma (affect-focused therapy). It does not work with the narrative of the trauma (talk therapy). It works with the body’s felt sense of the trauma — the pre-verbal, somatic, autonomic experience of the unfinished defensive response.

The SIBAM Model

Levine developed the SIBAM model as a framework for understanding the five channels through which traumatic experience is organized in the body-mind:

S — Sensation: The raw physical data: tightness, pressure, temperature, tingling, numbness, vibration, heaviness, lightness. In SE, sensation is the primary channel — the most direct access to the autonomic nervous system’s activation patterns. Trauma is stored as sensation before it is stored as anything else.

I — Image: Visual images, but also auditory, olfactory, gustatory, and kinesthetic imagery. Flashback images are the most dramatic, but subtler images also carry traumatic material: the color red that triggers nausea, the sound of a slamming door that produces freezing, the smell of cologne that activates panic.

B — Behavior: The body’s movement patterns — postures, gestures, impulses, actions. Trauma freezes the body’s defensive behaviors: the arms that wanted to push away but could not, the legs that wanted to run but were pinned, the voice that wanted to scream but was silenced. These incomplete motor patterns remain in the body as postural distortions, muscular bracing, movement restrictions, and spontaneous motor impulses.

A — Affect: The emotional dimension: fear, anger, grief, shame, disgust, helplessness. In SE, affect is understood as arising from the interaction of sensation, image, and behavior — not as an independent channel but as the experiential result of the body’s autonomic state. Fear is not merely an emotion; it is the subjective experience of sympathetic activation. Helplessness is the subjective experience of dorsal vagal collapse.

M — Meaning: The cognitive interpretations, beliefs, and narratives associated with the traumatic experience: “I am helpless,” “The world is dangerous,” “It was my fault,” “I will never be safe.” In SE, meaning is understood as the last channel to activate and the first to change when the underlying somatic channels (S, I, B) are resolved. Changing the belief without changing the body (“I know I’m safe, but I don’t feel safe”) is cognitive restructuring without somatic resolution — it does not hold.

The SIBAM model predicts that these five channels must be integrated — they must “couple” — for a traumatic experience to fully resolve. When channels are dissociated from one another (the client has images but no sensation, or sensation but no emotion, or emotion but no meaning), the experience remains fragmented and unresolved. SE’s clinical work involves helping the client access all five channels and allowing them to reconnect.

Pendulation: The Rhythm of Healing

Pendulation is Levine’s term for the natural oscillation between states of activation (distress, arousal, constriction) and states of settling (calm, ease, expansion). It is the most important concept in SE clinical practice because it describes the body’s innate healing rhythm.

A healthy nervous system pendulates naturally: activation (stress response) is followed by settling (recovery), which is followed by activation (new challenge), which is followed by settling (new recovery). This rhythmic oscillation maintains the nervous system’s flexibility and resilience.

In trauma, pendulation is disrupted. The nervous system becomes stuck in one state — either chronic activation (hyperarousal, anxiety, hypervigilance) or chronic settling that is actually collapse (dorsal vagal shutdown, dissociation, numbness). The system cannot oscillate. It is frozen.

SE facilitates the restoration of pendulation by gently guiding the client’s awareness between activation and resource:

Contact the activation: “What do you notice in your body right now?” (tightness, pressure, heat)
Note the activation without amplifying it: Stay with it briefly, with curiosity, without intensifying
Pendulate to resource: “And what else do you notice? Is there any place in your body that feels different — more settled, more open, more comfortable?”
Rest in the resource: Allow the client to fully experience the settling, the ease, the calm
Pendulate back to activation: “And now, what happens if you gently bring your attention back to that area of tightness?”
Notice the change: Often, the activation has shifted — it may have moved, decreased, changed quality

Each cycle of pendulation — activation to resource to activation to resource — builds the nervous system’s capacity for flexible oscillation. The stuck state begins to move. The frozen energy begins to thaw. The system remembers how to self-regulate.

Titration: The Dose Makes the Medicine

Titration is the SE principle that trauma must be processed in small, manageable doses. Levine borrowed the term from chemistry, where titration means adding a reagent drop by drop to control a reaction.

The opposite of titration is flooding — overwhelming the system with traumatic material in the hope that habituation will occur. Flooding is the logic of exposure therapy: expose the person to the feared stimulus until the fear extinguishes. The problem, in Levine’s view, is that flooding retraumatizes: it overwhelms the system’s processing capacity, reinforcing the helplessness and overwhelm that define trauma. The person may habituate to the specific stimulus, but the underlying autonomic dysregulation is not resolved — and may be worsened.

SE’s approach is the opposite: process the smallest amount of traumatic activation that the system can integrate. Touch the activation — briefly, gently — and then pendulate to resource. Process a drop of the accumulated survival energy, and allow the system to settle. Then another drop. And another.

This approach is slower than flooding. But it is safer, and Levine argues it is more thorough — because it works with the body’s natural processing capacity rather than overwhelming it.

Discharge: Completing the Defensive Response

When the titrated activation is allowed to move through the body — when the frozen survival energy is thawed through pendulation and titration — the body discharges. Discharge is the completion of the interrupted defensive response. It manifests through:

Trembling and shaking: The most fundamental discharge mechanism. The body shakes off the accumulated survival energy, as the impala does. In SE sessions, spontaneous trembling often begins in the legs (the legs that wanted to run), the arms (the arms that wanted to push away), or the jaw (the voice that wanted to scream).
Spontaneous breathing shifts: The breath deepens, slows, and becomes more rhythmic. Sighing, yawning, and spontaneous deep breaths are signs of parasympathetic activation replacing sympathetic hyperactivation.
Involuntary movements: The body spontaneously performs the defensive action that was interrupted — the hands may push outward (the push-away that was frozen), the legs may make running movements, the head may turn (the orienting response that was interrupted). These movements are not directed by the therapist or the client — they arise spontaneously from the body’s innate completion drive.
Heat and sweating: The release of held muscle tension produces heat. Sweating is a parasympathetic discharge mechanism.
Emotional release: Tears, laughter, anger, grief — these arise as the affect channel (the “A” in SIBAM) couples with the sensation and behavior channels during discharge.
Gurgling and digestive sounds: The enteric nervous system (gut brain) participates in discharge. Stomach gurgling, intestinal movement, and changes in digestive sensation often accompany the shift from sympathetic to parasympathetic dominance.

Levine (2010), in In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness, describes discharge as the body’s innate intelligence completing what was interrupted. The clinician’s role is not to produce discharge but to create the conditions (safety, pendulation, titration) that allow the body’s own completion drive to activate.

The Four Survival Responses

Building on Walter Cannon’s fight-or-flight model and expanding it through ethological research, Levine identifies four primary survival responses, each with a distinct autonomic signature:

Fight

Activation: High sympathetic. Energy flows to the arms, jaw, and upper body. Muscles tense for striking, pushing, biting. Adrenal output is high. Heart rate and blood pressure increase. Vision narrows (tunnel vision). The facial expression is aggressive — bared teeth, narrowed eyes, furrowed brow.

When fight is interrupted: The fight energy is frozen as chronic muscular tension in the arms, shoulders, jaw, and neck. The person may experience chronic anger, irritability, or a sense of being “ready to explode.” The body holds a perpetual readiness to strike.

Flight

Activation: High sympathetic. Energy flows to the legs and lower body. Muscles tense for running. Heart rate spikes. Breathing becomes rapid and shallow. Vision broadens (to scan for escape routes). The body orients toward exits.

When flight is interrupted: The flight energy is frozen as restlessness, anxiety, inability to sit still, chronic leg tension, or a persistent urge to escape. The person may experience claustrophobia, panic in confined spaces, or a restless need to keep moving.

Freeze

Activation: Simultaneous sympathetic and dorsal vagal. The body is immobilized but charged — like a car with the accelerator and brake pressed simultaneously. Heart rate may be high but the body cannot move. The person is alert but paralyzed. This is tonic immobility.

When freeze persists: The person experiences the paradox of being wired and exhausted simultaneously — hypervigilant but unable to act, anxious but immobilized. This is the signature state of many PTSD presentations.

Collapse (Shutdown)

Activation: Dominant dorsal vagal. Energy withdrawal from the periphery. Heart rate drops. Blood pressure falls. Muscle tone collapses. Consciousness may narrow or dissociate. The body goes limp. Pain is dulled. The person may feel “not in their body” or “watching from a distance.”

When collapse persists: The person experiences chronic dissociation, emotional numbness, fatigue, depression, disconnection from the body, and the sense that life is happening to someone else. This is the dorsal vagal shutdown that Stephen Porges’ polyvagal theory describes as the oldest and most primitive survival response.

Renegotiation vs. Reliving

One of Levine’s most important distinctions is between renegotiation and reliving. Reliving is what happens in flashbacks and in poorly conducted exposure therapy: the traumatic experience is re-experienced at full intensity, with all the helplessness and overwhelm of the original event. Reliving does not heal. It retraumatizes.

Renegotiation is the SE alternative. Through titration and pendulation, the traumatic experience is approached in small, manageable pieces. The client contacts the activation, processes a small amount of it, and then returns to resource. Each cycle changes the experience — the body discovers that it can handle the activation, that it can settle after contact with the traumatic material, that it has resources that were not available during the original event.

The key difference is agency. In reliving, the person is helpless — overwhelmed by the experience, unable to stop or control it. In renegotiation, the person has agency — they choose to approach the activation, they can withdraw to resource at any time, and they experience the gradual mastery of material that once overwhelmed them. This experience of agency is itself healing — it directly contradicts the helplessness that defines trauma.

Connection to Other Somatic Modalities

SE and EMDR

SE and EMDR share the same goal (resolution of traumatic memory) but work through different channels. EMDR works primarily through the SIBAM channels of Image and Meaning, using bilateral stimulation to process the visual and cognitive components of traumatic memory. SE works primarily through the Sensation and Behavior channels, using the felt sense to track and resolve the body’s stored survival responses.

The two approaches are complementary. EMDR may process a traumatic memory to a SUD of 0, but the body scan (Phase 6) may reveal residual somatic activation — the body has not yet completed its response. SE techniques (pendulation, titration, discharge) can resolve this residual somatic material.

SE and IFS

SE tracks the autonomic nervous system. IFS maps the psychological system. When a part activates in IFS, it produces an autonomic state that SE can track. When an autonomic state shifts in SE, it may correspond to a part’s activation or release in IFS. The practitioner trained in both modalities can navigate between the somatic and psychological dimensions of the same underlying process.

SE and Polyvagal Theory

SE and polyvagal theory are deeply intertwined. Porges’ description of the three autonomic states (ventral vagal, sympathetic, dorsal vagal) provides the neurobiological foundation for Levine’s four survival responses. Levine’s clinical techniques (pendulation, titration, discharge) provide the practical methodology for shifting autonomic states that Porges’ theory describes. SE is, in many ways, polyvagal theory applied.

SE and TCM

In TCM, the flow of qi through the meridian system parallels the flow of survival energy through the body in SE. Qi stagnation (blocked energy flow) parallels the frozen survival energy of unresolved trauma. Acupuncture points that release qi stagnation — particularly Liver 3 (Tai Chong, the “Great Rushing”), Gallbladder 34 (Yang Ling Quan), and Pericardium 6 (Nei Guan) — may be releasing the same held energy that SE discharge processes address. The trembling and shaking of SE discharge parallels the spontaneous movements (qi gong spontaneous movement, or zifagong) that advanced qigong practitioners experience when blocked qi releases.

The Four Directions in Somatic Experiencing

Serpent (South): SE is the Serpent’s therapy. It works exclusively through the body — through sensation, movement, breath, and the felt sense. The Serpent sheds its skin. SE facilitates the shedding of the body’s frozen survival responses.

Jaguar (West): The emotional dimension emerges naturally during SE processing. As the body discharges frozen energy, the emotions that were frozen with it surface — the terror, the rage, the grief that were part of the original survival response. The Jaguar’s work is to feel these emotions fully, to let them complete, to transform them from frozen pain into living wisdom.

Hummingbird (North): Meaning emerges last in SE processing — the “M” in SIBAM. After the body has discharged (S, B), the images have resolved (I), and the emotions have completed (A), the person spontaneously discovers new meaning. “I survived” becomes “I am a survivor.” “I was helpless” becomes “I have resources now.” This is the Hummingbird’s gift: the transformation of experience into soul-level meaning.

Eagle (East): The witnessing presence that SE cultivates — the capacity to observe one’s own body sensations without being overwhelmed by them — is the Eagle’s perspective. In SE, this witnessing capacity is developed through practice: each cycle of pendulation strengthens the person’s ability to be present with their own activation from a place of calm awareness.

References

Brom, D., Stokar, Y., Lawi, C., Nuriel-Porat, V., Ziv, Y., Lerner, K., & Ross, G. (2017). Somatic experiencing for posttraumatic stress disorder: A randomized controlled outcome study. Journal of Traumatic Stress, 30(3), 304-312.

Gendlin, E. T. (1978). Focusing. Everest House.

Levine, P. A. (1997). Waking the Tiger: Healing Trauma. North Atlantic Books.

Levine, P. A. (2010). In an Unspoken Voice: How the Body Releases Trauma and Restores Goodness. North Atlantic Books.

Payne, P., Levine, P. A., & Crane-Godreau, M. A. (2015). Somatic experiencing: Using interoception and proprioception as core elements of trauma therapy. Frontiers in Psychology, 6, 93.

Porges, S. W. (2011). The Polyvagal Theory: Neurophysiological Foundations of Emotions, Attachment, Communication, and Self-Regulation. W. W. Norton.

van der Kolk, B. A. (2014). The Body Keeps the Score: Brain, Mind, and Body in the Healing of Trauma. Viking.

Somatic Experiencing: Peter Levine's Body-Based Trauma Resolution