After a difficult call, there is often a period, in the car on the way back to the station, at the end of a shift, lying awake at 3 a.m., when the body is still running as if the incident is happening. Heart rate elevated, muscles tight, jaw clenched, mind replaying images without being asked to. The cognitive understanding that the incident is over does not turn this off, because the nervous system’s threat response does not consult the cognitive understanding.
Somatic techniques work with this directly. Not by thinking your way out of the physiological state, but by using the body’s own regulatory mechanisms to signal that the threat has passed. They require no therapeutic relationship, no appointment, no disclosure of what happened. They are things you can do in a car, in a bathroom, at the end of a shift, or in the middle of the night.
This article explains what is happening in the body after a critical incident and provides concrete techniques, with the physiology behind each one, that work with that response rather than against it.
The stress response system, the sympathetic branch of the autonomic nervous system, is designed for short-term survival. In the presence of a threat, it redirects resources: heart rate and blood pressure increase to push blood to the muscles, breathing shallows and quickens to take in more oxygen, the digestive system shuts down, pain sensitivity reduces, and the threat-processing centres of the brain come to the fore while the slower analytical functions take a back seat.
This system is extraordinarily effective for its purpose. It is also designed to be temporary. In the threat-response system’s evolutionary design, the activation completes through physical action, fight or flight, and then the system returns to baseline. What first responders experience repeatedly is the activation without the completion: the threat response fires at full intensity, professional function is maintained through the activation, and the discharge that would normally close the loop does not happen.
The result is incomplete activation, the body still holding the chemistry and muscular tension of the stress response after the incident has ended. Over time, repeated incomplete activations raise the baseline arousal level: the person becomes harder to calm, more reactive, less able to access the slower functions of the prefrontal cortex, and more physiologically costly to regulate. This is the mechanism by which cumulative critical incident stress produces PTSD, burnout, sleep disorders, and the cardiovascular and immune effects documented in first responder health research.
Somatic techniques work by completing the activation cycle, helping the nervous system do what it is designed to do after threat has passed, which is to return to baseline, rather than leaving the activation in an incomplete state.
The breath is the only autonomic function that can be easily and directly controlled by conscious action. This makes it the most accessible lever for nervous system regulation, and the reason breathing-based techniques appear in virtually every serious stress regulation protocol across military, emergency services, and clinical contexts.
Used by Special Forces, first responders, and clinical settings. Breathe in for a count of four. Hold for a count of four. Breathe out for a count of four. Hold for a count of four. Repeat four to six cycles.
The mechanism: the equal-phase rhythm activates the parasympathetic nervous system by extending both the inhalation (which mildly activates the sympathetic system) and the exhalation (which activates the parasympathetic system) equally, then using the holds to create a brief reset between phases. The rigidity of the count gives the mind something concrete to do, which reduces the space available for intrusive content.
Breathe in for four counts. Breathe out for six to eight counts. No holds required. Repeat.
The mechanism: the exhale specifically, not the inhale, activates the vagus nerve and the parasympathetic response. Extending the exhale beyond the inhale shifts the ratio in favour of the calming response. This is simpler and often more accessible than box breathing when activation is very high and rigid counting is difficult to maintain. The extended exhale can be practised without anyone nearby noticing.
Take a full inhale through the nose. At the top of the inhale, take a second sharp inhale to fully top up the lungs. Then release in one long, slow exhale through the mouth.
The mechanism: this technique, which is now supported by peer-reviewed research from Stanford, works by maximally inflating the alveoli, the small air sacs in the lungs that collapse slightly under sustained stress, and then triggering the strongest possible activation of the parasympathetic system through the extended exhale. One to three physiological sighs produce measurable heart rate reduction within seconds. It is the fastest acting of the three techniques described here.
Grounding techniques work by anchoring attention to present sensory experience, which activates the prefrontal cortex and reduces the dominance of the amygdala-driven threat response. They do not require the activation to have fully resolved, they work by shifting the balance of attention from internal threat signals to external present-moment sensory data.
Name, silently or aloud, five things you can see, four things you can touch or feel (and touch them if possible), three things you can hear, two things you can smell, one thing you can taste.
The mechanism: the systematic inventory of current sensory experience forces the attention-directing systems of the brain to orient to present reality rather than to internally generated threat content. The specificity required, five distinct visible things, not a general scan, prevents the exercise from being completed on autopilot and keeps the prefrontal cortex actively engaged. The physical touch component (four things you can feel) adds a somatic anchor.
Splash cold water on the face, especially around the forehead and eyes. Hold ice or something cold in the hands. If possible, submerge the face briefly in cold water.
The mechanism: cold water on the face activates the mammalian dive reflex, a deep evolutionary response that rapidly slows the heart rate and redirects blood flow. This is not a psychological technique; it operates at a physiological level that bypasses cognitive mediation entirely. Emergency departments use this technique (facial immersion in ice water) as a clinical tool to slow dangerously rapid heart rates. At lower intensities, cold water on the face, cold object in the hands, it produces a rapid, moderate reduction in sympathetic activation. It works whether or not the person wants it to.
The stress response prepares the body for action. When that action does not happen, when professional functioning requires the physical stress response to be suppressed rather than expressed, the activation remains incomplete. Physical movement is the most direct way to complete the cycle.
Twenty to thirty minutes of sustained moderate-intensity exercise, running, cycling, swimming, anything that elevates heart rate to a working but sustainable level, after a difficult shift is one of the most evidence-supported post-incident stress regulation tools available. The exercise uses the physical resources the stress response prepared, signals to the body that the threat has been engaged and passed, and triggers the neurochemical cascade (endorphins, BDNF, serotonin) that both reduces acute stress activation and provides longer-term protection against cumulative stress effects.
The important qualifier: this is sustained moderate exercise, not intense competitive training. High-intensity exercise that is itself physically stressful can extend rather than reduce the stress activation period. The goal is completion, not performance.
Allow, or deliberately induce, shaking in the hands, legs, or whole body. Shake the hands as if trying to get water off them. Allow the legs to tremble if they want to. Walk in place with exaggerated, loose movement.
The mechanism: trembling and shaking are the body’s natural discharge mechanism for the physical activation of the stress response, the same mechanism observed in animals after predator encounters. Humans typically suppress this response because visible trembling is not socially acceptable in most contexts, including professional ones. Done privately, allowing or inducing mild shaking for one to two minutes is a rapid way to begin discharging the physical tension of the stress response. It feels slightly odd the first few times. It works.
The techniques above are designed for managing the normal, temporary physiological activation that follows critical incident exposure. They are not sufficient when:
These patterns indicate that the response has moved beyond what self-regulation techniques can address. Our Critical Incident Desensitization Training addresses the organizational level; for individual first responders whose response requires clinical support, trauma counseling and PTSD treatment are available through Creative Space.
