10/15/2025
After the startle response, if danger is detected and confirmed, your stress response kicks in.
The biology tracks like this: danger is detected, which is the startle response (via the brainstem and amygdala) instantly activates your sympathetic nervous system. Then comes the stress response—adrenaline, glucose, heart rate, oxygen, muscle tone, all rise to help you act. This is a high-energy state, a surge, designed for purposeful short-term mobilization. Think of it as a sprint, not a marathon.
And it is our strength. Your biology is prepping the body letting you know, “you’ve got this!” It activates and serves one goal: to overcome the danger.
If your body’s surge of energy successfully resolves the threat, the system naturally resets: cortisol drops, the parasympathetic system returns, and balance is restored.
But if your efforts don’t succeed and you can’t fight, flee, or resolve, the stress response escalates and then stalls. The body is still flooded with energy, but with nowhere to discharge it. In biological terms:
* The amygdala keeps signaling danger.
* The hypothalamic-pituitary-adrenal (HPA) axis keeps pumping stress hormones.
* The prefrontal cortex, responsible for logic and choice, goes offline.
* Over time, this leads to chronic hyperarousal (anxiety, vigilance) or shutdown (freeze, collapse).
This mismatch between energy and effectiveness or mobilization without resolution is the essence of trauma physiology. The body learns that it’s not safe even when the threat is over, and the nervous system stays stuck in a loop of readiness with no release.