A nervous system that feels fragile or hypersensitive has a narrow window of tolerance for stimulation. Small changes in environment, emotion, or physical state can push the system into dysregulation. This reduced capacity develops when the system has been chronically overwhelmed.
The autonomic nervous system operates through learned associations between environmental cues and past events. When similar patterns appear in the present, the system activates the same physiological responses that occurred during previous threatening situations. This creates a feedback loop where heightened arousal generates more scanning behavior, which in turn reinforces the sense of danger.
Chronic activation depletes the body's resources over time. The system remains in a state of readiness that was originally a response to specific circumstances but has become a default mode of operation. Neural pathways that fire repeatedly become strengthened, making the activated state increasingly automatic and difficult to interrupt through conscious effort alone.