What is the Origin of Sympathetic Overdrive?

This term is a core concept in autonomic physiology and clinical cardiology, describing a pathological imbalance in the nervous system's control of involuntary functions. The overdrive component highlights the loss of homeostatic control, where the system is stuck in a heightened state of alert long after the initial stressor has passed. It is intimately linked to the stress response and HPA axis activity.

What is the Mechanism of Sympathetic Overdrive?

The overdrive is maintained by a positive feedback loop involving the brainstem and the adrenal medulla, often triggered by chronic psychological stress or underlying inflammation. High levels of circulating catecholamines lead to elevated heart rate, increased blood pressure, and impaired glucose tolerance by promoting hepatic glucose output. This sustained activation suppresses the parasympathetic rest-and-digest system, leading to poor recovery and digestive dysfunction.

Sympathetic Overdrive ∞ Area

Sympathetic Overdrive

Meaning

Sympathetic Overdrive is a state of chronic, excessive activation of the sympathetic nervous system (SNS), the division of the autonomic nervous system responsible for the “fight or flight” response, leading to a sustained release of catecholamines like adrenaline and noradrenaline. This persistent hyperarousal maintains the body in a state of high physiological alert, compromising the capacity for rest, repair, and parasympathetic function. It is a critical factor in stress-related hormonal and cardiovascular pathology.