Understanding autonomic dysregulation after concussion and its wide-ranging symptoms.
Your autonomic nervous system controls everything your body does automatically—heart rate, blood pressure, digestion, temperature, and energy regulation. After concussion, this \
Primary Neurologic Domain: Autonomic
When autonomic regulation becomes inefficient after concussion, secondary compensation often appears in the Brainstem and Limbic Prefrontal domains, which is why exercise tolerance drops, recovery slows, and symptoms amplify under stress.[1]
The autonomic nervous system (ANS) has two branches: the sympathetic (\
Autonomic dysregulation can manifest in many ways:
These symptoms are often dismissed as \
Autonomic inefficiency often overlaps with an underlying energy regulation problem, making even light activity feel disproportionately exhausting.[2] Persistent autonomic strain can also increase limbic reactivity, amplifying symptoms and reducing stress tolerance.
Autonomic dysfunction is measurable. Heart rate variability and orthostatic testing can reveal the specific patterns of dysregulation.
The brain regions that control autonomic function are vulnerable to the metabolic disruption that occurs after concussion.[3] The brainstem, hypothalamus, and insular cortex all play roles in autonomic regulation—and all can be affected by concussive forces.
Autonomic dysfunction is one of the most common, and most overlooked, consequences of concussion.
We evaluate autonomic function through:
These tests reveal whether your autonomic system is responding appropriately to physiologic challenges.
Treatment involves gradually rebuilding your autonomic system's ability to handle challenge. This typically includes:
The goal is to restore your body's ability to smoothly shift between sympathetic and parasympathetic states as demands change.
At PPC, identifying autonomic dysfunction as a primary driver, rather than a downstream stress response, helps determine what to address first in concussion recovery.
Schedule a comprehensive evaluation to identify the root cause of your symptoms.
Supporting literature for this article. View full Works Cited
Baguley, I. J., Heriseanu, R. E., Nott, M. T., Chapman, J., & Sandanam, J. (2008). Dysautonomia after severe traumatic brain injury: Evidence of persisting sympathetic and parasympathetic dysfunction. Journal of Neurology, Neurosurgery & Psychiatry, 79(11), 1237–1243. https://doi.org/10.1136/jnnp.2007.132142
This study documented persistent sympathetic and parasympathetic dysfunction in TBI survivors, including elevated heart rate, blood pressure lability, and sweating abnormalities. It establishes the neurobiological basis for the autonomic symptoms PPC tracks in its outcome registry.
Leddy, J. J., Baker, J. G., Kozlowski, K., Bisson, L., & Willer, B. (2012). Reliability of a graded exercise test for assessing recovery from concussion. Clinical Journal of Sport Medicine, 22(5), 381–386. https://doi.org/10.1097/JSM.0b013e3182639f22
This study validated the Buffalo Concussion Treadmill Test (BCTT) as a reliable measure of autonomic exercise tolerance after concussion. The BCTT is a key tool in PPC's autonomic assessment battery, allowing clinicians to identify exercise intolerance and set individualized sub-threshold training targets.
Task Force of the European Society of Cardiology and the North American Society of Pacing and Electrophysiology. (1996). Heart rate variability: Standards of measurement, physiological interpretation, and clinical use. Circulation, 93(5), 1043–1065. https://doi.org/10.1161/01.CIR.93.5.1043
This foundational consensus paper established the standards for measuring and interpreting heart rate variability (HRV) as a non-invasive window into autonomic nervous system balance. PPC uses HRV-informed metrics to monitor autonomic recovery and guide training load decisions throughout the episode of care.
Giza, C. C., & Hovda, D. A. (2014). The new neurometabolic cascade of concussion. Neurosurgery, 75(Suppl 4), S24–S33. https://doi.org/10.1227/NEU.0000000000000505
This review describes the ionic flux, neurotransmitter disruption, and metabolic crisis that follow concussion at the cellular level. Understanding this cascade informs PPC's phased approach to loading and recovery, particularly the rationale for avoiding excessive cognitive and physical demand during the acute metabolic window.
Leddy, J. J., Kozlowski, K., Donnelly, J. P., Pendergast, D. R., Epstein, L. H., & Willer, B. (2010). A preliminary study of subsymptom threshold exercise training for refractory post-concussion syndrome. Clinical Journal of Sport Medicine, 20(1), 21–27. https://doi.org/10.1097/JSM.0b013e3181c6c22c
This landmark study demonstrated that graded aerobic exercise below symptom threshold accelerated recovery in athletes with persistent post-concussion syndrome. It directly supports the PPC approach of using exercise as an active therapeutic tool rather than prescribing rest until symptom resolution.