Dizziness after standing, unexplained changes in heart rate, persistent fatigue, digestive discomfort, temperature sensitivity, and difficulty concentrating may seem unrelated. In some people, however, these symptoms can share a connection: disruption within the autonomic nervous system. Dysautonomia is an umbrella term for disorders involving this automatic regulatory network, rather than the name of one specific disease. Axon Integrative Health shares this educational overview for individuals throughout Denver, Cherry Creek, Cherry Hills, Highlands, and Greenwood Village who want to better understand the relationship between the nervous system and whole-body function.
Because the autonomic nervous system influences nearly every organ system, dysautonomia can look different from one person to another. Symptoms may be mild and occasional, or they may interfere substantially with exercise, work, sleep, digestion, and everyday activities. Understanding what the autonomic nervous system controls is an important first step toward recognizing why such a wide range of symptoms can occur.
The Autonomic Nervous System Works Behind the Scenes
The autonomic nervous system regulates processes that normally happen without conscious effort. These include heart rate, blood pressure, breathing patterns, digestion, sweating, pupil responses, bladder function, body temperature, and the distribution of blood throughout the body. It continuously gathers information about internal and external conditions and makes adjustments that help maintain a stable internal environment.
This network includes sympathetic and parasympathetic pathways. The sympathetic nervous system helps mobilize the body during activity, stress, or perceived danger. It may increase heart rate, redirect blood toward working muscles, and slow certain digestive processes. The parasympathetic nervous system is commonly associated with rest, digestion, recovery, and energy conservation. Healthy autonomic function does not depend on one side remaining dominant. Instead, the body must shift appropriately between activation and recovery according to the situation.
The autonomic nervous system also connects the brain, spinal cord, peripheral nerves, blood vessels, heart, lungs, digestive organs, and endocrine system. This helps explain why dysautonomia rarely creates just one isolated symptom. A disruption in autonomic signaling may influence several systems at the same time, even when those symptoms initially appear unrelated.
What Happens When Autonomic Regulation Is Disrupted?
Dysautonomia occurs when one or more parts of the autonomic nervous system do not regulate bodily processes effectively. The problem may involve communication within the brain, pathways in the spinal cord, peripheral autonomic nerves, or the organs and blood vessels responding to those signals. Dysautonomia may develop as a primary neurological disorder, but it can also occur alongside another illness or medical condition.
For example, when a person stands, gravity causes blood to move toward the legs and abdomen. The autonomic nervous system should quickly tighten blood vessels and adjust heart rate so that adequate blood continues reaching the brain. When this response is delayed or poorly coordinated, the person may experience lightheadedness, weakness, blurred vision, palpitations, or near-fainting. Symptoms may become more noticeable after prolonged standing, warm showers, large meals, illness, dehydration, or physical exertion.
Postural orthostatic tachycardia syndrome, commonly called POTS, is one form of dysautonomia. It involves an excessive increase in heart rate after standing and may produce dizziness, fatigue, exercise intolerance, brain fog, and other symptoms. POTS is only one autonomic disorder, however, and having occasional dizziness or a rapid heartbeat does not automatically mean that someone has it.
Symptoms Can Extend Far Beyond Heart Rate
Cardiovascular symptoms are often among the most recognizable signs of dysautonomia. These may include a racing or pounding heartbeat, unusual heart-rate fluctuations, low blood pressure, dizziness, fainting, and difficulty remaining upright. Some people feel relatively well while lying down but notice symptoms shortly after standing or walking. Others experience unpredictable episodes that vary in frequency and intensity.
Dysautonomia can also affect digestion, temperature control, energy, cognition, sleep, and sweating. A person might experience nausea, abdominal discomfort, constipation, diarrhea, early fullness after eating, excessive sweating, reduced sweating, heat intolerance, cold hands and feet, headaches, tremulousness, shortness of breath, or persistent fatigue. Problems with concentration and mental clarity are often described as “brain fog.”
Symptoms can overlap with those of anemia, thyroid disorders, heart conditions, medication effects, dehydration, anxiety, vestibular disorders, metabolic abnormalities, and other neurological conditions. For that reason, symptoms alone cannot identify dysautonomia or determine its cause. A thorough evaluation is important, particularly when symptoms are new, worsening, or affecting safety and daily function.
Why Dysautonomia Develops
There is no single cause of dysautonomia. In some cases, autonomic symptoms appear after a viral or bacterial infection. They may also occur in association with diabetes, autoimmune disorders, peripheral neuropathy, connective tissue conditions, neurological injuries, nutritional deficiencies, hormonal disturbances, or certain inherited disorders. Some individuals develop symptoms after surgery, pregnancy, concussion, or a period of prolonged inactivity.
An injury involving the brain or spinal cord may affect regions responsible for autonomic control. This is one reason the nervous system connection is especially relevant when symptoms begin after head trauma. Educational information about concussion rehabilitation and nervous system recovery can provide additional context about the many systems that may be affected following a concussion.
Peripheral nerves may also be involved. Autonomic fibers travel outside the brain and spinal cord to regulate blood vessels, sweat glands, digestive organs, and other structures. When these fibers are damaged or irritated, autonomic symptoms can occur alongside numbness, tingling, burning discomfort, or altered sensation. The relationship between sensory, motor, and autonomic nerves is discussed further in information about comprehensive neuropathy care.
Evaluating a Multisystem Pattern
An evaluation for possible autonomic dysfunction generally begins with a detailed medical history. The timing of symptoms, possible triggers, medications, recent infections, injuries, dietary patterns, sleep, hydration, and other health conditions may all provide useful clues. Clinicians may compare heart rate and blood pressure while a person is lying down, sitting, and standing. A neurological examination can also assess reflexes, strength, sensation, balance, eye movements, and other functions.
Depending on the symptoms, additional testing may include an electrocardiogram, heart monitoring, bloodwork, autonomic reflex testing, sweat testing, breathing-based assessments, or a tilt-table test. Laboratory testing can help investigate possible contributors such as anemia, blood sugar abnormalities, nutritional deficiencies, inflammation, or thyroid dysfunction. Information about blood lab testing and its role in evaluating systemic health helps illustrate why symptoms affecting the nervous system may sometimes require investigation beyond the nervous system itself.
The evaluation process may involve more than one medical discipline because dysautonomia can affect numerous organs. The goal is not simply to attach a label to a collection of symptoms. It is to determine which functions are being disrupted, identify possible underlying contributors, and rule out other conditions that may require different care.
Supporting Better Nervous System Regulation
Management depends on the type of dysautonomia, its cause, the person’s symptoms, and any coexisting conditions. Strategies may focus on maintaining circulation, reducing triggers, improving physical tolerance, supporting sleep, managing digestive symptoms, or addressing an underlying medical issue. Some individuals are advised to modify hydration or sodium intake, but these changes are not appropriate for everyone, especially people with certain kidney, heart, or blood pressure conditions.
Physical activity may also require a gradual and individualized approach. Attempting to push through severe symptoms can lead to setbacks, while prolonged inactivity may contribute to deconditioning. Carefully structured movement may begin in seated, reclined, or supported positions before progressing toward more upright exercise. Medical supervision is particularly important when symptoms include fainting, chest discomfort, severe shortness of breath, or dramatic heart-rate changes.
Dysautonomia demonstrates how closely the brain, nerves, cardiovascular system, digestion, metabolism, and movement are connected. Recognizing that connection can help people describe their symptoms more clearly and understand why a comprehensive evaluation may be necessary. Axon Integrative Health provides this educational information for the Denver, Cherry Creek, Cherry Hills, Highlands, and Greenwood Village communities to encourage greater awareness of the nervous system’s role in regulating everyday health.
Resources
Goldstein, D. S. (2024). Linking the Extended Autonomic System with the Homeostat Theory: New Perspectives on Dysautonomias. International Journal of Molecular Sciences.
Kanjwal, K., Karabin, B., Kanjwal, Y., & Grubb, B. P. (2021). Dysautonomia: A Forgotten Condition—Part 1. Journal of Innovations in Cardiac Rhythm Management.
National Institute of Neurological Disorders and Stroke. (2026). Postural Orthostatic Tachycardia Syndrome (POTS). National Institutes of Health.
