Autonomic nervous system symptoms · St. Louis
Autonomic symptoms: the system you never think about
Autonomic nervous system symptoms include lightheadedness or graying vision on standing, feeling full after a few bites, sweating that is too much or too little, bladder urgency, exercise intolerance and heat intolerance. Testing measures the system directly in twenty minutes.
The autonomic nervous system runs blood pressure, heart rate, temperature, digestion, sweating, bladder and sexual function without asking you. When it drifts, the symptoms are scattered enough that they are usually attributed to something else.
What does the autonomic nervous system do?
It regulates the processes you do not consciously control: blood pressure, heart rate, body temperature, digestion, metabolism, fluid and electrolyte balance, sweating, urination, defecation and sexual response. It has two divisions — sympathetic and parasympathetic — and most organs are controlled predominantly by one of them, with the other providing the counterweight.
Almost every symptom below is the result of the counterweight failing rather than the system switching off.
What are the signs of dysautonomia?
Cardiovascular
- Lightheadedness or graying vision on standing
- Fainting
- Heart rate that will not rise with exercise
- Exercise intolerance out of proportion to fitness
- Palpitations
Digestive
- Feeling full after a few bites
- Nausea or vomiting after meals
- Heartburn and difficulty digesting food
- Constipation alternating with diarrhea
Everything else
- Sweat abnormalities — too much, too little, in the wrong place
- Bladder urgency, hesitancy or incomplete emptying
- Sexual difficulties
- Blurred vision and poor dark adaptation
- Fatigue and heat intolerance
Why is dysautonomia so often missed?
Each of those symptoms has an ordinary explanation available. Lightheadedness gets attributed to dehydration. Early fullness gets attributed to reflux. Fatigue gets attributed to age. Each attribution is reasonable on its own, and collectively they hide a single system that can be measured directly in twenty minutes.
How is autonomic dysfunction tested?
Autonomic testing looks at heart rate and pulse waveform at rest and during standardized challenges — deep timed breathing, standing up, and a brief controlled exhale against resistance. Each challenge asks a specific branch of the system to respond, and the size and timing of the response is the measurement. Heart rate variability and the reflex tests describe the components.
What can autonomic testing not tell you?
It cannot tell you the cause. Diabetes, kidney disease, thyroid failure, hepatitis, Parkinson’s disease, medications and simple deconditioning all produce overlapping patterns. It also cannot distinguish, on its own, between a nerve problem and an artery problem — which is exactly why the vascular study is run in the same appointment. The treatments for those two are quite different, and telling them apart is the point of testing both.
If you are a clinician: the same subject written for the person ordering the test is at the full test description.
Talk to someone about testing
Tell us what you are trying to find out and we will explain which Measura assessments answer that question, what each one involves, and how the results are reviewed with a clinician.
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Frequently asked questions
Is this the same as dysautonomia?
Dysautonomia is the umbrella term for autonomic dysfunction. Testing measures how the system behaves; naming the syndrome is a clinical judgment on top of that. What the numbers mean.
Could my medication be causing this?
Frequently, yes — beta-blockers, anticholinergics, antidepressants and bladder medications all affect these measurements. Never stop one to make a test look better. Preparation and medications.
I feel dizzy standing up. Is that autonomic?
It is one of the classic presentations and it is directly measurable. Dizziness and the risk of falling.
Does poor sleep affect the result?
Considerably. So do alcohol, caffeine and a hard training session the day before, which is why preparation instructions exist. Why the number moves.
What mimics dysautonomia?
Ordinary explanations do. Lightheadedness gets blamed on dehydration, early fullness on reflux and fatigue on age. Each explanation is reasonable on its own, and together they hide one system that can be measured directly in twenty minutes. Testing also has to separate a nerve problem from an artery problem, which is why the vascular study runs in the same appointment.
How is dysautonomia diagnosed?
Autonomic testing records heart rate and pulse waveform at rest and during three standardized challenges: deep timed breathing, standing up, and a brief controlled exhale against resistance. The size and timing of each response is the measurement. The test shows how the system behaves; naming the syndrome, such as dysautonomia, is a clinical judgment made on top of those results.
What causes dysautonomia?
Many conditions can. Diabetes, kidney disease, thyroid failure, hepatitis, Parkinson’s disease, medications and simple deconditioning all produce overlapping patterns on autonomic testing. That is why the test cannot name the cause by itself. It measures how each branch of the system responds; finding the cause is the clinical work that follows.
Medically reviewed by Dr. Gurpreet Singh Padda, MD, MBA, MHP, medical director of Measura. Last reviewed .