What Is Dysautonomia? POTS, Vasovagal Syncope, and Autonomic Dysfunction, Defined

Short Answer

Dysautonomia is an umbrella term for problems with the autonomic nervous system — the part of your nervous system that runs “automatic” body functions you do not consciously control, including heart rate, blood pressure, blood-vessel tightening and widening, digestion, sweating, temperature regulation, and breathing patterns. When this system misfires, your body may have trouble keeping blood flow, pulse, blood pressure, gut function, or temperature steady. POTS and vasovagal syncope are two specific conditions within that broader dysautonomia family, not separate “opposites” of dysautonomia. (my.clevelandclinic.org)

In that family, POTS “is defined by chronic orthostatic intolerance accompanied by an excessive increment in sinus heart rate on standing in the absence of significant orthostatic hypotension” (Chopra, Frontiers in Neurology, 2026). In plain language: with POTS, standing up triggers an abnormal heart-rate response and symptoms such as dizziness, racing heart, fatigue, shakiness, brain fog, or feeling like you may faint; the pattern is tied to being upright and is assessed with heart-rate and blood-pressure changes over time. Consensus-based reviews commonly describe the adult heart-rate threshold as a sustained rise of at least 30 beats per minute within 10 minutes of standing or tilt, with a higher threshold — at least 40 beats per minute — for adolescents ages 12–19, and without sustained orthostatic hypotension. (my.clevelandclinic.org)

Vasovagal syncope is different: it is a reflex fainting response. A trigger — pain, fear, heat, standing too long, seeing blood, dehydration, or another stressor — can make the autonomic nervous system overreact. Heart rate and blood pressure may drop suddenly, blood flow to the brain falls for a short time, and you pass out. (my.clevelandclinic.org)

So the shortest definition is: dysautonomia means autonomic nervous system dysfunction; POTS is one dysautonomia pattern where standing causes excessive heart-rate increase and orthostatic symptoms; vasovagal syncope is another pattern where an autonomic reflex causes a sudden blood-pressure/heart-rate drop and fainting.

What is dysautonomia? (definition)

A plain dysautonomia definition is this: dysautonomia means your autonomic nervous system is not regulating automatic body functions the way it should. This system helps run the things you do not usually have to think about — heart rate, blood pressure, breathing, digestion, sweating, body temperature, bladder function, and how your pupils respond to light. When those signals are disrupted, symptoms can show up in more than one part of the body, which is why dysautonomia can feel confusing or “whole-body” rather than limited to one organ. (ninds.nih.gov)

Dysautonomia is not just one disease. It is an umbrella term for disorders that affect autonomic function. In some people, it is primary, meaning it happens on its own. In others, it is secondary, meaning it is linked to another condition, infection, medication effect, nerve disorder, autoimmune disease, connective tissue disorder, or another medical cause. That distinction matters because care often depends on what is driving the autonomic dysfunction. (my.clevelandclinic.org)

In everyday terms, dysautonomia can mean the body has trouble making smooth automatic adjustments. For example, standing up may require quick changes in blood vessel tone, heart rate, and blood pressure so enough blood reaches the brain. Digestion may require coordinated nerve signals between the gut and the brain. Temperature control may require sweating and blood-flow changes. If the autonomic system misfires, overreacts, underreacts, or sends signals at the wrong time, you may feel symptoms such as dizziness, fainting, palpitations, nausea, abnormal sweating, fatigue, “brain fog,” or trouble tolerating heat or standing — but the exact pattern depends on the type of dysautonomia and the person. (my.clevelandclinic.org)

So when clinicians use the term dysautonomia, they are usually describing a problem with regulation, not saying there is one single test result or one single symptom that proves it. The next step is usually to look at the pattern: what symptoms happen, what triggers them, how heart rate and blood pressure respond to posture or stress, and whether there is an underlying condition that could explain the autonomic dysfunction. (my.clevelandclinic.org)

What is autonomic dysfunction? (definition)

Autonomic dysfunction means your autonomic nervous system isn’t regulating body functions the way it should. In everyday language, it’s very close to dysautonomia: a problem with the “automatic” nervous-system controls that help manage heart rate, blood pressure, breathing, sweating, digestion, body temperature, bladder function, and other processes you don’t usually have to think about. Cleveland Clinic describes dysautonomia as a group of disorders that disrupt the autonomic nervous system, and notes that “autonomic dysfunction” is another, less common name for it. (my.clevelandclinic.org)

Your autonomic nervous system has several main branches. The sympathetic nervous system helps activate your body — for example, raising alertness, tightening blood vessels, and supporting a fight-or-flight response. The parasympathetic nervous system helps settle the body back down — supporting rest-and-digest functions. The enteric nervous system helps coordinate digestion. When these systems don’t communicate or respond normally, symptoms can show up in many different places, because the autonomic nervous system connects the brain, heart, blood vessels, gut, sweat glands, bladder, and more. (my.clevelandclinic.org)

So if someone says “autonomic dysfunction,” they may mean either:

• a broad body-state — the autonomic nervous system is not working or coordinating normally; or

• a dysautonomia diagnosis category — an umbrella term that can include conditions such as POTS, vasovagal syncope, orthostatic intolerance, autonomic neuropathy, or other autonomic disorders.

Johns Hopkins describes dysautonomia as an umbrella term for disorders of the autonomic nervous system and defines autonomic dysfunction as a state where the autonomic nervous system is not functioning and communicating between organ systems as expected. It also notes that autonomic dysfunction can appear in dysautonomia, but may also occur in other medical contexts, such as diabetes, neurodegenerative disorders, or inflammatory and autoimmune conditions. (hopkinsmedicine.org)

The important part: autonomic dysfunction is not one single symptom and not one single disease. It’s a way of describing a regulation problem. One person may mainly feel lightheaded when standing. Another may have fainting, racing heart, gut symptoms, abnormal sweating, heat intolerance, bladder issues, or fatigue. The pattern matters, the trigger matters, and the diagnosis depends on a clinician’s history, exam, and — when needed — autonomic or cardiovascular testing.

What is POTS?

POTS — postural orthostatic tachycardia syndrome — is a form of dysautonomia and orthostatic intolerance. In plain language, your autonomic nervous system is supposed to adjust blood-vessel tone and heart rate when you move upright. In POTS, that adjustment overshoots: standing triggers an excessive, sustained heart-rate rise, and symptoms tend to appear or worsen when you are upright.

The commonly used diagnostic definition is a sustained heart-rate increase of ≥30 beats per minute within 10 minutes of standing or head-up tilt in adults, or ≥40 beats per minute in adolescents, without significant orthostatic hypotension — meaning the heart rate rises too much without the blood pressure drop that defines orthostatic hypotension. The 2015 Heart Rhythm Society expert consensus describes POTS as a clinical syndrome with orthostatic symptoms, this heart-rate rise, and absence of orthostatic hypotension; Johns Hopkins gives the same adult/adolescent heart-rate thresholds for the first 10 minutes upright. (pmc.ncbi.nlm.nih.gov)

That definition matters because POTS is not just “a fast heart rate.” The fast rate is tied to posture. Your body is reacting to being upright — often because blood return, vessel tightening, nervous-system signaling, blood volume, or several of these systems are not coordinating smoothly. Many people describe lightheadedness, palpitations, fatigue, shakiness, nausea, blurred vision, exercise intolerance, or “brain fog,” but the exact symptom mix varies. (pmc.ncbi.nlm.nih.gov)

POTS also sits inside a bigger family of terms. Dysautonomia is the broad umbrella: the autonomic nervous system is not regulating automatic body functions normally. Orthostatic intolerance describes the upright-position problem: you feel worse standing and better lying down. POTS is one specific pattern under that umbrella, defined by the posture-related heart-rate rise plus symptoms and the absence of significant orthostatic hypotension.

A clinician makes the diagnosis using history, orthostatic vital signs or tilt-table testing, and checks for other explanations such as dehydration, blood loss, medication effects, anemia, thyroid disease, or other conditions. For the step-by-step workup, see the dedicated [POTS diagnosis guide](/pots/pots-diagnosis/). For the broader symptom picture and possible triggers, see [POTS symptoms](/pots/pots-symptoms/) and [POTS causes](/pots/pots-causes/).

What is vasovagal syncope? (definition)

Vasovagal syncope means fainting from a reflex in your autonomic nervous system. A trigger — such as standing for a long time, heat, pain, emotional stress, seeing blood, or having blood drawn — makes the body overreact. Heart rate may slow, blood vessels may widen, blood pressure drops, and for a short time less blood reaches the brain. That brief drop in brain blood flow is what makes you pass out. It’s also called neurocardiogenic syncope or reflex syncope, and it’s the most common form of reflex fainting. (mayoclinic.org)

The key idea is the direction of the response. In vasovagal syncope, the problem is usually a sudden drop in blood pressure and/or heart rate that can end in fainting. In POTS, the defining pattern is different: symptoms happen with standing and are tied to an excessive rise in heart rate rather than a primary fainting reflex. The two can still overlap in real life — someone may have orthostatic intolerance, near-fainting, or even fainting episodes and need a clinician to sort out which mechanism is driving which symptoms. (hopkinsmedicine.org)

Vasovagal fainting is often not dangerous by itself, but the fall can cause injury, and fainting can sometimes point to heart, neurologic, metabolic, or other causes that need medical evaluation. Seek urgent care if fainting happens with chest pain, trouble breathing, a new neurologic symptom, a serious injury, exertion, pregnancy concerns, or if it is new, recurrent, or unexplained. (mayoclinic.org)

How they relate

Think of these words as different zoom levels on the same body system: the autonomic nervous system — the part that runs background jobs like heart rate, blood pressure, breathing, digestion, sweating, and blood-vessel tone without you having to think about them. Dysautonomia is the broad umbrella: something in that automatic regulation is not working as it should. Autonomic dysfunction is the plain-language description of that same problem. NINDS defines dysautonomia as a problem in the autonomic nervous system, which controls involuntary functions such as heartbeat and blood pressure. (ninds.nih.gov)

Under that umbrella, POTS and vasovagal syncope describe different patterns. In POTS, the main pattern is orthostatic: when you move upright, your heart rate rises too much, while a major blood-pressure drop is not supposed to be the defining feature. The 2015 Heart Rhythm Society consensus describes POTS as symptoms with standing plus a sustained heart-rate rise — commonly ≥30 bpm in adults or ≥40 bpm in ages 12–19 — in the absence of orthostatic hypotension. (pmc.ncbi.nlm.nih.gov)

Vasovagal syncope is more of a reflex fainting pattern. A trigger — pain, blood, needles, heat, prolonged standing, emotional stress, dehydration, or sometimes no obvious trigger — can make the autonomic response overshoot. Heart rate and/or blood pressure drop, blood flow to the brain falls briefly, and you faint or nearly faint. Cleveland Clinic describes vasovagal syncope as the most common type of reflex syncope, and Johns Hopkins describes reflex syncope as a trigger-driven response in which the heart slows or blood vessels widen, lowering blood pressure and brain blood flow. (my.clevelandclinic.org)

One important nuance: these labels are related, but they do not always replace each other. A person can have POTS symptoms without fainting. A person can have vasovagal syncope without meeting POTS criteria. And the two can overlap — the Heart Rhythm Society consensus notes that POTS and vasovagal syncope are not mutually exclusive. (pmc.ncbi.nlm.nih.gov)

Types of dysautonomia

Dysautonomia is not one single disease. It is an umbrella term for problems in the autonomic nervous system — the wiring that helps control blood pressure, heart rate, sweating, digestion, bladder function, temperature regulation, and other “automatic” body processes. Clinicians often sort dysautonomia into primary forms, where the autonomic disorder is the main condition, and secondary forms, where autonomic dysfunction happens because of another illness, injury, medication effect, infection, or nerve damage. (my.clevelandclinic.org)

You may see searches like “what are the 15 types of dysautonomia,” but there is no single universal 15-item list used by every clinic. The main recognized types and related autonomic disorders include:

• Postural orthostatic tachycardia syndrome — POTS. A form of orthostatic intolerance where standing triggers an exaggerated heart-rate response with symptoms such as dizziness, fatigue, palpitations, brain fog, shakiness, or near-fainting. (my.clevelandclinic.org)

• Neurocardiogenic syncope / vasovagal syncope. A common fainting reflex. The nervous system overreacts to a trigger — such as standing, heat, pain, blood, dehydration, or emotional stress — and blood pressure and/or heart rate drop enough that the brain briefly gets less blood flow. (my.clevelandclinic.org)

• Orthostatic hypotension. A blood-pressure drop after standing. It can make you feel lightheaded, weak, blurry-visioned, or faint because the body is not tightening blood vessels and maintaining blood flow quickly enough when gravity pulls blood downward. (my.clevelandclinic.org)

• Orthostatic intolerance. A broader term for symptoms that get worse upright and improve when you lie down. POTS, orthostatic hypotension, and some fainting disorders can sit under this umbrella. (my.clevelandclinic.org)

• Multiple system atrophy — MSA. A rare, progressive neurodegenerative disease that affects movement and autonomic control. Autonomic problems may include orthostatic hypotension, urinary issues, bowel changes, sweating changes, and blood-pressure problems when lying down. (mayoclinic.org)

• Pure autonomic failure — PAF. A primary autonomic disorder where autonomic nerves gradually fail, often causing neurogenic orthostatic hypotension, reduced sweating, urinary changes, and sometimes high blood pressure while lying down. (dysautonomiainternational.org)

• Autonomic neuropathy. Damage to autonomic nerves. Diabetes is one common cause; autonomic neuropathy can affect digestion, bladder function, sexual function, sweating, pupils, heart rate, and blood-pressure control. (diabetes.org)

• Diabetic autonomic neuropathy. A diabetes-related form of autonomic nerve damage. It can show up as gastroparesis-like digestive symptoms, bladder problems, erectile dysfunction, reduced warning signs of low blood sugar, sweating changes, or dizziness and fainting when standing. (diabetes.org)

• Familial dysautonomia — FD / Riley-Day syndrome / HSAN type III. A rare inherited disorder that affects the development and survival of autonomic and sensory nerve cells. It often begins in infancy and can affect feeding, tears, temperature regulation, pain and temperature sensation, blood pressure, balance, breathing, and digestion. (medlineplus.gov)

• Autoimmune autonomic ganglionopathy — AAG. A rare immune-mediated autonomic disorder in which the body interferes with autonomic nerve signaling. It can cause widespread autonomic failure, including severe orthostatic hypotension, dry mouth or eyes, bladder and bowel problems, and sweating changes. (my.clevelandclinic.org)

• Baroreflex failure. A rare disorder of the blood-pressure sensing reflex. Because the body loses part of its normal “buffer” against pressure swings, people can have extreme blood-pressure lability — surges of high blood pressure, drops of low blood pressure, and abnormal heart-rate responses. (pmc.ncbi.nlm.nih.gov)

• Autonomic dysreflexia. A dangerous autonomic reaction most often associated with spinal cord injury. A trigger below the level of injury — such as bladder or bowel irritation — can cause sudden high blood pressure and other symptoms, so it needs urgent medical attention. (my.clevelandclinic.org)

• Secondary dysautonomia from other conditions. Autonomic dysfunction can also occur with conditions such as Parkinson’s disease, autoimmune disease, amyloidosis, Sjögren’s syndrome, lupus, Guillain-Barré syndrome, vitamin deficiencies, infections, toxins, spinal cord injury, traumatic brain injury, and long COVID. In these cases, the autonomic symptoms are part of a larger medical picture rather than a stand-alone diagnosis. (my.clevelandclinic.org)

The important point is that the type matters. Two people can both say “I have dysautonomia” and mean very different things: one may have POTS with upright tachycardia, another may have diabetic autonomic neuropathy affecting digestion and blood pressure, and another may have a progressive autonomic failure syndrome. That is why diagnosis usually focuses on the pattern: what changes when you stand, what happens to heart rate and blood pressure, which body systems are involved, what conditions you already have, and whether symptoms are stable, relapsing, or progressive.

How is dysautonomia diagnosed and treated? (overview)

Dysautonomia is usually diagnosed by putting together your story, your exam, and tests that show how your autonomic nervous system reacts under stress — especially posture change. A clinician will typically ask what happens when you stand, eat, get hot, exercise, faint, or feel your heart race; review medications and other conditions; check vital signs; and look for patterns that point to a specific type of autonomic dysfunction rather than “dysautonomia” as one single disease. Cleveland Clinic describes diagnosis as often involving a medical history, exam, and tests such as tilt table testing, blood tests, and other evaluations depending on the suspected cause. (my.clevelandclinic.org)

For orthostatic forms — symptoms that appear or worsen upright — the key question is often: what happens to your heart rate and blood pressure when your body moves from lying down to standing? That can be checked with orthostatic vitals, a 10-minute standing test, or a head-up tilt table test. Johns Hopkins notes that POTS can be diagnosed with a 10-minute standing test or head-up tilt table test, and its tilt-table overview explains that the test monitors ECG and blood pressure while posture is changed from lying down toward upright. (hopkinsmedicine.org)

Some people also need broader autonomic testing. That may include monitoring blood pressure and heart rhythm during breathing or Valsalva maneuvers, sweat testing, blood tests for catecholamines or other clues, skin biopsy when small-fiber neuropathy is suspected, or other specialty tests. NINDS describes autonomic evaluation as beginning with autonomic-focused history and physical examination, with testing that may monitor hemodynamics, sweating, orthostasis, catecholamines, skin biopsy, blood volume, pupils, gastrointestinal function, bladder function, and related measures when clinically appropriate. (ninds.nih.gov)

Treatment is not one-size-fits-all, because dysautonomia is an umbrella term. The plan depends on the condition underneath it — for example POTS, vasovagal syncope, autonomic neuropathy, medication-related autonomic dysfunction, or a neurodegenerative disorder — and on which symptoms are limiting your life. In practice, management often focuses on treating the underlying cause when one is found, reducing triggers, supporting blood pressure and circulation, improving daily function, and using condition-specific medications or rehabilitation when needed. Cleveland Clinic notes that treatment depends on the cause and may prioritize stopping or reversing a medication or treatment that triggered dysautonomia, while Johns Hopkins emphasizes that POTS treatment should be tailored to the individual because symptoms and underlying conditions vary widely. (my.clevelandclinic.org)

If your symptoms include fainting with injury, chest pain, severe shortness of breath, signs of stroke, a new irregular heartbeat, or a sudden “worst headache,” seek urgent medical care rather than trying to sort out autonomic symptoms on your own.

For more detail, see the dedicated diagnosis and treatment guides: [POTS diagnosis](/pots/pots-diagnosis/) and [POTS treatment](/pots/pots-treatment/).

Finding dysautonomia care in the US

There isn’t a single “best” dysautonomia clinic in the US for everyone. The right place depends on what your symptoms look like, what has already been ruled out, your insurance, travel limits, and whether you need cardiology, neurology, rehabilitation, or a more specialized autonomic testing lab.

A practical starting point is to look for clinicians who regularly evaluate autonomic disorders — often neurologists, cardiologists, electrophysiologists, or academic centers with autonomic or POTS programs. Dysautonomia can affect heart rate, blood pressure, sweating, digestion, temperature regulation, and other automatic body functions, so diagnosis often involves pattern-finding across systems rather than one simple test. Common workups may include a physical and neurological exam, orthostatic vitals, tilt-table or standing testing, heart testing, sweat testing such as QSART, and selected blood tests depending on the story. (my.clevelandclinic.org)

Use directories as a map, not as a ranking. Dysautonomia International has a Find a Doctor directory and notes that its list is not comprehensive, and that some clinicians may be better suited for certain autonomic conditions than others. That makes it useful for finding names to research — not for deciding who is automatically “the best.” (dysautonomiainternational.org)

When you compare options, ask concrete questions:

• Do they evaluate your main problem? For example: POTS, vasovagal syncope, orthostatic hypotension, small fiber neuropathy, autoimmune autonomic neuropathy, or another suspected cause.

• What testing can they do or order? A clinic that can measure heart rate and blood pressure responses to standing or tilt may be more useful than one that only reviews symptoms.

• Is care multidisciplinary? Some POTS and autonomic programs bring together cardiology, neurology, rehabilitation, physical therapy, and other fields because symptoms can cross body systems. (hopkinsmedicine.org)

• Will they coordinate with your local clinician? This matters if the specialist is far away or has a long waitlist.

• Do they treat adults, children, or both? Autonomic care is often age-specific.

• What does your insurance require? You may need a referral, prior authorization, or documentation of previous testing.

• How long is the wait, and what should you do meanwhile? Ask whether your primary care clinician can start basic evaluation, safety planning, or referrals while you wait.

Before the visit, bring a short symptom timeline, medication and supplement list, recent labs or ECGs, blood pressure/heart rate logs if you have them, and a list of triggers such as standing, heat, meals, dehydration, illness, or exertion. A clear record helps the clinician see the pattern your body is showing over time.

If you faint with injury, have chest pain, severe shortness of breath, new neurological symptoms, or symptoms that feel sudden and dangerous, don’t wait for a specialty appointment — seek urgent or emergency care.

When to see a doctor

Fainting is not something to “push through,” especially if it happens during exercise, causes an injury, or comes with chest pain, confusion, severe shortness of breath, or a heartbeat that feels unusually fast, slow, pounding, or irregular. Those symptoms can overlap with heart rhythm problems or other emergencies, so seek immediate medical attention — and if the symptoms are severe or you are unsure, call emergency services. (my.clevelandclinic.org)

You should also get checked if dizziness, lightheadedness when standing, palpitations, near-fainting, or fainting keeps happening, is new for you, or is getting worse. Dysautonomia can affect automatic body functions like heart rate and blood pressure, but similar symptoms can come from other causes, including heart, neurologic, medication-related, dehydration-related, or metabolic issues. A clinician can decide what work-up makes sense, such as orthostatic vitals, an ECG, heart rhythm monitoring, blood tests, or other testing based on your story. (my.clevelandclinic.org)

If you already have a diagnosis such as POTS, vasovagal syncope, or another form of dysautonomia, ask your healthcare provider for a clear “when to call / when to go in” plan. A good plan should spell out which symptoms are expected for you, which changes should trigger an office visit, and which signs mean urgent care or emergency care. (my.clevelandclinic.org)

How Welltory fits

Welltory can help you keep a clearer record of how your heart rate and body state change across the day — for example, after standing up, walking, resting, sleeping poorly, feeling stressed, or recovering from activity. That kind of context can be useful when you talk with a clinician about a dysautonomia-related question, because dysautonomia involves the autonomic nervous system — the system that helps regulate automatic functions like heart rate, blood pressure, sweating, digestion, and temperature control. (my.clevelandclinic.org)

This is especially relevant for conditions where posture matters. In POTS, for example, symptoms are linked to being upright and to an exaggerated heart-rate rise after moving from lying down to standing or during a tilt-table test. (hopkinsmedicine.org) Welltory is not a tilt-table test, an autonomic lab, or a diagnostic device. It cannot tell you whether you have POTS, vasovagal syncope, orthostatic hypotension, or another form of dysautonomia.

What it can do is give you a more organized “body diary” to bring into care: when symptoms tend to happen, what your heart rate looked like around those moments, how recovery changed after exertion, and whether certain triggers — heat, standing, meals, poor sleep, stress, or dehydration — seem to line up with how you feel. A clinician can then decide whether your story points toward orthostatic vitals, blood pressure checks, ECG, blood tests, autonomic testing, tilt-table testing, or another workup.

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