Postural Orthostatic Tachycardia Syndrome (POTS) does not have a single clear cause; instead, it seems to arise from several overlapping problems affecting the autonomic nervous system, blood volume, and the body’s stress responses.

What POTS Is

  • POTS is a syndrome where the heart rate rises abnormally (typically 30+ beats per minute in adults) within about 10 minutes of standing, often without a big drop in blood pressure.
  • It is thought to result from malfunction of the autonomic nervous system, which normally controls heart rate, blood vessel tone, and blood flow automatically.

Main Mechanisms Linked to POTS

  • Autonomic dysfunction: The nerves that control vessel constriction do not work properly, so blood pools in the legs and abdomen when standing, and the heart races to compensate.
  • Low blood volume (hypovolemia): Many people with POTS have less circulating blood than normal, which makes it harder to keep blood pressure stable when upright.
  • Neuropathic POTS: Damage to small nerve fibers that regulate blood flow in the limbs and abdomen can impair normal constriction of blood vessels on standing.
  • Hyperadrenergic POTS: Some patients have high levels of norepinephrine (a stress hormone) when upright, leading to exaggerated “fight-or-flight” responses and tachycardia.
  • Deconditioning: Long periods of illness or bed rest may weaken the cardiovascular system and contribute to POTS physiology in some people.

Triggers and Associated Conditions

POTS is often “secondary” to or triggered by other conditions or events rather than appearing in isolation.

Commonly reported triggers or associations include:

  • Infections and immune triggers
    • Viral illnesses such as mononucleosis, Epstein–Barr virus, Lyme disease, hepatitis C, and more recently SARS‑CoV‑2 (COVID‑19).
* Symptom onset after COVID infection or, in some reports, after COVID vaccination in previously healthy individuals.

* Post‑infectious autoimmune reactions are suspected in many cases.
  • Autoimmune and inflammatory diseases
    • Conditions like SjĂśgren’s syndrome, lupus, celiac disease, autoimmune autonomic ganglionopathy, sarcoidosis, and antiphospholipid syndrome are more common in people with POTS.
  • Connective tissue and genetic conditions
    • Ehlers–Danlos syndrome (especially hypermobile type), which affects collagen and can lead to stretchy veins and joint hypermobility.
* Other genetic or mitochondrial disorders that affect energy and vascular regulation.
  • Neurological and structural issues
    • Small fiber neuropathy affecting autonomic nerves.
* Conditions like Chiari malformation or multiple sclerosis in some patients.
  • Hormonal, hematologic, and metabolic factors
    • Anemia and certain vitamin deficiencies (for example B12 or iron) have been linked in subsets of patients.
* Diabetes or prediabetes, which can damage autonomic nerves over time.
  • Physical stressors and life events
    • Major surgery, physical trauma, concussion or head injury, pregnancy, and the onset of puberty are all reported as common starting points for POTS symptoms.
* Bodily trauma or serious illness may “flip” the nervous system into a persistent high‑alert state (persistent sympathetic activation), which then fails to reset.

Subtypes of POTS

Clinicians sometimes group POTS into subtypes based on predominant features.

  • Neuropathic POTS: Emphasis on partial autonomic neuropathy with blood pooling in the lower body.
  • Hypovolemic POTS: Marked by low blood volume and often low renin–aldosterone activity.
  • Hyperadrenergic POTS: Characterized by high norepinephrine levels when standing and strong “fight‑or‑flight” symptoms.
  • Many patients show a mix of these patterns rather than one pure type.

Is Anxiety the Cause?

  • Older medical views often blamed POTS symptoms on anxiety, but modern data show POTS is not caused by anxiety.
  • While anxiety symptoms and POTS can overlap (racing heart, shakiness), mental health scores in POTS patients are often similar to or even better than population averages, and autonomic testing confirms a physiological problem.

Why the Cause Can Be Hard to Pin Down

  • POTS is a heterogeneous syndrome: many different underlying problems can produce a similar symptom pattern of orthostatic intolerance and tachycardia.
  • In a significant number of people, no single clear cause is found, and the condition is labeled “idiopathic POTS” (of unknown origin), even though several mechanisms may still be involved.

Important note: POTS is complex and varies a lot from person to person. This information is not a diagnosis or medical advice. Anyone with suspected POTS symptoms (such as severe dizziness, rapid heartbeat or near‑fainting on standing) should discuss them with a clinician familiar with autonomic disorders for proper evaluation and individualized guidance.

Information gathered from public forums or data available on the internet and portrayed here.