POTSWhat Causes POTS? Subtypes, Triggers and What the Evidence Shows
The mechanisms researchers describe in POTS (low blood volume, hyperadrenergic, neuropathic, autoimmune, deconditioning), the conditions linked to it, and how strong the evidence is for each.
No single cause explains POTS. Experts describe several overlapping mechanisms, and one person can have more than one. The 2019 NIH consensus calls these categories neither fully inclusive nor mutually exclusive.
The main mechanisms
WHERE IT ACTS: LEG AND BELLY BLOOD VESSELS
Nerves that tell these vessels to tighten work poorly, so blood pools.
At least half of 152 Mayo patients had a sweat test pattern that fits.
Evidence: described in consensus statements152 MAYO CLINIC PATIENTS
Fluid and salt strategies target low blood volume. The autoimmune evidence conflicts: commercial antibody tests did not reliably show autoimmunity in the larger 2022 study, so autoimmune POTS remains a research hypothesis for most patients. Rebuilding fitness helps many people, which is why reconditioning exercise features in treatment plans. The 2015 HRS statement lists hypervigilance as a contributor in some patients, and the heart rate changes remain measurable.
Triggers people describe
Clinic cohorts often report viral illness (including COVID-19, see the long COVID guide), surgery, pregnancy, concussion and rapid growth in adolescence. Cause and effect is hard to prove.
Conditions that travel with POTS
- Met hEDS criteria (31%)
- Hypermobile without hEDS (24%)
- Neither
- Hypermobile Ehlers-Danlos syndrome and joint hypermobility. The NIH panel estimates 20 to 30%. The link holds up, and the reason for it remains unknown.
- Mast cell activation. A 2021 study of 69 patients found 42% with symptoms and a lab marker that fit, without a control group. A 2025 systematic review found no study that met its criteria to confirm the link. Treat it as unproven.
- Migraine, irritable bowel symptoms and chronic fatigue commonly co-occur. Mention them to your doctor.
Why subtype labels matter less than they sound
Subtype names guide research. Clinics start with measures that help most people (fluids, salt, compression, exercise) and add medicines by symptom. Read the treatment overview next.
This page informs and does not diagnose. Only a clinician who can examine you and see your whole history can interpret your numbers.
- Vernino S, et al. Auton Neurosci. 2021;235:102828
- Thieben MJ, et al. Mayo Clin Proc. 2007;82:308-313
- Sheldon RS, et al. Heart Rhythm. 2015;12:e41-e63
- Hall J, Bourne KM, Vernino S, et al. Detection of G protein-coupled receptor autoantibodies in postural orthostatic tachycardia syndrome using standard methodology. Circulation. 2022;146:613-622
- Miller AJ, Stiles LE, Sheehan T, et al. Prevalence of hypermobile Ehlers-Danlos syndrome in postural orthostatic tachycardia syndrome. Auton Neurosci. 2020;224:102637
- Kohno R, Cannom DS, Olshansky B, et al. Mast cell activation disorder and postural orthostatic tachycardia syndrome: a clinical association. J Am Heart Assoc. 2021;10:e021002
- Farley M, Estrada-Mendizabal R, Gansert A, Voelker D, et al. Prevalence of mast cell activation disorders and hereditary alpha tryptasemia among patients with POTS and EDS: a systematic review. Ann Allergy Asthma Immunol. 2025;135:97-102
- What Is POTS? A Plain-Language Explanation
- How to Test for POTS at Home: The 10-Minute Stand Test
- POTS Symptoms: The Common Ones and What They Mean
- How POTS Is Diagnosed: Criteria, Stand Test and Tilt Table
- NASA Lean Test for POTS: How to Do It at Home
- Do I Have POTS? What to Check Before You See a Doctor
- Tests to Ask For When You Suspect POTS
- Why Does My Heart Race When I Stand Up?
- POTS Heart Rate: How to Graph It with Apple Watch
- Orthostatic Intolerance: Types and How POTS Fits In
- Why Blood Pressure Matters in a POTS Stand Test
- What Is Dysautonomia, and How Does It Relate to POTS?
- POTS and Long COVID: What the Research Shows
- POTS in Teens, Young Adults and During Pregnancy
- POTS Treatment Overview: What Guidelines Recommend First
- Fluids and Salt for POTS: What the Trials Show
- Compression and Exercise for POTS: Two First-Line Treatments
- POTS Medications: What Each One Does and What the Trials Show
- Living With POTS: Triggers, Pacing, Heat, Meals and Sleep
Want a record to bring to your visit? The POTS app guides the stand test at home and graphs your heart rate. See the app