What is orthostatic intolerance, and what are its main forms?
What orthostatic intolerance covers, and how POTS, orthostatic hypotension and reflex syncope differ according to the published criteria.
- 6 sources
- 4 min read
- Clinical review
- Verified 9 November 2026
Key points
- Orthostatic intolerance refers to symptoms or a physiological difficulty linked to standing upright, often relieved by lying back down; it describes a phenomenon, not a single diagnosis [1, 2].
- Classic orthostatic hypotension is defined as a sustained fall in systolic blood pressure of at least 20 mmHg or in diastolic blood pressure of at least 10 mmHg within three minutes of standing up, measured in a standardized clinical setting; it is not a self-test [3, 1].
- POTS combines chronic orthostatic intolerance with an excessive rise in heart rate on standing, without sustained orthostatic hypotension meeting the classic thresholds; the thresholds depend on age and on the reference document [2, 3, 4].
- Reflex syncope (including vasovagal syncope) is a transient loss of consciousness caused by a fall in blood pressure and/or heart rate; it is not the same as POTS [3, 1].
Definition of orthostatic intolerance
Orthostatic hypotension
POTS
Reflex syncope and vasovagal syncope
Why are these entities not interchangeable?
Guidelines and geographic scope
References and level of evidence
- Thijs RD et al. Recommendations for tilt table testing and other provocative cardiovascular autonomic tests in conditions that may cause transient loss of consciousness: Consensus statement of the European Federation of Autonomic Societies (EFAS) endorsed by the American Autonomic Society (AAS) and the European Academy of Neurology (EAN). Clinical Autonomic Research, 31(3):369–384 2021. DOI: 10.1007/s10286-020-00738-6. PMID: 33740206.(guideline or consensus)Limitations: The authors state that this is not a formal evidence-based guideline. Technical recommendations; does not replace the overall clinical assessment. Population: provocative tests for syncope, OH and related presentations. Read: full text (Leiden University repository).Declared conflicts of interest: Several authors declare fees or industry funding outside the submitted work (Medtronic, UCB, Novo Nordisk, Boston Scientific…)
- Raj SR, Fedorowski A, Sheldon RS. Diagnosis and management of postural orthostatic tachycardia syndrome. CMAJ, 194(10):E378–E385 2022. DOI: 10.1503/cmaj.211373. PMID: 35288409.(evidence synthesis)Limitations: Narrative review; recommendations and treatment data limited by the available trials. Population: clinical review of POTS diagnosis and management; criteria and differential diagnosis. Read: full text (cmaj.ca).Declared conflicts of interest: All three authors declare research funding, fees or consulting activities; Raj and Sheldon also declare expert-witness work or patents
- Brignole M et al.; ESC Scientific Document Group. 2018 ESC Guidelines for the diagnosis and management of syncope. European Heart Journal, 39(21):1883–1948 2018. DOI: 10.1093/eurheartj/ehy037. PMID: 29562304.(guideline or consensus)Limitations: Guideline focused on syncope; 2018 version. Population: patients with syncope/transient loss of consciousness. Read: full text.Declared conflicts of interest: Not reviewed in the part of the source that was read
- Sivakoti K, Cortez MM, Fedorowski A, Fudim M, Lau DH, Novak P, Rowe PC, Schofield JR, Blitshteyn S, International POTS and Dysautonomia Expert Panel. Postural orthostatic tachycardia syndrome (POTS) and dysautonomia: International multidisciplinary expert consensus. American Journal of Medicine 2026. DOI: 10.1016/j.amjmed.2026.08.012. PMID: 42665152.(guideline or consensus)Limitations: Expert consensus; does not replace clinical studies or comparative trials. Population: international Delphi consensus, adults and children, POTS and non-POTS dysautonomia. Read: abstract.Declared conflicts of interest: Not visible in the abstract consulted
- Cortez MM, Cook G, Miglis MG, Raj SR, Robbins NM, Singer W, Sletten DM, Stino AM, Vernino S. Utility and best practices for clinical diagnostic testing of the autonomic nervous system: A Consensus Statement Endorsed by the American Autonomic Society and the American Association of Neuromuscular & Electrodiagnostic Medicine. Clinical Autonomic Research 2026. DOI: 10.1007/s10286-026-01238-9. PMID: 42766240.(guideline or consensus)Limitations: Expert consensus; not a comparative trial of all strategies. Population: specialist consensus, autonomic testing. Read: full text (open access, Springer).Declared conflicts of interest: Several authors declare consulting activities or industry funding (including Argenx, CSL Behring, Takeda); others declare none
- Raj SR, Guzman JC, Harvey P, Richer L, Schondorf R, Seifer C, Thibodeau-Jarry N, Sheldon RS. Canadian Cardiovascular Society Position Statement on Postural Orthostatic Tachycardia Syndrome (POTS) and Related Disorders of Chronic Orthostatic Intolerance. Canadian Journal of Cardiology, 36(3):357–372 2020. DOI: 10.1016/j.cjca.2019.12.024. PMID: 32145864.(guideline or consensus)Limitations: Consensus/position statement; several recommendations rest on weak to moderate evidence. Population: Canadian position statement on POTS and chronic orthostatic intolerance disorders. Read: abstract.Declared conflicts of interest: Not reviewed in the part of the source that was read