Postural orthostatic tachycardia syndrome (POTS) is a form of autonomic dysfunction that affects how the body regulates heart rate and blood flow when standing. It can cause dizziness, rapid heart rate, fatigue, and cognitive symptoms, and is increasingly recognised after viral infections including COVID.
For years, sufferers of POTS and related forms of orthostatic intolerance (OI) were told it was “all in their head.” But growing evidence shows these are real, often disabling conditions involving the nervous system, blood volume, and sometimes the immune system.
Standing Up Shouldn’t Hurt
When we stand, gravity pulls blood toward the legs. In a healthy person, the autonomic nervous system constricts blood vessels and keeps blood flowing to the brain.
In people with POTS, this system falters. Blood pools in the lower body. The heart races to compensate.
This leads to dizziness, palpitations, nausea, and fatigue.
It is not anxiety. It is measurable physiology and it can be life-changing.
What It Looks Like
Patients often describe:
- Light-headedness or near-fainting on standing
- Rapid heartbeat or palpitations
- Fatigue and brain fog
- Headaches or migraines
- Gastrointestinal issues such as nausea, bloating, constipation, or diarrhoea
- Temperature swings and sweating abnormalities
- Trembling or shakiness
- Sleep disturbance and anxiety-like symptoms (usually secondary)
Why It Happens
POTS is not a single disease. It is a syndrome with overlapping mechanisms:
- Neuropathic POTS: Damage to small autonomic nerve fibres prevents proper blood vessel constriction
- Hypovolaemic POTS: Low blood volume; increasing fluids and salt may help
- Hyperadrenergic POTS: Overactive sympathetic response causing palpitations and tremor
- Autoimmune mechanisms: Antibodies may interfere with autonomic receptors
- Deconditioning: Reduced cardiovascular response after illness or inactivity
Often, more than one mechanism is involved.
Comorbidities and Autoimmune Connections
POTS rarely exists in isolation. Associated conditions include:
- Hypermobility spectrum / Ehlers–Danlos syndrome (hEDS)
- Mast cell activation syndrome (MCAS)
- Small-fibre neuropathy
- Sjögren’s syndrome
- Systemic lupus erythematosus (SLE)
- Chronic fatigue syndrome / ME and Long Covid
Recognising these overlaps can guide treatment.
How It’s Diagnosed
GPs can screen using an active stand test:
- Rest lying down for 5–10 minutes
- Measure heart rate and blood pressure
- Stand and measure at 1, 3, 5, and 10 minutes
A diagnosis is typically considered when heart rate increases ≥30 bpm in adults (≥40 bpm in teenagers), without a significant drop in blood pressure.
Specialist tests may include tilt-table testing and autonomic function assessments.
Managing POTS
There is no universal cure, but many patients improve with a combination of strategies.
Lifestyle measures:
- Adequate hydration (2–3 litres daily)
- Increased salt intake under supervision
- Compression garments
- Avoiding prolonged standing and heat
- Gradual exercise, starting with recumbent activity
Medications (when needed):
- Fludrocortisone
- Midodrine
- Beta-blockers
- Ivabradine
- Pyridostigmine
- Clonidine
- Antihistamines (for MCAS overlap)
Treatment should be individualised and guided by a clinician.
Outlook
Some patients improve over time, particularly with early recognition and management. Others remain symptomatic but can maintain function with pacing and support.
Early diagnosis helps avoid years of misattribution to anxiety or stress.
Bottom Line
POTS and orthostatic intolerance are real, measurable conditions affecting multiple systems.
Understanding them helps patients regain control—and helps clinicians provide appropriate care.
FAQs
What is POTS?
A condition where heart rate increases abnormally when standing due to autonomic dysfunction.
Why does my heart race when I stand up?
Because blood pooling and impaired regulation require the heart to compensate.
Is POTS caused by anxiety?
No. While symptoms can feel similar, POTS is a physiological condition.
Can POTS improve over time?
Some people improve, especially with management and pacing.
What helps manage POTS symptoms?
Hydration, salt, compression, pacing, and sometimes medication.
Disclaimer
This article is for information and awareness only. It is not medical advice and should not replace professional assessment or treatment. Always consult a qualified healthcare professional before making changes to your care.
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