Postural Orthostatic Tachycardia Syndrome (POTS)

What POTS is

When you stand up, gravity pulls about 500 to 1,000 ml of blood into the legs and abdomen. Normally, the autonomic nervous system tightens blood vessels within seconds and nudges the heart rate up by 10 to 20 beats a minute to keep blood flowing to the brain.

In POTS, this adjustment does not work properly. Blood pools in the lower body, less returns to the heart, and the heart races to compensate. The brain may still receive less blood, causing lightheadedness and brain fog. Adrenaline surges add palpitations, tremor and anxiety-like feelings.

Subtypes

POTS is a syndrome with several overlapping mechanisms, not a single disease:

• Neuropathic POTS: damage to small nerves that tighten blood vessels in the legs.
• Hyperadrenergic POTS: high noradrenaline levels on standing, often with a rise in blood pressure, tremor and anxiety.
• Hypovolemic POTS: low blood volume.

Many people have features of more than one.

Symptoms of POTS

Symptoms appear or worsen when upright and improve when lying down:

• Lightheadedness or near-fainting.
• Racing heart or palpitations.
• Fatigue, often severe.
• Brain fog: trouble concentrating, finding words or thinking clearly.
• Shakiness and sweating.
• Blurred or tunnel vision.
• Headache.
• Nausea, bloating and other gut symptoms.
• Shortness of breath and chest discomfort.
• Exercise intolerance.
• Purple, mottled legs and feet on standing (blood pooling).
• Poor sleep.
• Feeling cold or heat intolerance.

Symptoms are often worse in the morning, after meals, in the heat, after prolonged standing, after illness, and around menstrual periods. Actual fainting occurs in a minority.

Causes and associated conditions

POTS often begins after a trigger:

• Viral infections, including COVID-19. POTS is a common feature of long COVID.
• Pregnancy, surgery or trauma.
• Prolonged bed rest and deconditioning.
• Puberty, in adolescents.

It is associated with:

• Ehlers-Danlos syndrome, hypermobile type, and joint hypermobility.
• Autoimmune conditions, such as celiac disease, Sjögren's syndrome and Hashimoto's thyroiditis.
• Mast cell activation disorders.
• Chronic fatigue syndrome (ME/CFS), which overlaps substantially.
• Migraine.

POTS is not a psychiatric disorder, although anxiety can coexist and the symptoms can resemble panic attacks.

How POTS is diagnosed

Diagnostic criteria for adults:

1. A sustained heart rate increase of 30 beats per minute or more within 10 minutes of standing (40 or more in ages 12 to 19).
2. No orthostatic hypotension (a blood pressure fall of 20/10 mmHg or more).
3. Symptoms of orthostatic intolerance for at least 3 months.
4. No other cause, such as dehydration, bleeding, medicines or an overactive thyroid.

Tests

• Active stand test (NASA lean test): heart rate and blood pressure are measured lying down and then every minute for 10 minutes standing. This can be done in a clinic.
• Tilt table test: you lie on a table that tilts upright while heart rate and blood pressure are monitored.
• Blood tests: blood count, iron and ferritin, thyroid function, electrolytes, morning cortisol and sometimes standing noradrenaline.
• ECG, echocardiogram and Holter monitor to rule out heart problems.
• Autonomic testing: sweat tests or skin biopsy for small fiber neuropathy, in specialist centers.

POTS vs similar conditions

POTS treatment

Treatment is individualized. Most people need several measures together, and improvement takes weeks to months.

Fluids and salt

• Drink about 2 to 3 liters (68 to 100 fl oz) of fluid a day.
• Drinking about 500 ml (16 fl oz) of water quickly before getting up helps morning symptoms.
• Increase salt intake as advised by your doctor, through food, broth, electrolyte drinks or salt tablets. This is not suitable if you have high blood pressure, heart failure or kidney disease.

Compression

Waist-high or abdominal compression garments (around 20 to 30 mmHg) reduce blood pooling. Knee-high socks are less effective.

Exercise reconditioning

A structured program is one of the most effective long-term treatments. Start with reclined or horizontal exercise, such as a recumbent bike, rowing machine or swimming, and core and leg strengthening. Build up gradually over about 3 months, adding upright exercise as tolerated. Expect symptoms to worsen briefly when starting.

Daily strategies

• Get up slowly, sitting for a minute before standing.
• Use counter-maneuvers when lightheaded: cross your legs and squeeze, clench buttocks, or squat.
• Raise the head of the bed slightly.
• Eat smaller, more frequent meals and limit refined carbohydrates, which can divert blood to the gut.
• Avoid long hot showers, saunas and prolonged standing.
• Limit alcohol, which widens blood vessels.

Medicines

Medicines are used when non-drug measures are not enough. None is FDA-approved specifically for POTS, so all are used off-label:

• Low-dose propranolol or ivabradine to slow the heart rate.
• Fludrocortisone to increase blood volume.
• Midodrine to tighten blood vessels.
• Pyridostigmine to enhance nerve signals.
• Desmopressin occasionally for short-term use.

Treatment of associated conditions, such as iron deficiency or mast cell disorders, can also help.

Outlook

Many people improve over time, especially teens and those whose POTS followed a viral illness. In one long-term study, most patients reported improvement within a few years. Others have ongoing symptoms that fluctuate. Symptoms can significantly affect school, work and daily life, so workplace or school adjustments, such as being able to sit and drink fluids, are often helpful.

Frequently asked questions

What are the main symptoms of POTS?

The main symptoms are lightheadedness, a racing or pounding heart, fatigue, brain fog, shakiness and nausea that start or worsen when you stand and improve when you lie down. Many people also have headaches, poor exercise tolerance, sleep problems and purple, mottled legs when standing.

How is POTS diagnosed?

A doctor measures your heart rate and blood pressure lying down and then standing for 10 minutes, or on a tilt table. POTS is diagnosed if your heart rate rises by 30 beats per minute or more (40 in teens) without a significant blood pressure drop, symptoms have lasted 3 months, and other causes are excluded.

What causes POTS?

There is no single cause. POTS often begins after a viral infection (including COVID-19), pregnancy, surgery or trauma. It is linked to small nerve damage, low blood volume, high adrenaline levels, deconditioning, and conditions such as hypermobile Ehlers-Danlos syndrome and autoimmune disease.

Can POTS go away?

It can improve significantly or resolve, particularly in young people and when POTS followed a viral illness. Many people see substantial improvement within a few years with fluids, salt, compression and exercise training. Others have long-term symptoms that come and go.

Is POTS dangerous?

POTS is not usually life-threatening, and it does not damage the heart. However, it can be very disabling and fainting can cause injuries. Chest pain, fainting during exercise, or a very fast heart rate at rest should be assessed promptly to rule out other heart conditions.

What helps POTS symptoms quickly?

Lying down with your legs raised, drinking about 500 ml (16 fl oz) of water quickly, and using counter-maneuvers such as crossing and squeezing your legs can ease symptoms within minutes. Compression garments and extra salt help through the day.