What Is POTS? A Plain-Language Guide to Postural Orthostatic Tachycardia Syndrome

POTS stands for postural orthostatic tachycardia syndrome. In plain terms: when you stand up, your heart rate climbs far more than it should, and you feel unwell because of it.

That is the whole definition. Everything else is detail about why it happens, how it is measured, and what makes it better.

If you have landed here because someone mentioned POTS and you are trying to work out whether it fits, this page is written to be read in one sitting, without medical training.

🫀 What is actually happening

Standing up is a small crisis your body solves several hundred times a day without telling you. Gravity pulls roughly half a litre of blood down into your legs and abdomen the moment you get upright. Less blood returns to your heart, so less goes out to your brain.

In most people the autonomic nervous system fixes this in seconds: blood vessels in the legs tighten, the heart rate rises slightly, and blood pressure holds steady.

In POTS that correction does not work properly. The vessels do not tighten enough, or the blood volume is too low, or the nervous system overshoots. The heart compensates the only way it can, by beating much faster. That racing heart is not the disease. It is your body's emergency response to a problem further upstream.

This matters because it explains why the symptoms are so much wider than a fast pulse: fatigue, brain fog, nausea, breathlessness, shaking, temperature swings. All of it follows from a circulation that does not adjust properly to being upright.

📏 How it is measured

The diagnostic criteria are unusually concrete for a condition this contested.

• A sustained heart rate rise of at least 30 bpm within ten minutes of standing, in adults.

• At least 40 bpm in adolescents, which is a different threshold and one that gets missed. Our guide to POTS in teens covers why a young person can look borderline against the wrong number.

• Without a significant drop in blood pressure. That absence is what separates POTS from orthostatic hypotension, and it is why a doctor checking only blood pressure can miss it entirely.

• Symptoms present for at least three months, and worse on standing.

The measurement is usually done with a tilt-table test or an active stand test. Both are described in our guide to the diagnostic tests, which is medically reviewed.

POTS is also a diagnosis of exclusion. Anaemia, thyroid problems, dehydration and cardiac causes all produce a fast heart rate on standing. Bloodwork is not your doctor doubting you. It is the step that makes the answer trustworthy.

🩺 What it feels like day to day

The symptom that gets named is the racing heart. The symptoms that actually shape someone's life are usually these:

• Dizziness and near-fainting on standing, in showers, in queues.

• Fatigue that rest does not fix, because staying upright is costing energy all day.

• Brain fog, which is a real and documented feature rather than a figure of speech.

• Nausea and early fullness, since digestion also depends on blood flow.

• Heat intolerance, because warmth dilates the vessels that were already not tightening enough.

• Symptoms worse in the morning, which has a specific physiological explanation.

One pattern is worth knowing because it is counter-intuitive: standing still is usually worse than walking. Walking runs the calf muscle pump that returns blood upward. Standing in a queue switches it off.

🔗 Want more like this? Browse all our POTS guides →

😟 Why it gets called anxiety

Because the symptoms overlap almost completely. Racing heart, breathlessness, shakiness, nausea. Anxiety is a legitimate thing to assess, and the two can genuinely coexist.

What separates them is posture. POTS symptoms track standing up and ease on lying down, and they frequently arrive while the person is perfectly calm. Anxiety does not follow gravity. Our guide to POTS versus anxiety goes through this in full.

Being unwell and disbelieved for a year is also a reasonable way to become anxious. Treating that does not mean the POTS was imaginary.

👥 Who gets it

POTS affects an estimated one to three million people in the United States alone, and it is diagnosed most often between the teenage years and the mid-thirties. In adults it is far more common in women, roughly four to one.

It frequently begins after a trigger: a viral infection, surgery, pregnancy, or a period of prolonged bed rest. Post-viral onset has become considerably more visible in recent years.

It also travels with other conditions often enough to have a nickname. POTS, hypermobile Ehlers Danlos syndrome and mast cell activation syndrome co-occur so regularly that the combination is called the trifecta.

🌱 What actually helps

Management is built in layers, and the unglamorous layers do most of the work.

• Fluid and salt. Increasing both raises blood volume, which is the variable most directly at fault. Amounts should be set by your doctor, particularly if you have kidney or blood pressure conditions. Our guide to salt and electrolytes covers what to look for on a label.

• Compression. Waist-high garments outperform knee-high ones, because most of the pooling happens in the abdomen rather than the calves. How to choose one is its own guide.

• Graded, recumbent-first exercise. Rowing, recumbent cycling and swimming build the leg and core muscles that pump blood upward, without the orthostatic cost of upright exercise. This must be progressed slowly and ideally supervised.

• Counter-manoeuvres. Crossing your legs, rising onto your toes, leaning on a trolley. Small, invisible, and they work in the moment.

• Medication, where the above is not enough. There are several classes used, and which one suits depends on the subtype. That is a conversation with a cardiologist or autonomic specialist rather than something to research alone.

🔭 Does it go away

Sometimes, and more often in younger people. Adolescent-onset POTS is generally regarded as having a better trajectory, with many improving substantially over a period of years.

In adults the more common picture is a condition that becomes manageable rather than one that disappears. That is a real distinction, and it is worth hearing honestly rather than being promised a recovery nobody can guarantee.

❓ Frequently asked questions

📚 Sources and further reading

The information in this article is drawn from the following sources. We encourage you to explore them, and to have any suspected POTS assessed by a qualified clinician.

• Dysautonomia International: Postural Orthostatic Tachycardia Syndrome

• Cleveland Clinic: Postural Orthostatic Tachycardia Syndrome (POTS)

• Johns Hopkins Medicine: Postural Orthostatic Tachycardia Syndrome

• NHS: Postural tachycardia syndrome (PoTS)