Why Is POTS So Often Missed or Misdiagnosed?
POTS symptoms can resemble many other conditions
Routine testing may be normal
The diagnostic clue may appear during standing
A patient may spend months or even years trying to understand why standing makes them feel sick.
They may describe a racing heart, dizziness, weakness, fatigue, brain fog, nausea, exercise intolerance, or a feeling that they might faint. Yet an electrocardiogram may be normal. Routine blood work may be unrevealing. A cardiac evaluation may not identify structural heart disease.
Some patients are told they are dehydrated, deconditioned, anxious, or simply need to exercise more.
Eventually, someone measures what happens when the patient goes from lying down to standing.
The heart rate rises substantially, symptoms appear or worsen, and suddenly the pattern begins to make sense.
So why is POTS misdiagnosis or delayed diagnosis so common?
There is no single explanation. Postural orthostatic tachycardia syndrome (POTS) is a multisystem disorder with symptoms that overlap with numerous other conditions. Symptoms may fluctuate, patients can look well during an office visit, and routine testing may not reproduce what happens when they remain upright.
Research suggests that diagnostic delays can be substantial. In a large survey of patients with POTS, participants reported seeing an average of seven physicians before diagnosis. Other research has reported a median diagnostic delay of approximately two years. In the large POTS survey, 77% of respondents reported encountering a physician who suggested that their symptoms were due to a psychiatric or psychological problem before the POTS diagnosis.
POTS is a pattern, not just a fast heart rate
POTS is a form of autonomic dysfunction characterized by orthostatic intolerance and an excessive increase in heart rate after becoming upright.
Consensus criteria generally require a sustained heart-rate increase of at least 30 beats per minute in adults within 10 minutes of standing or head-up tilt. For adolescents ages 12 to 19, the threshold is at least 40 beats per minute.
The heart-rate increase occurs without the sustained blood-pressure decrease that defines orthostatic hypotension.
But measuring heart rate alone is not enough.
Patients should also have chronic symptoms of orthostatic intolerance, and other conditions that could explain the tachycardia need to be considered.
That is one reason diagnosing POTS can be more complicated than simply looking for a particular number on a heart-rate monitor.
A routine office visit may miss what happens during standing
One of the simplest explanations for a missed POTS diagnosis is that the abnormality is postural.
A patient may have a relatively normal heart rate and blood pressure while lying down or sitting in an examination room.
The problem may become apparent only after standing.
Symptoms can intensify as the patient remains upright. The heart rate may increase, lightheadedness can develop, weakness may become more noticeable, vision may blur, thinking can become more difficult, and palpitations or feelings of near-fainting may appear.
If heart rate and blood pressure are measured only while the patient is seated, an important part of the clinical picture may never be documented.
A standing assessment or, in selected patients, a tilt-table test can provide information that a routine seated vital-sign measurement cannot.
POTS can look like many different illnesses
POTS does not always present as a patient saying, “My heart races when I stand.”
Some patients initially seek medical care because of fatigue.
Others are troubled by dizziness, headaches, exercise intolerance, gastrointestinal symptoms, tremulousness, weakness, sleep problems, brain fog, or difficulty tolerating heat.
This can send patients through several different specialties.
A patient with palpitations may see a cardiologist. Someone with dizziness may see a neurologist or ear specialist. A patient with nausea and digestive problems may see a gastroenterologist. Someone whose primary complaint is severe fatigue may undergo an entirely different evaluation.
Each evaluation may be reasonable, but the common orthostatic pattern can be missed when symptoms are considered separately.
Normal medical tests do not necessarily rule out POTS
POTS can be particularly confusing because many conventional tests may be normal.
An electrocardiogram may be normal between episodes. Cardiac imaging may not show structural disease. Routine laboratory testing may not explain the severity of the patient’s fatigue, dizziness, or exercise intolerance.
These tests are still important.
Part of evaluating suspected POTS is looking for other explanations for tachycardia and orthostatic symptoms. Depending on the presentation, clinicians may consider anemia, thyroid disease, dehydration, medication effects, arrhythmias, infection, blood loss, or other medical conditions.
But normal routine testing does not necessarily measure how well the autonomic nervous system regulates circulation when someone becomes upright.
That requires looking at the patient’s symptoms and what happens physiologically during standing.
POTS can be mistaken for anxiety
This is one of the more difficult parts of the diagnostic journey for some patients.
POTS can produce symptoms that overlap with anxiety or panic, including a rapid heartbeat, trembling, sweating, shortness of breath, chest discomfort, nausea, and lightheadedness.
That overlap can create diagnostic confusion.
Anxiety can also increase heart rate, and patients with POTS can have anxiety just like anyone else. The presence of anxiety therefore neither establishes nor excludes POTS.
The key is to look for an objective relationship with posture.
If symptoms repeatedly appear or worsen after becoming upright and improve after sitting or lying down, that pattern deserves attention. A reproducible orthostatic heart-rate response provides information that should not automatically be attributed to anxiety.
Symptoms may not be equally severe every day
Another reason POTS can be difficult to identify is that autonomic symptoms fluctuate.
A patient may have a very difficult day followed by a considerably better one.
Heat, dehydration, prolonged standing, physical exertion, illness, inadequate sleep, and other factors may worsen symptoms.
That means a patient can have a relatively uneventful medical appointment despite describing substantial difficulties at home, at work, while showering, shopping, exercising, or standing in line.
A single snapshot does not always capture a fluctuating disorder.
Patients may change their behavior without realizing it
Some patients adapt to orthostatic symptoms long before they know why they have them.
They sit while preparing food. They lean against counters. They avoid long checkout lines. They take shorter showers. They stop exercising. They choose a seat whenever one is available.
They may describe themselves as tired or out of shape rather than recognizing that remaining upright is specifically making them feel worse.
These adaptations can obscure one of the most useful diagnostic clues.
A question such as “Do you feel worse standing still than sitting or lying down?” may reveal information that a general question about dizziness does not.
POTS symptoms cross medical specialties
The autonomic nervous system helps regulate heart rate, blood pressure, circulation, digestion, sweating, temperature control, and other involuntary functions.
POTS can therefore look like a collection of unrelated problems.
This creates another diagnostic challenge: no single specialist necessarily sees the entire picture.
Limited familiarity with POTS and autonomic disorders may also contribute to delayed recognition. This does not mean physicians intentionally avoid diagnosing POTS.
Instead, recognizing a multisystem autonomic disorder requires familiarity with the syndrome and attention to the relationship between symptoms and posture.
Misdiagnosis can also occur in the opposite direction
There is another side to this problem.
Not every person with dizziness and a rapid heart rate has POTS.
Tachycardia can occur with dehydration, anemia, hyperthyroidism, infection, fever, medication effects, blood loss, inappropriate sinus tachycardia, and other conditions.
Orthostatic hypotension can also cause dizziness and weakness while standing, but its blood-pressure pattern differs from POTS.
A careful evaluation therefore has two goals: recognize POTS when it is present and avoid labeling another condition as POTS when it is not.
That distinction matters because treatment depends on identifying the correct problem.
Could infection be part of the history?
Some patients report that their POTS symptoms began after an infection or another significant physical stressor. Post-infectious POTS has received increasing attention, and infections are among the events reported before the onset of symptoms.
The distinction between what may initiate POTS and what subsequently worsens established symptoms is discussed further in what triggers POTS.
Lyme disease has also been discussed in relation to autonomic dysfunction. A 2024 review by Adler, Chung, Rowe, and Aucott examined the possible relationship between Lyme disease and dysautonomia, including POTS and other autonomic manifestations.
However, an association does not establish that Lyme disease is responsible for every case of POTS. Autonomic dysfunction is also broader than POTS, and patients can have autonomic abnormalities without meeting POTS criteria. This distinction is discussed in autonomic dysfunction without POTS.
For a patient with an appropriate exposure history and compatible symptoms, Lyme disease or another infection may be one part of the broader clinical evaluation rather than an assumption based on POTS alone.
What can help uncover a missed POTS diagnosis?
Sometimes the most useful clue is not another sophisticated test. It is recognizing the pattern.
Questions worth considering include whether symptoms appear or worsen after standing, how long the patient can remain upright comfortably, whether standing still feels worse than sitting or lying down, whether the heart races after becoming upright, and whether symptoms improve after lying down.
Everyday situations can also provide clues. Showering, shopping, preparing meals, exercising, or standing in line may expose an orthostatic pattern that is not obvious during a brief office examination.
When the history suggests orthostatic intolerance, measuring heart rate and blood pressure while lying down and during standing can help determine whether POTS or another form of orthostatic intolerance should be considered.
Frequently Asked Questions
Can POTS be missed on routine blood work?
Yes. Routine blood tests do not diagnose POTS. They can be valuable for identifying other conditions that may cause similar symptoms, such as anemia or thyroid disease, but POTS is primarily recognized through the clinical history and the heart-rate and blood-pressure response to upright posture.
Can POTS be mistaken for anxiety?
Yes. POTS and anxiety can share symptoms such as palpitations, trembling, sweating, and lightheadedness. A reproducible worsening of symptoms with standing accompanied by the characteristic orthostatic heart-rate response can help distinguish POTS from symptoms attributed solely to anxiety.
Can you have a normal ECG and still have POTS?
Yes. An ECG may be normal in a patient with POTS. POTS involves an abnormal physiologic response to upright posture rather than necessarily reflecting structural heart disease or an abnormal resting cardiac rhythm.
Why does POTS sometimes take years to diagnose?
POTS symptoms can involve several organ systems, routine testing may be unrevealing, symptoms can fluctuate, and clinicians may not measure heart rate and blood pressure over several minutes of standing. Patient surveys have documented substantial diagnostic delays before POTS is recognized.
Does dizziness when standing mean you have POTS?
No. Dizziness while standing has many possible causes. POTS requires a particular heart-rate response together with chronic orthostatic symptoms and the absence of another condition that adequately explains the tachycardia.
Clinical Takeaway
POTS can be missed because its symptoms are broad, fluctuate over time, overlap with other medical conditions, and may not appear during a routine seated examination.
Patients may undergo normal cardiac, neurologic, or laboratory testing because those tests are looking for different problems. At the same time, a rapid heart rate during standing should not automatically be labeled POTS because other causes of tachycardia and orthostatic symptoms need to be considered.
For patients who repeatedly feel worse while standing despite unrevealing routine testing, documenting heart rate, blood pressure, symptoms, and their relationship to posture may help reveal a pattern that otherwise remains hidden.
Related Articles
These articles explore related questions about autonomic dysfunction, infection, and orthostatic symptoms.
Autonomic Dysfunction in Lyme Disease: Symptoms and Treatment
Why Can Illness Affect Your Autonomic Nervous System?
References
- Raj SR, Bourne KM, Stiles LE, et al. Postural orthostatic tachycardia syndrome (POTS): Priorities for POTS care and research from a 2019 National Institutes of Health Expert Consensus Meeting—Part 2. Autonomic Neuroscience. 2021;235:102836.
- Vernino S, Bourne KM, Stiles LE, et al. Postural orthostatic tachycardia syndrome (POTS): State of the science and clinical care from a 2019 National Institutes of Health Expert Consensus Meeting—Part 1. Autonomic Neuroscience. 2021;235:102828.
- Sheldon RS, Grubb BP II, Olshansky B, et al. 2015 Heart Rhythm Society expert consensus statement on the diagnosis and treatment of postural tachycardia syndrome, inappropriate sinus tachycardia, and vasovagal syncope. Heart Rhythm. 2015;12(6):e41-e63.
- Shaw BH, Stiles LE, Bourne K, et al. The face of postural tachycardia syndrome—Insights from a large cross-sectional online community-based survey. Journal of Internal Medicine. 2019;286(4):438-448.
- Adler BL, Chung T, Rowe PC, Aucott J. Dysautonomia following Lyme disease: A key component of post-treatment Lyme disease syndrome? Frontiers in Neurology. 2024;15:1344862.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
