Postural orthostatic tachycardia syndrome (POTS) is diagnosed through a careful evaluation of symptoms and specific heart rate measurements when standing up. While many people experience dizziness or lightheadedness, POTS involves a distinct pattern of the heart racing excessively upon standing, along with other symptoms that can significantly affect daily life. Getting the right diagnosis is the first step toward finding relief and managing this complex condition.
Introduction: Who Should Seek POTS Diagnostics
If you frequently experience dizziness, a racing heart, or lightheadedness when you stand up from sitting or lying down, it may be time to seek medical evaluation for postural orthostatic tachycardia syndrome. These symptoms are not just about feeling a bit off-balance—they represent a pattern that consistently happens with position changes and can greatly interfere with your ability to work, attend school, or carry out everyday activities.[1]
You should consider consulting a healthcare provider if you notice that standing triggers multiple symptoms such as heart palpitations, fatigue, trouble concentrating (often called brain fog, which refers to difficulties with thinking clearly or remembering things), nausea, or trembling. These symptoms typically improve when you lie back down, which is a key characteristic of POTS.[3] Many people also experience additional problems like headaches, shortness of breath, chest pain, or digestive issues that seem to worsen when upright.[4]
Women between the ages of 15 and 50 are most commonly affected by POTS, though men and people outside this age range can also develop the condition. You may be at higher risk if you’ve recently experienced a significant illness such as a viral infection like mononucleosis, recovered from COVID-19, gone through pregnancy, had major surgery, or experienced physical trauma like a head injury.[1] People with certain autoimmune conditions such as Sjogren’s syndrome, lupus, or celiac disease, as well as those with joint hypermobility syndrome or chronic fatigue syndrome, are also more likely to develop POTS.[1][3]
It’s important to seek evaluation sooner rather than later because POTS symptoms can be mistaken for anxiety, depression, or other conditions. Many patients visit multiple doctors over several years before receiving the correct diagnosis.[10] If your symptoms significantly limit your ability to stand, walk, exercise, or perform daily tasks like bathing or eating, this warrants immediate medical attention. Some people with POTS experience such severe functional impairment that they are unable to work, with disability affecting about 25% of patients.[2]
Diagnostic Methods for Identifying POTS
Diagnosing postural orthostatic tachycardia syndrome requires meeting specific clinical criteria established by medical organizations. The main feature doctors look for is a significant increase in heart rate when you stand up, without a corresponding major drop in blood pressure. This distinguishes POTS from other conditions that cause dizziness upon standing.[2]
The standard diagnostic criteria for POTS include three key elements. First, you must have symptoms of orthostatic intolerance—meaning symptoms that occur when standing and improve when lying down—for at least three to six months. Second, your heart rate must increase by at least 30 beats per minute in adults (or 40 beats per minute in children and adolescents under age 20) within 10 minutes of standing or during a tilt table test. For some people, the heart rate may exceed 120 beats per minute, even if the increase is less than 30 beats. Third, there should be no significant drop in blood pressure when standing—specifically, no more than a 20 mmHg drop in systolic blood pressure.[2][5][13]
Your initial evaluation will typically start with your primary care doctor or a specialist such as a cardiologist or neurologist. The doctor will take a detailed medical history, asking about when your symptoms began, what triggers them, how long they last, and what makes them better or worse. They will want to know if you’ve had recent infections, surgeries, injuries, or other major health events, as these can trigger POTS.[12]
A physical examination will include checking your heart rate and blood pressure while you’re lying down and then after you stand up. This is called an Active Stand Test or measuring orthostatic vital signs. During this test, you’ll lie flat for several minutes while the doctor measures your blood pressure and heart rate. Then you’ll stand up, and the measurements will be repeated at 2, 5, and 10-minute intervals. The doctor is looking for that characteristic rapid increase in heart rate without a significant drop in blood pressure.[2][10]
While the Active Stand Test can be performed right in your doctor’s office, it may miss some cases of POTS. If your symptoms strongly suggest POTS but the bedside test doesn’t confirm it, your doctor may recommend more specialized testing. The most definitive test is called a Tilt Table Test. During this test, you lie on a special table that can be tilted to different angles. You start lying flat, and then the table is slowly tilted upward to simulate standing. Throughout the test, which typically lasts 10 to 45 minutes, your heart rate, blood pressure, and symptoms are continuously monitored. This test allows doctors to observe your body’s responses in a controlled environment and is considered more reliable than the Active Stand Test.[2][3]
Your doctor will also need to rule out other conditions that can cause similar symptoms. This process of elimination is crucial because conditions like dehydration, an overactive thyroid (thyrotoxicosis, which means the thyroid gland produces too much hormone), anemia (low red blood cell count), certain medications, and other heart or nervous system disorders can mimic POTS.[5] Blood tests are commonly ordered to check for these other conditions. Your doctor may test your thyroid function, blood count, electrolyte levels, and blood sugar to ensure these aren’t causing your symptoms.[3]
An electrocardiogram (ECG), which is a simple test that records the electrical activity of your heart, may be performed to check for heart rhythm abnormalities. Some doctors also order a 24-hour heart rate and blood pressure monitor, which you wear at home to track your heart’s behavior throughout the day and night. This can reveal patterns that might not be apparent during a brief office visit.[3]
In some cases, particularly when the diagnosis is uncertain or symptoms are complex, you may be referred to a specialist who can perform more detailed tests of your autonomic nervous system. These specialized tests might include a Quantitative Sudomotor Axon Reflex Test (QSART), which examines how your nerves control sweating, a Thermoregulatory Sweat Test (TST) that maps sweating patterns across your body, skin biopsies to look at small nerve fibers, or tests to evaluate how quickly your stomach empties food.[2] These tests help doctors understand which part of your autonomic nervous system isn’t functioning properly and may help identify specific subtypes of POTS.
It’s worth noting that diagnosing POTS can take time and persistence. Because the symptoms overlap with many other conditions—including anxiety disorders—many people see several doctors before receiving the correct diagnosis. If you feel your concerns aren’t being taken seriously or if initial tests don’t provide answers but your symptoms continue, don’t hesitate to seek a second opinion or ask for a referral to a specialist with expertise in autonomic disorders.[10][12]
Diagnostics for Clinical Trial Qualification
When researchers design clinical trials to study new treatments for POTS, they use standardized diagnostic criteria to ensure all participants truly have the condition. This consistency is essential for determining whether a treatment actually works. If you’re considering participating in a POTS clinical trial, you’ll need to undergo specific diagnostic testing to confirm you meet the study’s eligibility requirements.
Clinical trials for POTS typically require participants to meet the established diagnostic criteria from organizations like the American Autonomic Society and Heart Rhythm Society. This means you must demonstrate a sustained heart rate increase of at least 30 beats per minute (or 40 beats per minute if you’re under 20 years old) within 10 minutes of standing or during a tilt table test, without a significant drop in blood pressure. You must also have chronic symptoms of orthostatic intolerance that have persisted for at least three to six months.[5][13]
Most clinical trials will require objective documentation of your heart rate and blood pressure response to standing. This typically means you’ll need to undergo either an Active Stand Test or, more commonly, a formal Tilt Table Test as part of the screening process. The tilt table test is preferred in research settings because it provides more standardized and reproducible measurements. During this test, researchers can precisely control the angle of tilt and carefully monitor all your vital signs while documenting any symptoms you experience.[2]
Blood tests are usually required to rule out other conditions that might disqualify you from participating. These typically include tests to check your thyroid function, blood count, kidney and liver function, and electrolyte levels. Some studies may also require pregnancy testing for women of childbearing age, as many medications being studied may not be safe during pregnancy.[3]
Clinical trials may also require an electrocardiogram (ECG) to ensure your heart’s electrical system is functioning normally and to rule out other heart conditions that could either disqualify you from the study or confuse the interpretation of results. Some studies looking at specific subtypes of POTS may require more detailed autonomic testing to determine which type of POTS you have.[2]
Researchers often need documentation of how POTS affects your daily functioning. This might include questionnaires about your quality of life, symptom severity scales, or assessments of your ability to perform daily activities. These baseline measurements help researchers determine whether a treatment improves not just your heart rate response, but also your actual ability to function in everyday life.[12]
If you’re interested in participating in a POTS clinical trial, it’s important to have comprehensive medical records documenting your diagnosis and treatment history. Many trials require that you’ve tried standard treatments without adequate improvement before enrolling. Some studies may exclude people taking certain medications or require you to stop specific treatments before joining the trial, so it’s essential to discuss these requirements carefully with the research team.
