The hallmark sign of POTS (postural orthostatic tachycardia syndrome) is a heart rate that jumps at least 30 beats per minute within 10 minutes of standing up, without a major drop in blood pressure. For adolescents under 19, the threshold is 40 beats per minute. But that heart rate spike is only one piece of the picture. POTS affects your autonomic nervous system, the part of your body that controls things you don’t think about like heart rate, blood pressure, digestion, and temperature, so symptoms can show up in surprising ways that don’t seem connected at first.
The Symptoms That Point to POTS
The most obvious symptom is feeling your heart pound or race when you stand up. Many people also feel lightheaded, dizzy, or like they might faint. These symptoms tend to improve when you sit or lie back down, which is a strong clue that something positional is going on.
Beyond the cardiovascular symptoms, POTS commonly causes what people describe as “brain fog,” a difficulty concentrating, finding words, or thinking clearly that gets worse when you’re upright. Fatigue is another near-universal complaint, and it’s not the kind that improves with a good night’s sleep. Many people with POTS also experience digestive problems like nausea, bloating, or feeling full after eating very little. Some notice their hands or feet change color when standing, turning red or purple, or that they sweat too much or too little.
What makes POTS tricky to recognize is that these symptoms can look like anxiety, dehydration, or simply being out of shape. The distinguishing feature is the pattern: symptoms reliably worsen when you’re upright and improve when you’re horizontal.
A Simple Test You Can Do at Home
Before seeing a doctor, you can get a rough sense of what’s happening with your heart rate using a home test sometimes called the “poor man’s tilt table test.” Lie flat for five to ten minutes, then check your heart rate (a pulse oximeter or smartwatch works well). Stand up and stay still. Check your heart rate again at two minutes, five minutes, and ten minutes.
If your heart rate consistently rises 30 or more beats per minute above your resting rate (or hits 120 or above) within those ten minutes, and you feel symptomatic, that’s worth bringing to a doctor. Do this test on a few different days and write down the numbers. A log of your heart rate readings and symptoms gives a doctor something concrete to work with rather than a vague description of “feeling off.”
How Doctors Diagnose POTS
A POTS diagnosis requires meeting three criteria. First, your heart rate increases by at least 30 beats per minute (40 for adolescents) within 10 minutes of standing. Second, you don’t have orthostatic hypotension, which is a significant blood pressure drop (20 points systolic or 10 points diastolic) in the first three minutes of standing. Third, the symptoms have been present for at least three to six months and aren’t explained by dehydration, blood loss, or another condition.
The gold standard test is a tilt table test. You lie on a table that tilts you to about a 70-degree angle, nearly upright, while your heart rate and blood pressure are continuously monitored. You stay in that position for up to 45 minutes. It’s not painful, but it can provoke the exact symptoms you’ve been experiencing, which is the point. Some doctors use a simpler standing test in the office, which involves lying down and then standing while they take repeated vitals.
Your doctor will also run blood work to rule out other causes of a fast heart rate. A complete blood count checks for anemia. Thyroid hormone levels rule out an overactive thyroid. An electrolyte panel screens for imbalances that could affect your heart. Depending on your specific symptoms, they may also check for conditions like pheochromocytoma (a rare adrenal gland tumor) using a plasma metanephrine test.
Conditions That Look Like POTS
Several conditions share symptoms with POTS and need to be ruled out. Inappropriate sinus tachycardia causes a fast heart rate even when you’re lying down, which distinguishes it from POTS, where the issue is specifically positional. Anxiety disorders can cause palpitations and lightheadedness, but the heart rate pattern on standing is different. Dehydration and anemia both cause a fast heart rate and fatigue but resolve once the underlying problem is treated.
Autoimmune conditions like Sjögren syndrome can occasionally present with POTS-like symptoms, so your doctor may screen for these depending on your other health concerns.
The Three Subtypes of POTS
Not everyone with POTS has the same underlying problem. Understanding which subtype you have can shape how it’s managed.
Neuropathic POTS is the most common form. It happens when small nerve fibers that line your blood vessels are damaged. These nerves are supposed to tell your blood vessels to tighten when you stand so blood doesn’t pool in your legs. When they stop working properly, blood pools, your brain gets less blood flow, and your heart speeds up to compensate.
Hyperadrenergic POTS involves an overactive fight-or-flight system. Your body pumps out too much norepinephrine (a stress hormone), which drives up both heart rate and blood pressure. People with this subtype often feel tremulous, anxious, or jittery on standing, and their blood pressure may actually increase rather than stay stable.
Hypovolemic POTS is tied to low blood volume. This can develop after an illness involving vomiting or diarrhea, a significant injury, or for reasons that aren’t always clear. With less blood circulating, your heart has to work harder to maintain flow when you’re upright.
Conditions That Often Occur Alongside POTS
POTS frequently shows up alongside other conditions, particularly hypermobile Ehlers-Danlos syndrome (hEDS), a connective tissue disorder that causes unusually flexible joints, stretchy skin, and tissue fragility. If you’ve always been “double-jointed,” bruise easily, or have chronic joint pain along with your POTS symptoms, it’s worth mentioning to your doctor.
Mast cell activation syndrome (MCAS), which involves immune cells releasing chemicals inappropriately and causing symptoms like flushing, hives, and gastrointestinal distress, is also frequently discussed in connection with POTS. However, a 2025 systematic review found no adequate studies demonstrating a clear association between the two conditions when strict diagnostic criteria were applied. One study came close but didn’t fully meet the bar. The overlap may be real, but the science isn’t settled yet.
Which Doctors Diagnose and Treat POTS
Getting a POTS diagnosis often takes time because many primary care doctors aren’t deeply familiar with the condition. If your doctor isn’t sure what’s going on, ask for a referral to a neurologist or cardiologist who specializes in autonomic disorders. Neurologists are particularly well-positioned to evaluate POTS because it’s fundamentally a problem with your autonomic nervous system.
Before your appointment, keep a symptom log for at least one to two weeks. Record your resting and standing heart rates at different times of day, note what you were doing when symptoms flared, and track things like fluid intake, sleep, and meals. This kind of data is far more useful to a specialist than a general list of complaints. If you have a smartwatch or fitness tracker that logs heart rate continuously, bring that data too.
Many people with POTS report seeing multiple doctors before getting a diagnosis, with an average delay of several years. Bringing organized data and specifically asking about POTS by name can shorten that timeline considerably.