POTS (postural orthostatic tachycardia syndrome) is measured by tracking how much your heart rate increases when you move from lying down to standing up. The key number: a sustained heart rate rise of 30 beats per minute or more within 10 minutes of standing, without a significant drop in blood pressure. For adolescents aged 12 to 19, the threshold is 40 beats per minute. This can be measured in a clinical setting with specialized equipment or screened at home with a basic blood pressure monitor.
What the Numbers Mean
A POTS diagnosis requires all of these criteria to be met: a sustained heart rate increase of at least 30 bpm (40 bpm for teens) within 10 minutes of standing upright, confirmed by at least two measurements taken at least one minute apart. The heart rate often exceeds 120 bpm total. Critically, blood pressure stays relatively stable during this rise. That’s what separates POTS from orthostatic hypotension, where blood pressure drops significantly on standing but heart rate may not spike the same way.
The rapid heartbeat typically improves when you lie back down. Many people also experience lightheadedness, dizziness, palpitations, or fainting when standing, and these symptoms are an important part of the clinical picture alongside the numbers.
How to Test at Home
The simplest home screening method uses an electronic blood pressure monitor with an upper-arm cuff. Wrist-cuff monitors are less accurate and not recommended for this purpose. A POTS specialist from PoTS UK has specifically recommended arm-cuff monitors as the best device for collecting diagnostic-quality data at home.
Here’s how to do it:
- Lie down for 5 to 10 minutes in a quiet room. Relax and let your heart rate settle.
- Take a baseline reading of your heart rate and blood pressure while still lying flat.
- Stand up and remain standing still for 10 minutes.
- Take readings at regular intervals while standing: at 1, 2, 3, 5, and 10 minutes. Record both heart rate and blood pressure each time.
- Note any symptoms you feel at each time point, such as dizziness, lightheadedness, brain fog, nausea, or visual changes.
If your heart rate consistently rises 30 or more bpm above your resting rate during the standing period, that’s a meaningful result to bring to your doctor. Keep in mind that a home test is a screening tool, not a formal diagnosis. But detailed, well-documented readings give a clinician something concrete to work with, especially if your symptoms are intermittent or hard to reproduce on demand.
The NASA Lean Test
The NASA Lean Test is a validated alternative that can be done in a primary care office with just a pulse oximeter, a blood pressure cuff, and an exam table. Researchers at the Bateman Horne Center, along with teams from the University of Utah and Columbia University, have validated its effectiveness. It follows a similar protocol to the home active stand test but in a supervised setting, which makes the results more clinically credible. If your doctor doesn’t have access to a tilt table, this is a reasonable option to ask about.
The Tilt Table Test
The tilt table test is the gold standard for diagnosing POTS, though it requires specialized equipment that many clinics don’t have. You lie flat on a motorized table, and after a resting period, the table tilts you to a near-standing position. Heart rate and blood pressure are monitored continuously throughout. Most tests last 30 to 45 minutes, though you may remain upright for up to 60 minutes if results aren’t clear-cut.
Because the table supports your body weight, the test isolates the cardiovascular response to position change without the confounding effects of muscle effort. That’s why it’s considered more precise than a simple standing test.
What to Avoid Before Testing
Several things can artificially raise or lower your heart rate and skew the results. Caffeine is a common culprit, as it stimulates the cardiovascular system and can push heart rate readings higher than your baseline. Dehydration makes POTS symptoms worse and can produce exaggerated readings. On the flip side, drinking a large volume of water right before testing can temporarily suppress the heart rate response.
Certain medications also interfere with results. Diuretics reduce blood volume, which worsens the tachycardia response. Medications that dilate blood vessels (venodilators) decrease the amount of blood returning to the heart, triggering a compensatory heart rate spike. Some antidepressants, particularly those that affect norepinephrine, can also exacerbate symptoms. If you’re on any of these, your doctor may ask you to pause them before formal testing. Don’t stop medications on your own for a home test.
Time of day matters too. POTS symptoms tend to be worse in the morning and after meals, so testing at the same time on different days helps you compare results accurately.
Choosing the Right Monitor
An upper-arm electronic blood pressure cuff is the most practical and accurate option for home testing. It captures both heart rate and blood pressure in one reading, which is exactly what you need.
Other devices have trade-offs:
- Smartwatches can be accurate to within 5 bpm at rest in normal rhythm, but their blood pressure readings don’t consistently meet medical standards. They’re useful for spotting trends but not for generating diagnostic data.
- Chest strap heart rate monitors use electrical sensors similar to a clinical ECG and are close to perfectly accurate for heart rate, even during exercise. They don’t measure blood pressure.
- Finger pulse oximeters measure heart rate and oxygen saturation but can produce inaccurate readings, particularly in people with poor circulation, which is common in POTS.
- Forearm Bluetooth monitors with optical sensors tend to be more accurate than wrist-based devices because the forearm has better blood flow and less motion artifact.
- Ear-based sensors like the Cosinuss One have shown accuracy comparable to a standard ECG for heart rate monitoring.
For the purpose of screening for POTS specifically, the arm-cuff blood pressure monitor remains the best single device because it gives you both numbers you need in a format your doctor will take seriously.
Documenting Your Results
If you’re testing at home to build a case for a clinical evaluation, documentation is everything. Record the date, time, and conditions (what you ate, how much water you drank, medications taken). Log your resting heart rate and blood pressure, then each standing measurement with timestamps. Write down symptoms as they happen, noting when they start and how severe they feel.
Repeat the test on multiple days. A single abnormal reading could reflect dehydration, stress, or a poor night’s sleep. Consistent results across several tests paint a much clearer picture. Aim for at least three to five tests under similar conditions before drawing conclusions or presenting results to your doctor.