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PotsTrack
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NASA Lean Test calculator

A free web tool to work out your standing heart-rate delta against the threshold used in the POTS literature. Enter your readings and the calculator does the rest. Nothing leaves your browser.

Standing readings

Calculations happen in your browser. Nothing is uploaded.

Fill in your supine baseline and at least one standing reading to see the delta and threshold.

How to do the test properly at home

The home-friendly version of the NASA Lean Test was popularised by Dr Peter Rowe's group and is what most patients run in between clinic visits. Done carefully, the numbers it produces are good enough to discuss with your specialist.

  1. Lie flat for at least 5 minutes. Quiet room, no scrolling, no conversation. After 5 minutes (longer is fine), read your supine heart rate and write it down.
  2. Stand and lean against a wall. Shoulder blades touching, heels around 15 cm forward, arms relaxed by your sides. The lean is the difference between this test and a tilt table: it removes the muscle pump that masks orthostatic intolerance when you stand actively.
  3. Take readings at 1, 3, 5 and 10 minutes. Stay leaning the whole time. A smartwatch or fingertip pulse oximeter both work; a manual radial pulse for 60 seconds also works. Note any symptoms next to each reading.
  4. Stop early if you need to. If you start to feel pre-syncopal — vision narrowing, ringing in the ears, hot-cold flush — sit down or lie down immediately. Your safety is more important than completing the test.

What the result actually means

The adult POTS criterion in the 2015 Heart Rhythm Society consensus statement is a sustained increase of ≥30 bpm within 10 minutes of standing or head-up tilt, in the absence of orthostatic hypotension. For adolescents (under 19) the threshold is ≥40 bpm, based on the higher baseline heart-rate response children have to standing.

What the calculator can tell you: whether a given session reaches those thresholds. That's a useful data point.

What it can't tell you: whether you have POTS. The official criterion is a sustained response across multiple sessions, with chronic symptoms, in the absence of other causes ( dehydration, deconditioning, anaemia, thyroid issues, acute illness). Your specialist puts that picture together.

What this can't tell you

  • Whether you have POTS. POTS is a clinical diagnosis that takes sustained findings plus symptoms plus a clinician to rule out other causes.
  • Whether your delta is being skewed by something benign. Dehydration, heat, having just eaten, recent caffeine, anxiety about doing the test itself, and being deconditioned can all push your delta up.
  • What subtype you have if you do have POTS — hyperadrenergic, neuropathic, hypovolaemic and others all look similar on a single lean test.
  • Anything about treatment. Please talk to your specialist about medications, hydration targets, salt and compression.

Use this regularly? Try the app

A single lean test is one data point. The pattern is what your specialist needs. PotsTrack runs the same test with a guided timer, stores the readings in an encrypted on-device database, and lets you export a clean PDF for your next appointment.

What PotsTrack does

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