Orthostatic Hypotension calculator

What "orthostatic hypotension" means

A sustained fall in blood pressure on standing — by convention, a drop of ≥20 mmHg systolic or ≥10 mmHg diastolic within 3 minutes of standing up. It is a different pattern from POTS, although they sometimes coexist.

How to take the readings properly

• Use an upper-arm cuff. Wrist monitors are less accurate for this.
• Same arm for every reading, supported at heart level.
• 5 minutes lying flat before the baseline; longer is fine. No talking, no phone, no caffeine in the last hour.
• Stand smoothly. No leaning. Stop the test if you feel pre-syncopal.

What this can't tell you

• Whether the drop is benign (dehydration, recent meal, medication) or a sign of autonomic failure. That is your specialist's call.
• Anything about POTS — POTS is a heart-rate pattern, not a BP one.
• What to do about it. Always discuss with the clinician who knows your medical history.

See also the NASA Lean Test calculator for the heart-rate-based POTS screening test.