Home blood pressure: how to measure it properly (and why most people do it wrong)

Home readings predict heart attacks and strokes better than clinic readings, but only if they are taken properly. A badly taken home reading is worse than useless because it gets averaged into decisions. The method below is what NICE and the European Society of Hypertension actually recommend.

The setup

• Use a validated upper-arm cuff monitor, not a wrist device. Check yours against the STRIDE BP validated-device list.
• Cuff size matters: a cuff too small overreads, too large underreads. Measure your arm circumference and match the cuff range printed on it.
• Sit quietly for 5 minutes first, back supported, feet flat, legs uncrossed, arm supported at heart level.
• No caffeine, smoking, or exercise in the 30 minutes before.
• Do not talk during the measurement.

The schedule

For diagnosis or medication review, take two readings one minute apart, morning and evening, for 4 to 7 days. Discard day one and average the rest. That average, not any single reading, is the number guidelines act on. A one-off 145/95 after a stressful commute tells your clinician almost nothing; a 7-day average of 138/88 tells them a great deal.

What the thresholds are at home

Home averages run lower than clinic values. The usual cut-off is an average of 135/85 mmHg or more at home, equivalent to 140/90 in clinic. Readings averaging 180/120 or higher, or any reading with chest pain, breathlessness, weakness, or visual symptoms, need same-day medical attention, not an app.

Why tracking beats remembering

Nobody remembers fourteen readings accurately, and white-coat effects mean the readings you choose to report are biased. Log every reading with the time and posture, and share the full series. CardioTrack stores readings on your device, plots the trend, and computes the same discard-day-one average your clinician would.