Blood pressure (BP) is the force exerted by circulating blood against the walls of the arteries. It is recorded as two numbers — systolic pressure (peak force during a heartbeat) over diastolic pressure (resting force between beats) — expressed in millimetres of mercury (mmHg).

Regular monitoring is one of the most effective ways to detect and manage hypertension, often called the 'silent killer' because it rarely produces symptoms in its early stages. High blood pressure significantly increases the risk of heart attack, stroke, heart failure, and kidney disease.

Home blood pressure tracking — when done correctly — provides valuable longitudinal data that clinical visits alone cannot capture. White-coat hypertension (elevated BP only in clinical settings) and masked hypertension (normal in-clinic, elevated at home) are both identifiable through consistent home monitoring.

Two major guideline systems are in current use. The ACC/AHA 2017 guidelines (American College of Cardiology / American Heart Association) classify blood pressure as: Normal (<120/80), Elevated (120–129/<80), Hypertension Stage 1 (130–139/80–89), Hypertension Stage 2 (≥140/90), and Hypertensive Crisis (>180/120).

The ESC/ESH 2018 guidelines (European Society of Cardiology / European Society of Hypertension) set a higher Stage 1 threshold of 140/90 mmHg, classifying 130–139 mmHg systolic as 'High normal' rather than a treatment-triggering stage. This tracker supports both systems, allowing you to switch between them.

A hypertensive crisis (systolic >180 or diastolic >120) warrants immediate medical evaluation. If accompanied by symptoms such as chest pain, severe headache, or visual disturbance, emergency care is required without delay.

Preparation matters significantly. Sit quietly for at least five minutes before taking a reading. Avoid caffeine, exercise, and smoking for at least 30 minutes beforehand. Empty your bladder — a full bladder can raise BP by 10–15 mmHg.

Posture and positioning are critical. Sit with your back supported, feet flat on the floor, and the measurement arm resting at heart level on a flat surface. Legs should be uncrossed. Using the left arm is preferred in clinical settings, but consistency across readings matters more than which arm you choose.

Cuff size affects accuracy more than most people realise. A cuff that is too small will over-read; one that is too large will under-read. The inflatable bladder should encircle at least 80% of the arm circumference.

Take two to three readings, at least one minute apart, and record the average. Single readings are unreliable. Discard the first reading if it differs substantially from subsequent ones — the first measurement is often elevated due to the startle response.

Each entry captures systolic and diastolic pressure, pulse rate, date and time, measurement arm, body position, and an optional personal note. These contextual fields help identify patterns — for example, whether BP is consistently higher in the morning (morning surge) or varies by measurement arm.

The tracker plots your readings as a time-series line chart, making trends immediately visible. A colour-coded classification badge accompanies each entry, aligned to whichever guideline system you prefer — ACC/AHA or ESC/ESH.

Recorded data can be exported as a CSV file, making it straightforward to share your complete history with a clinician at your next appointment. The export includes all fields: timestamps, values, classification labels, arm, position, and notes.