Ambulatory blood pressure monitoring results over a 24-hour period showing elevated blood pressure (hypertension) at night (grey shaded area). The average readings are given at lower centre. A typical healthy reading is 120/80 millimetres of mercury (mmHg). The abbreviations are Sys (systolic pressure, upper line), Dia (diastolic pressure, middle line), HR (heart rate), MAP (mean arterial pressure), PP (pulse pressure) and Afib (atrial fibrillation). The pulse in beats per minute (bpm) is the lower line.