There are three types of methods to measure blood pressure: 1) in-office blood pressure, which is when a doctor measures a patient’s blood pressure through a mercury meter; 2) home blood pressure measurement, where patients buy electronic products at a pharmacy and measure their blood pressure through their wrists and arms; and 3) ambulatory blood pressure, which is a special device provided in hospitals to monitor a patient’s blood pressure for 24h. All three devices can measure blood pressure and have different criteria to diagnose if a patient has high blood pressure. The common office blood pressure is also known as mercury meter blood pressure, generally normal blood pressure systolic blood pressure <140mmHg, that is, high pressure <140mmHg, low pressure <90mmHg is called normal blood pressure. If the systolic blood pressure is ≥ 140 mmHg or the diastolic blood pressure is ≥ 90 mmHg, it is called hypertension. The blood pressure measured at home, called home blood pressure, will require a low value of blood pressure, systolic blood pressure ≤ 135 mmHg or diastolic blood pressure ≤ 85 mmHg, called normal blood pressure.