Blood pressure usually refers to arterial blood pressure, which is the lateral pressure of the blood in the arteries against the walls of the blood vessels. The normal average blood pressure varies with age, and the older you are, the higher the average blood pressure. In addition, normal human blood pressure has significant fluctuations. Typically, a person’s blood pressure is lowest at night while sleeping: it begins to rise in the morning upon awakening. In addition, factors such as age, heart rate, arterial wall elasticity, physical activity, mental state and environment all affect blood pressure. Here is some general knowledge on the diagnosis of hypertension. First, the normal range of blood pressure Normal blood pressure: systolic blood pressure <130 mmHg, diastolic blood pressure <85 mmHg. Ideal blood pressure: systolic blood pressure <120 mmHg, diastolic blood pressure <80 mmHg. Normal high limit: systolic blood pressure 130-139 mmHg, diastolic blood pressure 85-89 mmHg. Second, the classification of hypertension The main diagnostic basis is the results of blood pressure measurement in the office: the first diagnosis of systolic blood pressure ≥ 140 mmHg and/or diastolic blood pressure 140 mmHg systolic and/or diastolic blood pressure ≥ 90 mmHg1, it is recommended that the diagnosis be confirmed by two follow-up examinations within 4 weeks, and that the above diagnostic threshold be reached in all three measurements on different days. Hypertension is classified into 3 classes according to brachial artery levels, as follows: Class 1 hypertension: 140-159 mmHg systolic and 90-99 mmHg diastolic (subgroup: critical hypertension, 140-149 mmHg systolic and 90-94 mmHg diastolic). Grade 2 hypertension: systolic blood pressure 160-179 mmHg, diastolic blood pressure 100-109 mmHg. Grade 3 hypertension: systolic blood pressure ≥180, diastolic blood pressure ≥110 mmHg. Systolic hypertension alone: systolic blood pressure ≥140 mmHg (subgroup: critical systolic hypertension, systolic blood pressure 140-149 mmHg),diastolic blood pressure <90 mmHg. When the systolic and diastolic blood pressure belong to different grades, the higher grade will be used as the standard. The goal of hypertension treatment is to lower the blood pressure in general patients. The goal of hypertension is: systolic blood pressure < 140 mmHg and diastolic blood pressure < 90 mmHg. 2. Patients aged ≥ 80. In principle, the antihypertensive target is systolic blood pressure < 150 mmHg and diastolic blood pressure < 90 mmHg. The target blood pressure for elderly patients without clinical coexisting diseases is < 145 to 150/90 mmHg. ② For patients with coexisting cardiac, cerebral and renal diseases, the blood pressure should be lowered to < 150/90 mmHg first, and then to < 140/90 mmHg if well tolerated. ③ The blood pressure of elderly patients should not be lower than 130/60 mmHg.