According to the diagnostic criteria for hypertension, blood pressure in patients with a high pressure of 135 and a low pressure of 85 is considered normal high. In the absence of antihypertensive medication, blood pressure is diagnosed as hypertension if systolic blood pressure is ≥140 mmHg and/or diastolic blood pressure is ≥90 mmHg when measured once daily for three days, respectively. Patients with a previous history of hypertension, who have received regular blood pressure lowering treatment, were diagnosed with hypertension despite a blood pressure <140/90 mmHg. Blood pressure levels in the population are continuously normally distributed, and there is no clear boundary between normal blood pressure and elevated blood pressure, and the criteria for hypertension are defined based on clinical and epidemiological data. (Chinese hypertension prevention and treatment guideline criteria: Currently, China uses normotension (systolic blood pressure <120 mmHg and diastolic blood pressure <80 mmHg), normal high [systolic blood pressure 120-139 mmHg and/or diastolic blood pressure 80-89 mmHg] and hypertension [systolic blood pressure ≥140 mmHg and/or diastolic blood pressure ≥90 mmHg] for blood pressure level classification.) Hypertension was further classified into three classes according to the level of elevated blood pressure. Class I hypertension (mild) is systolic blood pressure 140-159 mmHg and/or diastolic blood pressure 90-99 mmHg; Class II hypertension (moderate) is systolic blood pressure 160-179 mmHg and/or diastolic blood pressure 100-109 mmHg; Class III hypertension (severe) is systolic blood pressure ≥180 mmHg and/or diastolic blood pressure ≥110 mmHg. (Note: When systolic and diastolic blood pressure are classified (Note: When the systolic and diastolic blood pressure scores belong to different levels, the higher classification prevails.) The above criteria apply to men and women over 18 years of age, while children use the 95th percentile of blood pressure values for different age groups, which are usually lower than adult levels. It should be noted that the above blood pressure values are office blood pressure, and in the case of home self-measured blood pressure, the diagnostic criteria for hypertension is ≥135/85 mmHg, which corresponds to the office blood pressure of 140/90 mmHg. According to the above blood pressure criteria, the blood pressure of a patient with an office blood pressure of 135 high and 85 low is considered normal high. Regular review of blood pressure levels and improvement of lifestyle are needed to prevent the occurrence of hypertension.