According to the diagnostic criteria for hypertension, patients with a low pressure of 90 and a high pressure of 140 have mild hypertension for both systolic and diastolic blood pressure. In the absence of antihypertensive medication, the diagnosis of hypertension is made if the systolic blood pressure is ≥140 mmHg and/or the diastolic blood pressure is ≥90 mmHg when the blood pressure is measured in the office three times on non-same day. Patients with a previous history of hypertension, who have received regular blood pressure lowering therapy, were diagnosed with hypertension despite a blood pressure <140/90 mmHg. In a population with a continuous normal distribution of blood pressure levels, there is no clear line of demarcation between normotension and elevated blood pressure, and the criteria for hypertension are defined based on clinical and epidemiological data. Hypertension is further classified into three levels according to the level of elevated blood pressure. Class I hypertension (mild) is 140-159 mmHg systolic and 90-99 mmHg diastolic; Class II hypertension (moderate) is 160-179 mmHg systolic and 100-109 mmHg diastolic; Class III hypertension (severe) is ≥180 mmHg systolic and ≥110 mmHg diastolic. The above criteria apply to men and women over 18 years of age. For children, the 95% median of blood pressure values in different age groups, usually below adult levels, was used. Patients with a low blood pressure of 90 and a high blood pressure of 140 are considered mildly hypertensive. If the patient has a combination of clinical disease and risk factors, oral antihypertensive medications are initiated. If no other conditions are present, treatment is based on lifestyle improvement.