Hypertension stages are generally divided into 4 classes, namely, critical hypertension, mild hypertension, moderate hypertension, and severe hypertension. What is critical hypertension? Critical hypertension is a stage where the blood pressure level exceeds the normal range but does not meet the criteria for hypertension, systolic blood pressure of 130-139 mmHg and diastolic blood pressure of 85-86 mmHg, which is called critical hypertension. What is mild hypertension? Mild hypertension is defined as a systolic blood pressure of 140-159 mmHg and a diastolic blood pressure of 90-99 mmHg, such a range that hypertension is called mild hypertension, which generally refers to first-degree hypertension. Moderate hypertension is defined as systolic blood pressure in the range of 160-179 mm and diastolic blood pressure in the range of 100-109 mmHg, such a range, also known as hypertension grade 2. Severe hypertension is defined as systolic blood pressure greater than 180mmHg and diastolic blood pressure greater than 110mmHg, such a range of blood pressure, known as hypertension level three, it will be cerebral hemorrhage, heart failure, kidney failure and other conditions, and may even be life-threatening.