According to the JNC7 blood pressure classification, a systolic blood pressure <120mmHg and a diastolic blood pressure <80mmHg are within the normal range when the blood pressure is measured at two or more different times, individually and repeatedly, in a steady state. If the systolic blood pressure is 120~139mmHg and the diastolic blood pressure is 80~90mmHg, it is pre-hypertension and requires attention to lifestyle adjustment. If the systolic blood pressure is 140-159mmHg or the diastolic blood pressure is 90-99mmHg, it is classified as grade 1 hypertension, which requires lifestyle adjustments as well as medication if necessary. If the systolic blood pressure is ≥160mmHg or diastolic blood pressure is ≥100mmHg, it is classified as grade 2 hypertension, which requires active lifestyle modification and drug treatment. If the systolic blood pressure is ≥180 mmHg or diastolic blood pressure is ≥110 mmHg, it is categorized as grade 3 hypertension, which is relatively more dangerous and requires active treatment.