Blood pressure is an important indicator of human vital signs. The blood pressure measured in normal adults is 120/80 mmHg or less. A systolic blood pressure of ≥140 mmHg and/or a diastolic blood pressure of ≥90 mmHg obtained from 3 or more measurements on a non-same day is diagnostic of hypertension. That is, a simple elevation of systolic blood pressure above 140 mmHg can be diagnosed as hypertension even if the diastolic blood pressure is normal. Similarly, hypertension can be diagnosed even if the diastolic blood pressure alone is ≥90 mmHg while the systolic blood pressure is within the normal range. Treatment includes dietary control (e.g., low-salt diet, avoidance of excessive intake of saturated fatty acids), exercise (mainly aerobic exercise), smoking cessation and alcohol restriction, and oral antihypertensive drug therapy as necessary. Another condition that can be seen clinically is a diastolic blood pressure between 130-140 mmHg, called a critical elevation of blood pressure. Studies have shown that as time progresses, this group is likely to eventually develop hypertension, so non-pharmacological treatments such as diet and exercise are also needed.