High pressure, i.e. systolic blood pressure, is normally 90 to 139 mmHg in a quiet state; low pressure, i.e. diastolic blood pressure, is normally 60 to 89 mmHg. Systolic pressure is when the heart begins to contract, the arterial pressure gradually rises, the blood on the inner wall of the blood vessel side pressure. The normal range is 90 to 139 mmHg; diastolic blood pressure is the side pressure produced by the blood on the inner wall of blood vessels when the heart diastole, the normal range is 60 to 89 mmHg. Systolic and diastolic blood pressure can be measured with a sphygmomanometer. When blood pressure decreases, it may lead to diseases such as insufficient blood supply to the heart and insufficient blood supply to the brain, with symptoms such as dizziness, fatigue, chest tightness, shortness of breath, and palpitations; and when blood pressure increases, it may also lead to diseases such as cerebral infarction and cerebral hemorrhage, with symptoms such as dizziness, hemiplegia, and hemianopsia. So be sure to monitor your blood pressure and keep it normal. If your blood pressure rises or falls you should go to the hospital in time to avoid delaying your condition.