Low blood pressure, also known as diastolic blood pressure, is not normal if it is 91 mmHg, and this condition belongs to first-degree hypertension, also called mild hypertension. Although this condition is abnormal, the condition is not serious. It is recommended that the patient can first make lifestyle adjustments, and it is likely that active lifestyle improvements may restore blood pressure to normal levels, such as paying attention to exercise and weight loss, quitting smoking and drinking, low salt and low fat diet, regular work and rest, avoiding exertion and staying up late, and maintaining a happy mood. Patients are also advised to have ambulatory blood pressure monitoring again if necessary to assess the overall blood pressure over 24 hours. This will also provide a more objective assessment of the severity of the patient’s blood pressure, as it is difficult to assess whether the patient’s blood pressure is abnormal or how severe it is through a single blood pressure measurement.