Blood pressure fluctuates throughout the day, and the best time to measure blood pressure is in the morning when you first wake up, i.e. between 6-8 am. During the day, blood pressure has the characteristics of “two peaks and a valley”, that is, 6-8 am and 4-6 pm are the two peaks of blood pressure, and 6-8 am is the highest peak of blood pressure, and at night, due to the excitement of the vagus nerve, blood pressure will be lower. In addition, there are more factors that affect blood pressure, such as running, after meals, and emotional excitement will make blood pressure slightly higher. Since most of the morning sleep and wake up time is between 6-8 am, and just wake up in a quiet state, avoiding the influence of factors such as eating and exercise, this time period can best reflect the human blood pressure situation. In addition, blood pressure can be measured 24 hours a day, but you need to make sure that you are in a quiet state 30 minutes before the measurement and that you are not emotionally excited, and that you are relaxed during the measurement.