Normal human blood pressure has two peaks and one trough throughout the day. Blood pressure is higher during the day and lower at night, and is higher in the morning than at night. Normally blood pressure rises slowly from 6 a.m., peaks from 9 to 10 a.m., and then gradually plateaus. Then there is another peak from 4 to 8 pm. The lowest blood pressure point is between 1:00 and 3:00 midnight and is maintained until 4-5:00. The results of 24-hour ambulatory blood pressure monitoring show that the fluctuation pattern of 24-hour ambulatory blood pressure in normotensive patients shows a trend of rising during the day and falling during the night, and the fluctuation range of systolic blood pressure is larger than diastolic blood pressure, and the fluctuation range of blood pressure during the day is larger than that during the night. Patients with hypertension can use 24-hour ambulatory blood pressure monitoring to find the pattern of blood pressure changes throughout the day and determine the high value of blood pressure for the day. Patients with hypertension generally have the highest blood pressure in the morning, so they generally take their blood pressure medication in the morning. Blood pressure is generally higher in the morning than in the evening, which is related to the physiological changes of people. If the blood pressure is much higher than normal, 24-hour ambulatory blood pressure monitoring is recommended.