First, everyone's blood pressure changes greatly in one day. Strictly speaking, people's blood pressure is different at every moment. It changes with the changes of people's psychological state, time, season, temperature, and the measured position (arm or wrist) and body position (sitting or lying). Therefore, it is normal to measure different blood pressure values each time. For example, due to nervousness and anxiety, the systolic blood pressure (high pressure) measured by people in the hospital is generally 25 mmHg~30 mmHg (.. 4 kPa~4.0 kPa) higher than that measured at home, and some even differ by 50 mmHg (6.67 kPa).

Second, the measurement method is incorrect. The following three points should be noted during measurement: first, the height of the cuff should be at the same height as the heart position, and the rubber tube of the cuff should be placed at the pulsation point of the brachial artery, and the bottom of the cuff should be 1~2 cm higher than the elbow; At the same time, the tightness of the cuff should be able to just insert a finger. Secondly, keep quiet for about 10 minutes before measuring. Finally, the time interval between two measurements should not be less than 3 minutes, and the position and position should be consistent. For these three points, it should be said that the measured blood pressure is accurate and objective.

Alternating method measurement:

For the first time, the doctor uses a mercury sphygmomanometer to measure blood pressure. After a rest of 3 minutes, the doctor uses an electronic sphygmomanometer to measure blood pressure for the second time, and then takes a rest of 3 minutes. Finally, the doctor uses a mercury sphygmomanometer to measure blood pressure for the third time. Take the average value of the first and third times as the doctor's measurement value. Compared with the measurement value of the electronic sphygmomanometer, the difference should generally be less than 10 mm Hg (1.33 kPa). You can use the electronic sphygmomanometer that meets this condition safely.