First of all, human blood pressure is not a relatively fixed value like height and weight, but is constantly changing. People’s blood pressure rises during excitement, nervousness, and exercise, and decreases after drinking, bathing, and smoking. Medical tests have proved that: a normal person has fluctuations in blood pressure during a day, and the blood pressure is the lowest during sleep. The blood pressure is highest from 8 am to 10 am. The range of change of systolic blood pressure (high pressure) of normal people is between 20 and 40mmHg, and the range of change of diastolic blood pressure (low pressure) is between 10 and 20mmHg. Even at night, people are During sleep, there are also fluctuations of 5 to 10 mmHg. In addition, the posture during measurement also affects the measurement results. The results of the study show that the blood pressure value decreases by about 8mmHg for every 10cm increase in the height of the heart from the measuring position, and the blood pressure value increases by about 8mmHg for every 10cm decrease in the height. Therefore, only when we measure the blood pressure by the same method at the same time every day, can the blood pressure results be comparable.

First of all, the measurement principle is different. The mercury electronic sphygmomanometer uses the Coriolis method, and the electronic sphygmomanometer uses the oscillometric method; the Coriolis method uses a stethoscope to listen to the sound of blood flow in the blood vessel. The method is to measure the vibration of the blood vessel wall when the blood flows; although the measurement principle is different, the test result is theoretically the same. In fact, the Coriolis method has different hearing response speeds for each doctor, and sometimes the blood pressure readings are not recorded immediately during the measurement, resulting in larger errors. Therefore, the measurement of each doctor will also produce errors, and the electronic sphygmomanometer eliminates the human error; in addition, the doctor often ignores some errors and rounds up, such as 128mmHg, 131mmHg; maybe the doctor reads it directly as 130mmHg; but the sphygmomanometer No, the value is displayed as much as the measurement is. Moreover, the measurement of blood pressure is related to the emotion of the person. When someone goes to the hospital, there will be a certain degree of anxiety in front of the doctor, emotional tension and mental stress, and the measured blood pressure monitor will High, and relaxed at home, the measured blood pressure value is relatively low, and this is the real blood pressure value of the human body.

The best time to measure blood pressure is within 1 hour after getting up in the morning, or before eating in the evening. For the morning measurement, please take it within 1 hour after waking up, after urination, and before breakfast (if you are taking antihypertensive drugs, before taking the medicine). For evening measurements, it is recommended to measure before meals.

In the case of not taking antihypertensive drugs, the systolic blood pressure (high pressure) is greater than or equal to 140mmHg, or the diastolic blood pressure (low pressure) is greater than or equal to 90mmHg.

In terms of design accuracy and manufacturing accuracy of electronic blood pressure monitors, the inspection specifications of the wrist type and the arm type are the same, and there is no obvious difference in principle. Therefore, as long as the registered sphygmomanometer has obtained the registration certificate, the wrist type and the arm type are accurate The degrees are the same. However, because the measurement result of the sphygmomanometer is greatly affected by the measurement posture, the arm is close to the heart, and is basically parallel to the heart position. The measurement requirements are not as strict as the wrist type; the wrist is far away from the heart, and the measurement must be consistent with the heart. A slight change will cause a large error, which will affect the measurement result.

There may be shaking during the measurement, or the blood pressure of the person being measured is low, the detection function of the sphygmomanometer will pressurize the sphygmomanometer to the ideal value again and measure the accurate blood pressure.

It can be seen from the working principle of common sphygmomanometers on the market that in fact, it can be used regardless of the left upper limb or the right upper limb, and there is no strict definition of which hand must be used. In most cases, the blood pressure measured by the right hand is higher than that of the left hand. Therefore, the hospital usually recommends the right hand measurement, because the 'higher' blood pressure is the value closer to the real blood pressure in the body. It is recommended for home use to measure with the left hand because it is convenient to control the sphygmomanometer and the trachea is at the same height as the heart.