The number of people with hypertension is increasing, so self-monitoring of blood pressure is becoming more and more relevant, but people still have many questions about the interpretation of the readings when taking blood pressure. Why is the blood pressure reading high or low? Many people ask why my blood pressure is higher in the hospital than at home. Because of the noisy and crowded environment in the hospital, usually the blood pressure measured by hypertensive patients in outdoor and public places is higher than the blood pressure measured at home. This is called “white coat hypertension”, but some people have lower blood pressure when they see a doctor in a white coat, which requires 24-hour ambulatory blood pressure monitoring. Usually we are familiar with the environment at home, quiet, more relaxed, not affected by medical personnel and other, measured blood pressure is the general state of daily life blood pressure information, so the standard value of home self-measurement blood pressure is generally lower than the clinic measurement value of about 5 mmHg, self-measurement hypertension standards need to be lower than 135/85 mmHg. We will make the measured blood pressure reading of the reasons for high: 1, the environment and Mental factors: cold environment, after activity or exercise, within one hour after meal, just after bathing, after drinking alcohol, just after drinking tea or coffee, after smoking, holding urine, nervousness or greater mental activity (such as emotional anxiety); 2, mechanical factors: balloon valve leakage, obstruction of the sphygmomanometer’s channel, stethoscope head too cold, cuff too narrow, cuff tied too loosely, cuff tied too short, gas not released from the cuff before measurement. 3, personal factors: the subject’s upper arm is mildly paralyzed, holding his breath, staying up late, insomnia, pain, the subject’s measured arm angle is too small (should be 135°), legs are crossed (should be vertically down), talking to others while measuring blood pressure, upper arm position is higher than the heart (right atrium), the line of sight is higher than the mercury column when reading (looking down), the inflation compression time is too long, only one measurement was taken, too slow deflation will make the diastolic pressure misread on the high side. And what factors can cause a low blood pressure value? There are factors such as a recent meal, arrhythmia, shock, hypoglycemia, inadequate mercury, wide cuff, tight cuff, excessive stethoscope head pressure, upper arm position below the heart, reading with the line of sight below the mercury column (elevation), rapid deflation can cause systolic blood pressure to be misinterpreted as low, morning and early morning values can be lower than afternoon or evening values, and low values can be measured when wearing warm, thick clothing or feeling somewhat hot or hyperthermic environments. In some patients, the pulse sound does not disappear until the pressure in the cuff drops to zero. This situation is more common in children, patients with aortic valve insufficiency, high cardiac output (such as anemia, hyperthyroidism, pregnancy) and obvious vasodilation (after exercise), when the sound suddenly becomes smaller as diastolic pressure. In addition, the level of reading is also related to the choice of blood pressure monitor. Now home blood pressure measurement is usually used electronic sphygmomanometer, divided into arm type, wrist type and finger type, because the measurement of blood pressure is mainly measured brachial artery, so it is best to use the arm type electronic sphygmomanometer. But the most accurate or hospital use of mercury sphygmomanometer, other types of sphygmomanometer readings with which there is no specific reading high or low. So barometer and electronic sphygmomanometers are calibrated at least once every 6 months. Another thing to keep in mind when taking readings is that bilateral brachial blood pressure in healthy people is not equal, and the difference between the two can be 10-20 mmHg, generally measured in the right upper extremity (heart on the left). If there is a large difference between the blood pressure of the two arms, the higher side is used. The normal range of blood pressure: systolic (90-139) mmHg, diastolic (60-89) mmHg. Normal blood pressure shows obvious diurnal fluctuations, with the lowest blood pressure at night and a gradual rise after morning activity, with a variation of 30-40 mmHg and a “two peaks and a valley” distribution. The distribution of blood pressure is “two peaks and a valley”, with a peak at 6:00-10:00 am and 4:00-8:00 pm, followed by a slow decline. The overall level of diurnal variation in blood pressure in hypertensive patients is higher and fluctuates more. There is also a difference between winter and summer, with seasonal changes all causing changes in blood pressure. Blood pressure fluctuates with mood, rest, and weather. Blood pressure is lower in the peak summer months than in the fall and winter. Patients with hypertension should have their blood pressure measured at regular intervals, in a regular position, and with a regular sphygmomanometer. This will give the most comparable blood pressure. (Repeated continuous measurements can also lead to differences, and generally the more you measure, the lower it gets.) There is a difference between the left and right hand blood pressure of each person. Those with stable blood pressure control should preferably monitor their blood pressure daily after waking up in the morning and before going to bed. Blood pressure is measured 1-2 times a week when it is stable, and at least 1-2 times a day when it fluctuates. It is best to measure blood pressure at the same time every day, such as at 8:00 a.m. every day, which is good for comparing blood pressure levels and finding out the pattern of blood pressure fluctuations. In addition to the fixed time, you can also measure at any time according to the patient’s self-perception. What is the significance of blood pressure pulse pressure difference: pulse pressure difference: refers to the difference between systolic and diastolic blood pressure, the normal range is 30-40mmHg . Generally greater than 60 mmHg, known as an increase in pulse pressure difference, less than 20 mmHg known as a decrease in pulse pressure difference. Any factor that can affect the systolic and diastolic blood pressure can affect the pulse pressure difference. Common diseases that cause large pulse pressure difference: aortic valve closure insufficiency, aortic sclerosis, hyperthyroidism, severe anemia, rheumatic heart disease, syphilitic heart disease, some congenital heart disease and hypertensive heart disease, bacterial endocarditis, etc. For example, simple systolic hypertension with normal diastolic blood pressure and increased pulse pressure differential in the elderly due to atherosclerosis of the aorta and other large arteries and reduced elasticity and stretch of the arterial wall. Common diseases that cause decreased pulse pressure difference: massive pericardial effusion, constrictive pericarditis, severe mitral stenosis, aortic stenosis, severe heart failure, peripheral circulation failure, shock, and due to obesity, increased blood viscosity or combined diabetes mellitus, hyperlipidemia, etc. Once the difference in pulse pressure is found to be abnormal, the cause should be promptly identified at the hospital and the primary cause should be treated. For example, organic aortic insufficiency must rely on cardiac surgery to resolve. When a significant decrease in pulse pressure difference is found, if no clear cause is found after detailed examination, it should be considered as a somatic blood pressure reduction (mainly referring to systolic blood pressure). To treat somatic hypotension, in addition to enhancing physical fitness and proper nutrition, it is necessary to prevent dizziness or fall when standing. It can be treated with drugs such as glutamate and vitamins that have a regulating effect on the vegetative nerves. It is not necessary to pay too much attention to the small pulse pressure difference without discomfort, as it will not have too much impact on health.