Patients often ask their doctors, “Why is my blood pressure always unstable? Why is my blood pressure always fluctuating?” Today I’m going to talk about what exactly is going on with fluctuating blood pressure. Is fluctuating blood pressure normal? Before we talk about blood pressure volatility let’s first recognize how blood pressure is formed. The blood flowing in the blood vessels exerts pressure on the walls of the vessels, and this lateral pressure is called blood pressure, which we usually refer to as arterial blood pressure. The blood pressure in the human body depends on the beating of the heart and the tension of the blood vessels. The following is a simple physical phenomenon that we can easily understand: the blood flowing in the blood vessels is like the liquid flowing in an elastic pipe. The human blood vessels are similar to pipes and not exactly the same as pipes, in addition to having elasticity and tension, they are also regulated by the body’s neuroendocrine regulation. The human heart is like a pump upstream of the pipeline, but not as simple as the structure of a pump. The normal heart contracts and diastole at a regular rhythm of 60-100 times per minute to pump the blood that flows back into the heart from the venous system into the arterial system in a rhythmic manner. When the heart is constantly contracting and diastolic, the blood flowing in the blood vessels will have a “fluctuating” pressure on the walls, which is the fluctuating blood pressure. When the heart’s systolic and diastolic functions and rhythm change, and the tension of the blood vessels change, the volatility of blood pressure will increase. On the contrary, when the body is in a quiet state, sympathetic excitability is low, and blood pressure is relatively low. When blood pressure fluctuates, this pressure receptor will automatically transmit the information of pressure changes to the brain, which will subtly issue a command to stabilize the fluctuating blood pressure by regulating the heart, blood vessels and neuroendocrine functions. Our daily life content can not be exactly the same every moment, blood pressure fluctuations in addition to the heart beating constantly, but also with the different daily life events related to the normal human blood pressure fluctuation range of about 20-30mmHg, sometimes up to 40mmHg, but rarely in 140/90mmHg or more fluctuations. Most patients with hypertension have varying degrees of vascular sclerosis, and the elasticity of blood vessels is reduced, and the function of the heart, especially diastolic function, is often reduced. In particular, in elderly people and patients with severe atherosclerosis combined with reduced pressure receptor function, blood pressure fluctuates greatly, such as sometimes 90/55 mmHg, sometimes 170/90 mmHg or even higher within 24 hours. This is also a common concern for people with hypertension. If this happens, there is no need to be afraid and you should first consult a hypertension specialist, regardless of whether you feel unwell or not. The most accurate tool for determining blood pressure fluctuations is the ambulatory blood pressure monitor (which is completely different from taking multiple measurements at home with a blood pressure monitor). The device will automatically measure the patient’s blood pressure according to the set parameters, with minimal influence from the subject, the measurer and environmental factors, and can objectively reflect the subject’s 24-hour blood pressure, including the high peak and low values and the time of occurrence, the correlation between blood pressure volatility and life events, and the blood pressure during sleep, so that the doctor can accurately grasp the subject’s 24-hour blood pressure fluctuation In addition, ambulatory blood pressure can also accurately rule out “pseudohypertension” and white coat hypertension. We understand the reasons for blood pressure fluctuations here, the blood pressure of normal people fluctuates in the normal range, and the blood pressure of hypertensive patients fluctuates at a higher level when the blood pressure has not dropped to normal. There are some situations that doctors or patients should pay attention to. When the results of ambulatory blood pressure testing do belong to blood pressure fluctuations significantly, or when the patient has postural blood pressure changes, the first thing to look for is the cause of large fluctuations in blood pressure.