In the clinic, we often encounter patients who ask, “Why is my blood pressure unstable and fluctuates a lot? Many patients do not understand, and even believe that blood pressure is unchanging. In fact, this is not the case. For blood pressure fluctuations, we generally need to clarify several issues: First, human blood pressure is constantly changing human blood pressure is regulated by a variety of internal and external factors, its own in the process of continuous change to adapt to the internal and external environment. Blood pressure fluctuates from 20-30 mmHg throughout the day, and this fluctuation will increase with age, and the fluctuation of the elderly is much larger than that of the young. The time of day when blood pressure changes the most is early in the morning, when the hormones and nerve activity secreted by the body are mainly excited to wake up the body as soon as possible, so blood pressure rises rapidly to a higher level. In general, blood pressure has 2 peaks and 2 valleys in a day: the first peak is at 6-8 a.m.; after 8 a.m., it starts to fall, and the first valley is from noon to 2 p.m.; then blood pressure starts to rise, and the second peak is at 5-8 p.m.; after that, blood pressure falls, and blood pressure during sleep is generally at the lowest range in a day, which is the second valley, and then blood pressure gradually rises. If we look at a larger time span, blood pressure is generally higher in winter than in summer, which is due to vasodilation caused by temperature; blood pressure in the elderly tends to rise gradually and shows a tendency for systolic blood pressure to rise and diastolic blood pressure to fall as a result of changes in vascular elasticity. Therefore, cardiovascular diseases such as angina pectoris, myocardial infarction and stroke are particularly likely to occur in the early morning and morning hours in winter. Accordingly, it is best to take antihypertensive medication before the morning peak of blood pressure, which is usually recommended by doctors as soon as you wake up every morning. And try to take long-acting antihypertensive drugs, in order to smoothly, safely and permanently control the blood pressure level.