Detailed Explanation of Blood Pressure Fluctuation Patterns and Correct Measurement Methods

Does blood pressure fluctuate? The answer is yes. Blood pressure readings often differ at different times, sometimes significantly. This is due to the individual's natural blood pressure variations, external environmental factors, or measurement errors.

Like most living organisms, humans exhibit cyclical changes throughout the day. For example, hormone secretion is generally suppressed in the morning, gradually increasing from noon and peaking in the afternoon. Blood pressure follows the same pattern. As discussed earlier, blood pressure is often higher in winter than in summer, a phenomenon known as seasonal variation, regardless of whether the individual has normal or high blood pressure. Similarly, blood pressure fluctuates throughout the 24-hour period, peaking between 9 and 10 AM, gradually decreasing, and reaching its lowest point during sleep. This difference can be as high as 40 mmHg. Upon waking, blood pressure can rise by about 19.5 mmHg, and further increases after getting up and moving around, making this a high-risk time for sudden death from coronary heart disease. This 24-hour blood pressure fluctuation is primarily due to changes in the sensitivity of baroreceptors and the level of norepinephrine in the blood plasma.

Fluctuations in plasma norepinephrine levels parallel blood pressure fluctuations. However, when baroreceptor sensitivity is high and neural inhibition is effective, blood pressure fluctuations are smaller, and vice versa. For example, middle-aged and elderly individuals experience larger blood pressure fluctuations due to lower baroreceptor sensitivity.

Furthermore, blood pressure can be temporarily affected by factors such as alcohol consumption, smoking, caffeine intake, and emotional excitement. Therefore, these factors must be avoided when measuring blood pressure.

Recognizing the variability of blood pressure is crucial for the diagnosis and treatment of hypertension. Due to this variability, we cannot determine an individual's blood pressure level based solely on a single indirect blood pressure reading. Repeated blood pressure checks in a comfortable, quiet environment, under appropriate surgical techniques, are essential.