There are Some one have said that while measuring their blood pressure, they initially didn't notice anything unusual, but later discovered that a particular model of blood pressure monitor consistently provided higher readings compared to other types of blood pressure measurements. This has led them to suspect if there might be an issue with that specific blood pressure monitor. It is not uncommon to observe variations in blood pressure readings among different devices. There have also been cases where people have noticed significant differences even when using the same model of blood pressure monitor, whether measuring from the wrist or switching to the upper arm. This has left many individuals confused about which reading represents their true blood pressure. So, how should one choose a blood pressure monitor for home use?

1. Nearly half of the patients are unaware that they have hypertension (high blood pressure).

In a study conducted by over 1,100 doctors and scientists, the largest global study on hypertension trends to date, it was found that over 700 million adults aged 30 to 79 were unaware of their high blood pressure condition.

Doctors state that hypertension often presents no noticeable symptoms and is often only detected when the long-term damage caused by persistently high blood pressure, such as heart attacks and organ damage, becomes evident after 10 to 20 years.

There is also a condition known as "masked hypertension" where blood pressure rises during specific periods, such as in the morning or at night. If blood pressure measurements are taken during periods when it is not elevated, such as during outpatient visits, this type of hypertension can be easily missed. The dangers of masked hypertension are similar to those of typical hypertension.

It is evident that infrequent or occasional blood pressure measurements can lead to missed diagnoses. In the current consensus on hypertension diagnosis and treatment, the "gold standard" for diagnosing hypertension is ambulatory blood pressure monitoring. Ambulatory blood pressure monitoring provides higher accuracy and comprehensive data. However, it can be expensive and may require scheduling appointments at hospitals, which is why home blood pressure monitoring has become an important supplementary method.

Many households rely on electronic blood pressure monitors to track blood pressure changes at home. However, some patients have reported that when using electronic blood pressure monitors, the readings sometimes become lower with each measurement, and there can be significant differences between consecutive measurements. Why does this happen?

2. Fluctuations in electronic blood pressure readings and their continued use

Some individuals with hypertension may believe that electronic blood pressure monitors provide inaccurate measurements and consider switching to mercury sphygmomanometers, thinking that traditional devices offer more accurate readings. However, in most cases, there is no need to use mercury sphygmomanometers. Mercury devices are bulky, inconvenient to use, and require professional calibration. In terms of convenience and clarity, electronic blood pressure monitors are more suitable for home use. Regular calibration every one or two years at a service center is sufficient. 

But why do electronic blood pressure monitors sometimes show variations between consecutive readings? Could it be a quality issue with the purchased device? There are several reasons why blood pressure monitors may not be accurate:

Different types and brands of electronic blood pressure monitors:

When electronic blood pressure monitors were initially introduced, there was a wide range of quality levels. Many products did not pass international certification standards. However, due to their low price, these non-compliant products gained popularity. Moreover, there are various types of electronic blood pressure monitors available, such as wrist-style, finger-style, and sleeveless models. Different categories can result in significant differences in data accuracy.

It is generally recommended to purchase upper-arm fully automatic electronic blood pressure monitors that have been certified according to recognized standards (such as AAMI/ESH/ISO). These devices tend to provide relatively accurate measurements. For example, the Pangao electronic blood pressure monitor is a brand with over 20 years of history and produces monitors that have passed international certifications.

It is important to note that due to the sensitivity of electronic blood pressure monitors and the constant fluctuations in blood pressure within the human body, fluctuations in measurement values are common. It is rare to have exactly the same measurement values in consecutive measurements.

Fluctuations in individual blood pressure:

In a healthy adult, blood pressure can fluctuate by 15-30 mmHg within a day due to factors such as time, temperature, season, and emotions. The fluctuations in individuals with hypertension can be even greater. For instance, anger, tension, fear, and stress can elevate systolic blood pressure, while exposure to cold temperatures can increase blood pressure. Smoking, alcohol consumption, coffee intake, and bathing can lower blood pressure. Blood pressure can also differ between the right and left upper limbs by 2-4 mmHg, and the blood pressure in the lower limbs can be 20-40 mmHg higher than in the upper limbs.

Not everyone is suitable for electronic blood pressure monitors:

Electronic blood pressure monitors use oscillometric methods, which may not be suitable for individuals who are excessively obese, have arrhythmias, Parkinson's disease, weak pulses, severe respiratory distress, low body temperature, heart rates below 40 beats per minute or above 240 beats per minute, significant bleeding, low blood volume, shock, or experience rapid fluctuations in blood pressure. Measurements from electronic blood pressure monitors may differ from actual blood pressure values in these cases.

Incorrect measurement technique:

Some individuals place the cuff around their elbow joint when measuring blood pressure. This prevents the cuff from properly fitting around the upper arm, resulting in a large gap and potential measurement errors. Additionally, body movement and limb activity during measurement can significantly affect the accuracy of blood pressure readings. To obtain more accurate data, it is recommended to measure blood pressure 2 to 3 times, take the average value, maintain a minimum 3-minute interval between measurements, and ensure consistent positioning and posture.

3. Does a blood pressure reading of 140/90 mean high blood pressure?

In the perception of many people, a blood pressure reading of 140/90 mmHg is considered indicative of high blood pressure. However, this answer is incorrect. There are strict diagnostic criteria for hypertension. In a medical setting, it is required to have multiple measurements on different days, with readings exceeding 140/90 mmHg at least three times. For home blood pressure monitoring, the threshold for diagnosing hypertension is typically adjusted to readings equal to or higher than 135/85 mmHg.

Repeating the measurements multiple times is important because factors such as unfamiliar environment, anxiety, inadequate rest before measurement, or failure to repeat the measurement may lead to occasional elevations in blood pressure readings.

High blood pressure poses significant risks to cardiovascular health. So, what blood pressure level is considered safe? According to a study published in the New England Journal of Medicine by a research team from the Hypertension Center at Fuwai Hospital, Chinese Academy of Medical Sciences, it is recommended to adjust the blood pressure target for elderly hypertensive patients to below 130 mmHg, which is relatively safe in terms of clinical benefits.

In terms of daily blood pressure management, Dr. Zhong Nanshan advises patients to adhere to the prescribed medication in terms of timing and dosage to avoid and minimize the harm caused by high blood pressure.

In addition to necessary medication, it is also important to pay attention to regular physical exercise, healthy diet, adequate sleep, and stress reduction. Developing these habits will naturally help in controlling blood pressure.