Measuring blood pressure (BP), At first glance, this is a fairly simple procedure, especially if you have an electronic tonometer. You just need to put a cuff on your arm and wait a while until the device itself measures the pressure and provides the results. However, in reality, everything is not so simple – scientists are concerned that many people make an error when measuring BP, which greatly affects the results. This difference is so serious that it can affect the diagnosis. For example, with the correct measurement, the indicators may be normal, and with the wrong one – indicate hypertension. Accordingly, because of this difference, people may incorrectly take drugs that lower blood pressure.
A study has shown that people often measure blood pressure incorrectly. Photo source: densaulyksemey.kz
Contents
- 1 What is blood pressure
- 2 What mistake do people make when measuring blood pressure
- 3 Why does the position of your hand affect the results of your blood pressure measurement
- 4 How to hold your hand correctly when measuring your blood pressure
What is blood pressure
Blood pressure is an indicator of the force with which blood acts on the walls of blood vessels. As you know, when blood pressure is measured, two indicators are taken – the so-called “upper” and “lower” pressure. What is this connected with? The fact is that in the work of blood circulation, two phases are distinguished – the ejection of blood from the heart as a result of muscle contraction (systolic, or upper pressure occurs) and the return of blood to the heart, when the muscle relaxes and the heart cavities expand (diastolic, or lower pressure occurs).
As you might guess, the upper pressure is always higher than the lower pressure, as it is related to muscle tension. The difference between these indicators is called pulse pressure. When measuring blood pressure, it is extremely important that each indicator is accurate, as the diagnosis that doctors can make depends on it.
People often hold their hand incorrectly when measuring blood pressure. Photo source: stethoscopes.ru
What mistake do people make when measuring blood pressure
Researchers from Johns Hopkins University have found that there are common hand positions that distort blood pressure measurements. For their work, they recruited more than 130 people aged 18 to 80. All participants in the experiment had their blood pressure measured several times with different hand positions – in the first case, the hand was lying on the table (as recommended), in the second case, the hand was placed on the knee, and in the third, it was simply hanging down.
When volunteers placed their hand on their knee, the upper and lower pressures were overestimated by four points. When measuring pressure with the arm completely hanging, the pressure readings were distorted even more – the upper pressure was overestimated by about seven points, and the lower by 4.4 points.
The authors then conducted the same experiment, but with people who already suffer from high blood pressure. As it turned out, in this group all the indicators were even higher. When the participants hung their arm along the body or even just put it on their knee while sitting, the distortion of the indicators reached 10 points. It should be taken into account that most often it is people who have health problems who measure their blood pressure. Healthy people usually do not need to do this.
Due to incorrect blood pressure measurement, many people are misdiagnosed. Photo source: vedomosti.ru
As the authors of the work report in the JAMA Internal Medicine publication, due to the incorrect position of the hand when changing the pressure, in the US alone about 54 million people are misdiagnosed with hypertension. That is, people are told about high blood pressure, although in fact they do not have health problems.
Why the position of the hand affects the results of blood pressure measurement
The results of the study clearly showed how important it is to follow the technique of measuring blood pressure. But why does the position of the hand affect the results so much? Most likely, there are several reasons for this.
First of all, gravity affects blood pressure. The lower the hand is at the level of the heart, the higher the blood pressure. In addition, incorrect hand position can lead to muscle tension, which in turn changes the blood flow. This can also cause increased pressure.
When measuring blood pressure, the hand should be relaxed and lie on the table. Photo source: csmedica.ru
How to hold your hand correctly when measuring blood pressure
Before measuring blood pressure, experts recommend sitting down and sitting quietly for five minutes. Smokers are advised to measure blood pressure no earlier than half an hour after smoking a cigarette. Also, you should not measure blood pressure after drinking alcohol or caffeine.
When measuring blood pressure, you need to sit correctly on a chair – both feet should be on the floor, your back should be straight and leaning against the back of the chair. The environment should be calm and quiet. The arm on which the pressure is measured should lie on a table or desk. The cuff should be put on a bare arm. It should be positioned so that it is at heart level. As we have previously said, it is advisable to measure blood pressure on both arms.
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As the authors of the work report, not all medical institutions comply with the above rules. So if you are having your blood pressure measured, don't be shy about asking for a table to get accurate results.