Blood pressure is one of the most common health checks in the world. Many people have had their blood pressure measured at a clinic, pharmacy, or even at home.
It seems like a simple and reliable test. However, new research suggests that the way blood pressure is usually measured may not always give accurate results.
Scientists from the University of Cambridge have found new evidence explaining why the traditional method can sometimes give wrong readings. Their findings, published in the journal PNAS Nexus, show that small changes in how the test is done could make it much more accurate.
Blood pressure is the force of blood pushing against the walls of your arteries. When this pressure is too high, it is called hypertension. High blood pressure is a major health problem around the world. It is strongly linked to heart disease, strokes, and heart attacks, and it is one of the leading causes of early death.
Because of this, getting the correct blood pressure reading is very important. If the reading is wrong, doctors may miss the chance to diagnose and treat high blood pressure early. Researchers estimate that up to 30% of people with high blood pressure may not be diagnosed correctly because of errors in measurement.
The most common way to measure blood pressure is with a cuff placed around the upper arm. The cuff is inflated to stop blood flow and then slowly deflated. As the air is released, a healthcare worker listens with a stethoscope for sounds that show blood is flowing again.
These sounds help determine the systolic pressure, which is the top number, and the diastolic pressure, which is the bottom number.
This method is known as the auscultatory method and has been used for many years. It is often called the “gold standard.” A normal blood pressure reading is usually around 120 over 80.
However, the Cambridge researchers found that this method is not perfect. It often gives a systolic reading that is lower than the true value and a diastolic reading that is higher than the real value. While doctors already understood why the diastolic number might be too high, the reason for the systolic error was not clear until now.
To study this problem, the research team created a new model to better understand what happens inside the arm during a blood pressure test.
In the past, scientists used rubber tubes to represent arteries, but these did not behave like real human arteries when squeezed. The Cambridge team designed more realistic models that flatten and close in the same way real arteries do.
Their experiments showed that when the cuff squeezes the arm, it not only stops blood flow but also creates very low pressure in the part of the arm below the cuff. This low pressure keeps the artery closed for longer than expected as the cuff deflates.
Because of this delay, the moment when blood flow starts again is detected later than it should be. This leads to a systolic reading that is lower than the person’s true blood pressure. In simple terms, the test may miss the real peak pressure.
This discovery helps explain why many people with high systolic blood pressure may not be diagnosed. Since healthcare workers do not usually adjust for this effect, the error can go unnoticed.
The good news is that fixing this problem may not require new machines or expensive technology. The researchers suggest that simple changes in how the test is done could improve accuracy. For example, raising the patient’s arm before taking a reading may help balance pressure in the arm and reduce the error.
In the future, new devices could also be designed to take into account factors such as a person’s age, body shape, and tissue characteristics. These details could help provide more personalized and accurate readings.
The research team now hopes to test their findings in real patients. They are looking for partners and funding to carry out clinical studies. Their goal is to improve blood pressure measurement for people of all backgrounds.
This study offers a clear explanation for a long-standing problem in medicine and points to a simple way forward. More accurate blood pressure readings could lead to better diagnosis and treatment, helping people live longer and healthier lives.
If you care about blood pressure, please read studies about unhealthy habits that could increase high blood pressure risk, and eating eggs in a healthy diet may reduce risks of diabetes, high blood pressure.
For more information about blood pressure, please see recent studies that early time-restricted eating could help improve blood pressure, and results showing 12 foods that lower blood pressure.
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