Most people have their blood pressure checked while sitting during a visit to the doctor. This simple test has been used for many years to help detect high blood pressure and estimate a person’s risk of heart disease.
However, recent research suggests that measuring blood pressure only while sitting may miss an important warning sign in some people.
Researchers discovered that some people have normal blood pressure while sitting but high blood pressure when they are lying flat on their backs. Even though their sitting readings appear healthy, these people may still face a higher risk of heart disease, stroke, heart failure, and early death.
High blood pressure, also called hypertension, is one of the leading causes of heart disease around the world. It usually develops slowly and often causes no symptoms, which is why it is sometimes called the “silent killer.” If it is left untreated, it can damage blood vessels and important organs for many years before problems become obvious.
Our bodies constantly adjust blood pressure depending on our position. When we stand up, sit down, or lie down, the heart and blood vessels work together to keep blood flowing properly to the brain and the rest of the body. In some people, however, these adjustments do not work as they should. As a result, blood pressure may become high in one body position but not in another.
The study was led by Duc M. Giao, a medical student at Harvard Medical School. His team analyzed health information from more than 11,000 adults whose blood pressure was measured while lying down between 1987 and 1989. The researchers then followed these participants for nearly 30 years to see how their health changed over time.
The results were surprising. About 16% of the participants had high blood pressure only when lying down, even though their blood pressure was normal while sitting. This means that nearly one in six people had a hidden form of high blood pressure that could easily be missed during a routine medical check-up.
As expected, people with high blood pressure while both sitting and lying down had a greater risk of developing heart disease, stroke, heart failure, and dying earlier than those with normal blood pressure.
More importantly, the researchers found that people whose blood pressure was high only while lying down faced almost the same increased risks. This suggests that high blood pressure in the lying position should be taken just as seriously as high blood pressure found while sitting.
These findings may change the way doctors think about blood pressure testing. Measuring blood pressure in more than one body position could provide a more complete picture of a person’s heart health.
For people who already have risk factors such as diabetes, kidney disease, obesity, smoking, or a family history of heart disease, additional blood pressure measurements may help uncover hidden problems earlier.
The researchers also suggested that some people could benefit from blood pressure monitoring outside the doctor’s office. Home blood pressure monitors, 24-hour blood pressure monitoring, and overnight measurements may reveal changes that cannot be detected during a single clinic visit.
This study mainly involved middle-aged adults, so future research will need to examine whether the same pattern is seen in older adults and other groups. Scientists also hope to learn why some people develop high blood pressure only while lying down and whether treating it can lower the risk of future heart problems.
The findings remind us that heart health is sometimes more complicated than a single blood pressure reading. Checking blood pressure in different body positions may help doctors identify hidden risks earlier, allowing treatment to begin before serious complications develop.
A simple extra measurement while lying down could one day become another useful tool for protecting heart health and saving lives.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and coconut sugar could help reduce blood pressure and artery stiffness.
For more information about blood pressure, please see recent studies about added sugar in your diet linked to higher blood pressure, and results showing plant-based foods could benefit people with high blood pressure.
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