Most people know that high blood pressure is bad for the heart, but many do not fully understand what the two numbers in a blood pressure reading actually mean.
Every blood pressure result includes a top number and a bottom number, and both tell doctors important things about how the heart and blood vessels are working.
The top number is called systolic blood pressure. It measures the force created when the heart pumps blood through the arteries. The bottom number is called diastolic blood pressure. It shows the pressure inside the arteries when the heart is resting between beats.
For many years, doctors have used both numbers to evaluate a person’s risk of heart disease. However, in recent decades, greater attention has been placed on systolic pressure, especially in older adults. Studies have shown that high systolic pressure strongly increases the risk of heart attacks, strokes, heart failure, and early death.
Now, a large new study from the University of Southern Denmark suggests that the lower number—diastolic pressure—may still play a very important role, especially for younger adults.
The research followed more than 107,000 people between the ages of 19 and 97 for 26 years. None of the participants had heart disease when the study started. During the following decades, researchers tracked who developed heart problems, suffered strokes or heart attacks, or died from heart-related conditions.
The study was led by Dr. Michael Hecht Olsen and was published in the journal Hypertension.
The results confirmed that systolic pressure remains a powerful predictor of heart disease at every age. High systolic readings increased the risk of heart problems in both men and women, whether they were young or old.
But the researchers also made an important discovery about younger adults. For people under the age of 50, high diastolic pressure was also strongly linked to future heart disease risk. This means that the bottom number may provide an early warning sign that should not be ignored in younger people.
The findings challenge the idea that only systolic pressure matters. In younger adults, paying attention only to the top number could mean missing signs of future heart trouble.
Scientists believe this difference may be partly related to how blood vessels change with age. In younger people, the arteries are usually more flexible and elastic. When diastolic pressure rises, it may reflect increased resistance inside the blood vessels, which can place extra strain on the heart over time.
As people get older, arteries often become stiffer. At that stage, systolic pressure usually becomes the more important indicator because stiff arteries make the heart work harder during each heartbeat.
The researchers also studied another blood pressure measurement called mean arterial pressure, or MAP. MAP is calculated using both systolic and diastolic pressure and represents the average pressure inside the arteries during one full heartbeat cycle.
The study found that MAP was a strong predictor of heart disease and death across all age groups. This suggests that using several blood pressure measurements together may help doctors better understand a person’s overall cardiovascular risk.
High blood pressure, also called hypertension, is one of the most common health problems in the world. In the United States alone, nearly half of adults have high blood pressure. According to current guidelines, hypertension is generally defined as a systolic reading of 130 or higher or a diastolic reading of 80 or above.
Many people think high blood pressure mainly affects older adults, but this is not true. Health experts say more than one in five adults between the ages of 18 and 39 already have high blood pressure.
Unfortunately, younger adults are often less likely to check their blood pressure regularly because they may feel healthy and have no symptoms.
This is dangerous because high blood pressure is often called a “silent killer.” It can quietly damage blood vessels, the heart, kidneys, brain, and eyes for many years before serious symptoms appear.
The researchers say the new findings highlight the importance of checking both blood pressure numbers, especially in younger adults. Early detection could allow people to make lifestyle changes before major health problems develop later in life.
Doctors recommend several ways to help control blood pressure naturally. Eating a healthy diet with plenty of fruits and vegetables, staying physically active, reducing salt intake, limiting alcohol, maintaining a healthy weight, sleeping well, and managing stress can all help support healthy blood pressure.
For some people, lifestyle changes alone are not enough, and medication may be needed. In those cases, it is important to follow medical advice carefully and continue regular blood pressure monitoring.
The study may also influence future medical guidelines by encouraging doctors to consider age more carefully when interpreting blood pressure results. Instead of focusing mostly on the top number for everyone, doctors may increasingly look at both numbers together, especially in younger patients.
The findings are an important reminder that blood pressure is more complex than many people realize. Both numbers can reveal valuable information about heart health, and understanding them better may help prevent heart disease long before it starts.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
For more health information, please see recent studies about added sugar in your diet linked to higher blood pressure, and results showing vitamin D could improve blood pressure in people with diabetes.
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