Most people have heard about blood pressure and know it has two numbers. The top number is called systolic blood pressure.
It shows how hard the blood pushes against the artery walls when the heart beats. The bottom number is called diastolic blood pressure. It shows the pressure when the heart is resting between beats.
Doctors usually focus more on the top number when checking for heart disease. But a new study suggests the bottom number might be just as important—especially for brain health.
This study was done by researchers from the University of Miami and published in the journal *Stroke*. The scientists studied over 1,200 adults aged 50 and older. They wanted to find out if blood pressure was connected to tiny scars in the brain called white matter lesions.
These white matter lesions are not something you can feel. They don’t cause pain or show symptoms at first. But over time, they can harm brain function. These lesions are linked to problems with memory, balance, thinking clearly, and even a higher risk of stroke and dementia.
Using brain scans (MRIs), the researchers looked at the size and location of these white matter lesions. They found something interesting. People who had lower diastolic blood pressure—below 80—had fewer and smaller brain scars.
But those with higher diastolic pressure—especially over 90—had more of these lesions. The damage was seen in important areas of the brain that help with memory and movement.
This finding adds to what scientists already know. High systolic pressure is known to hurt blood vessels and lead to brain damage. But this study shows that high diastolic pressure can also cause harm, especially to brain areas that are sensitive to changes in blood flow.
White matter in the brain helps carry messages between brain regions and the rest of the body. When it’s damaged, those messages don’t travel as well. That can make it harder to move, stay balanced, or remember things. It can also raise the chance of falling.
According to the American Heart Association, about 10% to 20% of people in their 60s already have these brain scars. By the time people reach their 90s, most have them.
The study also pointed out one brain region that’s very sensitive to blood flow: the periventricular area. When lesions show up there, they are more likely to cause memory and thinking problems.
The researchers explained that different parts of the brain are served by different blood vessels. So, blood pressure problems may affect some areas more than others. Even a small change in blood pressure could make a big difference, depending on where in the brain it happens.
In simple terms, this study shows that both the top and bottom blood pressure numbers matter. Taking care of your blood pressure could help protect your brain as you get older. It’s not just about avoiding heart attacks—it’s also about keeping your memory, balance, and thinking sharp.
If it’s been a while since you had your blood pressure checked, now is a great time to ask your doctor. Knowing your numbers could help you stay healthier, longer.
If you care about blood pressure, please read studies about the ideal blood pressure for older people and common high blood pressure drugs may cause memory problems.
For more information about blood pressure, please read studies about A common blood pressure medication that could help you live longer and 1 in 5 people with high blood pressure takes a medication that harms blood pressure.
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