A recent study has found that the bottom number in a blood pressure reading—known as diastolic blood pressure—may be more important for brain health than many people realize.
The research, published in the journal Stroke and led by scientists from the University of Miami, suggests that high diastolic pressure could be linked to silent damage in the brain that raises the risk of dementia, stroke, and even falls.
Most people know that blood pressure has two numbers. The top number, called systolic blood pressure, measures the force of blood against the artery walls when the heart beats. The bottom number, diastolic blood pressure, measures the force when the heart is resting between beats.
Health experts often focus more on the top number, especially when it comes to predicting heart disease. But this new study shows the bottom number might also deserve attention—especially when it comes to the brain.
In this study, researchers looked at more than 1,200 men and women aged 50 and older. They wanted to see if blood pressure had any connection to tiny scars on the brain, called white matter lesions.
These scars are not usually felt or noticed at first but can show up on brain scans and are linked to problems with thinking, balance, and memory. They also increase the chances of stroke and dementia.
The researchers used MRI scans to check the size and location of these white matter lesions in different parts of the brain. They found that people with lower diastolic blood pressure—specifically below 80—had fewer and smaller brain lesions. In contrast, people with higher diastolic pressure, especially over 90, had more of these lesions in key brain regions.
While earlier studies already showed that high systolic blood pressure (the top number) is tied to narrowed blood vessels and these brain lesions, this new research adds important detail: diastolic pressure might also play a strong role.
White matter is made up of nerve fibers that help carry messages within the brain and between the brain and body. When this white matter becomes damaged or scarred, the brain’s communication system weakens. This can cause problems with movement, balance, and memory, and increases the risk of falling.
By age 60, around 10% to 20% of people already have these lesions, according to the American Heart Association. By age 90, most adults show signs of them.
The researchers also found that lesions in a specific area of the brain—called the periventricular region—were more strongly tied to cognitive decline. This region is especially sensitive to changes in blood flow, and damage there can lead to more serious thinking and memory issues.
The team explains that different parts of the brain get blood from different arteries, and certain health problems may affect some areas more than others. That’s why even small changes in blood pressure can matter, depending on which part of the brain is involved.
In short, this study shows that knowing both your top and bottom blood pressure numbers is important—not just for your heart, but also for your brain. Keeping your blood pressure in a healthy range could help protect your memory, balance, and mental sharpness as you age.
If you haven’t checked your blood pressure in a while, now might be a good time to talk to your doctor.
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.
Copyright © 2025 Knowridge Science Report. All rights reserved.
