Most people know that keeping blood pressure under control is important for heart health. However, growing evidence suggests it is just as important for protecting the brain.
A recent study from the University of Miami has found that the lower number in a blood pressure reading, called diastolic blood pressure, may play a key role in reducing damage to the brain as we get older.
The research was published in the journal Stroke and included more than 1,200 adults aged 50 and older. The scientists wanted to understand how blood pressure affects the brain’s white matter, which is made up of millions of nerve fibers that connect different brain regions and allow them to communicate with each other.
When white matter becomes damaged, signals cannot travel through the brain as efficiently. This can lead to problems with memory, thinking, balance, walking, and daily activities. White matter damage is also linked with a higher risk of stroke and dementia.
The researchers paid close attention to white matter lesions. These are tiny areas of damage, sometimes described as scars, that appear on brain scans. They become increasingly common with age and are considered an important sign of declining brain health.
Blood pressure is measured using two numbers. The top number, called systolic pressure, measures the force of blood against artery walls when the heart beats.
The bottom number, known as diastolic pressure, measures the pressure when the heart relaxes between beats. While doctors have traditionally focused more on systolic pressure, this study suggests the lower number deserves more attention.
The findings showed that people with lower diastolic blood pressure, especially readings below 80 millimeters of mercury, had fewer white matter lesions. In contrast, participants with diastolic readings above 90 tended to have more brain damage. Some important brain regions also had smaller lesions among people with lower diastolic pressure.
Previous studies have already shown that high systolic blood pressure can damage blood vessels in the brain. The new findings add to this knowledge by suggesting that keeping diastolic blood pressure in a healthy range may provide extra protection against age-related brain changes.
White matter lesions become much more common as people grow older. Researchers estimate that between 10% and 20% of people around age 60 already have these changes, and the vast majority of people over 90 show signs of them on brain scans. Finding ways to slow this process could help reduce the burden of dementia and stroke in aging populations.
The researchers emphasize that this study shows an association rather than proving that high diastolic blood pressure directly causes brain lesions. Even so, the results highlight another reason to monitor blood pressure carefully throughout adulthood.
Simple lifestyle habits remain some of the best ways to protect both the heart and the brain. Regular physical activity, a balanced diet, maintaining a healthy weight, getting enough sleep, avoiding smoking, and following medical advice to control blood pressure may all help preserve brain function as people age.
The findings published in Stroke provide further evidence that paying attention to both blood pressure numbers—not just the top one—may support healthier aging.
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