Most people know that keeping blood pressure under control is important for a healthy heart. When doctors measure blood pressure, they record two numbers. The top number is called systolic blood pressure.
It shows how strongly blood pushes against the walls of the arteries each time the heart beats. The lower number is called diastolic blood pressure. It measures the pressure inside the arteries while the heart is resting between beats.
Many people pay attention only to the higher number because it is often used to judge the risk of heart disease. However, new research suggests that the lower number may also tell doctors a great deal about the health of the brain.
Scientists from the University of Miami wanted to learn whether diastolic blood pressure is linked to hidden brain damage that can develop over many years. These changes often happen quietly before a person notices any symptoms. By finding these early warning signs, doctors may be able to help people lower their risk of memory problems, stroke, and falls later in life.
The researchers studied 1,205 adults who were 50 years of age or older. Each volunteer had their blood pressure measured and also received a magnetic resonance imaging (MRI) scan. MRI is a safe imaging method that allows doctors to see detailed pictures of the brain without surgery.
The team looked for tiny damaged areas called white matter lesions. White matter is a network of nerve fibers that acts like a communication system inside the brain.
It carries messages between different brain regions so people can move, think, remember, and feel normally. When white matter becomes damaged, these messages travel less smoothly. Over time, this can affect balance, walking, memory, decision-making, and other thinking skills.
The scans showed a clear pattern. People whose diastolic blood pressure was below 80 generally had fewer white matter lesions. In contrast, those with diastolic blood pressure above 90 had more of these damaged areas. The findings suggest that the lower blood pressure number may provide important information about brain health that has often been overlooked.
Earlier research had already shown that high systolic blood pressure can damage blood vessels and reduce healthy blood flow to the brain. This new study adds another piece to the puzzle by showing that diastolic blood pressure also appears to be linked with changes inside the brain, especially in areas involved in memory and thinking.
The researchers were especially interested in a type of damage called periventricular white matter lesions.
These lesions develop close to the brain’s fluid-filled spaces and have been strongly linked with problems involving memory, attention, and clear thinking. If doctors can identify people at greater risk earlier, they may have more opportunities to slow or prevent further damage.
Brain damage caused by high blood pressure usually develops slowly. Many people do not notice any warning signs until serious problems appear. This is why regular blood pressure checks are so important. High blood pressure can quietly damage blood vessels throughout the body, including those that supply oxygen and nutrients to the brain.
According to the American Heart Association, white matter lesions become more common with age. Around 10% to 20% of people have them by age 60, and almost everyone over the age of 90 has at least some of these changes. Although aging is a natural process, managing blood pressure may help reduce the amount of damage that builds up over time.
The brain receives blood through many different arteries, and high blood pressure does not affect every part of the brain in the same way. Learning exactly how blood pressure changes influence different brain regions could help researchers develop better ways to prevent stroke, dementia, and other conditions that affect thinking and memory.
The researchers encourage people to know both of their blood pressure numbers instead of focusing only on the top one.
Speaking with a doctor about healthy blood pressure, regular exercise, eating a balanced diet, maintaining a healthy weight, limiting salt, avoiding smoking, and taking prescribed medicines when needed are all important steps for protecting both heart and brain health.
The study was led by Michelle R. Caunca of the University of Miami and was published in the journal Stroke. While more research is needed to better understand exactly why diastolic blood pressure affects the brain, the findings suggest that this often-overlooked number may become an important tool for identifying people at risk of future brain disease before symptoms appear.
If you care about dementia, please read studies about dietary strategies to ward off dementia, and how omega-3 fatty acids fuel your mind.
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