The study from the Australian National University found that keeping blood pressure at an optimal level (110/70 mmHg) that’s a bit lower than the level considered normal (120/80 mmHg), appears to keep your brain at least six months younger than your chronological age.
“The most surprising thing about our findings is that the effect (association between higher blood pressure and older brain age) was similar across the age range studied (44 to 64 years),” Nicolas Cherbuin, PhD, head of the Centre for Research on Ageing, Health, and Wellbeing at Australian National University, Canberra and the study’s lead author, tells Verywell.
Cherbuin says that finding is important because it “suggests this effect started developing at younger ages,"—say, in a person’s 20s or 30s.
Determining ‘BrainAGE’
Elevated blood pressure is a known risk factor for cognitive decline and dementia, but as Cherbuin and coauthors note, what is unknown is the point at which blood pressure starts to compromise brain health.
To find out, the researchers looked at brain scans from 686 healthy people from Australia, New Zealand, and Germany. They were organized into 40+ and 60+ age cohorts. As part of the Personality and Total Health (PATH) Through Life study, each participant had several brain scans and blood pressure measurements taken over the course of 12 years.
To determine the age of the participants’ brains, the researchers used a biomarker called BrainAGE, (which stands for brain age gap estimation). It uses data from magnetic resonance imaging (MRI) scans to calculate the age of an individual’s brain, which can be compared to the person’s actual (chronological) age.
When the researchers looked at the data, the results showed that for every 10 mmHg increase in blood pressure—either in the first number of the reading (systolic) or the second number (diastolic)—BrainAGE increased by about 51 days. The increase was seen for all levels of blood pressure—not just in the participants with high blood pressure.
Limitations
Kyle Womack, MD, a professor of neurology at Washington University School of Medicine in St. Louis, tells Verywell that the BrainAGE biomarker is “kind of unique to this group” of researchers and is not a common measure for the health or age of the brain. Rather, it’s an attempt to create a global measurement of sorts.
It’s also not clear how BrainAGE correlates to brain function or to whether dementia develops. None of the participants in the study had signs of dementia or any other cognitive issues—and this was intentional.
Cherbuin says that participants older than age 60 “were screened for dementia and those who met clinical criteria were excluded from the study.” Since there is “a very low risk of having dementia” in people under the age of 60, those participants “were not clinically screened.”
Participants with a history of stroke, Parkinson’s disease, or other neurological disorders were also excluded from the study, which Cherbuin says was “only focused on brain health.” However, future research could involve examining cognitive function as well.
Rethinking ‘Normal’ Blood Pressure
Blood pressure is usually measured using a monitor and cuff on the arm, which is convenient and noninvasive. However, Womack says that this method does not necessarily tell you what the blood pressure in other areas is.
For example, blood pressure in the aorta and the brain can be affected by stiffness in the aorta, which can amplify the pressure of the blood as it’s being delivered to the brain. Pulse pressure—the difference between systolic and diastolic pressure— is another factor. Cherbuin says that these central pressures might be “something more important.”
Womack says that the study’s findings “aren’t particularly surprising,” in part because, in recent years, “there’s kind of been this kind of gradual ratcheting down of what optimal blood pressure is.”
Cherbuin says that at this stage, the researchers “are not advocating for a change to the ‘normal’ blood pressure range,” but that they would “suggest that current guidelines should be extended to include advice to maintain an optimal blood pressure, around 100/70, rather than a normal blood pressure.”
