Brain health warning sign could be hiding in plain sight, say researchers

04 Nov 2025 By foxnews

A new study from the University of Southern California suggests that the way blood pressure fluctuates from one heartbeat to the next may be just as important as the overall blood pressure reading - especially when it comes to brain health in aging adults.

Researchers found that older adults who experienced greater beat-to-beat changes in blood pressure had smaller brain volumes in areas tied to memory, and higher levels of a protein linked to nerve-cell injury.

"Even when blood pressure is well-controlled with medication, the rapid fluctuation in blood pressure from heartbeat to heartbeat is associated with worse memory and signs of brain shrinkage and brain cell injury," USC Professor Daniel Nation, senior author of the study, told Fox News Digital.

"Blood pressure isn't static; it's always adapting to the body's needs," he added in a press release. "But as we age, that regulation can become less precise."

The study included 105 adults between the ages of 55 and 89. The researchers measured the participants' blood pressure continuously for several minutes while they underwent brain scans.

SCIENTISTS UNCOVER HOW SOME 80-YEAR-OLDS HAVE THE MEMORY OF 50-YEAR-OLDS

In particular, they measured the stiffness of the adults' arteries and how much their blood pressure changed between heartbeats.

Even when participants' average blood pressure seemed healthy, those with the most erratic readings - combined with stiffer arteries - showed telltale signs of brain aging, the study found.

Specifically, they had smaller hippocampal and entorhinal cortex regions, which are among the first areas of the brain affected in Alzheimer's disease. They also had higher blood levels of neurofilament light, a biomarker of nerve-cell damage.

These findings were described as significant even after taking into account factors like age, sex and average blood pressure - suggesting that the fluctuations themselves, and not just overall pressure, may be a key risk factor.

The findings were first published online in the Journal of Alzheimer's Disease on Oct. 17.

For years, doctors have warned that high blood pressure raises dementia risk, but the USC study explores specifically how moment-to-moment instability can be a cause for concern.

Nation said the researchers were surprised to find that these rapid fluctuations in blood pressure were linked to brain injury, "regardless of whether they have hypertension or are treated with blood pressure-lowering medications."

CLICK HERE TO SIGN UP FOR OUR HEALTH NEWSLETTER

In other words, someone could have "good" readings at the doctor's office and still have dangerous spikes and dips that quietly stress the brain's delicate blood vessels, the research suggests. Over time, that instability could contribute to memory decline and neurodegeneration.

The researchers emphasized, however, that this study only shows correlation and does not prove causation, and that more research is needed.

"The findings are correlations in a cross-sectional study, which is like a snapshot in time," Nation said. "Future studies should examine how these rapid blood pressure fluctuations change over time and whether they predict future brain shrinkage, brain cell injury and memory decline."

TEST YOURSELF WITH OUR LATEST LIFESTYLE QUIZ

The team says there are currently no treatments specifically for these fluctuations.

"But it remains very important that people monitor their blood pressure and take blood pressure-lowering medications as prescribed in order to reduce their risk for brain injury and memory decline," Nation said.

CLICK HERE FOR MORE HEALTH STORIES

"Development of therapies to address rapid blood pressure fluctuations should be a priority, since these rapid fluctuations are not fully addressed by existing treatments that focus on lowering average blood pressure," he added.