Frequent changes in blood pressure can impact cognitive health and contribute to dementia risk, new Australian research has revealed.

While high blood pressure has long been recognised as a risk factor for cognitive decline, a Monash University study found that fluctuations in blood pressure throughout the day was also associated with poorer cognition including in memory, problem solving, and planning.

Researchers used continuous monitoring devices to track the blood pressure of 225 Australians aged between 55 and 80 for 24 hours.

Even a modest increase in blood pressure changes was linked to lower performance on cognitive tests, equivalent to around seven years of additional ageing.

Higher average blood pressure over 24 hours was also associated with greater evidence of vascular brain injury, which happens when blood vessels are blocked, narrowed, or weakened.

Lead author Madeline Gibson, a Monash PhD candidate, said the study highlighted several ways in which abnormal blood pressure could contribute to dementia.

This included injury to the brain’s white matter tracts and altered function of the blood-brain barrier — the brain’s protective filtering system.

“Our study shows that blood pressure is associated with subtle brain changes that can occur long before memory or thinking problems become apparent,” she said.

“Whether managing blood pressure variability could slow or reverse these brain changes is not yet known but these findings add to growing evidence that the heart and brain are closely linked.

“This is especially important in midlife, which may be a key window for protecting brain health and reducing later risk of cognitive decline.”

Professor Matthew Pase added that the study highlighted the importance of extended blood pressure monitoring.

“The research indicates that standard blood pressure readings taken at a doctor’s clinic may not provide the full picture,” he said.

“Blood pressure rises and falls across the day and night, and those fluctuations may carry important information about brain health.”