The study, published in the journal Neurology, revealed that high 24-hour blood pressure fluctuations are associated with a decline in cognitive abilities, such as planning, problem-solving, and memory. It also showed that higher average blood pressure during the same period is linked to increased markers of blood vessel damage in the brain.
High blood pressure is a known risk factor for cognitive decline, but the impact of daily blood pressure changes is still less understood.
Researchers from the Turner Institute for Brain and Mental Health at Monash University used continuous blood pressure monitoring devices to measure the blood pressure of 225 people in Australia, aged between 55 and 80, over a 24-hour period.
The study's lead author, Madeleine Gibson, explained that the findings reveal potential mechanisms linking blood pressure disorders to brain changes that may precede memory problems by years, including damage to white matter and disruption of the blood-brain barrier responsible for protecting the brain.
Gibson added: "Our results show that blood pressure is linked to subtle changes in the brain that may occur before obvious symptoms appear in memory or thinking."
She continued: "Even a slight increase in blood pressure fluctuations was associated with a decline in cognitive performance, equivalent to roughly seven years of aging."
She noted that it is still unknown whether adjusting for these fluctuations can slow down or reverse these changes, but she emphasized that the findings reinforce the growing understanding of the relationship between heart health and brain health.
She also stressed the importance of these findings in middle age, as it is a potentially crucial period in preventing later cognitive decline.
For his part, Professor Matthew Bass, the lead author of the study, said that relying solely on blood pressure measurements taken in clinics may not give a complete picture of the health condition.
Bass added: "Many people think that blood pressure is a fixed number measured in a clinic, but in reality it changes constantly throughout the day and night, and these fluctuations may hold important clues about brain health."
