New Delhi, Oct 31 : Older adults whose blood pressure fluctuates widely may indicate a greater risk of brain shrinkage and nerve cell injury, according to a new study.

The study, published in the Journal of Alzheimer's Disease, reveals that short-term 'dynamic instability' in blood pressure -- moment-to-moment changes measured over just minutes -- is linked to loss of brain tissue in regions critical for memory and cognition, as well as to blood biomarkers of nerve cell damage.

'Our findings show that even when average blood pressure is normal, instability from one heartbeat to the next may place stress on the brain,' said Daniel Nation, from the University of Southern California's Leonard Davis School of Gerontology.

'These moment-to-moment swings appear to be associated with the same kinds of brain changes we see in early neurodegeneration,' added the Professor of Gerontology and Medicine.

While high average blood pressure has long been known to increase the risk of dementia, this study focuses on blood pressure variability, or how much blood pressure rises and falls over short time periods.

Recent evidence suggests that such fluctuations can strain small blood vessels in the brain and reduce their ability to deliver steady blood flow.

In this study, the researchers combined two complementary measures: Average Real Variability (ARV) and Arterial Stiffness Index (ASI).

ARV captures how much systolic blood pressure (the top number in a blood pressure reading) changes between each heartbeat, while ASI reflects how flexible or stiff the arteries are as they respond to those changes in pressure.

Together, these measures indicate how much blood flow changes over a short period of time, or what the researchers call 'blood pressure dynamic instability.'

"This study suggests that excessive fluctuations could be a sign of vascular ageing that contributes to brain injury,' Nation explained.

The team conducted MRI scans of 105 community-dwelling older adults between the ages of 55 and 89 who were generally healthy and had no major neurological disease.

Participants with both high ARV and high ASI were found to have smaller hippocampal and entorhinal cortex volumes -- brain regions vital for learning and memory, also the first affected by Alzheimer's disease.

Blood samples showed that the same individuals also had higher levels of neurofilament light (NfL), a blood-based marker that rises when nerve cells are damaged.

The findings open a new window into how cardiovascular changes contribute to cognitive decline and may offer novel prevention strategies.

/IANS