Exercise alters brain blood flow and improves cognitive performance in older adults, according to research by the University of Maryland School of Public Health (UMD).

The study, published in the Journal of Alzheimer’s Disease, showed that exercise was associated with improved brain function in a group of adults diagnosed with mild cognitive impairment (MCI).

Perhaps surprisingly, the positive effects of exercise recorded in the study were thanks to a decrease in the blood flow in key brain regions.

“A reduction in blood flow may seem a little contrary to what you would assume happens after going on an exercise programme,” explained Dr. J. Carson Smith, associate professor of UMD's Department of Kinesiology and one of the report's authors.

“But after 12-weeks of exercise, adults with MCI experienced decreases in cerebral blood flow. They simultaneously improved significantly in their scores on cognitive tests.”

According to Smith, the effects are down to the effects of MCI.

Those beginning to experience subtle memory loss, the brain is in “crisis mode” and may try to compensate for the inability to function optimally by increasing cerebral blood flow.

While elevated cerebral blood flow is usually considered beneficial to brain function, there is evidence to suggest it may actually be a harbinger of further memory loss in those diagnosed with MCI.

The results of the study by Dr. Smith and his team suggests exercise may have the potential to reduce this compensatory blood flow and improve cognitive efficiency in those in the very early stages of Alzheimer’s Disease.

A control group of cognitively healthy older adults without MCI also underwent the exercise training programme, consisting of four 30-minute sessions of moderate-intensity treadmill walking per week.

The programme, however, yielded different responses from each group.

Unlike the group with MCI, whose exercise training decreased cerebral blood flow, the exercise training increased cerebral blood flow in the frontal cortex in the healthy group after 12 weeks.

Their performance on the cognitive tests also significantly improved, as was observed the MCI group.

“Our findings provide evidence that exercise can improve brain function in people who already have cognitive decline,” Smith added.

“We have an interest in targeting people who are at increased risk for developing Alzheimer’s earlier in the disease process. We are seeing that exercise can impact biomarkers of brain function in a way that might protect people by preventing or postponing the onset of dementia.”

To download the full report, click here to access the Journal of Alzheimer's Disease through the IOS website.