Study Finds Exercise Benefits Brains, Changes Blood Flow in Older Adults

As exercise improves brain health of older adults with memory loss and leads to higher scores on cognitive tests, it also changes the way blood flows in the brain—but in a counterintuitive twist, it reduces the flow rather than pumping up the flow, according to new findings by School of Public Health researchers.

“A reduction in blood flow may seem a little contrary to what you would assume happens after going on an exercise program,” said J. Carson Smith, associate professor in the Department of Kinesiology and lead author on the study published in the Journal of Alzheimer’s Disease.

The research was conducted among older adults with mild cognitive impairment (MCI). For those beginning to experience subtle memory loss, Smith said, the brain is in crisis mode. Increased blood flows in regions known to be associated with Alzheimer’s disease may be a result of the body’s attempt to compensate for problems in the brain by increasing cerebral blood flow.

So while increased blood flow is normally 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 suggest 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)fter 12 weeks of exercise, adults with MCI experienced decreases in cerebral blood flow,” Smith said. “They simultaneously improved significantly in their scores on cognitive tests.”

A control group of cognitively healthy older adults, meanwhile, experienced increases in cerebral blood flow when they underwent the same exercise program, which consisted of four 30-minute sessions of moderate intensity treadmill walking per week. Like the group with MCI, the control group also had increases in cognitive performance.