Summary: A 12-week aerobic exercise program was linked to improved cognitive performance and reduced cerebral blood flow in older adults with mild cognitive impairment (MCI), according to a new study.
Source: University of Maryland.
Regular aerobic exercise can change brain blood flow patterns and improve cognition in older adults, but the changes differ depending on cognitive status. Researchers from the University of Maryland School of Public Health report in the Journal of Alzheimer’s Disease that a moderate-intensity walking program produced measurable improvements in cognitive tests for older adults both with and without mild cognitive impairment (MCI), while producing opposite effects on cerebral blood flow in key brain regions.
Dr. J. Carson Smith, associate professor in the Department of Kinesiology, explains that the findings may at first seem counterintuitive: “After 12 weeks of exercise, adults with MCI experienced decreases in cerebral blood flow, yet they improved significantly on cognitive tests.” This contrasts with cognitively healthy older adults in the same training program, who showed increased blood flow in frontal regions alongside cognitive gains.
Researchers propose that the brain of someone beginning to experience subtle memory loss may be operating in a compensatory “crisis mode,” increasing regional blood flow to try to maintain cognitive function. While elevated cerebral blood flow is generally thought to support brain health, in the context of early cognitive decline it might reflect inefficient compensatory activity and could be an indicator of progressive dysfunction. The study suggests that exercise may help rebalance this response, lowering compensatory blood flow and improving the efficiency of neural processes in people in the early stages of Alzheimer’s disease.
The exercise intervention consisted of four 30-minute sessions of moderate-intensity treadmill walking per week for 12 weeks. Both groups—participants diagnosed with MCI and cognitively healthy control participants—completed the identical training protocol and cognitive testing before and after the program. Although both groups improved on cognitive measures, their cerebral blood flow responses diverged.
In the healthy control group, exercise increased cerebral blood flow in the frontal cortex, a region associated with executive functions such as planning, problem solving and attention. In contrast, the MCI group experienced decreased blood flow in specific regions that are implicated early in the pathogenesis of Alzheimer’s disease, including the insula and the anterior cingulate cortex. Importantly, these decreases in regional blood flow correlated with better performance on a word association test used to assess memory and verbal fluency.
The study focused measurements on brain regions known to be important in memory, cognition, and the early stages of Alzheimer’s disease. These included the insula, which supports perception, motor control and self-awareness; the anterior cingulate cortex, involved in decision making, anticipation, impulse control and emotion; and the inferior frontal gyrus, which contributes to language processing and speech. Changes in blood flow within these localized regions were used as biomarkers to assess how exercise affected brain physiology alongside cognitive outcomes.
Earlier publications from the same research project examined how aerobic exercise influenced neural network connectivity and biomarkers associated with memory decline and amyloid accumulation—biological signals often observed in MCI and Alzheimer’s disease. Together, these findings support a model in which exercise can modify both brain physiology and functional connectivity in ways that are potentially protective or restorative.
“Our findings provide evidence that exercise can improve brain function in people who already have cognitive decline,” Dr. Smith said. “We are particularly interested in intervening earlier in the disease process, when people are at increased risk for developing Alzheimer’s. Exercise appears to affect biomarkers of brain function in a manner that could delay or reduce the risk of progression to dementia.”
Source: Kelly Blake — University of Maryland
Publisher: Organized by NeuroscienceNews.com
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Original Research: The study is scheduled to appear in the Journal of Alzheimer’s Disease.
MLA: University of Maryland. “Exercise Benefits Brains and Blood Flow Changes in Older Adults.” NeuroscienceNews, 31 January 2019.
APA: University of Maryland (2019, January 31). Exercise Benefits Brains and Blood Flow Changes in Older Adults. NeuroscienceNews.
Chicago: University of Maryland. “Exercise Benefits Brains and Blood Flow Changes in Older Adults.” NeuroscienceNews. (accessed January 31, 2019).