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Researchers examined the blood flow of individuals with mild cognitive impairment in order to understand the effects of exercise on the brain.
It is believed that changes in blood flow in the brain result in the impairments experienced by those with mild cognitive impairment (MCI). There is currently no cure for the condition, but as exercise has been shown to improve vascular health, researchers are interested in the effects of exercise on the brain of individuals with MCI.
Almost a quarter of older American adults suffer from MCI, which is characterized by a reduction in memory and thinking skills, among other cognitive abilities. In addition to these deficits, individuals with MCI are at an increased risk of developing dementia. In a recent article published in the Journal of Alzheimer’s Disease, researchers analyzed the brain function of participants with MCI before and after an exercise program.
Potential participants with several neurological disorders, such as multiple sclerosis and Parkinson’s disease, were excluded from the study. In all, 17 participants with MCI and 18 participants with healthy brains were part of the study.
Before the study began, MRI was used to measure blood flow in areas of participants’ brains implicated in Alzheimer’s Disease, and cognitive tests were administered. For four weeks, the participants walked on a treadmill for 30 minutes, with the intensity increasing each week. Then for 8 weeks, participants maintained that intensity. At the end of 12 weeks, they took cognitive tests and underwent an MRI again.
Exercise decreased blood flow in the brains of individuals with MCI
Following exercise, blood flow decreased in participants with MCI, but increased in those without any neurological impairments. Interestingly, in both groups, test scores for cognitive functioning increased.
Researchers believe that in response to brain function declining, as experienced with MCI, the brain increases blood flow to help improve cognitive abilities, but this may, in fact, do the opposite and cause further decline. This may explain why exercise caused a decrease in blood flow and an increase in cognitive health.
Studies in the future should include a group that does not participate in the exercise, for comparison, as well as assess if these changes in blood flow following exercise are long-term or short-lived.
Written by Monica Naatey-Ahumah, BSc
Reference: Alfini, A.J., Weiss,L.R., Nielson, K.A., Verber, M.D., & Smith, J.S. (2019). Resting Cerebral Blood Flow After Exercise Training in Mild Cognitive Impairment. Journal of Alzheimer’s Disease, 67, 671-684. https://doi.org/10.3233/JAD-180728