Resting Cerebral Blood Flow After Exercise Training in Mild Cognitive Impairment

Abstract

Background: Exercise training has been associated with greater cerebral blood flow (CBF) in cognitively normal older adults (CN). Alterations in CBF, including compensatory perfusion in the prefrontal cortex, may facilitate changes to the brain’s neural infrastructure. Objective: To examine the effects of a 12-week aerobic exercise intervention on resting CBF and cognition in CN and those with mild cognitive impairment (MCI). We hypothesized individuals with MCI (vs. CN) would exhibit greater whole brain CBF at baseline and that exercise would mitigate these differences. We also expected CBF changes to parallel cognitive improvements. Methods: Before and after a 12-week exercise intervention, 18 CN and 17 MCI participants (aged 61–88) underwent aerobic fitness testing, neuropsychological assessment, and an MRI scan. Perfusion-weighted images were collected using a GE 3T MR system. Repeated measures analyses of covariance were used to test within- and between-group differences over time, followed by post-hoc analyses to examine links between CBF changes and cognitive improvement. Results: At baseline, individuals with MCI (vs. CN) exhibited significantly elevated perfusion in the left insula. Twelve weeks of aerobic exercise reversed this discrepancy. Additionally, exercise improved working memory (measured by the Rey Auditory Verbal Learning Test) and verbal fluency (measured by the Controlled Oral Word Association Test) and differentially altered CBF depending on cognitive status. Among those with MCI, decreased CBF in the left insula and anterior cingulate cortex was associated with improved verbal fluency. Conclusions: Exercise training alters CBF and improves cognitive performance in older adults with and without cognitive impairment. Future studies must evaluate the mediating effects of CBF on the association between exercise training and cognition.

The Effect of Exercise Training on Brain Structure and Function in Older Adults: A Systematic Review Based on Evidence from Randomized Control Trials

“…Previous research has shown that cognitive performance (e.g., information processing speed, memory, executive function) declines with advancing age [4][5][6]. Age-related impairments also reflect brain atrophy and decreased brain function in several regions, including the prefrontal and temporal cortices, and the hippocampus [7][8][9]. As such, the healthcare field must identify novel therapeutic strategies to combat the rising rate of age-related cognitive decline.…”

Six weeks of high‐intensity interval training to exhaustion attenuates dynamic cerebral autoregulation without influencing resting cerebral blood velocity in young fit men

“…CRF‐related benefits are not confided to the cardiovascular function and rather extend to the cerebrovascular system (Lucas et al, ; Tarumi and Zhang, ). For instance, aerobic exercise training alters favorably cerebrovascular health in varying clinical conditions ranging from chronic obstructive pulmonary disease (Lewis et al, ), cognitive impairments (Alfini et al, ), stroke (Ivey et al, ) and following cancer (Northey et al, ). Evidence show that life‐long aerobic training individuals with elevated CRF have higher resting intracranial blood velocity in the anterior circulation (as indexed by transcranial Doppler sonography of mean blood velocity in middle cerebral artery (MCAv mean ) (Ainslie et al, ; Bailey et al, ), and in the posterior circulation (as indexed by arterial spin labeling in posterior cingular cortex/precuneus) (Thomas et al, ) and higher extracranial blood flow (as indexed by carotid Doppler) (Braz et al, ) than their sedentary counterparts.…”

Voluntary running does not increase capillary blood flow but promotes neurogenesis and short-term memory in the APP/PS1 mouse model of Alzheimer’s disease

“…Consistent with our findings in APP/PS1 mice, however, recent studies in patients with dementia (diagnosed as mild to moderate AD in Refs. [83] and [84]) showed that 3 times per week 60 min of aerobic exercise led to improved cognition [83, 85, 86], but this effect was not correlated with increased cerebral blood flow [84, 87]. Finally, we did not observe changes in the density or geometry of cortical capillaries in APP/PS1 mice that exercised, compared to sedentary controls.…”