[P2–571]: EXERCISE TRAINING AND CEREBRAL BLOOD FLOW IN PRECLINICAL ALZHEIMER's DISEASE: RESULTS FROM THE AEROBIC EXERCISE AND COGNITIVE HEALTH (REACH) STUDY
Year: 2017
Type: article
Study design: Clinical Trial
Abstract: Decreased cerebral blood flow (cBF) is observed in aging and Alzheimer's disease (AD). Aerobic exercise acutely increases cBF, however whether there are sustained effects of exercise training on basal cBF remains equivocal. Levels of cardiorespiratory fitness (CRF), physical activity (PA), and sedentary behavior (SB) have been linked to AD and may be improved following exercise training; however, previous exercise trials in older adults have reported inconsistent results with these three modifiable risk-factors. Twenty-four cognitively healthy adults (age=64.8±4.6 years) from the Wisconsin Registry for Alzheimer's Prevention participated. Subjects were randomized to an individualized 6-month aerobic exercise program or a control group. Baseline and post-intervention measurements included a CRF test (VO2peak,ml/kg/min), 7 days of PA/SB monitoring with accelerometry, and 3D pseudocontinuous arterial spin labeling (ASL) MRI scanning. Cerebral blood flow was sampled from 5 brain regions implicated in AD using the Alzheimer's Disease Neuroimaging Initiative FDG Meta-ROI suite. A repeated measure ANOVA design, adjusted for age, gender, and global cBF was used to examine changes in cBF, CRF, PA, and SB. There were significant group by time interactions for CRF (p=.018; ηp=.260), PA (p=.003; ηp=.389) and SB (p=.026; ηp=.234), however not for cBF (p=.397; ηp=.040). Participants displaying the highest baseline SB (upper quartile) showed a large effect (ηp=.308) of exercise on cBF. Six months of an individualized incremental exercise program resulted in improved CRF, increased PA and decreased SB compared with controls. There were no differential group effects in cBF; however, amongst highly sedentary participants those in the exercise group displayed increased cBF while the control group exhibited decreased cBF at follow-up. Our results suggest that highly sedentary adults in the preclinical stage of AD enrolled in an exercise program may experience improved cBF in regions known to decline with age and AD. More robust findings may have been precluded by the fact that the trial enrolled adults above the targeted activity level. These findings can be used to inform exercise prescription as our protocol had large effects on three primary modifiable outcomes that are associated with risk for AD and displayed favorable effects on cBF in participants exhibiting high sedentary behavior.
Source: Alzheimer s & Dementia
Language: English
Topic: Physical Activity and Health
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4253064523