Aerobic exercise for Alzheimer's disease: A randomized controlled pilot trial

Abstract

BackgroundThere is increasing interest in the role of physical exercise as a therapeutic strategy for individuals with Alzheimer’s disease (AD). We assessed the effect of 26 weeks (6 months) of a supervised aerobic exercise program on memory, executive function, functional ability and depression in early AD.Methods and findingsThis study was a 26-week randomized controlled trial comparing the effects of 150 minutes per week of aerobic exercise vs. non-aerobic stretching and toning control intervention in individuals with early AD. A total of 76 well-characterized older adults with probable AD (mean age 72.9 [7.7]) were enrolled and 68 participants completed the study. Exercise was conducted with supervision and monitoring by trained exercise specialists. Neuropsychological tests and surveys were conducted at baseline,13, and 26 weeks to assess memory and executive function composite scores, functional ability (Disability Assessment for Dementia), and depressive symptoms (Cornell Scale for Depression in Dementia). Cardiorespiratory fitness testing and brain MRI was performed at baseline and 26 weeks. Aerobic exercise was associated with a modest gain in functional ability (Disability Assessment for Dementia) compared to individuals in the ST group (X2 = 8.2, p = 0.02). There was no clear effect of intervention on other primary outcome measures of Memory, Executive Function, or depressive symptoms. However, secondary analyses revealed that change in cardiorespiratory fitness was positively correlated with change in memory performance and bilateral hippocampal volume.ConclusionsAerobic exercise in early AD is associated with benefits in functional ability. Exercise-related gains in cardiorespiratory fitness were associated with improved memory performance and reduced hippocampal atrophy, suggesting cardiorespiratory fitness gains may be important in driving brain benefits.Trial registrationClinicalTrials.gov NCT01128361

Moderate‐ to high‐intensity exercise does not modify cortical β‐amyloid in Alzheimer's disease

“…As outlined previously, different lines of evidence demonstrate the positive effect of exercise on cognitive function and risk of dementia [10][11][12][13][14][15][16][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. However, the biological mechanisms by which this effect may be mediated remain to be clarified.…”

“…In humans, most of the studies have focused on exercise and hippocampal volume [17]. Results have been divergent, although most studies have shown a lack of association in both intervention [18][19][20][21][22] and observational studies [23][24][25][26][27][28]. There have been discrepancies in results from observational studies examining the association between Ab or tau and physical activity [29][30][31][32][33][34].…”

The Neuroprotective Effects of Exercise on Cognitive Decline: A Preventive Approach to Alzheimer Disease

“…Morris et al recently studied the role of physical exercise as a therapeutic strategy in AD [46]. They carried out a 26-week randomized controlled trial and compared the effect of 150m aerobic exercise vs non-aerobic stretching.…”

Protocol of Aerobic Exercise and Cognitive Health (REACH): A Pilot Study

“…Preliminary randomized controlled trials (RCTs) in adults with normal cognition [17] and with mild cognitive impairment [18] indicate that aerobic exercise training can impart benefit on measures related to AD. Even when exercise training is reported to not improve cognition in individuals in the early stages of AD, increased CRF is positively related to brain health [19]. Further RCTs, however, are needed to definitively test the effect of aerobic exercise training and CRF on markers of AD risk.…”

“…Exercise interventions implemented in later disease stages [20][21][22] demonstrate less benefit than those implemented in the early stages of AD [18,19,23]; it may be important to halt the disease process earlier in life because there is little evidence that exercise training can reverse AD biomarker accumulation. Moreover, cognitively normal adults may respond to aerobic exercise interventions with greater CRF improvement than older, cognitively impaired individuals [19]. Family history of AD and carriage of the apolipoprotein E4 (APOE4) allele confer specific risk for developing AD [24,25].…”