Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) are common conditions in older age and are associated with an increased risk of future cognitive decline and dementia. As there ...is currently no effective pharmacological treatment available for SCD and MCI, modifiable risk factors for cognitive decline and dementia have received increasing attention in the literature as a focus for clinical trials. Physical activity (PA) is one of the strongest protective lifestyle factors. This clinical review aims to highlight the accumulating evidence about the benefits of PA for SCD and MCI. Whilst there is agreement that at least 150 minutes of moderate aerobic PA per week in combination with additional resistance training is necessary to support brain health in people with SCD and MCI, future research is required to help inform specific advice on type of exercise, intensity, "dose" and effective strategies to encourage behavior change.
Many observational studies have shown that physical activity reduces the risk of cognitive decline; however, evidence from randomized trials is lacking.
To determine whether physical activity reduces ...the rate of cognitive decline among older adults at risk.
Randomized controlled trial of a 24-week physical activity intervention conducted between 2004 and 2007 in metropolitan Perth, Western Australia. Assessors of cognitive function were blinded to group membership.
We recruited volunteers who reported memory problems but did not meet criteria for dementia. Three hundred eleven individuals aged 50 years or older were screened for eligibility, 89 were not eligible, and 52 refused to participate. A total of 170 participants were randomized and 138 participants completed the 18-month assessment.
Participants were randomly allocated to an education and usual care group or to a 24-week home-based program of physical activity.
Change in Alzheimer Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) scores (possible range, 0-70) over 18 months.
In an intent-to-treat analysis, participants in the intervention group improved 0.26 points (95% confidence interval, -0.89 to 0.54) and those in the usual care group deteriorated 1.04 points (95% confidence interval, 0.32 to 1.82) on the ADAS-Cog at the end of the intervention. The absolute difference of the outcome measure between the intervention and control groups was -1.3 points (95% confidence interval,-2.38 to -0.22) at the end of the intervention. At 18 months, participants in the intervention group improved 0.73 points (95% confidence interval, -1.27 to 0.03) on the ADAS-Cog, and those in the usual care group improved 0.04 points (95% confidence interval, -0.46 to 0.88). Word list delayed recall and Clinical Dementia Rating sum of boxes improved modestly as well, whereas word list total immediate recall, digit symbol coding, verbal fluency, Beck depression score, and Medical Outcomes 36-Item Short-Form physical and mental component summaries did not change significantly.
In this study of adults with subjective memory impairment, a 6-month program of physical activity provided a modest improvement in cognition over an 18-month follow-up period.
anzctr.org.au Identifier: ACTRN12605000136606.
Subjective cognitive decline (SCD) and mild cognitive impairment (MCI) are common conditions in older age and are associated with an increased risk of future cognitive decline and dementia. As there ...is currently no effective pharmacological treatment available for SCD and MCI, modifiable risk factors for cognitive decline and dementia have received increasing attention in the literature as a focus for clinical trials. Physical activity (PA) is one of the strongest protective lifestyle factors. This clinical review aims to highlight the accumulating evidence about the benefits of PA for SCD and MCI. Whilst there is agreement that at least 150 minutes of moderate aerobic PA per week in combination with additional resistance training is necessary to support brain health in people with SCD and MCI, future research is required to help inform specific advice on type of exercise, intensity, "dose" and effective strategies to encourage behavior change.
White matter hyperintensities (WMHs) are a risk factor for cognitive decline. Physical activity (PA) is associated with lower WMH. Whether long-term exposure to PA programs has beneficial effects on ...WMH progression in older adults with memory complaints and comorbid conditions has had limited exploration. This study explored whether a 24-month moderate-intensity PA intervention can delay the progression of WMH and hippocampus loss in older adults at risk for cognitive decline. Data acquired on magnetic resonance imaging were used to measure the progression of WMH and hippocampus loss. The results of this study showed no effect of intervention on either the primary outcome measure “WMH” or the secondary outcome measure “hippocampal volume.” In addition, neither beta amyloid status nor the adherence to the intervention had any effect on the outcome. In this cohort of subjective memory complaints and mild cognitive impairment participants with vascular risk factors, there was no effect of long-term moderate-intensity PA on WMH or hippocampal loss.
•Results of a 24-month physical activity intervention in adults at risk of cognitive decline.•Minutes of physical activity per week was different between groups only at 6 months.•No intervention effect on primary outcome measure “white matter hyperintensities.”•Cognitive status or beta amyloid status did not affect outcome.•Secondary outcome measure “hippocampal volume loss” was not affected by intervention.
To examine the hypothesis that exercise training induces adaptation in cerebrovascular function, we recruited 63 older adults (62 ± 7 yr, 46 females) to undertake 24 wk of either land walking or ...water walking, or participate in a nonexercise control group. This is the first multi-interventional study to perform a comprehensive assessment of cerebrovascular function in response to longer term (6-month) training interventions, including water-based exercise, in older healthy individuals.
Intracranial blood flow velocities (middle cerebral artery (MCAv) and posterior cerebral artery) were assessed at rest and in response to neurovascular coupling, hypercapnic reactivity, and cerebral autoregulation.
We observed no change in resting MCAv in response to either training intervention (pre vs post, mean (95% confidence interval), land walking: 65 (59-70) to 63 (57-68) cm·s-1, P = 0.33; water walking: 63 (58-69) to 61 (55-67) cm·s-1, P = 0.92) compared with controls and no change in neurovascular coupling (land walking: P = 0.18, water walking: P = 0.17). There was a significant but modest improvement in autoregulatory normalized gain after the intervention in the water-walking compared with the land-walking group (P = 0.03). Hypercapnic MCAv reactivity was not different based on exercise group (land: P = 087, water: P = 0.83); however, when data were pooled from the exercise groups, increases in fitness were correlated with decreases in hypercapnic reactivity (r2 = 0.25, P = 0.003).
Although exercise was not associated with systematic changes across multiple domains of cerebrovascular function, our data indicate that exercise may induce modest changes in autoregulation and CO2 reactivity. These findings should encourage further studies of the longer-term implications of exercise training on cerebrovascular health.
There is a need to develop interventions to reduce the risk of dementia in the community by addressing lifestyle factors and chronic diseases over the adult life course.
This study aims to evaluate a ...multidomain dementia risk reduction intervention, Body Brain Life in General Practice (BBL-GP), targeting at-risk adults in primary care.
A pragmatic, parallel, three-arm randomized trial involving 125 adults aged 18 years or older (86/125, 68.8% female) with a BMI of ≥25 kg/m
or a chronic health condition recruited from general practices was conducted. The arms included (1) BBL-GP, a web-based intervention augmented with an in-person diet and physical activity consultation; (2) a single clinician-led group, Lifestyle Modification Program (LMP); and (3) a web-based control. The primary outcome was the Australian National University Alzheimer Disease Risk Index Short Form (ANU-ADRI-SF).
Baseline assessments were conducted on 128 participants. A total of 125 participants were randomized to 3 groups (BBL-GP=42, LMP=41, and control=42). At immediate, week 18, week 36, and week 62 follow-ups, the completion rates were 43% (18/42), 57% (24/42), 48% (20/42), and 48% (20/42), respectively, for the BBL-GP group; 71% (29/41), 68% (28/41), 68% (28/41), and 51% (21/41), respectively, for the LMP group; and 62% (26/42), 69% (29/42), 60% (25/42), and 60% (25/42), respectively, for the control group. The primary outcome of the ANU-ADRI-SF score was lower for the BBL-GP group than the control group at all follow-ups. These comparisons were all significant at the 5% level for estimates adjusted for baseline differences (immediate: difference in means -3.86, 95% CI -6.81 to -0.90, P=.01; week 18: difference in means -4.05, 95% CI -6.81 to -1.28, P<.001; week 36: difference in means -4.99, 95% CI -8.04 to -1.94, P<.001; and week 62: difference in means -4.62, 95% CI -7.62 to -1.62, P<.001).
A web-based multidomain dementia risk reduction program augmented with allied health consultations administered within the general practice context can reduce dementia risk exposure for at least 15 months. This study was limited by a small sample size, and replication on a larger sample with longer follow-up will strengthen the results.
Australian clinical trials registration number (ACTRN): 12616000868482; https://anzctr.org.au/ACTRN12616000868482.aspx.
Exercise improves vascular function, but it is unclear whether benefits are mediated by traditional cardiovascular risk factors or whether sex differences in training effects exist in older adults. ...We hypothesized that exercise would improve cardiovascular risk factors, that males and females would benefit similarly, and that improvements in risk factors would correlate with changes in vascular function.
Seventy-two healthy middle-aged/older adults (age, 62 ± 7 yr; 26%♂) were randomized to a land-walking ( n = 23), water-walking ( n = 25), or a nonexercise control group (C; n = 23). The exercise groups undertook supervised and monitored training three times a week for 50 min per session, across 24 wk. Blood pressure, body composition (dual x-ray absorptiometry), blood lipids and glucose, and flow-mediated brachial artery dilation were assessed in all participants at weeks 0 and 24. To maximize power for sex differences and correlation analyses, we pooled the training groups (land-walking + water-walking).
Training prevented increases in LDL and total cholesterol/HDL ratio observed in the nonexercise control group. No group by time interactions were observed for other risk factors. Sex differences in training effects existed for visceral fat (-187 ± 189 g♂ vs -15 ± 161 g♀; P = 0.006) and lean mass (-352 ± 1045 g♂ vs 601 ± 1178 g♀; P = 0.008). Improvement in flow-mediated brachial artery dilation was correlated with decreased waist girth ( r = -0.450, P = 0.036), but not with other risk factors.
Exercise training prevented deterioration in lipid levels, whereas sex differences existed for body composition changes with training. Improvement in vascular function was not dependent on changes in risk factors in middle-aged/older adults, suggesting that artery health may be dependent on other exercise-related stimuli.
This study aimed to examine the evolution of relationships between measures of muscle strength and endurance with individual cardiometabolic risk factors from childhood to late adolescence in a ...prospective population-based cohort.
Participants from the Western Australian Pregnancy Cohort (Raine) Study at ages 10, 14 and 17 were analysed, using longitudinal linear mixed model analyses.
Handgrip strength after adjusting for the confounding effects of BMI was positively associated with SBP, but not DBP. The association between handgrip strength and SBP was stronger in men than women at all time points coefficient (women): 0.18, P < 0.001; sex × handgrip strength coefficient: 0.09, P = 0.002. The association was strongest at 10 years and significantly attenuated over time (year × handgrip coefficient from 10 to 14 years: -0.11, P = 0.003; year × handgrip coefficient from 10 to 17 years: -0.19, P ≤ 0.001). After the inclusion of BMI as a confounder, handgrip strength was significantly negatively associated with homeostatic model assessment of insulin resistance and high-sensitivity C-reactive protein over time in both sexes. Back muscle endurance was positively associated with SBP, but not DBP, after adjustment for the confounding effects of BMI (coefficient: 0.01, P = 0.002). There were small, albeit significant, inverse associations between back muscle endurance and log homeostatic model assessment of insulin resistance and log high-sensitivity C-reactive protein.
The positive association between handgrip strength and back muscle endurance with SBP throughout childhood and adolescence contrasts with beneficial effects on other related traditional cardiometabolic risk factors. Mechanisms underlying these paradoxical effects on SBP warrant further investigation.
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