Long-Term Effects of Resistance Exercise Training on Cognition and Brain Volume in Older Women: Results from a Randomized Controlled Trial.

Aerobic exercise training has been shown to attenuate cognitive decline and reduce brain atrophy with advancing age. The extent to which resistance exercise training improves cognition and prevents brain atrophy is less known, and few studies include long-term follow-up cognitive and neuroimaging assessments. We report data from a randomized controlled trial of 155 older women, who engaged in 52 weeks of resistance training (either once- or twice-weekly) or balance-and-toning (twice-weekly). Executive functioning and memory were assessed at baseline, 1-year follow-up (i.e., immediately post-intervention), and 2-year follow-up. A subset underwent structural magnetic resonance imaging scans at those time points. At 2-year follow-up, both frequencies of resistance training promoted executive function compared to balance-and-toning (standardized difference [d]=.31-.48). Additionally, twice-weekly resistance training promoted memory (d=.45), reduced cortical white matter atrophy (d=.45), and increased peak muscle power (d=.27) at 2-year follow-up relative to balance-and-toning. These effects were independent of one another. These findings suggest resistance training may have a long-term impact on cognition and white matter volume in older women.

Larger Lateral Prefrontal Cortex Volume Predicts Better Exercise Adherence Among Older Women: Evidence From Two Exercise Training Studies.

BACKGROUND: Recent research has suggested an important role of lateral prefrontal cortex (lPFC) in consistent implementation of positive health behaviors and avoidance of negative health behaviors. METHODS: We examined whether gray matter volume in the lPFC prospectively predicts exercise class attendance among older women (n = 122) who underwent either a 52-week or 26-week exercise training intervention. Structural magnetic resonance imaging determined gray matter volume at baseline. RESULTS: Independent of intracranial volume, age, education, body composition, mobility, depressive symptoms, and general cognitive functioning, larger lPFC volume predicted greater exercise class attendance (all p values < .05). Follow-up whole-brain analyses further confirmed that regions in the lPFC-especially the left middle frontal gyrus (p < .005)-predicted future exercise adherence as well as identified other regions, especially in the insula and temporal cortex, that predicted exercise adherence. CONCLUSIONS: These findings suggest that sustained engagement in exercise training might rely in part on functions of the lPFC and that lPFC volume might be a reasonable proxy for such functions.

Cross-Sectional Relationships of Physical Activity and Sedentary Behavior With Cognitive Function in Older Adults With Probable Mild Cognitive Impairment.

Background: Mild cognitive impairment (MCI) represents a transition between normal cognitive aging and dementia and may represent a critical time frame for promoting cognitive health through behavioral strategies. Current evidence suggests that physical activity (PA) and sedentary behavior are important for cognition. However, it is unclear whether there are differences in PA and sedentary behavior between people with probable MCI and people without MCI or whether the relationships of PA and sedentary behavior with cognitive function differ by MCI status. Objective: The aims of this study were to examine differences in PA and sedentary behavior between people with probable MCI and people without MCI and whether associations of PA and sedentary behavior with cognitive function differed by MCI status. Design: This was a cross-sectional study. Methods: Physical activity and sedentary behavior in adults dwelling in the community (N = 151; at least 55 years old) were measured using a wrist-worn actigraphy unit. The Montreal Cognitive Assessment was used to categorize participants with probable MCI (scores of <26/30) and participants without MCI (scores of ≥26/30). Cognitive function was indexed using the Alzheimer Disease Assessment Scale-Cognitive-Plus (ADAS-Cog Plus). Physical activity and sedentary behavior were compared based on probable MCI status, and relationships of ADAS-Cog Plus with PA and sedentary behavior were examined by probable MCI status. Results: Participants with probable MCI (n = 82) had lower PA and higher sedentary behavior than participants without MCI (n = 69). Higher PA and lower sedentary behavior were associated with better ADAS-Cog Plus performance in participants without MCI (ß = -.022 and ß = .012, respectively) but not in participants with probable MCI (ß < .001 for both). Limitations: This study was cross-sectional and therefore could not establish whether conversion to MCI attenuated the relationships of PA and sedentary behavior with cognitive function. The diagnosis of MCI was not confirmed with a physician; therefore, this study could not conclude how many of the participants categorized as having probable MCI would actually have been diagnosed with MCI by a physician. Conclusions: Participants with probable MCI were less active and more sedentary. The relationships of these behaviors with cognitive function differed by MCI status; associations were found only in participants without MCI.

Economic evaluation of aerobic exercise training in older adults with vascular cognitive impairment: PROMoTE trial.

BACKGROUND/OBJECTIVES: Evidence suggests that aerobic exercise may slow the progression of subcortical ischaemic vascular cognitive impairment (SIVCI) by modifying cardiovascular risk factors. Yet the economic consequences relating to aerobic training (AT) remain unknown. Therefore, our primary objective was to estimate the incremental cost per quality-adjusted life years (QALYs) gained of a thrice weekly AT intervention compared with usual care. DESIGN: Cost-utility analysis alongside a randomised trial. SETTING: Vancouver, British Columbia, Canada. PARTICIPANTS: 70 adults (mean age of 74 years, 51% women) who meet the diagnostic criteria for mild SIVCI. INTERVENTION: A 6-month, thrice weekly, progressive aerobic exercise training programme compared with usual care (CON; comparator) with a follow-up assessment 6 months after formal cessation of aerobic exercise training. MEASUREMENTS: Healthcare resource usage was estimated over the 6-month intervention and 6-month follow-up period. Health status (using the EQ-5D-3L) at baseline and trial completion and 6-month follow-up was used to calculate QALYs. The incremental cost-utility ratio (cost per QALY gained) was calculated. RESULTS: QALYs were both modestly greater, indicating a health gain. Total healthcare costs (ie, 1791±1369 {2015 $CAD} at 6 months) were greater, indicating a greater cost for the thrice weekly AT group compared with CON. From the Canadian healthcare system perspective, the incremental cost-utility ratios for thrice weekly AT were cost-effective compared with CON, when using a willingness to pay threshold of $CAD 20 000 per QALY gained or higher. CONCLUSIONS: AT represents an attractive and potentially cost-effective strategy for older adults with mild SIVCI. TRIAL REGISTRATION NUMBER: NCT01027858.

Structural neural correlates of impaired mobility and subsequent decline in executive functions: a 12-month prospective study.

Impaired mobility, such as falls, may be an early biomarker of subsequent cognitive decline and is associated with subclinical alterations in both brain structure and function. In this 12-month prospective study, we examined whether there are volumetric differences in gray matter and subcortical regions, as well as cerebral white matter, between older fallers and non-fallers. In addition, we assessed whether these baseline volumetric differences are associated with changes in cognitive function over 12months. A total of 66 community-dwelling older adults were recruited and categorized by their falls status. Magnetic resonance imaging occurred at baseline and participants' physical and cognitive performances were assessed at baseline and 12-months. At baseline, fallers showed significantly lower volumes in gray matter, subcortical regions, and cerebral white matter compared with non-fallers. Notably, fallers had significantly lower left lateral orbitofrontal white matter volume. Moreover, lower left lateral orbitofrontal white matter volume at baseline was associated with greater decline in set-shifting performance over 12months. Our data suggest that falls may indicate subclinical alterations in regional brain volume that are associated with subsequent decline in executive functions.