Data-driven MRI analysis reveals fitness-related functional change in default mode network and cognition following an exercise intervention.

Previous research has indicated that cardiorespiratory fitness (CRF) is structurally and functionally neuroprotective in older adults. However, questions remain regarding the mechanistic role of CRF on cognitive and brain health. The purposes of this study were to investigate if higher pre-intervention CRF was associated with greater change in functional brain connectivity during an exercise intervention and to determine if the magnitude of change in connectivity was related to better post-intervention cognitive performance. The sample included low-active older adults (n = 139) who completed a 6-month exercise intervention and underwent neuropsychological testing, functional neuroimaging, and CRF testing before and after the intervention. A data-driven multi-voxel pattern analysis was performed on resting-state MRI scans to determine changes in whole-brain patterns of connectivity from pre- to post-intervention as a function of pre-intervention CRF. Results revealed a positive correlation between pre-intervention CRF and changes in functional connectivity in the precentral gyrus. Using the precentral gyrus as a seed, analyses indicated that CRF-related connectivity changes within the precentral gyrus were derived from increased correlation strength within clusters located in the Dorsal Attention Network (DAN) and increased anti-correlation strength within clusters located in the Default Mode Network (DMN). Exploratory analysis demonstrated that connectivity change between the precentral gyrus seed and DMN clusters were associated with improved post-intervention performance on perceptual speed tasks. These findings suggest that in a sample of low-active and mostly lower-fit older adults, even subtle individual differences in CRF may influence the relationship between functional connectivity and aspects of cognition following a 6-month exercise intervention.

Yoga Impacts Cognitive Health: Neurophysiological Changes and Stress Regulation Mechanisms.

Yoga, a physical and contemplative practice, offers the practitioner a unique mind-body exercise experience demonstrating preliminary efficacy in improving cognitive health. We examine the evidence for underlying mechanisms that explain the yoga-cognition relationship in healthy older adults. The cognitive benefits of yoga may be the result of improved stress regulation and neurocognitive resource efficiency that facilitate bidirectional brain-body communication.

Feasibility and impact of a remote moderate-intensity yoga intervention on stress and executive functioning in working adults: a randomized controlled trial.

The feasibility of a moderate-intensity yoga intervention, delivered remotely via supervised and unsupervised sessions, and its psychosocial and cognitive effects have not been thoroughly investigated. This randomized controlled trial assessed feasibility and preliminary efficacy of an 8-week moderate-intensity yoga intervention (3×/week, 50 min) delivered remotely (vs. a waitlist control arm), on stress and cognitive functioning. Participants (n = 86) were low active, full-time working adults (81.40% female; Mage = 41 years) with symptoms of stress. Feasibility was assessed via adherence, enjoyment, and safety; stress and anxiety via self-report questionnaires; and executive functioning via neuropsychological tests. Overall attendance was 75.1%, 100% of participants enjoyed the intervention, and only one adverse event was reported. At follow-up, the yoga group had significantly lower stress and anxiety, and higher accuracy on working memory tasks. Remote moderate intensity yoga practice proved safe, enjoyable, and may reduce stress and improve cognitive functioning. This study was pre-registered on ClinicalTrials.gov (NCT04740229).

White matter plasticity in healthy older adults: The effects of aerobic exercise.

White matter deterioration is associated with cognitive impairment in healthy aging and Alzheimer's disease. It is critical to identify interventions that can slow down white matter deterioration. So far, clinical trials have failed to demonstrate the benefits of aerobic exercise on the adult white matter using diffusion Magnetic Resonance Imaging. Here, we report the effects of a 6-month aerobic walking and dance interventions (clinical trial NCT01472744) on white matter integrity in healthy older adults (n = 180, 60-79 years) measured by changes in the ratio of calibrated T1- to T2-weighted images (T1w/T2w). Specifically, the aerobic walking and social dance interventions resulted in positive changes in the T1w/T2w signal in late-myelinating regions, as compared to widespread decreases in the T1w/T2w signal in the active control. Notably, in the aerobic walking group, positive change in the T1w/T2w signal correlated with improved episodic memory performance. Lastly, intervention-induced increases in cardiorespiratory fitness did not correlate with change in the T1w/T2w signal. Together, our findings suggest that white matter regions that are vulnerable to aging retain some degree of plasticity that can be induced by aerobic exercise training. In addition, we provided evidence that the T1w/T2w signal may be a useful and broadly accessible measure for studying short-term within-person plasticity and deterioration in the adult human white matter.

Effects of a DVD-delivered randomized controlled physical activity intervention on functional health in cancer survivors.

BACKGROUND: Supervised physical activity interventions improve functional health during cancer survivorship, but remain costly and inaccessible for many. We previously reported on the benefits of a DVD-delivered physical activity program (FlexToBa™) in older adults. This is a secondary analysis of the intervention effects among cancer survivors in the original sample. METHODS: Low active, older adults who self-reported a history of cancer (N = 46; M time since diagnosis = 10.7 ± 9.4 years) participated in a 6-month, home-based physical activity intervention. Participants were randomized to either the DVD-delivered physical activity program focused on flexibility, toning, and balance (FlexToBa™; n = 22) or an attentional control condition (n = 24). Physical function was assessed by the Short Physical Performance Battery (SPPB) at baseline, end of intervention, and at 12 and 24 months after baseline. RESULTS: Repeated measures linear mixed models indicated a significant group*time interaction for the SPPB total score (ß = - 1.14, p = 0.048), driven by improved function from baseline to six months in the FlexToBa™ group. The intervention group also had improved balance (ß = - 0.56, p = 0.041) compared with controls. Similar trends emerged for the SPPB total score during follow-up; the group*time interaction from 0 to 12 months approached significance (ß = - 0.97, p = 0.089) and was significant from 0 to 24 months (ß = - 1.84, p = 0.012). No significant interactions emerged for other outcomes (ps > 0.11). CONCLUSIONS: A DVD-delivered physical activity intervention designed for cancer-free older adults was capable of eliciting and maintaining clinically meaningful functional improvements in a subgroup of cancer survivors, with similar effects to the original full sample. These findings inform the dissemination of evidence-based physical activity programs during survivorship. TRIAL REGISTRATION: ClinicalTrials.gov NCT01030419 . Registered 11 December 2009.

Examining the effects of light versus moderate to vigorous physical activity on cognitive function in African American adults.

BACKGROUND: Physical activity (PA) recommendations for older adults often endorse participation in moderate to vigorous intensity (MVPA). However, health disparities are evident such that African Americans engage in lower levels of MVPA, have a higher prevalence of chronic health and cognitive impairments. The purpose of this cross-sectional study was to examine the role of light PA in addition to MVPA and their associations with measures of executive function among African American older adults. METHODS: One hundred and ten participants (mean age = 64.78 ± 5.7, males = 14) completed measures of cognitive functioning, including the Trail making, Flanker and the N-back tasks. Additionally, participants completed a 6-minute walk test to estimate their cardiovascular fitness and were given an Actigraph accelerometer for 7-days to objectively assess their light and MVPA. RESULTS: Regression analyses controlling for age, fitness and education showed that higher levels of light PA but not MVPA predicted better cognitive performance on the incongruent flanker reaction time (ß=-.24), trails B (ß=-.24) and 1-back accuracy (ß=.28). Both light PA and MVPA predicted faster reaction times on the 1-back and 2-back conditions of the n-back (light PA: ß's=-.22-.23; MVPA: ß's=-.28). CONCLUSIONS: Light PA demonstrated similar or better associations than MVPA with cognitive functions which are known to decline with age. Designing and promoting light PA interventions in African American older adults maybe more feasible given the prevalence of disability and functional health disparities. Intervention studies testing the efficacy and effectiveness of light PA are needed and could have a significant public health impact among aging African Americans.

Development of a Multicomponent Intervention to Initiate Health Behavior Change in Primary Care: The Kickstart Health Program.

There is a growing movement to integrate behavioral health specialists into primary care settings in order to better manage patients' health behaviors. Group interventions in healthcare settings can provide services to multiple individuals simultaneously; however, the participants' experiences taking part in these activities and the logistics of integrating them into clinical settings are largely under-studied. This article describes the development and implementation of a novel group intervention for health behavior change, The Kickstart Health Program, which integrates components of cognitive, behavioral, acceptance, and experiential therapies. Participant feasibility, acceptability, experiences, and treatment course were assessed. Acceptability among a small sample of attendees was high, and initial data on behavior change suggest there were benefits to patients who attended the program. Increases in mindfulness practice and decreases in exercise barriers from baseline to 10-week follow-up were detected as were improvements in overall perceived health and well-being. Participants expressed that the program was acceptable and successful at helping them reach their individual health goals; however, enrollment barriers negatively impacted the feasibility of the program in regard to attendance. Modification to the enrollment process such as embedding referrals into the electronic medical record, encouraging spouse or family co-enrollment, and peer coaching may address these barriers. The Kickstart Health Program has the potential to improve health behaviors and paves the way for unique studies of dissemination and implementation of efficacious behavioral health interventions into real-world healthcare settings.

Physical Activity, Sleep and Quality of Life in Older Adults: Influence of Physical, Mental and Social Well-being.

Introduction: Physical activity and sleep quality have been consistently associated with quality of life (QOL) in a number of clinical and non-clinical populations. However, mechanisms underlying this relationship are not well understood. The purpose of this study was to longitudinally test a model examining how changes in physical activity and sleep quality, predict physical, mental and social well-being and global QoL across a 6-month exercise trial in a sample of healthy older adults. Methods: Participants (N = 247, mean age 65.4 ± 4.6) wore an accelerometer to assess objective levels of physical activity and completed measures of sleep, physical and mental well-being, social well-being and QOL at baseline and following a 6-month physical activity intervention. Relationships among model constructs were examined over time using panel analysis within a covariance-modeling framework. Results: The hypothesized model provided a good model-data fit (χ2 = 58.77, df = 41, p = .036); CFI = 0.98; SRMR = 0.05; RMSEA = 0.04). At both time-points, physical activity and sleep quality were significantly correlated. Sleep quality indirectly influenced QOL via physical, mental and social well-being (QOL R2 = .47, p < .001). These relationships were also supported across time at month 6 (QOL R2 = .50, p < .001). Neither physical activity nor sleep quality directly influenced QOL. Conclusion: Our results support a novel sleep and QOL model that may inform the design of health interventions to promote sleep quality, and thereby influencing QOL by targeting physical activity and modifiable mediators of physical, mental and social health. Our findings may have significant implications for older adults as well as clinical populations that report compromised sleep, impaired health related and global QOL.

Validity of wearable activity monitors for tracking steps and estimating energy expenditure during a graded maximal treadmill test.

The purpose of this study was to assess the accuracy of energy expenditure (EE) estimation and step tracking abilities of six activity monitors (AMs) in relation to indirect calorimetry and hand counted steps and assess the accuracy of the AMs between high and low fit individuals in order to assess the impact of exercise intensity. Fifty participants wore the Basis watch, Fitbit Flex, Polar FT7, Jawbone, Omron pedometer, and Actigraph during a maximal graded treadmill test. Correlations, intra-class correlations, and t-tests determined accuracy and agreement between AMs and criterions. The results indicate that the Omron, Fitbit, and Actigraph were accurate for measuring steps while the Basis and Jawbone significantly underestimated steps. All AMs were significantly correlated with indirect calorimetry, however, no devices showed agreement (p < .05). When comparing low and high fit groups, correlations between AMs and indirect calorimetry improved for the low fit group, suggesting AMs may be better at measuring EE at lower intensity exercise.

Correlates of Physical Activity in Urban African American Adults and Older Adults: Testing the Social Cognitive Theory.

Background: Older adults, especially ethnic minorities continue to be the least active segment of the U.S. population. Health disparities are evident in that African Americans participate in less physical activity (PA) and are less likely to meet PA guidelines compared with non-Hispanic Caucasians. Purpose: Using the social cognitive theory (SCT), this study examined the individual, social, and physical environmental correlates of PA behavior. Methods: Participants (N = 110, females = 96, mean age = 64.8 ± 5.7 years) were urban, community-dwelling African American adults and older adults who completed demographics and psychosocial questionnaires assessing (SCT) constructs of self-efficacy, outcome expectations, social support, and perceptions of the physical environment. A latent factor PA construct represented self-report (Godin Leisure-time Exercise Questionnaire, Physical Activity Scale for the Elderly) and objective (accelerometer worn for 7 days) PA. Results: The direct and indirect effects of SCT constructs on PA were tested using structural equation modeling, and the overall model fit was adequate (comparative fit index = 0.94, root mean square error of approximation = 0.04, standardized root mean square residual = 0.05, chi square = 67.03, p = .17). Results indicated that: (a) self-efficacy was the strongest direct predictor of PA (ß = 0.79) and also influenced outcome expectations (ß = 0.457, p < .001); and (b) outcome expectations directly (ß = 0.36) predicted PA. Among demographic moderators, only age was inversely associated with outcome expectations (ß = -0.28). Social support or physical environment did not influence PA. Conclusions: Our findings suggest that self-efficacy and outcome expectations are important correlates of PA for African American adults and older adults. Future studies should examine the direct and indirect impact of PA interventions targeting self-efficacy and outcomes expectations to promote behavior change.

Fitness, but not physical activity, is related to functional integrity of brain networks associated with aging.

Greater physical activity and cardiorespiratory fitness are associated with reduced age-related cognitive decline and lower risk for dementia. However, significant gaps remain in the understanding of how physical activity and fitness protect the brain from adverse effects of brain aging. The primary goal of the current study was to empirically evaluate the independent relationships between physical activity and fitness with functional brain health among healthy older adults, as measured by the functional connectivity of cognitively and clinically relevant resting state networks. To build context for fitness and physical activity associations in older adults, we first demonstrate that young adults have greater within-network functional connectivity across a broad range of cortical association networks. Based on these results and previous research, we predicted that individual differences in fitness and physical activity would be most strongly associated with functional integrity of the networks most sensitive to aging. Consistent with this prediction, and extending on previous research, we showed that cardiorespiratory fitness has a positive relationship with functional connectivity of several cortical networks associated with age-related decline, and effects were strongest in the default mode network (DMN). Furthermore, our results suggest that the positive association of fitness with brain function can occur independent of habitual physical activity. Overall, our findings provide further support that cardiorespiratory fitness is an important factor in moderating the adverse effects of aging on cognitively and clinically relevant functional brain networks.

White matter microstructure mediates the relationship between cardiorespiratory fitness and spatial working memory in older adults.

White matter structure declines with advancing age and has been associated with a decline in memory and executive processes in older adulthood. Yet, recent research suggests that higher physical activity and fitness levels may be associated with less white matter degeneration in late life, although the tract-specificity of this relationship is not well understood. In addition, these prior studies infrequently associate measures of white matter microstructure to cognitive outcomes, so the behavioral importance of higher levels of white matter microstructural organization with greater fitness levels remains a matter of speculation. Here we tested whether cardiorespiratory fitness (VO2max) levels were associated with white matter microstructure and whether this relationship constituted an indirect pathway between cardiorespiratory fitness and spatial working memory in two large, cognitively and neurologically healthy older adult samples. Diffusion tensor imaging was used to determine white matter microstructure in two separate groups: Experiment 1, N=113 (mean age=66.61) and Experiment 2, N=154 (mean age=65.66). Using a voxel-based regression approach, we found that higher VO2max was associated with higher fractional anisotropy (FA), a measure of white matter microstructure, in a diverse network of white matter tracts, including the anterior corona radiata, anterior internal capsule, fornix, cingulum, and corpus callosum (PFDR-corrected<.05). This effect was consistent across both samples even after controlling for age, gender, and education. Further, a statistical mediation analysis revealed that white matter microstructure within these regions, among others, constituted a significant indirect path between VO2max and spatial working memory performance. These results suggest that greater aerobic fitness levels are associated with higher levels of white matter microstructural organization, which may, in turn, preserve spatial memory performance in older adulthood.

Yoga and Cognition: A Meta-Analysis of Chronic and Acute Effects.

OBJECTIVES: To review and synthesize the existing literature on the effects of yoga on cognitive function by determining effect sizes that could serve as a platform to design, calculate statistical power, and implement future studies. METHODS: Through electronic databases, we identified acute studies and randomized controlled trials (RCTs) of yoga that reported cognitive outcomes. Inclusion criteria included the following: use of an objective measure of cognition and sufficient data reported to estimate an effect size. The meta-analysis was conducted using Comprehensive Meta-Analysis software. A random-effects model was used to calculate the overall weighted effect sizes, expressed as Hedge g. RESULTS: Fifteen RCTs and 7 acute exposure studies examined the effects of yoga on cognition. A moderate effect (g = 0.33, standard error = 0.08, 95% confidence interval = 0.18-0.48, p < .001) of yoga on cognition was observed for RCTs, with the strongest effect for attention and processing speed (g = 0.29, p < .001), followed by executive function (g = 0.27, p = .001) and memory (g = 0.18, p = .051). Acute studies showed a stronger overall effect of yoga on cognition (g = 0.56, standard error = 0.11, 95% confidence interval = 0.33-0.78, p < .001). The effect was strongest for memory (g = 0.78, p < .001), followed by attention and processing speed measures (g = 0.49, p < .001) and executive functions (g = 0.39, p < .003). CONCLUSIONS: Yoga practice seems to be associated with moderate improvements in cognitive function. Although the studies are limited by sample size, heterogeneous population characteristics, varied doses of yoga interventions, and a myriad of cognitive tests, these findings warrant rigorous systematic RCTs and well-designed counterbalanced acute studies to comprehensively explore yoga as a means to improve or sustain cognitive abilities across the life span.

Physical activity levels and patterns in older adults: the influence of a DVD-based exercise program.

The use of multimedia to influence health behaviors offers unique advantages over more traditional center-based programs, however, little is known about the effectiveness of such approaches in improving physical activity levels over time. The purpose of this study was to examine the efficacy of a progressive and age-appropriate, DVD-delivered exercise program in promoting physical activity levels among older adult cohorts. Community dwelling older adults (N = 307, Mean age = 71 years) were randomized to one of two groups: a 6-month home-based DVD-delivered exercise (i.e., FlexToBa™) intervention group or a healthy aging DVD control group. Physical activity was assessed objectively using a standard 7-day accelerometer wear period and subjectively using the Godin Leisure Time Exercise Questionnaire, at baseline and follow-up. Analysis of covariances indicated a statistically significant treatment effect for subjectively [F(1,250) = 8.42, P = .004, η(2) = .03] and objectively [F(1,240) = 3.77, P = .05, η(2) = .02] measured physical activity. The older cohort (>70) in the FlexToBa condition further had significantly larger improvements in physical activity levels compared to their younger counterparts. From a public health perspective, media-delivered interventions such as the FlexToBa program might prove to be cost-effective, have a broader reach and at the same time be effective in improving physical activity levels in older adults.

Influence of allowable interruption period on estimates of accelerometer wear time and sedentary time in older adults.

The criteria one uses to reduce accelerometer data can profoundly influence the interpretation of research outcomes. The purpose of this study was to examine the influence of 3 different interruption periods (i.e., 20, 30, and 60 min) on the amount of data retained for analyses and estimates of sedentary time among older adults. Older adults (N = 311, M age = 71.1) wore an accelerometer for 7 d and reported wear time on an accelerometer log. Accelerometer data were downloaded and scored using 20-, 30-, and 60-min interruption periods. Estimates of wear time, derived using each interruption period, were compared with self-reported wear time, and descriptive statistics were used to compare estimates of sedentary time. Results showed a longer interruption period (i.e., 60 min) yields the largest sample size and the closest approximation of self-reported wear time. A short interruption period (i.e., 20 min) is likely to underestimate sedentary time among older adults.

Physical activity-related individual differences in functional human connectome are linked to fluid intelligence in older adults.

The study examined resting state functional connectivity (rs-FC) associated with moderate-to-vigorous physical activity (MV-PA), sedentary time (ST), TV viewing, computer use, and their relationship to cognitive performance in older adults. We used pre-intervention data from 119 participants from the Fit & Active Seniors trial. Multivariate pattern analysis revealed two seeds associated with MV-PA: right superior frontal gyrus (SFG; spanning frontoparietal [FPN] and ventral attention networks [VAN]) and right precentral (PrG) and postcentral gyri (PoG) of the somatosensory network (SN). A positive correlation between the right SFG seed and a cluster spanning default mode (DMN), dorsal attention (DAN), FPN, and visual networks (VIS) was linked to higher fluid intelligence, as was FC between the right PrG/PoG seed and a cluster in VIS. No significant rs-FC patterns associated with ST, TV viewing, or computer use were found. Our findings suggest that greater functional integration within networks implementing top-down control and within those supporting visuospatial abilities, paired with segregation between networks critical and those not critical to top-down control, may help promote cognitive reserve in more physically active seniors.

The influence of aerobic fitness on cerebral white matter integrity and cognitive function in older adults: results of a one-year exercise intervention.

Cerebral white matter (WM) degeneration occurs with increasing age and is associated with declining cognitive function. Research has shown that cardiorespiratory fitness and exercise are effective as protective, even restorative, agents against cognitive and neurobiological impairments in older adults. In this study, we investigated whether the beneficial impact of aerobic fitness would extend to WM integrity in the context of a one-year exercise intervention. Further, we examined the pattern of diffusivity changes to better understand the underlying biological mechanisms. Finally, we assessed whether training-induced changes in WM integrity would be associated with improvements in cognitive performance independent of aerobic fitness gains. Results showed that aerobic fitness training did not affect group-level change in WM integrity, executive function, or short-term memory, but that greater aerobic fitness derived from the walking program was associated with greater change in WM integrity in the frontal and temporal lobes, and greater improvement in short-term memory. Increases in WM integrity, however, were not associated with short-term memory improvement, independent of fitness improvements. Therefore, while not all findings are consistent with previous research, we provide novel evidence for correlated change in training-induced aerobic fitness, WM integrity, and cognition among healthy older adults.

Neurobiological markers of exercise-related brain plasticity in older adults.

The current study examined how a randomized one-year aerobic exercise program for healthy older adults would affect serum levels of brain-derived neurotrophic factor (BDNF), insulin-like growth factor type 1 (IGF-1), and vascular endothelial growth factor (VEGF) - putative markers of exercise-induced benefits on brain function. The study also examined whether (a) change in the concentration of these growth factors was associated with alterations in functional connectivity following exercise, and (b) the extent to which pre-intervention growth factor levels were associated with training-related changes in functional connectivity. In 65 participants (mean age=66.4), we found that although there were no group-level changes in growth factors as a function of the intervention, increased temporal lobe connectivity between the bilateral parahippocampus and the bilateral middle temporal gyrus was associated with increased BDNF, IGF-1, and VEGF for an aerobic walking group but not for a non-aerobic control group, and greater pre-intervention VEGF was associated with greater training-related increases in this functional connection. Results are consistent with animal models of exercise and the brain, but are the first to show in humans that exercise-induced increases in temporal lobe functional connectivity are associated with changes in growth factors and may be augmented by greater baseline VEGF.

A profile for predicting attrition from exercise in older adults.

The purpose of this study was to determine a profile for predicting attrition among older adults involved in a 12-month exercise program. The parent study was a single-blinded randomized controlled trial. The study took place between 2006 and 2009 within a university setting. Older adults (N = 179) completed baseline assessments of functional performance and psychosocial measures. Participants who were randomized, elected to receive treatment, and did not complete the exercise program were considered "dropouts" (n = 35). Those who completed the program (n = 144) were classified as "completers." A latent profile analysis revealed two distinct patterns of memory complaints, self-efficacy to overcome barriers to exercise, balance performance, and stair performance. Dropouts were nearly twice as likely to be members of the profile that exhibited a higher degree of memory complaints, lower self-efficacy for overcoming exercise barriers, poorer single leg balance, and longer times to walk down stairs. The results provide an initial validation of a profile for discriminating between "dropouts" and "completers," one that may have considerable utility for screening older adults prior to study entry.

Evaluation of the Factor Structure of the Rosenberg Self-Esteem Scale in Older Adults.

The Rosenberg Self-Esteem Scale is the most utilized measure of global self-esteem. Although psychometric studies have generally supported the uni-dimensionality of this 10-item scale, more recently, a stable, response-bias has been associated with the wording of the items (Marsh, Scalas, & Nagengast, 2010). The purpose of this report was to replicate Marsh et al.'s findings in a sample of older adults and to test for invariance across time, gender and levels of education. Our results indicated that indeed a response-bias does exist in esteem responses. Researchers should investigate ways to meaningfully examine and practically overcome the methodological challenges associated with the RSE scale.