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.

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.

Symmetric data-driven fusion of diffusion tensor MRI: Age differences in white matter.

In the past 20 years, white matter (WM) microstructure has been studied predominantly using diffusion tensor imaging (DTI). Decreases in fractional anisotropy (FA) and increases in mean (MD) and radial diffusivity (RD) have been consistently reported in healthy aging and neurodegenerative diseases. To date, DTI parameters have been studied individually (e.g., only FA) and separately (i.e., without using the joint information across them). This approach gives limited insights into WM pathology, increases the number of multiple comparisons, and yields inconsistent correlations with cognition. To take full advantage of the information in a DTI dataset, we present the first application of symmetric fusion to study healthy aging WM. This data-driven approach allows simultaneous examination of age differences in all four DTI parameters. We used multiset canonical correlation analysis with joint independent component analysis (mCCA + jICA) in cognitively healthy adults (age 20-33, n = 51 and age 60-79, n = 170). Four-way mCCA + jICA yielded one high-stability modality-shared component with co-variant patterns of age differences in RD and AD in the corpus callosum, internal capsule, and prefrontal WM. The mixing coefficients (or loading parameters) showed correlations with processing speed and fluid abilities that were not detected by unimodal analyses. In sum, mCCA + jICA allows data-driven identification of cognitively relevant multimodal components within the WM. The presented method should be further extended to clinical samples and other MR techniques (e.g., myelin water imaging) to test the potential of mCCA+jICA to discriminate between different WM disease etiologies and improve the diagnostic classification of WM diseases.

Embedding lifestyle interventions into cancer care: has telehealth narrowed the equity gap?

Lifestyle interventions targeting energy balance (ie, diet, exercise) are critical for optimizing the health and well-being of cancer survivors. Despite their benefits, access to these interventions is limited, especially in underserved populations, including older people, minority populations and those living in rural and remote areas. Telehealth has the potential to improve equity and increase access. This article outlines the advantages and challenges of using telehealth to support the integration of lifestyle interventions into cancer care. We describe 2 recent studies, GO-EXCAP and weSurvive, as examples of telehealth lifestyle intervention in underserved populations (older people and rural cancer survivors) and offer practical recommendations for future implementation. Innovative approaches to the use of telehealth-delivered lifestyle intervention during cancer survivorship offer great potential to reduce cancer burden.

Prospective associations between accelerometry-derived physical activity and sedentary behaviors and mortality among cancer survivors.

BACKGROUND: Survival benefits of self-reported recreational physical activity (PA) during cancer survivorship are well-documented in common cancer types, yet there are limited data on the associations between accelerometer-derived PA of all domains, sedentary behavior, and mortality in large, diverse cohorts of cancer survivors. METHODS: Participants included adults who reported a cancer diagnosis in the National Health and Nutrition Examination Survey and wore an accelerometer for up to 7 days in 2003-2006. Participants were followed for subsequent mortality through 2015. We examined the association of light PA, moderate to vigorous PA, total PA, and sedentary behavior, with all-cause mortality. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs), adjusting for demographics and health indicators. RESULTS: A total of 480 participants (mean age of 68.8 years [SD = 12.4] at the time of National Health and Nutrition Examination Survey assessment) reported a history of cancer. A total of 215 deaths occurred over the follow-up period. For every 1-h/d increase in light PA and moderate to vigorous PA (MVPA), cancer survivors had 49% (HR = 0.51, 95% CI = 0.34 to 0.76) and 37% (HR = 0.63 , 95% CI = 0.40 to 0.99) lower hazards of all-cause mortality, respectively. Total PA demonstrated similar associations with statistically significantly lower hazards of death for each additional hour per day (HR = 0.68, 95% CI = 0.54 to 0.85), as did every metabolic equivalents of task-hour per day increase in total PA estimations of energy expenditure (HR = 0.88, 95% CI = 0.82 to 0.95). Conversely, more sedentary time (1 h/d) was not associated with statistically significantly higher hazards (HR = 1.08, 95% CI = 0.94 to 1.23). CONCLUSIONS: These findings reinforce the current recommendations for cancer survivors to be physically active and underscore the continued need for widespread PA promotion for long-term survival in older cancer survivors.

Designing home-based physical activity programs for rural cancer survivors: A survey of technology access and preferences.

Background: While technology advances have increased the popularity of remote interventions in underserved and rural cancer communities, less is understood about technology access and preferences for home-based physical activity programs in this cancer survivor population. Purpose: To determine access, preferences, and needs, for a home-based physical activity program in rural cancer survivors. Methods: A Qualtrics Research Panel was recruited to survey adults with cancer across the United States. Participants self-reported demographics, cancer characteristics, technology access and usage, and preferences for a home-based physical activity program. The Godin Leisure Time Exercise Questionnaire (GLTEQ) assessed current levels of physical activity. Descriptive statistics included means and standard deviations for continuous variables, and frequencies for categorical variables. Independent samples t-tests explored differences between rural and non-rural participants. Results: Participants (N=298; mean age=55.2 ± 16.5) had a history of cancer (mean age at diagnosis=46.5), with the most commonly reported cancer type being breast (25.5%), followed by prostate (16.1%). 74.2% resided in rural hometowns. 95% of participants reported accessing the internet daily. On a scale of 0-100, computer/laptop (M=63.4) and mobile phone (M=54.6) were the most preferred delivery modes for a home-based physical activity intervention, and most participants preferred balance/flexibility (72.2%) and aerobic (53.9%) exercises. Desired intervention elements included a frequency of 2-3 times a week (53.5%) for at least 20 minutes (75.7%). While there were notable rural disparities present (e.g., older age at diagnosis, lower levels of education; ps<.001), no differences emerged for technology access or environmental barriers (ps>.08). However, bias due to electronic delivery of the survey should not be discounted. Conclusion: These findings provide insights into the preferred physical activity intervention (e.g., computer delivery, balance/flexibility exercises) in rural cancer survivors, while highlighting the need for personalization. Future efforts should consider these preferences when designing and delivering home-based interventions in this population.

Brain Structure and Function Predict Adherence to an Exercise Intervention in Older Adults.

INTRODUCTION: Individual differences in brain structure and function in older adults are potential proxies of brain reserve or maintenance and may provide mechanistic predictions of adherence to exercise. We hypothesized that multimodal neuroimaging features would predict adherence to a 6-month randomized controlled trial of exercise in 131 older adults (age, 65.79 ± 4.65 yr, 63% female), alone and in combination with psychosocial, cognitive, and health measures. METHODS: Regularized elastic net regression within a nested cross-validation framework was applied to predict adherence to the intervention in three separate models (brain structure and function only; psychosocial, health, and demographic data only; and a multimodal model). RESULTS: Higher cortical thickness in somatosensory and inferior frontal regions and less surface area in primary visual and inferior frontal regions predicted adherence. Higher nodal functional connectivity (degree count) in default, frontoparietal, and attentional networks and less nodal strength in primary visual and temporoparietal networks predicted exercise adherence ( r = 0.24, P = 0.004). Survey and clinical measures of gait and walking self-efficacy, biological sex, and perceived stress also predicted adherence ( r = 0.17, P = 0.056); however, this prediction was not significant when tested against a null test statistic. A combined multimodal model achieved the highest predictive strength ( r = 0.28, P = 0.001). CONCLUSIONS: Our results suggest that there is a substantial utility of using brain-based measures in future research into precision and individualized exercise interventions older adults.

Resting state functional connectivity provides mechanistic predictions of future changes in sedentary behavior.

Sedentary behaviors are increasing at the cost of millions of dollars spent in health care and productivity losses due to physical inactivity-related deaths worldwide. Understanding the mechanistic predictors of sedentary behaviors will improve future intervention development and precision medicine approaches. It has been posited that humans have an innate attraction towards effort minimization and that inhibitory control is required to overcome this prepotent disposition. Consequently, we hypothesized that individual differences in the functional connectivity of brain regions implicated in inhibitory control and physical effort decision making at the beginning of an exercise intervention in older adults would predict the change in time spent sedentary over the course of that intervention. In 143 healthy, low-active older adults participating in a 6-month aerobic exercise intervention (with three conditions: walking, dance, stretching), we aimed to use baseline neuroimaging (resting state functional connectivity of two a priori defined seed regions), and baseline accelerometer measures of time spent sedentary to predict future pre-post changes in objectively measured time spent sedentary in daily life over the 6-month intervention. Our results demonstrated that functional connectivity between (1) the anterior cingulate cortex and the supplementary motor area and (2) the right anterior insula and the left temporoparietal/temporooccipital junction, predicted changes in time spent sedentary in the walking group. Functional connectivity of these brain regions did not predict changes in time spent sedentary in the dance nor stretch and tone conditions, but baseline time spent sedentary was predictive in these conditions. Our results add important knowledge toward understanding mechanistic associations underlying complex out-of-session sedentary behaviors within a walking intervention setting in older adults.

Physical Activity Patterns and Relationships With Cognitive Function in Patients With Breast Cancer Before, During, and After Chemotherapy in a Prospective, Nationwide Study.

PURPOSE: Physical activity (PA) is a promising intervention for cancer-related cognitive decline, yet research assessing its use during chemotherapy is limited. This study evaluated patterns of PA before, during, and after chemotherapy in patients with breast cancer and the association between PA and cognitive function. METHODS: In a nationwide, prospective cohort study, we assessed PA (Aerobics Center Longitudinal Study PA measure) and perceived and objectively measured cognitive functioning (Functional Assessment of Cancer Therapy-Cognitive, Delayed Match to Sample, and Rapid Visual Processing measures) at prechemotherapy (T1), postchemotherapy (T2), and 6 months postchemotherapy (T3) in patients with breast cancer and cancer-free, age-matched controls at equivalent time points. Longitudinal linear mixed-effects models (LMMs) characterized PA changes over time between patients and controls, adjusting for demographic and clinical factors. LMMs further estimated the role of prechemotherapy PA and changes in PA during chemotherapy on cognitive changes over time. RESULTS: Patients with stage I-IIIC breast cancer (n = 580; age M [standard deviation] = 53.4 [10.6] years) and controls (n = 363; age M [standard deviation] = 52.6 [10.3] years) were included. One third of patients met national PA guidelines at T1, dropping to 21% at T2 before rising to 37% at T3. LMMs revealed declines in PA from T1 to T2 in patients compared with controls (all P < .001). Patients meeting guidelines at T1 demonstrated better cognitive scores over time on the Functional Assessment of Cancer Therapy-Cognitive and Rapid Visual Processing (all P < .05), with similar patterns of objectively-measured cognitive function as controls. In patients, greater moderate-to-vigorous PA at the previous time point was significantly associated with better cognitive trajectories (all P < .05), and adherence to PA guidelines throughout chemotherapy was associated with better self-reported cognition (P < .01). CONCLUSION: This nationwide study demonstrates that PA maintenance before and during chemotherapy is associated with better cognitive function immediately and 6 months after chemotherapy completion.

Sedentary Behavior in U.S. Adults: 2019.

PURPOSE: Higher levels of sedentary behavior are associated with early mortality, but the distribution of sedentary time by classes of behavior and demographic groups is poorly described in U.S. adults. To quantify the amount and sources of sedentary time in U.S. adults, we conducted a nationwide survey using a novel validated self-administered previous-day recall method and compared these values with a commonly used sitting time question. METHODS: Participants from the AmeriSpeak panel 20 to 75 yr of age (N = 2640) completed up to two activities completed over time in 24 h (ACT24) previous-day recalls. Recalls were conducted on randomly selected days in October and November 2019. Survey sample designs were applied to reflect the U.S. population. RESULTS: Mean age was 45.3 yr, 51% were female, 67% non-Hispanic White, and 37% had a body mass index of ≥30 kg·m-2. U.S. adults reported a mean 9.5 h·d-1 of sedentary time (95% confidence interval = 9.4, 9.7 h·d-1), which was 34% more than reported using a common surveillance measure (P < 0.01). Most daily sedentary time was accumulated in the leisure and work life domains, with leisure accounting for 47% (4.3 h·d-1, 95% confidence interval = 4.2, 4.5 h·d-1) of the total sedentary time. Eighty-two percent of leisure time was spent sedentary, mainly watching television/videos or engaged in Internet/computer use. CONCLUSIONS: U.S. adults appear to spend more time in sedentary behavior than previously thought, and the majority of this time is accumulated at work and in leisure time. Reducing sedentary screen time during leisure in favor of physically active could be an important intervention target in the effort to increase physical activity in U.S. adults.

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.

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.

Ambulatory Function and Mortality among Cancer Survivors in the NIH-AARP Diet and Health Study.

BACKGROUND: There is limited evidence describing associations between cancer and function in diverse cancer types and its relationship with mortality. We investigated the relationship between cancer and poor ambulatory function and associations between ambulatory function and subsequent mortality. METHODS: Participants included 233,135 adults (n = 30,403 cancer and n = 202,732 cancer free) in the NIH-American Association of Retired Persons Diet and Health Study (1994-1996) who self-reported ambulatory function (e.g., walking pace and mobility disability: being unable to walk or walking at the slowest pace) in 2004-2006. Participants were followed for mortality from the assessment of ambulatory function through 2011. Multinomial logistic regression quantified the association between cancer and ambulatory function. We then explored the independent effects of walking pace and mobility disability in cancer survivors, and the joint effects of both a cancer diagnosis and poor ambulatory function on mortality using Cox proportional hazards models. Models explored type-specific associations across 15 cancer types. RESULTS: Survivors had 42% greater odds of walking at the slowest pace [OR, 1.42 (confidence interval (CI), 1.30-1.54)] and 24% greater odds of mobility disability [OR, 1.24 (CI, 1.17-1.31)], compared with cancer-free participants, adjusting for baseline demographics, health indicators, and cancer type. Survivors reporting the slowest pace were at increased hazards than those who walked the fastest: all-cause mortality [HR, 2.22 (CI, 2.06-2.39)] and cancer mortality [HR, 2.12 (CI, 1.83-2.45)]. Similar trends emerged for mobility disability (HRs > 1.64). All-cause mortality associations were significant for more than nine cancer types. CONCLUSIONS: A diagnosis of cancer is associated with poorer ambulatory function, which is subsequently associated with increased mortality. IMPACT: Widespread efforts should target ambulatory function during cancer survivorship for survival benefits.

Increased frequency of intentional weight loss associated with reduced mortality: a prospective cohort analysis.

BACKGROUND: Due to the high prevalence of obesity and the difficulty in maintaining weight loss, repeated bouts of weight loss are a common occurrence. However, there are inconsistencies in epidemiological studies regarding repetitive weight fluctuations being associated with increased risk of mortality. Therefore, the purpose of this prospective cohort analysis was to determine the long-term association of the frequency of weight loss attempts on mortality. METHODS: This prospective cohort study used data collected from adult AARP members living in 6 states (California, Florida, Louisiana, New Jersey, North Carolina, or Pennsylvania) or 2 metropolitan areas (Atlanta, Georgia, or Detroit, Michigan) and participating in the National Institutes of Health-AARP Diet and Health Study between 2004 and 2006. Self-reported data were analyzed for 161,738 middle-aged adults. During an average 7 years of follow-up, 21,194 deaths were recorded. Hazard ratios of all-cause, cardiovascular, and cancer mortality were estimated adjusting for demographic, lifestyle, and behavioral risk factors. RESULTS: Increased frequency of weight loss attempts of at least five pounds was associated with lower mortality (ptrend < 0.010). Multivariate hazard ratios (95% confidence intervals) for all-cause death among individuals who successfully attempted weight loss compared with those who did not make any attempts were 0.94 (0.90-0.98) for 1-2 attempts, 0.96 (0.91-1.01) for 3-4 attempts, 0.91 (0.85-0.96) for 5-6 attempts, 0.91 (0.85-0.98) for 7-8 attempts, 0.87 (0.80-0.95) for 9-10 attempts, and 0.88 (0.82-0.94) for 11+ attempts. Similar results were noted for men and women, participants with healthy weight and overweight/obesity, and even among those who gained weight over time. Protective associations were also observed for deaths due to cardiovascular disease and cancer. CONCLUSIONS: Increased frequency of intentionally losing at least five pounds in mid-life was associated with a lower risk of future death. Repeated attempts with moderate amounts of weight loss may provide benefit in terms of longevity. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov number, NCT00340015.

Sensor-measured sedentariness and physical activity are differentially related to fluid and crystallized abilities in aging.

Aerobic exercise and physical activity (PA) are known to benefit cognition in adulthood. However, a typical older adult spends most of the day sedentary or in light PA, behaviors that are typically poorly captured by questionnaires. To better understand the associations between time spent in different intensities of lifestyle PA and cognition, we measured average time spent daily in sedentariness, light, and moderate to vigorous PA using hip-worn sensors (ActiGraph accelerometers). We studied baseline data from 228 cognitively normal adults (Age 60-80) who took part in a clinical trial (clinical study identifier: NCT01472744). Fluid (processing speed, memory, and reasoning) and crystallized abilities (vocabulary knowledge) were assessed with the Virginia Cognitive Aging Battery. Adjusting for age, sex, and several modifiable socioeconomic, physical and functional health factors, time spent daily in moderate to vigorous PA was positively related with fluid abilities (perceptual speed and reasoning). Furthermore, we found that those spending more time sedentary performed better on vocabulary knowledge and reasoning tasks. In contrast, time spent in light PA was not related to either fluid or crystallized abilities. Our results add to the previous literature by providing the first sensor-based evidence that crystallized and fluid abilities in older age may be associated with engagement in different intensities of daily activity. Moreover, our findings suggest that the behavior of moderate to vigorous PA is at least as important in relation to cognition as the desirable long-term physiological effects of higher intensity PA and exercise. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Occupational Physical Stress Is Negatively Associated With Hippocampal Volume and Memory in Older Adults.

Our jobs can provide intellectually and socially enriched environments but also be the source of major psychological and physical stressors. As the average full-time worker spends >8 h at work per weekday and remains in the workforce for about 40 years, occupational experiences must be important factors in cognitive and brain aging. Therefore, we studied whether occupational complexity and stress are associated with hippocampal volume and cognitive ability in 99 cognitively normal older adults. We estimated occupational complexity, physical stress, and psychological stress using the Work Design Questionnaire (Morgeson and Humphrey, 2006), Quantitative Workload Inventory and Interpersonal Conflict at Work Scale (Spector and Jex, 1998). We found that physical stress, comprising physical demands and work conditions, was associated with smaller hippocampal volume and poorer memory performance. These associations were independent of age, gender, brain size, socioeconomic factors (education, income, and job title), duration of the job, employment status, leisure physical activity and general stress. This suggests that physical demands at work and leisure physical activity may have largely independent and opposite effects on brain and cognitive health. Our findings highlight the importance of considering midlife occupational experiences, such as work physical stress, in understanding individual trajectories of cognitive and brain aging.

Dose-Response Effects of Acute Aerobic Exercise Duration on Cognitive Function in Patients With Breast Cancer: A Randomized Crossover Trial.

OBJECTIVE: To examine the differential effects of acute exercise duration on domains of executive function and processing speed in patients with breast cancer. METHODS: Participants (N = 48, M age = 56.02 ± 10.99) completed two sessions in counterbalanced order: moderate-intensity treadmill walking and sitting. Participants were also randomized to one of three duration conditions: 10 (n = 15), 20 (n = 16), or 30 (n = 17) min, reflecting the length of time spent walking and sitting. Immediately before and after each session, women completed a battery of cognitive tasks (e.g., inhibition, cognitive flexibility, spatial working memory, and processing speed). RESULTS: Within- and between-subjects repeated-measures analyses of variance revealed time by condition interactions on both processing speed (p = 0.02) and spatial working memory (ps < 0.07), such that women demonstrated improved cognitive functioning regardless of the time spent walking. There were also several moderately sized three-way (e.g., time by condition by duration) interactions driven by declines in cognitive functioning after sitting on cognitive flexibility in the 10 (d = -0.96) and 30-min (d = -0.52) groups and inhibition in the 20-min group (d = 0.75). On the processing speed task, women performed significantly faster after walking compared with after sitting in the 20-min group (d = -0.24). CONCLUSIONS: For select cognitive domains, walking anywhere from 10 to 30 min is associated with significant benefits. Our findings suggest the need for further research into the mechanisms and dose-response relationships between acute exercise and cognition as well as how such acute bouts may be accumulated for larger, lasting cognitive benefits after breast cancer. CLINICAL TRIAL REGISTRATION: www.ClinicalTrials.gov, identifier NCT04255225.

The effects of exercise on cancer-related fatigue in breast cancer patients during primary treatment: a meta-analysis and systematic review.

INTRODUCTION: Cancer-related fatigue is one of the most prevalent symptoms reported by breast cancer survivors. Despite a corpus of literature dedicated to understanding and identifying evidence-based treatments for cancer-related fatigue, gaps in the literature remain, particularly for breast cancer survivors during their primary treatment. Exercise training may represent an efficacious behavioral modality for mitigating fatigue symptoms in cancer survivors; yet, the effects of exercise during adjuvant therapy is an understudied area. AREAS COVERED: In this review, we synthesize the most recent evidence of exercise's effects on cancer-related fatigue during active treatment for breast cancer. We summarize the overall effects of exercise, moderators of these effects, and areas requiring further research. EXPERT OPINION: Strong evidence supports at least modest effects of exercise on cancer-related fatigue during breast cancer treatment. However, several knowledge gaps persist, including the need to: risk stratify patients to tailor exercise promotion strategies; implement higher-quality studies and translate this evidence to clinical practice; adopt biobehavioral models to better understand exercise's effects on cancer-related fatigue; evaluate the effects of exercise modes besides aerobic and combined training; and integrate technology to better understand and promote fatigue-reducing behaviors, such as exercise, across cancer care.

Exploration of Confounding Due to Poor Health in an Accelerometer-Mortality Study.

PURPOSE: Confounding due to poor health is a concern in accelerometer-based studies of physical activity and health, but detailed investigations of this source of bias are lacking. METHODS: US adults (n = 4840) from the National Health and Nutrition Examination Survey (2003 to 2006) wore an accelerometer for 1 to 7 d (mean = 5.7 d) and were followed for mortality through 2015. Logistic regression was used to examine odds ratios between poor health (chronic conditions, self-reported health, mobility limitations, frailty) and low physical activity levels; Cox models were used to estimate adjusted hazard ratios (HR) and 95% CI for mortality associations for a 1 h·d increase in moderate-to-vigorous-intensity physical activity (MVPA) using two commonly used cut-points (MVPA760, MVPA2020). Modeling scenarios with shorter and longer follow-up time, increasing adjustment for poor health, by age group, and after excluding early years of follow-up were used to assess bias. RESULTS: Over a mean of 10.1 yr of follow-up, 1165 deaths occurred. Poor health was associated with low MVPA760 levels and increased mortality risk. In fully adjusted MVPA760 models, HR was 26% stronger comparing 0 to 4 yr (HR = 0.46) with 0 to 12 yr of follow-up (HR = 0.62), particularly in older adults (65 yr and older). Increasing statistical adjustment for poor health attenuated MVPA760 associations by 13% to 15%, and exclusion of the first 2 yr of follow-up had limited effects. Comparable results were obtained with the MVPA2020 cut-point. CONCLUSIONS: We did not find evidence that confounding by health status resulted in entirely spurious MVPA-mortality associations; however, potential bias was appreciable in modeling scenarios involving shorter follow-up (<6 yr), older adults, and more limited statistical adjustment for poor health. The strength of MVPA-mortality associations in studies reflecting these scenarios should be interpreted cautiously.