Physical Activity, Sedentary Behavior, and Suicidal Ideation in Major Depressive Disorder.

OBJECTIVE: Identifying risk factors for suicidal ideation (SI) is necessary for suicide prevention. Associations between self-reported physical activity (PA) and sedentary time and SI in the general population have been found. The current study examines these associations in adults with major depressive disorder (MDD) using objective measures of PA and sedentary time. METHOD: Sedentary time and PA were measured with an activPAL inclinometer/accelerometer over 7 days in 52 adults with MDD. Presence and severity of SI was examined with the Mini International Neuropsychiatric Interview. Multinomial logistic regressions examined associations between accelerometer-derived behaviors and SI classification in the full sample and a subsample experiencing a major depressive episode (MDE). RESULTS: Sedentary time and PA measures were not significantly associated with SI in the full sample. In those experiencing an MDE, higher light ambulatory PA was associated with lower odds of reporting Low SI compared to None and for Moderate/High SI compared to None. Sedentary time was not significantly associated with SI severity. CONCLUSION: Sedentary time and PA were not associated with SI severity, although results could be due to the small sample size. The small effect found for the subsample may suggest that low levels of light ambulatory PA may be a modifiable risk factor for SI during an MDE. We also demonstrated the feasibility of collecting objective data with accelerometers in this population. Future studies are needed to replicate findings to determine whether increasing light ambulatory PA could be useful in suicide prevention during an MDE.HighlightsLight physical activity was associated with lower odds of suicidal ideation.Suicidal ideation was not associated with sedentary or moderate-to-high activity.It is possible to collect objective data for adults with depression.

Safety and efficacy of short-term structured resistance exercise in Gulf War Veterans with chronic unexplained muscle pain: A randomized controlled trial.

AIMS: Chronic widespread musculoskeletal pain (CMP) is a primary condition of Veterans suffering from Gulf War illness. This study evaluated the influence of resistance exercise training (RET) on symptoms, mood, perception of improvement, fitness, and total physical activity in Gulf War Veterans (GWV) with CMP. MAIN METHODS: Fifty-four GWV with CMP were randomly assigned to 16 weeks of RET (n = 28) or wait-list control (n = 26). Supervised exercise was performed twice weekly starting at a low intensity. Outcomes, assessed at baseline, 6, 11 and 17 weeks and 6- and 12-months post-intervention, were: pain, fatigue, mood, sleep quality, perception of improvement, and physical activity via self-report and accelerometry. Muscular strength was assessed at baseline, 8 and 16 weeks. Accelerometer data yielded estimates of time spent in sedentary, light, and moderate-to-vigorous physical activities. Analyses used separate linear mixed models with group and time point as fixed effects. All models, except for perceived improvement, included baseline values as a covariate. KEY FINDINGS: Participants assigned to RET completed 87% of training sessions and exhibited strength increases between 16 and 34% for eight lifts tested (Hedges' g range: 0.47-0.78). The treatment by time interaction for perceived improvement (F1,163 = 16.94, p < 0.001) was characterized by greater perceived improvement since baseline for RET at each time point, until the 12-month follow-up. Effects were not significant for other outcomes (p > 0.05). RET caused no adverse events. SIGNIFICANCE: After 16 weeks of RET, GWV with CMP reported improvements in their condition and exhibited increases in muscular strength, without symptom exacerbation or reductions in total physical activity.

Nociceptive stress interferes with neural processing of cognitive stimuli in Gulf War Veterans with chronic musculoskeletal pain.

AIMS: Disrupted cognition and chronic musculoskeletal pain (CMP) are prevalent experiences among Gulf War Veterans (GWV). A negative association between CMP and cognition (i.e., chronic pain-related cognitive interference) has been observed in some chronic pain populations but has not been evaluated in GWV. Additional research suggests that disrupted cognition in GWV with CMP may be exacerbated by stressing the nociceptive system. Therefore, we compared cognitive performance and related neural activity between CMP and healthy control (CO) GWV in the absence and presence of experimental pain. MAIN METHODS: During functional magnetic resonance imaging (fMRI), Veterans (CMP = 29; CO = 27) completed cognitive testing via congruent and incongruent conditions of a modified Stroop task (Stroop-only). A random subset (CMP = 13; CO = 13) also completed cognitive testing with experimental pain (Pain+Stroop). Yuen's modified t-test and robust mixed-model analysis of variance (ANOVA) models were used for analyzing cognitive performance data. Independent t-tests and repeated-measures ANOVA models were employed for fMRI data with thresholding for multiple-comparisons (p < 0.005) and cluster size (> 320 mm3). KEY FINDINGS: Functional MRI analysis revealed significant between-group differences for the incongruent but not congruent-Stroop run. Neither correct responses nor reaction time differed between groups in either Stroop condition (all p ≥ 0.21). Significant group (CMP, CO) by run (Stroop-only, Pain+Stroop) interactions revealed greater neural responses in CMP Veterans during Pain+Stroop runs. No significant interactions were observed for correct responses or reaction time (p ≥ 0.31). SIGNIFICANCE: GWV with CMP require a greater amount of neural resources to sustain cognitive performance during nociceptive stress.

A qualitative analysis of barriers and facilitators to reducing sedentary time in adults with chronic low back pain.

BACKGROUND: Sedentary time (SED) is associated with many detrimental health outcomes, yet little is known about what factors influence one's ability to reduce SED. Even less is known about these factors in specific patient populations for whom high levels of SED may influence symptoms, such as those with chronic low back pain (cLBP). The purpose of this study was to qualitatively explore participants' perceptions of factors that influenced their ability to reduce SED across an 8-week intervention to reduce SED in adults with cLBP and elevated depressive symptoms. METHODS: Three months after a theory-based intervention to break up and reduce sitting, semi-structured interviews explored factors that influenced reducing SED. Three researchers independently coded each conversation. Codes were charted and mapped with participants reviewing their own transcripts and the merged codes. The research team then defined key themes. Factors that were perceived to either facilitate behavior change or acted as barriers were identified and thematized as positive or negative determinants. RESULTS: Common barriers for reducing SED included environmental constraints, opposing social norms, and productivity; these barriers were frequently encountered in the workplace. Common facilitators for reducing SED included habit development, self-monitoring tools, restructuring the physical environment, and social accountability. Notably, back pain was not a frequently reported barrier or facilitator for reducing SED. CONCLUSION: This sample of patients with cLBP and elevated depressive symptoms had similar determinants for reducing SED as previously reported in non-patient populations and did not appear to need strategies specific to dealing with chronic pain. Since work-related social norms and environmental factors were perceived as significant barriers to sitting less, workplace interventions that provide standing desks, offer standing meetings rooms, and/or institution-wide standing breaks may help reduce SED at work. The use of an activity monitor with sitting reminders and education regarding how to use the reminders as external cues to develop new sitting habits may also aid in adoption and adherence to this behavior change across settings. Developing coping plans and restructuring physical environments were perceived as successful strategies for overcoming social and environmental barriers. Future interventions targeting SED reductions may benefit from incorporating these strategies.

Current and 1-Year Psychological and Physical Effects of Replacing Sedentary Time With Time in Other Behaviors.

INTRODUCTION: Sedentary time is inversely associated with health. Capturing 24 hours of behavior (i.e., sleep, sedentary, light physical activity, and moderate-to-vigorous physical activity) is necessary to understand behavior-health associations. METHODS: Healthy young adults aged 20-35 years (n=423) completed the Profile of Mood States, the Perceived Stress Scale, and dual-energy x-ray absorptiometry and anthropometric measures at baseline and 12 months. Time spent sedentary (total, in prolonged [>30 minutes] and short [≤30 minutes] bouts), in light physical activity (1.5-3.0 METs), moderate-to-vigorous physical activity (>3.0 METs), and asleep, were assessed through SenseWear armband worn 24 hours/day for 10 days at baseline. Isotemporal substitution modeling evaluated cross-sectional and longitudinal psychological and physical health associations of substituting sedentary time with sleep, light physical activity, or moderate-to-vigorous physical activity. Data were collected from 2010 to 2015 and analyzed in 2019. RESULTS: Cross-sectional analyses revealed substituting prolonged sedentary time for sleep was associated with lower stress (standardized ß= -0.11), better mood (-0.12), and lower BMI (-0.10). Substituting total or prolonged sedentary for moderate-to-vigorous physical activity was associated with lower body fat percentage (total, -0.22; prolonged, -0.23) and BMI (-0.40; -0.42). Higher BMI was associated with substituting total or prolonged sedentary for light physical activity (0.15; 0.17); lower BMI with substituting prolonged sedentary for short bouts (-0.09). Prospective analyses indicated substituting total or prolonged sedentary with light physical activity was associated with improved mood (-0.16; -0.14) and lower BMI (-0.15; -0.16); substituting with moderate-to-vigorous physical activity was associated with improved mood (-0.15; -0.15). CONCLUSIONS: Short- and long-term psychological benefits may result from transitioning sedentary time to light physical activity or sleep, whereas increasing moderate-to-vigorous physical activity may be required to influence physical health. TRIAL REGISTRATION: This study is registered at www.clinicaltrials.gov NCT01746186.

Sedentary Behavior and Quality of Life in Individuals With Parkinson's Disease.

Background. Sedentary behavior is a growing public health concern and may have particular relevance for the Parkinson disease (PD) population. However, the influence of sedentary time on factors associated with quality of life (QOL) in PD is unknown. The primary purpose of this study was to examine relationships between sedentary behaviors and markers of PD-specific QOL. A secondary purpose was to examine relationships between physical activity behaviors and QOL. Methods. We assessed sedentary and active behaviors using objective and interview measures and examined relationships between these behaviors and a measure of PD-specific QOL in individuals with PD. Results. Results demonstrated that sedentary time was significantly related to several aspects of QOL, including perceived deficits in the domains of mobility, cognitive processing, and communication. Additionally, results showed that time spent watching television was more strongly associated with lower levels of QOL than other more engaging sedentary activities. For physical activity, relationships between objective measures and QOL were weaker and only significantly associated with mobility. Time spent doing housework was associated with lower levels of QOL, whereas time spent in recreational activity was associated with lower levels of discomfort. Discussion. These results suggest that targeting decreases in sedentary behaviors (eg, reducing time spent watching television, breaking up prolonged bouts of sedentary time) may be effective for improving QOL in individuals with PD.

The Behavioral Wellness in Pregnancy study: a randomized controlled trial of a multi-component intervention to promote appropriate weight gain.

BACKGROUND: Adequate weight gain during pregnancy is important to both maternal and fetal outcomes. To date, randomized controlled trials have not been effective at increasing the proportion of women meeting gestational weight-gain guidelines. OBJECTIVES: The aim of this study was to determine whether a multi-component behavioral intervention with a Registered Dietitian Nutritionist significantly improves the proportion of women who adhere to the 2009 Institute of Medicine weight-gain guidelines. METHODS: Participants were randomly assigned to usual care (UC; n = 24) or intervention (n = 23) between 8 and 14 weeks of gestation. The intervention included a minimum of 6 one-on-one counseling sessions over ∼30 wk focusing on healthy diet and physical activity (PA) goals. In addition to the face-to-face visits, weekly communication via email supported healthy eating, PA, and appropriate weight gain. Gestational weight gain, PA, and diet were assessed at 8-14, 26-28, and 34-36 weeks of gestation; weight retention was measured 2 mo postpartum. RESULTS: The proportion of women meeting the guidelines was significantly greater in those receiving the intervention than UC (60.8% compared with 25.0%, OR: 4.7; 95% CI: 1.3, 16.2; P = 0.019). Furthermore, 36.4% of the intervention women were at or below their prepregnancy weight at 2 mo postpartum compared with 12.5% in the UC group (P = 0.05). CONCLUSIONS: A multi-component behavioral intervention improved adherence to the 2009 Institute of Medicine weight-gain guidelines. This trial was registered with clinicaltrials.gov as NCT02168647.

Intervening to reduce sedentary behavior in older adults - pilot results.

Background: Older adults spend most of their day in sedentary behavior (SB) (i.e., prolonged sitting), increasing risk for negative health outcomes, functional loss, and diminished ability for activities of daily living. The purpose of this study was to develop and pilot test an intervention designed to reduce SB in older adults that could be translated to communities. Methods: Two pilot studies implementing a 4-week SB intervention were conducted. SB,physical function, and health-related quality of life were measured via self-report and objective measures. Participants (N=21) completed assessments pre- and post-intervention (studies 1 and 2) and at follow-up (4-weeks post-intervention; study 2). Due to the pilot nature of this research, data were analyzed with Cohen's d effect sizes to examine the magnitude of change in outcomes following the intervention. Results: Results for study 1 indicated moderate (d=0.53) decreases in accelerometry-obtained total SB and increases (d=0.52) in light intensity physical activity post-intervention. In study 2,there was a moderate decrease (d=0.57) in SB evident at follow-up. On average SB decreased by approximately 60 min/d in both studies. Also, there were moderate-to-large improvements in vitality (d=0.74; study 1) and gait speed (d=1.15; study 2) following the intervention. Further,the intervention was found to be feasible for staff to implement in the community. Conclusion: These pilot results informed the design of an ongoing federally funded randomized controlled trial with a larger sample of older adults from underserved communities. Effective,feasible, and readily-accessible interventions have potential to improve the health and function of older adults.

Evaluating Motivational Interviewing and Habit Formation to Enhance the Effect of Activity Trackers on Healthy Adults' Activity Levels: Randomized Intervention.

BACKGROUND: While widely used and endorsed, there is limited evidence supporting the benefits of activity trackers for increasing physical activity; these devices may be more effective when combined with additional strategies that promote sustained behavior change like motivational interviewing (MI) and habit development. OBJECTIVE: This study aims to determine the utility of wearable activity trackers alone or in combination with these behavior change strategies for promoting improvements in active and sedentary behaviors. METHODS: A sample of 91 adults (48/91 female, 53%) was randomized to receive a Fitbit Charge alone or in combination with MI and habit education for 12 weeks. Active and sedentary behaviors were assessed pre and post using research-grade activity monitors (ActiGraph and activPAL), and the development of habits surrounding the use of the trackers was assessed postintervention with the Self-Reported Habit Index. During the intervention, Fitbit wear time and activity levels were monitored with the activity trackers. Linear regression analyses were used to determine the influence of the trial on outcomes of physical activity and sedentary time. The influence of habits was examined using correlation coefficients relating habits of tracker use (wearing the tracker and checking data on the tracker and associated app) to Fitbit wear time and activity levels during the intervention and at follow-up. RESULTS: Regression analyses revealed no significant differences by group in any of the primary outcomes (all P>.05). However, personal characteristics, including lower baseline activity levels (beta=-.49, P=.01) and lack of previous experience with pedometers (beta=-.23, P=.03) were predictive of greater improvements in moderate and vigorous physical activity. Furthermore, for individuals with higher activity levels at the baseline, MI and habit education were more effective for maintaining these activity levels when compared with receiving a Fitbit alone (eg, small increase of ~48 steps/day, d=0.01, vs large decrease of ~1830 steps/day, d=0.95). Finally, habit development was significantly related to steps/day during (r=.30, P=.004) and following the intervention (r=.27, P=.03). CONCLUSIONS: This study suggests that activity trackers may have beneficial effects on physical activity in healthy adults, but benefits vary based on individual factors. Furthermore, this study highlights the importance of habit development surrounding the wear and use of activity trackers and the associated software to promote increases in physical activity. TRIAL REGISTRATION: ClinicalTrials.gov NCT03837366; https://clinicaltrials.gov/ct2/show/NCT03837366.

Changes in sedentary time are associated with changes in mental wellbeing over 1 year in young adults.

Excessive sedentary time is related to poor mental health. However, much of the current literature uses cross-sectional data and/or self-reported sedentary time, and does not assess factors such as sedentary bout length. To address these limitations, the influence of objectively measured sedentary time including sedentary bout length (i.e. <30 min, ≥30 min) on mood, stress, and sleep, was assessed in 271 healthy adults (49% women; age 27.8 ±â€¯3.7) across a 1-year period between 2011 and 2013 in Columbia, SC. Participants completed the Profile of Mood States and the Perceived Stress Scale, and wore a Sensewear Armband to assess sedentary time, physical activity, and sleep for ten days at baseline and one year. A series of fixed-effects regressions was used to determine the influence of both baseline levels and changes in daily sedentary time (total and in bouts) and physical activity on changes in mood, stress, and sleep over one year. Results showed that across the year, decreases in total sedentary time, and time in both short and long bouts, were associated with improvements in mood, stress and sleep (p < 0.05). Increases in physical activity were only significantly predictive of increases in sleep duration (p < 0.05). Thus, reductions in sedentary time, regardless of bout length, positively influenced mental wellbeing. Specifically, these results suggest that decreasing daily sedentary time by 60 min may significantly attenuate the negative effects of high levels of pre-existing sedentary time on mental wellbeing. Interventions manipulating sedentary behavior are needed to determine a causal link with wellbeing and further inform recommendations.

Catastrophizing Interferes with Cognitive Modulation of Pain in Women with Fibromyalgia.

Background: Pain modulation is a critical function of the nociceptive system that includes the ability to engage descending pain control systems to maintain a functional balance between facilitation and inhibition of incoming sensory stimuli. Dysfunctional pain modulation is associated with increased risk for chronic pain and is characteristic of fibromyalgia (FM). Catastrophizing is also common in FM. However, its influence on pain modulation is poorly understood. Objective: To determine the role of catastrophizing on central nervous system processing during pain modulation in FM via examining brain responses and pain sensitivity during an attention-distraction paradigm. Methods: Twenty FM patients and 18 healthy controls (CO) underwent functional magnetic resonance imaging while receiving pain stimuli, administered alone and during distracting cognitive tasks. Pain ratings were assessed after each stimulus. Catastrophizing was assessed with the Pain Catastrophizing Scale (PCS). Results: The ability to modulate pain during distraction varied among FM patients and was associated with catastrophizing. This was demonstrated by significant positive relationships between PCS scores and pain ratings (P < 0.05) and brain responses in the dorsolateral prefrontal cortex (P < 0.01). Relationships between catastrophizing and pain modulation did not differ between FM and CO (P > 0.05). Conclusions: FM patients with higher levels of catastrophizing were less able to distract themselves from pain, indicative of catastrophizing-related impairments in pain modulation. These results suggest that the tendency to catastrophize interacts with attention-resource allocation and may represent a mechanism of chronic pain exacerbation and/or maintenance. Reducing catastrophizing may improve FM symptoms via improving central nervous system regulation of pain.

Comparison of In-Person and Online Motivational Interviewing-Based Health Coaching.

Health coaching is a common approach for promoting lifestyle changes, but little is known about the effectiveness of different delivery methods. The purpose of this study was to evaluate the effectiveness of in-person versus online health coaching when used as part of a facilitated behavior change program. To increase translatability, the study used a naturalistic design that enabled participants to self-select the coaching delivery method (Group) as well as the target behavior (diet, physical activity, or weight management). Regardless of group, participants were provided with a behavior-based monitoring device and guided to use it by the health coach. A sample of 92 adults participated and 86 completed pre-post evaluations to assess behavior change strategies and posttest outcome measurements for their specific goal. Two-way (Group × Time) analyses of variance were used to evaluate changes in behavioral strategies. Intent-to-treat regression analyses were used to compare postintervention outcomes for groups. The in-person group had significantly higher Healthy Eating Index scores than the online group ( p < .05), but nonsignificant group differences were observed for those targeting physical activity or weight change ( p > .05). The results support the use of health coaching for promoting behavior change and suggest that online coaching may be equally effective as in-person methods.

Adapted Sojourn Models to Estimate Activity Intensity in Youth: A Suite of Tools.

The challenges of using physical activity data from accelerometers have been compounded with the recent focus on wrist-worn monitors and raw acceleration (as opposed to activity counts). PURPOSE: This study developed and systematically evaluated a suite of new accelerometer processing models for youth. METHODS: Four adaptations of the Sojourn method were developed using data from a laboratory-based experiment in which youth (N = 54) performed structured activity routines. The adaptations corresponded to all possible pairings of hip or wrist attachment with activity counts (AC) or raw acceleration (RA), and they estimated time in sedentary behavior, light activity, and moderate-to-vigorous physical activity. Criterion validity was assessed using direct observation in an independent free-living sample (N = 27). Monitors were worn on both wrists to evaluate the effect of handedness on accuracy, and status quo methods for each configuration were also evaluated as benchmarks for comparison. Tests of classification accuracy (percent accuracy, κ statistics, and sensitivity and specificity) were used to summarize utility. RESULTS: In the development sample, percent accuracy ranged from 68.5% (wrist-worn AC, κ = 0.42) to 71.6% (hip-worn RA, κ = 0.50). Accuracy was lower in the free-living evaluation, with values ranging from 49.3% (hip-worn RA, κ = 0.25) to 56.7% (hip-worn AC, κ = 0.36). Collectively, the suite predicted moderate-to-vigorous physical activity well, with the models averaging 96.5% sensitivity and 67.5% specificity. However, in terms of overall accuracy, the new models performed similarly to the status quo methods. There were no meaningful differences in performance at either wrist. CONCLUSIONS: The new models offered minimal improvements over existing methods, but a major advantage is that further tuning of the models is possible with continued research.

Nonworksite Interventions to Reduce Sedentary Behavior among Adults: A Systematic Review.

PURPOSE: Sedentary behavior has been identified as a major health risk. While interventions to reduce time spent sedentary have become increasingly prevalent, the vast majority of this work in adults has been focused on workplace sedentary behavior, and often pairs sedentary reduction interventions with increasing physical activity. As research designed to specifically decrease sedentary time that is not limited to the workplace becomes available, identifying strategies and approaches, along with feasibility and efficacy of these interventions, is warranted. METHODS: Electronic databases were searched for sedentary interventions with eligibility criteria including: (a) interventions designed to explicitly reduce sedentary behavior that were not limited to the workplace, (b) outcomes specific to sedentary behavior, (c) adults aged at least 18 years, and (d) written in English. RESULTS: A total of 767 full-text manuscripts were identified, with thirteen studies meeting all eligibility criteria. While intervention characteristics and methodological quality varied greatly among studies, ten of the thirteen studies observed a significant reduction in objectively measured sitting time post-intervention. In those studies that collected participant feasibility/acceptability data, all reported that the intervention was viewed as "favorable to very favorable," would use again, and that participant burden was quite low, suggesting that these interventions were feasible. CONCLUSION: Sedentary behavior interventions not limited to the workplace appear to be largely efficacious. While results varied with respect to the magnitude of the decrease in time spent sedentary, they are encouraging. However, due to the small body of evidence and the variability of study designs, our ability to make overarching statements regarding "best practices" at this time is limited. Well-controlled trials of longer duration with larger samples, using theoretically-based interventions with consistent prescriptions for limiting sedentary time are needed.

Cerebral white matter structure is disrupted in Gulf War Veterans with chronic musculoskeletal pain.

Chronic musculoskeletal pain (CMP) affects ∼25% of the 700,000 Veterans deployed during the Persian Gulf War (1990-1991). The cause of their pain is unknown, and there are no efficacious treatments. A small body of literature suggests that brain abnormalities exist in Gulf War Veterans (GVs), yet relationships between brain abnormalities and disease symptoms remain largely unexplored. Our purpose was to compare white matter (WM) integrity between GVCMP and matched, healthy Veteran controls (GVCO) and investigate relationships between cerebral WM integrity and symptoms. Thirty GVCMP and 31 controls completed magnetic resonance imaging with diffusion tensor imaging. Tract-based spatial statistics estimated WM fractional anisotropy, mean diffusivity, radial diffusivity, and axial diffusivity over the whole brain (P < 0.05) and were corrected using threshold-free cluster enhancement. GVCMP had greater pain symptoms and mood disturbance and lower quality of life and physical function compared with GVCO (P < 0.05). GVCMP had lower WM integrity across several brain regions implicated in chronic pain (P < 0.05) including the middle and inferior frontal gyrus, corpus callosum, corona radiata, precentral gyrus, external capsule, and posterior thalamic radiation. For GVCMP, WM integrity was associated with pain and mood symptoms in widespread brain areas that were found to be different between groups (P < 0.05). Results indicate widespread WM microstructure disruption across brain regions implicated in pain processing and modulation in chronic pain. The observed relationships between WM microstructure and symptoms encourage the testing of treatments designed to improve the brain health of affected Veterans.

Lab-based validation of different data processing methods for wrist-worn ActiGraph accelerometers in young adults.

The wrist is increasingly being used as the preferred site for objectively assessing physical activity but the relative accuracy of processing methods for wrist data has not been determined. OBJECTIVE: This study evaluates the validity of four processing methods for wrist-worn ActiGraph (AG) data against energy expenditure (EE) measured using a portable metabolic analyzer (OM; Oxycon mobile) and the Compendium of physical activity. APPROACH: Fifty-one adults (ages 18-40) completed 15 activities ranging from sedentary to vigorous in a laboratory setting while wearing an AG and the OM. Estimates of EE and categorization of activity intensity were obtained from the AG using a linear method based on Hildebrand cutpoints (HLM), a non-linear modification of this method (HNLM), and two methods developed by Staudenmayer based on a Linear Model (SLM) and using random forest (SRF). Estimated EE and classification accuracy were compared to the OM and Compendium using Bland-Altman plots, equivalence testing, mean absolute percent error (MAPE), and Kappa statistics. MAIN RESULTS: Overall, classification agreement with the Compendium was similar across methods ranging from a Kappa of 0.46 (HLM) to 0.54 (HNLM). However, specificity and sensitivity varied by method and intensity, ranging from a sensitivity of 0% (HLM for sedentary) to a specificity of ~99% for all methods for vigorous. None of the methods was significantly equivalent to the OM (p > 0.05). SIGNIFICANCE: Across activities, none of the methods evaluated had a high level of agreement with criterion measures. Additional research is needed to further refine the accuracy of processing wrist-worn accelerometer data.

Surveillance of Youth Physical Activity and Sedentary Behavior With Wrist Accelerometry.

INTRODUCTION: Accurate tracking of physical activity (PA) and sedentary behavior (SB) is important to advance public health, but little is known about how to interpret wrist-worn accelerometer data. This study compares youth estimates of SB and moderate to vigorous PA (MVPA) obtained using raw and count-based processing methods. METHODS: Data were collected between April and October 2014 for the National Cancer Institute's Family Life, Activity, Sun, Health, and Eating Study: a cross-sectional Internet-based study of youth/family cancer prevention behaviors. A subsample of 628 adolescents (aged 12-17 years) wore the ActiGraph GT3X+ on the wrist for 7 days. In 2015-2016, SB and MVPA time were calculated from raw data using R-package GGIR and from activity counts data using published cutpoints (Crouter and Chandler). Estimates were compared across age, sex, and weight status to examine the impact of processing methods on behavioral outcomes. RESULTS: ActiGraph data were available for 408 participants. Large differences in SB and MVPA time were observed between processing methods, but age and gender patterns were similar. Younger children (aged 12-14 years) had lower sedentary time and greater MVPA time (p-values <0.05) than older children (aged 15-17 years), consistent across methods. The proportion of youth with ≥60 minutes of MVPA/day was highest with the Crouter methods (~50%) and lowest with GGIR (~0%). CONCLUSIONS: Conclusions about youth PA and SB are influenced by the wrist-worn accelerometer data processing method. Efforts to harmonize processing methods are needed to promote standardization and facilitate reporting of monitor-based PA data.

Comparative effectiveness of guided weight loss and physical activity monitoring for weight loss and metabolic risks: A pilot study.

Many consumer-based physical activity monitors (PAMs) are available but it is not clear how to use them to most effectively promote weight loss. The purpose of this pilot study was to compare the effectiveness of a personal PAM, a guided weight loss program (GWL), and the combination of these approaches on weight loss and metabolic risk. Participants completed the study in two cohorts: Fall 2010 and Spring 2011. A sample of 72 obese individuals in the Ames, IA area were randomized to one of 3 conditions: 1) (GWL, N = 31), 2) PAM, N = 29, or 3) a combination group (PAM + GWL, N = 29). Weight and metabolic syndrome score (MetS), computed from waist circumference (WC), BMI, blood pressure (BP), and lipids were assessed at baseline and following an 8-week intervention. Weight was also assessed four months later. Two-way (Group × Time) ANOVAs examined intervention effects and maintenance. Effect sizes were used to compare magnitude of improvements among groups. During the intervention, all groups demonstrated significant improvements in weight and MetS (mean weight loss = 4.16 kg, p < 0.001). Mean weight continued to decline modestly during follow-up, with average weight loss of 4.82 kg from baseline (p < 0.01). There were no group differences for weight loss but the PAM + GWL group had significantly larger changes in MetS score (d = 0.06-0.77). The use of PAM resulted in significant improvements in weight and MetS that were maintained across a four-month follow-up. Evidence suggests that the addition of GWL contributed to enhanced metabolic outcomes.

Relationships between cardiorespiratory fitness, hippocampal volume, and episodic memory in a population at risk for Alzheimer's disease.

INTRODUCTION: Cardiorespiratory fitness (CRF) has been shown to be related to brain health in older adults. In individuals at risk for developing Alzheimer's disease (AD), CRF may be a modifiable risk factor that could attenuate anticipated declines in brain volume and episodic memory. The objective of this study was to determine the association between CRF and both hippocampal volume and episodic memory in a cohort of cognitively healthy older adults with familial and/or genetic risk for Alzheimer's disease (AD). METHODS: Eighty-six enrollees from the Wisconsin Registry for Alzheimer's Prevention participated in this study. Participants performed a graded maximal exercise test, underwent a T-1 anatomical magnetic resonance imaging scan, and completed the Rey Auditory Verbal Learning Test (RAVLT). RESULTS: There were no significant relationships between CRF and HV or RAVLT memory scores for the entire sample. When the sample was explored on the basis of gender, CRF was significantly associated with hippocampal volume for women. For men, significant positive associations were observed between CRF and RAVLT memory scores. SUMMARY: These results suggest that CRF may be protective against both hippocampal volume and episodic memory decline in older adults at risk for AD, but that the relationships may be gender specific.