Effect of varying accelerometry criteria on physical activity: the look ahead study

Association of accelerometer-measured physical activity and its change with progression to chronic kidney disease in adults with type 2 diabetes and overweight/obesity

OBJECTIVE

To examine the long-term association of objectively measured moderate-to-vigorous physical activity (MVPA) and its longitudinal changes with progression to chronic kidney disease (CKD) in patients with type 2 diabetes (T2D) and overweight/obesity.

METHODS

This study included 1746 participants in the Look AHEAD trial with baseline estimated glomerular filtration rate (eGFR)≥60 mL/min/1.73 m2. MVPA was measured at baseline, year 1, year 4 and year 8 using an RT3 accelerometer. The outcome was progression to CKD, defined as eGFR<60 mL/min per 1.73 m2 with a drop of ≥30% or end-stage kidney disease. Cox hazards models were fitted to examine the association between MVPA and outcomes.

RESULTS

Over a median follow-up of 12.0 years, 567 participants experienced progression to CKD. Overall, there was a linear inverse association of cumulative average total MVPA (per 100 min/week higher amount, HR: 0.91; 95% CI: 0.86 to 0.96) and MVPA accumulated in bouts of ≥10 min (per 100 minutes/week higher amount, HR: 0.81; 95% CI: 0.72 to 0.91) with progression to CKD. Moreover, an increase in total MVPA from baseline to year 4 (the fourth quartile, ≥63.2 min/week) was associated with a 33% lower risk of progression to CKD compared with the largest MVPA reduction (the first quartile, <-198.3 min/week). A lower risk of progression to CKD was also observed for increases in MVPA accumulated in bouts of both <10 min and ≥10 min.

CONCLUSIONS

Longer MVPA time and increases in MVPA was associated with a reduced risk of progression to CKD in adults with overweight/obesity and T2D.

Association of Timing of Moderate-to-Vigorous Physical Activity With Changes in Glycemic Control Over 4 Years in Adults With Type 2 Diabetes From the Look AHEAD Trial

OBJECTIVE

We aimed to determine the association of the time-of-day of bout-related moderate-to-vigorous physical activity (bMVPA) with changes in glycemic control across 4 years in adults with overweight/obesity and type 2 diabetes.

RESEARCH DESIGN AND METHODS

Among 2,416 participants (57% women; mean age, 59 years) with 7-day waist-worn accelerometry recording at year 1 or 4, we assigned bMVPA timing groups based on the participants' temporal distribution of bMVPA at year 1 and recategorized them at year 4. The time-varying exposure of bMVPA (≥10-min bout) timing was defined as ≥50% of bMVPA occurring during the same time period (morning, midday, afternoon, or evening), <50% of bMVPA in any time period (mixed), and ≤1 day with bMVPA per week (inactive).

RESULTS

HbA1c reduction at year 1 varied among bMVPA timing groups (P = 0.02), independent of weekly bMVPA volume and intensity. The afternoon group had the greatest HbA1c reduction versus inactive (-0.22% [95%CI -0.39%, -0.06%]), the magnitude of which was 30-50% larger than the other groups. The odds of discontinuation versus maintaining or initiating glucose-lowering medications at year 1 differed by bMVPA timing (P = 0.04). The afternoon group had the highest odds (odds ratio 2.13 [95% CI 1.29, 3.52]). For all the year-4 bMVPA timing groups, there were no significant changes in HbA1c between year 1 and 4.

CONCLUSIONS

bMVPA performed in the afternoon is associated with improvements in glycemic control in adults with diabetes, especially within the initial 12 months of an intervention. Experimental studies are needed to examine causality.

Identifying Predictors of Adherence to the Physical Activity Goal: A Secondary Analysis of the SMARTER Weight Loss Trial

INTRODUCTION/PURPOSE

Research is needed to inform tailoring supportive strategies for promoting physical activity (PA) in the context of behavioral treatment of obesity. We aimed to identify baseline participant characteristics and short-term intervention response predictors associated with adherence to the study-defined PA goal in a mobile health (mHealth) weight loss trial.

METHODS

A secondary analysis was conducted of a 12-month weight loss trial (SMARTER) that randomized 502 adults with overweight or obesity to either self-monitoring of diet, PA, and weight with tailored feedback messages ( n = 251) or self-monitoring alone ( n = 251). The primary outcome was average adherence to the PA goal of ≥150 min·wk -1 of moderate- and vigorous-intensity aerobic activities (MVPA) from Fitbit Charge 2™ trackers over 52 wk. Twenty-five explanatory variables were considered. Machine learning methods and linear regression were used to identify predictors of adherence to the PA goal.

RESULTS

The sample ( N = 502) was mostly female (80%), White (82%) with the average age of 45 ± 14.4 yr and body mass index of 33.7 ± 4.0 kg·m -2 . Machine learning methods identified PA goal adherence for the first week as the most important predictor of long-term PA goal adherence. In the parsimonious linear regression model, higher PA goal adherence for the first week, greater PA FB messages opened, older age, being male, higher education, being single and not having obstructive sleep apnea were associated with higher long-term PA goal adherence.

CONCLUSIONS

To our knowledge, this is the first study using machine learning approaches to identify predictors of long-term PA goal adherence in a mHealth weight loss trial. Future studies focusing on facilitators or barriers to PA among young and middle-age adults and women with low PA goal adherence are warranted.

Protocol for a cluster randomized clinical trial of a mastery-climate motor skills intervention, Children's Health Activity and Motor Program (CHAMP), on self-regulation in preschoolers

INTRODUCTION

Self-regulation (SR) is critical to healthy development in children, and intervention approaches (i.e., professional training, classroom-based curricula, parent-focused intervention) have shown to support or enhance SR. However, to our knowledge, none have tested whether changes in children's SR across an intervention relate to changes in children's health behavior and outcomes. This study, the Promoting Activity and Trajectories of Health (PATH) for Children-SR Study uses a cluster-randomized control trial to examine the immediate effects of a mastery-climate motor skills intervention on SR. Secondly, this study examines the associations between changes in SR and changes in children's health behaviors (i.e., motor competence, physical activity, and perceived competence) and outcomes (i.e., body mass index and waist circumference) (ClinicalTrials.gov Identifier, NCT03189862).

METHODS AND ANALYSIS

The PATH-SR study will be a cluster-randomized clinical trial. A total of 120 children between the ages of 3.5 to 5 years of age will be randomized to a mastery-climate motor skills intervention (n = 70) or control (n = 50) condition. SR will be assessed using measures that evaluate cognitive SR (cognitive flexibility and working memory), behavioral SR (behavioral inhibition), and emotional SR (emotional regulation). Health behaviors will be assessed with motor skills, physical activity, and perceived competence (motor and physical) and health outcomes will be waist circumference and body mass index. SR, health behaviors, and health outcomes will be assessed before and after the intervention (pre-test and post-test). Given the randomization design, 70 children in the intervention group and 50 in the control group, we have 80% power to detect an effect size of 0.52, at a Type I error level of 0.05. With the data collected, we will test the intervention effect on SR with a two-sample t-test comparing the intervention group and the control group. We will further evaluate the associations between changes in SR and changes in children's health behaviors and health outcomes, using mixed effect regression models, with a random effect to account for within-subject correlations. The PATH-SR study addresses gaps in pediatric exercise science and child development research. Findings hold the potential to help shape public health and educational policies and interventions that support healthy development during the early years.

ETHICS AND DISSEMINATION

Ethical approval for this study was obtained through the Health Sciences and Behavioral Sciences Institutional Review Board, University of Michigan (HUM00133319). The PATH-SR study is funded by the National Institutes of Health Common Fund. Findings will be disseminated via print, online media, dissemination events and practitioner and/or research journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov Identifier, NCT03189862.

Objectively measured physical activity levels and adherence to physical activity guidelines in people with multimorbidity-A systematic review and meta-analysis

Objective

To determine levels of objectively measured physical activity (PA) and the proportion of adults with multimorbidity that adheres to PA guidelines.

Methods

All studies, where PA was measured at baseline using an activity monitor in an adult (≥18 years) multimorbid (≥80% of the population had ≥2 chronic conditions) population. A systematic literature search was performed in Medline, EMBASE, CINAHL, CENTRAL, ClinicalTrials.gov, opengrey.eu and google.com from inception up until 18^th of January 2022. Risk of bias was assessed with a modified version of the Quality Assessment Tool for Quantitative Studies. A random-effects meta-analyses was performed to estimate daily minutes of sedentary behavior (SB), light PA (LPA), moderate PA (MPA), moderate to vigorous PA (MVPA) and steps. Proportions adhering to PA guidelines was narratively synthesized. Certainty of evidence was determined using The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

Results

Fifteen studies (2,172 participants) were included. The most frequent combination of conditions were type 2 diabetes and hypertension (six studies). Participants spent a daily average of 500.5 (95% CI: 407.1 to 593.9) minutes in SB, 325.6 (95% CI: 246.4 to 404.7 minutes in LPA and 32.7 (95% CI: 20.2 to 45.3) minutes in MVPA. The mean daily number of steps was 5,145 (95% CI: 4264 to 6026) for people in free-living conditions. The proportion adhering to PA guidelines ranged widely (7.4% to 43%). All studies were rated as at high risk of bias and the certainty of evidence was very low.

Conclusions

PA levels and adherence varied from low to above guideline recommended levels for adults with chronic conditions, depending on PA intensity. The very low certainty of evidence calls for high quality studies focusing on detailed descriptions of PA behavior in people with multimorbidity.

PROSPERO registration number

CRD42020172456.

Association Between Change in Accelerometer-Measured and Self-Reported Physical Activity and Cardiovascular Disease in the Look AHEAD Trial

OBJECTIVE

To conduct post hoc secondary analysis examining the association between change in physical activity. Measured with self-report and accelerometry, from baseline to 1 and 4 years and cardiovascular disease (CVD) outcomes in the Look AHEAD Trial.

RESEARCH DESIGN AND METHODS

Participants were adults with overweight/obesity and type 2 diabetes with physical activity. Data at baseline and year 1 or 4 (n = 1,978). Participants were randomized to diabetes support and education or intensive lifestyle intervention. Measures included accelerometry-measured moderate-to-vigorous physical activity (MVPA), self-reported physical activity, and composite (morbidity and mortality) CVD outcomes.

RESULTS

In pooled analyses of all participants, using Cox proportional hazards models, each 100 MET-min/week increase in accelerometry-measured MVPA from baseline to 4 years was associated with decreased risk of the subsequent primary composite outcome of CVD. Results were consistent for changes in total MVPA (hazard ratio 0.97 [95% CI 0.95, 0.99]) and MVPA accumulated in ≥10-min bouts (hazard ratio 0.95 [95% CI 0.91, 0.98]), with a similar pattern for secondary CVD outcomes. Change in accelerometry-measured MVPA at 1 year and self-reported change in physical activity at 1 and 4 years were not associated with CVD outcomes.

CONCLUSIONS

Increased accelerometry-measured MVPA from baseline to year 4 is associated with decreased risk of CVD outcomes. This suggests the need for long-term engagement in MVPA to reduce the risk of CVD in adults with overweight/obesity and type 2 diabetes.

How Many Hours of Device Wear Time Are Required to Accurately Measure Physical Activity Post Stroke?

Background. Inadequate physical activity participation is a risk factor for secondary stroke. Before implementing appropriate management strategies, we need to accurately measure the physical activity of stroke survivors. We aimed to determine the duration of physical activity monitoring post-stroke that constitutes a valid day. Methods. We sampled stroke survivors’ physical activity for one week following discharge from inpatient rehabilitation using the Sensewear Armband (Bodymedia, Pittsburgh, PA, USA). To determine the impact of total daily wear time on activity estimate (sedentary, light, and moderate to vigorous physical activity) accuracy, we performed simulations, removing one, two, three, or four hours from a 14-h reference day, and analysed them with linear mixed models. Results. Sixty-nine participants (46 male, 65 ± 15 years) with 271 days of physical activity data were included. All physical activity variables were significantly underestimated for all data sets (10, 11, 12, or 13 h) compared to the 14-h reference data set. The number of days classified as not meeting physical activity recommendations increased as daily monitoring duration decreased: 13% misclassification with 10-h compared to 14-h dataset (p = 0.011). Conclusions. The accuracy of physical activity estimates increases with longer daily monitoring periods following stroke, and researchers should aim to monitor post-stroke physical activity for 14 daytime hours.

Association of Objectively Measured Timing of Physical Activity Bouts With Cardiovascular Health in Type 2 Diabetes

OBJECTIVE

Moderate- to vigorous-intensity physical activity (MVPA) improves cardiovascular health. Few studies have examined MVPA timing. We examined the associations of timing of bout-related MVPA with cardiorespiratory fitness and cardiovascular risk in adults with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Baseline 7-day hip-worn accelerometry data from Look AHEAD participants (n = 2,153, 57% women) were analyzed to identify bout-related MVPA (≥3 METs/min for ≥10 min). Cardiorespiratory fitness was assessed by maximal graded exercise test. Participants were categorized into six groups on the basis of the time of day with the majority of bout-related MVPA (METs × min): ≥50% of bout-related MVPA during the same time window (morning, midday, afternoon, or evening), <50% of bout-related MVPA in any time category (mixed; the reference group), and ≤1 day with bout-related MVPA per week (inactive).

RESULTS

Cardiorespiratory fitness was highly associated with timing of bout-related MVPA (P = 0.0005), independent of weekly bout-related MVPA volume and intensity. Importantly, this association varied by sex (P = 0.02). In men, the midday group had the lowest fitness (β = -0.46 [95% CI -0.87, -0.06]), while the mixed group in women was the least fit. Framingham risk score (FRS) was associated with timing of bout-related MVPA (P = 0.02), which also differed by sex (P = 0.0007). The male morning group had the highest 4-year FRS (2.18% [0.70, 3.65]), but no association was observed in women.

CONCLUSIONS

Timing of bout-related MVPA is associated with cardiorespiratory fitness and cardiovascular risk in men with type 2 diabetes, independent of bout-related MVPA volume and intensity. Prospective studies are needed to determine the impacts of MVPA timing on cardiovascular health.

Weekend and weekday associations between the residential built environment and physical activity: Findings from the ENABLE London study

Background

We assessed whether the residential built environment was associated with physical activity (PA) differently on weekdays and weekends, and contributed to socio-economic differences in PA.

Methods

Measures of PA and walkability, park proximity and public transport accessibility were derived for baseline participants (n = 1,064) of the Examining Neighbourhood Activities in Built Living Environments in London (ENABLE London) Study. Multilevel-linear-regressions examined associations between weekend and weekday steps and Moderate to Vigorous PA (MVPA), residential built environment factors, and housing tenure status as a proxy for socio-economic position.

Results

A one-unit decrease in walkability was associated with 135 (95% CI [28; 242]) fewer steps and 1.2 (95% CI [0.3; 2.1]) fewer minutes of MVPA on weekend days, compared with little difference in steps and minutes of MVPA observed on weekdays. A 1km-increase in distance to the nearest local park was associated with 597 (95% CI [161; 1032]) more steps and 4.7 (95% CI [1.2; 8.2]) more minutes of MVPA on weekend days; 84 fewer steps (95% CI [-253;420]) and 0.3 fewer minutes of MVPA (95%CI [-2.3, 3.0]) on weekdays. Lower public transport accessibility was associated with increased steps on a weekday (767 steps, 95%CI [–13,1546]) compared with fewer steps on weekend days (608 fewer steps, 95% CI [–44, 1658]). None of the associations between built environment factors and PA on either weekend or weekdays were modified by socio-economic status. However, socio-economic differences in PA related moderately to socio-economic disparities in PA-promoting features of the residential neighbourhood.

Conclusions

The residential built environment is associated with PA differently at weekends and on weekdays, and contributes moderately to socio-economic differences in PA.

Effect of handling breaks on estimation of heart rate responses to bouts of physical activity among young women: An accelerometer research issue

BACKGROUND

One of the research interests with regard to accelerometry is the evaluation of physical activity bout under free-living conditions.

RESEARCH QUESTION

This study aimed to examine the effect of treatment interruption on the estimation of heart rate (HR) response to moderate-to-vigorous intensity physical activity (MVPA) bout.

METHODS

Twenty-five young women performed at least 30 min of MVPA during 24 h while wearing a uniaxial accelerometer on their waist and a portable HR monitor on their chest simultaneously. Based on the time series data, MVPA bout was defined as physical activity that was maintained at no less than 3 metabolic equivalents (METs) for >10 min without or with interruption, i.e., a 1-, 2-, or 3-min interruption.

RESULTS

The frequency and duration of MVPA bout significantly increased with interruption (p < 0.01). The HR and estimated MET value for an MVPA bout with interruption were significantly lower than those without interruption (p < 0.01), and the difference gradually increased depending on the duration of the interruptions (p < 0.01).

SIGNIFICANCE

These findings indicate that treatment interruptions could influence the estimation of cardiorespiratory response to MVPA bout under free-living conditions, and interruptions could result in an overestimation of the actual intensity of an MVPA bout.

A Cross-Sectional Examination of Patterns of Sedentary Behavior and Cardiometabolic Risk in Community-Dwelling Adults Aged 55 Years and Older

Introduction

Sedentary behavior (SB) is highly prevalent among older adults, with more than 25% engaging in 6 hours or more of SB daily. SB has been associated with several cardiometabolic biomarkers in younger adults; however, there is a paucity of research in older populations. This study examined associations between patterns of SB and cardiometabolic biomarkers in community-dwelling adults aged 55 years and older.

Methods

Data were drawn from a convenience sample of 54 community-dwelling individuals (12 males, 42 females; mean age = 72.6 ± 6.8 years, range = 56–89 years). Cardiometabolic biomarkers assessed included systolic (SBP) and diastolic blood pressure (DBP), body mass index, waist circumference, and fasting blood glucose and cholesterol parameters. SB was assessed via accelerometry over a 7-day period, and measures included daily time in SB, number and length of sedentary bouts, the number and length of breaks between sedentary bouts, moderate-to-vigorous physical activity (MVPA), and light physical activity (LPA). Associations between the SB measures and each cardiometabolic risk factor were examined using separate stepwise multiple regression models, controlling for sex, MVPA, and accelerometer wear time. Isotemporal substitution models were used to examine the change in cardiometabolic outcomes when SB is replaced by an equal duration of either LPA or MVPA.

Results

Adjusted regression analyses showed that daily sedentary time was positively associated with DBP (β = 0.052, ∆R² = 0.112, p = 0.022) and inversely associated with HDL cholesterol (β = −0.111, ∆R² = 0.121, p = 0.039). Sedentary bout length was also associated with DBP and HDL cholesterol (β = 0.575, ∆R² = 0.152, p = 0.007; β = −1.529, ∆R² = 0.196, p = 0.007, respectively). Replacement of 10 minutes of SB a day with LPA was associated with improved DBP and HDL cholesterol (p ≤ 0.05). No other significant associations (p ≤ 0.05) were found.

Conclusion

Sitting for prolonged periods of time without interruption is unfavorably associated with DBP and HDL cholesterol. Prospective studies should identify causal relationships and observe specific changes in cardiometabolic profiles in older populations.

Minimum accelerometer wear-time for reliable estimates of physical activity and sedentary behaviour of people receiving haemodialysis

BACKGROUND

Low levels of physical activity are implicated in low life expectancies of people receiving maintenance haemodialysis. Accelerometers are increasingly being used to quantify activity behaviours of this population but guidance to quality-assure such data is lacking. The objective of this study was to provide data processing and reduction recommendations to ensure accelerometer-derived outcomes are sufficiently reliable for interpretative analysis.

METHODS

Seventy people receiving maintenance haemodialysis (age 55.9 ± 15.7 years, 34% women, 23% diabetic) from a single outpatient renal unit volunteered for the study. Participants wore Actigraph GT3x and ActivPAL monitors during waking hours over seven days. Reliability of accelerometer output (normalised to wear-time) was assessed via intraclass correlation coefficient (ICC). The Spearman-Brown prophecy formula was subsequently applied to the ICCs to derive the minimum required accelerometer wear-time for each behavioural outcome.

RESULTS

Monitor wear compliance was greater on dialysis compared to non-dialysis days (90% v 77%). Participants were significantly more active on non-dialysis days compared to dialysis days but there were no significant differences in estimated behaviours between days within the same condition. Average measure ICCs for all accelerometer outcomes were high (range 0.76-0.96). Computations indicated that habitual physical activity and sedentary behaviour could be estimated with a minimum reliability level of 0.80 from one dialysis day and two non-dialysis days, and at least eight hours monitor wear per day. Applying this rubric allowed 90% of participant data to be retained for further analysis.

CONCLUSIONS

Regardless of accelerometer, one dialysis and two non-dialysis days data with a minimum of eight hours wear each day should enable habitual activity of people receiving maintenance haemodialysis to be characterised with acceptable reliability. These recommendations reconcile the tension between wear-time criteria stringency and retention of an adequately representative sample.

Protocol for a two-cohort randomized cluster clinical trial of a motor skills intervention: The Promoting Activity and Trajectories of Health (PATH) Study

INTRODUCTION

Data supports that motor skills are an underlying mechanism that influence physical activity along with perceived motor and physical competence, but the relationship between motor skills and physical activity during the early years is unclear. The goal of this study, Promoting Activity and Trajectories of Health (PATH) for Children, is to examine and compare the immediate (pre-test to post-test) and sustained (3-year follow-up) effect of an intervention on motor performance, physical activity and perceived physical competence to a control condition (ie, standard practice) in preschool-age children.

METHODS AND ANALYSIS

The PATH study is a two-cohort, randomised cluster clinical trial. 300 children between the ages of >3.5 to 5 years of age will be randomised to the motor skill intervention (n=153) or control (n=147) condition. Each assessment involves a measure of motor skill performance; product and process, seven consecutive days of physical activity monitoring and perceived physical competence. These measures will be assessed before and after the intervention (pre-test to post-test) and then each academic year across 3 years, grades kindergarten, first grade and second grade (3-year follow-up). To assess the clustered longitudinal effect of the intervention on outcome measures, random-effects models (eg, mixed model regression, growth curve modelling and structural equation modelling) will be used. The PATH study addresses gaps in paediatric exercise science research. Findings hold the potential to help shape public health and educational policies and interventions that support healthy development and active living during the early years.

ETHICS AND DISSEMINATION

Ethical approval for this study was obtained through the Health Sciences and Behavioral Sciences Institutional Review Board, University of Michigan (HUM00133319). The PATH study is funded by the National Institutes of Health. Findings will be disseminated via print, online media, dissemination events and practitioner and/or research journals.

TRIAL REGISTRATION NUMBER

NHLBI ClinicalTrials.gov Identifier, NCT03189862. Registered 17 August 2017, https://clinicaltrials.gov/ct2/show/NCT03189862.

Examining barriers, physical activity, and weight change among parents and nonparents in a weight loss intervention

INTRODUCTION

Little is known about the influence of children in the home on physical activity and weight among adults in weight loss interventions. This study evaluated the association between number of children in the home, weight loss, and weight regain in a behavioural weight loss intervention, and whether those relationships were mediated in sequence by physical activity barriers and physical activity changes.

METHODS

The sample included 267 participants from a randomized trial who had complete data on study variables. Variables at baseline, 6, and 18 months included physical activity barriers, objectively measured minutes of moderate-to-vigorous physical activity (MVPA), and objectively measured weight used to calculate percent weight loss (PWL) from baseline to 6 months and percent weight regained (PWG) from 6 to 18 months.

RESULTS

A greater number of children in the home was associated with less PWL at 6 months. This relationship was mediated by greater baseline physical activity barriers and a smaller increase in MVPA at 6 months. The mediated effect was no longer significant when controlling for changes in dietary intake. There was no relationship between number of children and PWG from 6 to 18 months.

CONCLUSIONS

Parents may need unique intervention supports to overcome barriers to initiation of physical activity to help them reach optimal weight loss.

Increasing the Duration of Light Physical Activity Ameliorates Insulin Resistance Syndrome in Metabolically Healthy Obese Adults

Obesity is a well-known risk factor for insulin resistance syndrome (IRS). Nevertheless, limited data are available regarding the effects of physical activity (PA) intensity on the ability to modulate IRS. The study aim was to investigate the beneficial effects of the longer duration of light PA vs. a single bout of the acute moderate or vigorous PA for improvement in IRS indicators. Sixty metabolically healthy obese (MHO) participants, 30 males and 30 females, with body mass index (BMI) of ≥30 were enrolled in this study. PA levels were measured using an accelerometer, and the expression of monocytic surface markers was analyzed using flow cytometry. Plasma cytokines’ secretion was determined by enzyme-linked immunosorbent assay (ELISA). Univariate regression analysis evaluated the actigraphy-assessed PA measures, inflammatory cytokines, and insulin resistance. The longer duration of PA was found to be associated with the homeostatic model assessment of insulin resistance (HOMA-IR), a lower lipid profile, and the expression of inflammatory cytokines by monocytes. Even though, higher intensities of PA were found to be associated with lower body fat percentage, only the light intensity PA was found to be beneficial as it associated with the improved insulin sensitivity and lower expression of inflammatory markers. In conclusion, maintaining the longer duration of low-intensity PA throughout the day could be more beneficial for reducing inflammation and improving insulin resistance. This study supports a more feasible approach model to gain beneficial lifestyle changes for the prevention of IRS in metabolically healthy adults with obesity.

Evaluating the performance of raw and epoch non-wear algorithms using multiple accelerometers and electrocardiogram recordings

Accurate detection of accelerometer non-wear time is crucial for calculating physical activity summary statistics. In this study, we evaluated three epoch-based non-wear algorithms (Hecht, Troiano, and Choi) and one raw-based algorithm (Hees). In addition, we performed a sensitivity analysis to provide insight into the relationship between the algorithms’ hyperparameters and classification performance, as well as to generate tuned hyperparameter values to better detect episodes of wear and non-wear time. We used machine learning to construct a gold-standard dataset by combining two accelerometers and electrocardiogram recordings. The Hecht and Troiano algorithms achieved poor classification performance, while Choi exhibited moderate performance. Meanwhile, Hees outperformed all epoch-based algorithms. The sensitivity analysis and hyperparameter tuning revealed that all algorithms were able to achieve increased classification performance by employing larger intervals and windows, while more stringently defining artificial movement. These classification gains were associated with the ability to lower the false positives (type I error) and do not necessarily indicate a more accurate detection of the total non-wear time. Moreover, our results indicate that with tuned hyperparameters, epoch-based non-wear algorithms are able to perform just as well as raw-based non-wear algorithms with respect to their ability to correctly detect true wear and non-wear episodes.

Compositional analysis of the associations between 24-h movement behaviours and cardio-metabolic risk factors in overweight and obese adults with pre-diabetes from the PREVIEW study: cross-sectional baseline analysis

BACKGROUND

Physical activity, sedentary time and sleep have been shown to be associated with cardio-metabolic health. However, these associations are typically studied in isolation or without accounting for the effect of all movement behaviours and the constrained nature of data that comprise a finite whole such as a 24 h day. The aim of this study was to examine the associations between the composition of daily movement behaviours (including sleep, sedentary time (ST), light intensity physical activity (LIPA) and moderate-to-vigorous activity (MVPA)) and cardio-metabolic health, in a cross-sectional analysis of adults with pre-diabetes. Further, we quantified the predicted differences following reallocation of time between behaviours.

METHODS

Accelerometers were used to quantify daily movement behaviours in 1462 adults from eight countries with a body mass index (BMI) ≥25 kg·m- 2, impaired fasting glucose (IFG; 5.6-6.9 mmol·l- 1) and/or impaired glucose tolerance (IGT; 7.8-11.0 mmol•l- 1 2 h following oral glucose tolerance test, OGTT). Compositional isotemporal substitution was used to estimate the association of reallocating time between behaviours.

RESULTS

Replacing MVPA with any other behaviour around the mean composition was associated with a poorer cardio-metabolic risk profile. Conversely, when MVPA was increased, the relationships with cardiometabolic risk markers was favourable but with smaller predicted changes than when MVPA was replaced. Further, substituting ST with LIPA predicted improvements in cardio-metabolic risk markers, most notably insulin and HOMA-IR.

CONCLUSIONS

This is the first study to use compositional analysis of the 24 h movement composition in adults with overweight/obesity and pre-diabetes. These findings build on previous literature that suggest replacing ST with LIPA may produce metabolic benefits that contribute to the prevention and management of type 2 diabetes. Furthermore, the asymmetry in the predicted change in risk markers following the reallocation of time to/from MVPA highlights the importance of maintaining existing levels of MVPA.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT01777893).

Stronger Association between High Intensity Physical Activity and Cardiometabolic Health with Improved Assessment of the Full Intensity Range Using Accelerometry

An improved method of physical activity accelerometer data processing, involving a wider frequency filter than the most commonly used ActiGraph filter, has been shown to better capture variations in physical activity intensity in a lab setting. The aim of the study was to investigate how this improved measure of physical activity affected the relationship with markers of cardiometabolic health. Accelerometer data and markers of cardiometabolic health from 725 adults from two samples, LIV 2013 and SCAPIS pilot, were analyzed. The accelerometer data was processed using both the original ActiGraph method with a low-pass cut-off at 1.6 Hz and the improved method with a low-pass cut-off at 10 Hz. The relationship between the physical activity intensity spectrum and a cardiometabolic health composite score was investigated using partial least squares regression. The strongest association between physical activity and cardiometabolic health was shifted towards higher intensities with the 10 Hz output compared to the ActiGraph method. In addition, the total explained variance was higher with the improved method. The 10 Hz output enables correctly measuring and interpreting high intensity physical activity and shows that physical activity at this intensity is stronger related to cardiometabolic health compared to the most commonly used ActiGraph method.

Objectively measured physical activity and depressive symptoms in adult outpatients diagnosed with major depression. Clinical perspectives

Physical activity (PA) is linked to reduced risk of depression, but research on the objectively measured PA in clinically diagnosed adult outpatients with major depressive disorder (MDD) is scarce. This study aimed to examine relationships of objectively measured PA with depression and mood. A total of 19 outpatients (6 males) with MDD, a mean age of 47.79 ± 11.67 years and mild-moderate depression participated in the study. To record PA, participants wore a triaxial accelerometer device on the right hip during waking hours for seven consecutive days. Depression and mood were assessed with self-reports immediately after day seven. Participants wore the accelerometers for a high number of days (M = 6.26 ± 1.24 days) and hours per day (13.40 ± 2.61 h), recording light (266.01 ± 100.74 min/day) or moderate (31.19 ± 24.90 min/day) PA, and sedentary time (515.33 ± 155.71 min/day). Stepwise regression analysis yield a significant prediction (p < .05) with only moderate PA contributing to the prediction of depression (Beta = -0.47, p < .05). The model explained 22% of the variance of depression. Our findings provide valuable preliminary evidence regarding the relationship between objectively measured PA and lower depression in clinically diagnosed outpatients with MDD, suggesting moderate PA may help alleviating depressive symptoms.

A pedometer-based walking intervention in 45- to 75-year-olds, with and without practice nurse support: the PACE-UP three-arm cluster RCT

BACKGROUND

Guidelines recommend walking to increase moderate to vigorous physical activity (MVPA) for health benefits.

OBJECTIVES

To assess the effectiveness, cost-effectiveness and acceptability of a pedometer-based walking intervention in inactive adults, delivered postally or through dedicated practice nurse physical activity (PA) consultations.

DESIGN

Parallel three-arm trial, cluster randomised by household.

SETTING

Seven London-based general practices.

PARTICIPANTS

A total of 11,015 people without PA contraindications, aged 45-75 years, randomly selected from practices, were invited. A total of 6399 people were non-responders, and 548 people self-reporting achieving PA guidelines were excluded. A total of 1023 people from 922 households were randomised to usual care (n = 338), postal intervention (n = 339) or nurse support (n = 346). The recruitment rate was 10% (1023/10,467). A total of 956 participants (93%) provided outcome data.

INTERVENTIONS

Intervention groups received pedometers, 12-week walking programmes advising participants to gradually add '3000 steps in 30 minutes' most days weekly and PA diaries. The nurse group was offered three dedicated PA consultations.

MAIN OUTCOME MEASURES

The primary and main secondary outcomes were changes from baseline to 12 months in average daily step counts and time in MVPA (in ≥ 10-minute bouts), respectively, from 7-day accelerometry. Individual resource-use data informed the within-trial economic evaluation and the Markov model for simulating long-term cost-effectiveness. Qualitative evaluations assessed nurse and participant views. A 3-year follow-up was conducted.

RESULTS

Baseline average daily step count was 7479 [standard deviation (SD) 2671], average minutes per week in MVPA bouts was 94 minutes (SD 102 minutes) for those randomised. PA increased significantly at 12 months in both intervention groups compared with the control group, with no difference between interventions; additional steps per day were 642 steps [95% confidence interval (CI) 329 to 955 steps] for the postal group and 677 steps (95% CI 365 to 989 steps) for nurse support, and additional MVPA in bouts (minutes per week) was 33 minutes per week (95% CI 17 to 49 minutes per week) for the postal group and 35 minutes per week (95% CI 19 to 51 minutes per week) for nurse support. Intervention groups showed no increase in adverse events. Incremental cost per step was 19p and £3.61 per minute in a ≥ 10-minute MVPA bout for nurse support, whereas the postal group took more steps and cost less than the control group. The postal group had a 50% chance of being cost-effective at a £20,000 per quality-adjusted life-year (QALY) threshold within 1 year and had both lower costs [-£11M (95% CI -£12M to -£10M) per 100,000 population] and more QALYs [759 QALYs gained (95% CI 400 to 1247 QALYs)] than the nurse support and control groups in the long term. Participants and nurses found the interventions acceptable and enjoyable. Three-year follow-up data showed persistent intervention effects (nurse support plus postal vs. control) on steps per day [648 steps (95% CI 272 to 1024 steps)] and MVPA bouts [26 minutes per week (95% CI 8 to 44 minutes per week)].

LIMITATIONS

The 10% recruitment level, with lower levels in Asian and socioeconomically deprived participants, limits the generalisability of the findings. Assessors were unmasked to the group.

CONCLUSIONS

A primary care pedometer-based walking intervention in 45- to 75-year-olds increased 12-month step counts by around one-tenth, and time in MVPA bouts by around one-third, with similar effects for the nurse support and postal groups, and persistent 3-year effects. The postal intervention provides cost-effective, long-term quality-of-life benefits. A primary care pedometer intervention delivered by post could help address the public health physical inactivity challenge.

FUTURE WORK

Exploring different recruitment strategies to increase uptake. Integrating the Pedometer And Consultation Evaluation-UP (PACE-UP) trial with evolving PA monitoring technologies.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN98538934.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 37. See the NIHR Journals Library website for further project information.

Telemedicine-Based Health Coaching Is Effective for Inducing Weight Loss and Improving Metabolic Markers

BACKGROUND

To assess the efficacy of health coaching (HC) delivered through videoconferencing (VC) to favorably change physical activity (PA), weight, and metabolic markers in adults with high body mass index (BMI).

MATERIALS AND METHODS

Thirty adults (BMI ≥30 kg/m2) were randomly assigned to one of three groups: VC, in-person (IP), or control group (CG). Participants received wireless watches and weight scales to sync with their personal smartphones; recorded data were wirelessly uploaded to a secure database. Participants assigned to VC and IP received individualized HC by a multidisciplinary team (registered dietitian, exercise physiologist, and medical doctor) based on data uploaded over the 12-week intervention. Steps/day and weight loss were analyzed through analyses of covariance.

RESULTS

Within- and between-group changes in weight (kg), glucose, insulin, hemoglobin A1c (HbA1c), and Homeostasis Model Assessment estimate of insulin resistance (HOMA-IR) were analyzed through analyses of variance. Weight loss was greater (p < 0.05) for VC (8.23 ± 4.5 kg; 7.7%) than IP (3.2 ± 2.6 kg; 3.4%) and CG (2.9 ± 3.9 kg; 3.3%), respectively. Steps/day were significantly higher in VC than IP at week 4 and VC was significantly higher than the CG at weeks 6, 8, 9, and 11 (p ≤ 0.05). No within- or between-group differences were found for glucose, insulin, or HbA1C. HOMA-IR decreased for VC only (p ≤ 0.05).

CONCLUSIONS

Our innovative, multidisciplinary, telemedicine HC delivered through VC led to more favorable changes in weight loss, PA (steps/day), and HOMA-IR than IP or no HC. VC may be an economical approach to improve health and promote behavior change in obese adults.

CLINICAL TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier NCT03278951.

The Effects of a Mobile Wellness Intervention with Fitbit Use and Goal Setting for Workers

Background and Introduction: There is strong evidence that worksite wellness programs can significantly improve the health profile of participating workers. To date, little is known about research on the effects of mobile wellness interventions in worksite settings. Furthermore, no studies have been conducted to evaluate mobile wellness interventions with activity trackers and tailoring strategies for physically inactive workers in manufacturing companies. This study aimed to examine the effects of a mobile wellness intervention with Fitbit and goal setting using brief counseling and text messaging among workers. Materials and Methods: A total of 79 (n = 79) workers from large manufacturing companies were allocated into an experimental group (n = 41) and a control group (n = 38). All participants were asked to wear an activity tracker (Fitbit Charger HR) during all waking hours for 5 weekdays. Participants in the experimental group received Fitbit, daily motivational text messaging, and biweekly counseling with a specifically designed workbook for 12 weeks, whereas Fitbit was only provided to the control group. Results: At the 12-week measurement, there were significant differences between the experimental group and control group on wellness (p < 0.001), physical activity behavior (p < 0.001), daily walking steps (p < 0.001), and physical activity self-efficacy (p < 0.001). Discussion and Conclusions: Although Fitbit facilitates an individual's activities by providing information about daily steps, the tracker itself, without additional goal-setting techniques, may be insufficient to encourage behavior change. These findings indicate that the mobile wellness intervention with Fitbit and goal setting using brief counseling and tailored text messaging is more effective for physically inactive workers.

Two Days of Measurement Provides Reliable Estimates of Physical Activity Poststroke: An Observational Study

OBJECTIVE

The aim of this study was to determine the duration of physical activity (PA) monitoring required for reliable measurements following stroke.

DESIGN

Single-center, prospective, observational study.

SETTING

PA was measured in a community setting.

PARTICIPANTS

Adults (N=70) poststroke.

MAIN OUTCOME MEASURES

The SenseWear armband was used to monitor PA for 5 days (≥10 hours wear per day).

DATA ANALYSIS

Variance among 2, 3, 4, and 5 days of consecutive measurements for PA variables was examined using intraclass correlation coefficients (ICCs). The minimum number of days to achieve acceptable reliability (ICC ≥0.8) was calculated. Differences between weekdays and weekend days were investigated using paired t tests and Wilcoxon signed rank tests.

RESULTS

Two days of measurement was sufficient to achieve an ICC ≥0.8 for daily averages of total energy expenditure, step count, and time spent sedentary (≤1.5 metabolic equivalent tasks [METs]) and in light (1.5-3 METs) and moderate- to vigorous-intensity (>3 METs) PA. At least 3 days were required to achieve an ICC ≥0.8 when investigating the number of and time spent in bouts (≥10 minutes) of moderate to vigorous PA and sedentary behavior. Participants took significantly more steps (P=.03) and spent more time in light PA (P=.03) on weekdays than weekends.

CONCLUSION

Following stroke, 2 days of measurement appears sufficient to represent habitual PA for many simple variables. Three or more days may be necessary for reliable estimates of bouts of PA and sedentary behavior. Consistent inclusion or exclusion of a weekend day is recommended for measuring step count and light PA. Short periods of monitoring provide reliable PA information and may make PA measurement more feasible in the clinical setting.

Development of a lifestyle intervention for the metabolic syndrome: Discovery through proof-of-concept

OBJECTIVE

The aim was to describe the early phases of the progressive development of a lifestyle treatment for sustained remission of the metabolic syndrome (MetS) using the Obesity-Related Behavioral Intervention Trials (ORBIT) model for behavioral treatment development as a guide.

METHODS

Early discovery and design phases produced a 3-component (diet, physical activity, stress), group-based lifestyle treatment with an intensive 6-month phase followed by monthly, participant-led maintenance meetings. In the proof-of-concept phase, 26 participants with the MetS (age 53 ± 7 years, 77% female, and 65% ethnic minority) were recruited in a quasi-experimental design to determine if treatment could achieve the prespecified benchmark of MetS remission in ≥50% at 2.5 years. Exploratory outcomes focused on MetS components, weight, and patient-centered benefits on energy/vitality and psychosocial status.

RESULTS

MetS remission was achieved in 53.8% after a median of 2.5 years. At 2.5 years, an increase of +15.4% reported eating ≥3 servings of vegetables/day, +7.7% engaged in ≥150 minutes of moderate-to-vigorous physical activity/week; and +11.5% reported experiencing no depression in the past 2 weeks. Weight loss ≥5% was achieved by 38.5%, and energy/vitality, negative affect, and social support improved. Median group attendance over 2.5 years was 73.8%.

CONCLUSIONS

It is plausible that this lifestyle program can produce a remission in the MetS, sustained through 2.5 years. After refinements to enhance precision and strength, progression to feasibility pilot testing and a randomized clinical trial will determine its efficacy as a cost-effective lifestyle option for managing the MetS in the current health care system. (PsycINFO Database Record

Validation of the Stanford Leisure-Time Activity Categorical Item (L-Cat) using armband activity monitor data

OBJECTIVE

Accurate assessment of physical activity (PA) in public health and healthcare settings remains a challenge given limitations of existing brief assessment tools. The Stanford Leisure-Time Activity Categorical Item (L-Cat), a single item with six categories, has previously demonstrated excellent reliability and adequate validity relative to pedometer steps. However, pedometers cannot assess key dimensions of PA intensity or duration.

METHODS

We evaluated the L-Cat's criterion validity and sensitivity to change relative to objectively measured Sensewear armband activity monitors among 76 adults with overweight/obesity (mean age 50.8 ± 11.9 years, BMI = 33.1 ± 3.4 kg m-2) at baseline and end of a 6-month behavioural weight management pilot trial.

RESULTS

At baseline, L-Cat category was associated with armband-measured daily steps (Spearman's ρ = 0.41, p < 0.001), total weekly minutes of moderate/vigorous-intensity PA (MVPA) (ρ = 0.40, p < 0.001) and weekly minutes of MVPA accumulated in bouts ≥10 min (ρ = 0.47, p < 0.0001). Participants increasing ≥1 L-Cat category from baseline to 6 months had greater increases in steps (1,110.1 ± 1,852.1 vs. -18.0 ± 2,005.6 steps/d, p = 0.032), total minutes of MVPA (145.7 ± 180.6 vs. -2.1 ± 215.8 min/week, p = 0.007) and greater weight losses (-7.4 ± 7.7% vs. -3.1 ± 4.8%, p = 0.013) than those who stayed the same/decreased L-Cat categories.

CONCLUSION

The L-Cat demonstrated adequate criterion validity and excellent sensitivity to change relative to objectively measured PA among behavioural weight management pilot trial participants. The L-Cat may be particularly useful for identifying individuals at lower activity levels and when using all six categories.

Pattern of Daily Steps is Associated with Weight Loss: Secondary Analysis from the Step-Up Randomized Trial

OBJECTIVE

The aim of this study was to examine the association between the amount, intensity, and pattern of steps·day^-1 with weight loss.

METHODS

Participants (N = 260; age = 42.8 ± 8.9 y; BMI = 32.8 ± 3.5 kg/m² ) completed an 18-month weight-loss intervention that included a calorie-restricted diet and prescribed physical activity. Participants were categorized by 18-month weight loss as weight gain (GAIN), weight loss of 0% to < 5% (WL < 5%), 5% to < 10% (WL < 10%), or ≥ 10% (WL ≥ 10%). Steps·day^-1 were measured at 0, 6, 12, and 18 months and defined as total steps·day^-1 , total steps·day^-1 of moderate-to-vigorous physical activity (MVPA) (≥3 metabolic equivalents) in bouts of ≥ 10 minutes (BOUT-MVPA), MVPA in bouts of < 10 minutes (NON-BOUT-MVPA), or non-MVPA steps·day^-1 (NON-MVPA).

RESULTS

There was a weight-loss category by time interaction (P < 0.0001) for total and BOUT-MVPA steps·day^-1 . The total steps·day^-1 at 18 months were WL ≥ 10% = 9,822 (95% CI: 9,073-10,571), WL < 10% = 8,612 (7,613-9,610), WL < 5% = 7,802 (6,782-8,822), and GAIN = 7,801 (6,549-9,053). BOUT-MVPA steps·day^-1 at 18 months were WL ≥ 10% = 3,482 (2,982-3,981), WL < 10% = 1,949 (1,269-2,629), WL < 5% = 1,735 (1,045-2,426), and GAIN = 1,075 (210-1,941). Participants were also categorized based on achieving ≥ 10% weight loss at either 6 or 18 months, and a similar pattern was observed.

CONCLUSIONS

These findings show that 10,000 steps·day^-1 , with approximately 3,500 steps·day^-1 performed as BOUT-MVPA, are associated with enhanced weight loss in a behavioral intervention.

Free-Living Responses in Energy Balance to Short-Term Overfeeding in Adults Differing in Propensity for Obesity

OBJECTIVE

Free-living adaptive responses to short-term overfeeding (OF) were explored as predictors of longitudinal weight change in adults classified as having obesity resistance (OR) or obesity proneness (OP) based on self-identification and personal/family weight history.

METHODS

Adults identified as OP (n = 21; BMI: 23.8 ± 2.5 kg/m² ) and OR (n = 20; BMI: 20.2 ± 2.1 kg/m² ) completed 3 days of eucaloric feeding (EU; 100% of energy needs) and 3 days of OF (140% of energy needs). Following each condition, adaptive responses in physical activity (PA), total daily energy expenditure, ad libitum energy intake, and energy balance were objectively measured for 3 days in a free-living environment. Body mass and composition were measured annually by using dual-energy x-ray absorptiometry for 5 years. Adaptive responses to OF were correlated with 5-year changes in body mass and composition.

RESULTS

Increases in sedentary time correlated with longitudinally measured changes in fat mass (r = 0.34, P = 0.04) in the cohort taken as a whole. Those with OP reduced their levels of PA following OF, whereas those with OR maintained or increased their PA. No other variables were found to correlate with weight gain.

CONCLUSIONS

Failure to decrease sedentary behavior following short-term OF is one mechanism that may be contributing to fat mass gain.

Identifying and describing segments of office workers by activity patterns

Purpose

The purpose of this paper is to identify and characterize patterns of physical activity among office workers employed in largely sedentary occupations at a major health insurer located in the Southeastern USA.

Design/methodology/approach

The authors used latent class analysis to identify segments of office workers (n=239) based on their self-reported activities of daily living and exercise behaviors. The authors examined the association of demographic characteristics with segment membership, and differences in accelerometer-measured weekly minutes of light and moderate-vigorous physical activity across segments.

Findings

The authors identified two segments and labeled them “exerciser” and “non-exerciser.” Being female was associated with lower odds of membership in the “exerciser” segment (OR=0.18; 95% CI=0.06, 0.52), while those with at least a bachelor’s degree were more likely to be in the “exerciser” segment (OR=2.12; 95% CI=1.02, 4.40). Mean minutes of moderate-vigorous physical activity per week were greater for the “exerciser” segment than the “non-exerciser” segment.

Practical implications

Based on this sample, the authors found that office workers in sedentary occupations were roughly equally divided and distinguished by their engagement in exercise-type behaviors. The findings underscore the need for innovative workplace programming that enhances activity opportunities particularly for those that are not likely to exercise.

Originality/value

A scarcity of research on activity patterns among office workers inhibits development of targeted worksite activity programming. The present research reveals two segments of workers with regard to their activity patterns and suggests ways for worksites to meet their unique needs.

Objectively Assessed Physical Activity and Weight Loss Maintenance among Individuals Enrolled in a Lifestyle Intervention

OBJECTIVE

To examine the relationship between objectively assessed moderate-to-vigorous intensity physical activity (MVPA) and 4-year weight loss (WL) and WL maintenance among individuals with diabetes enrolled in the Look AHEAD trial.

METHODS

MVPA was measured in a subgroup of lifestyle intervention participants with accelerometry data at baseline and at 1 and 4 years (n = 553; age: 59.7 ± 6.8 y; BMI: 35.5 ± 5.9 kg/m2 ). Minutes per week of bout-related MVPA were calculated (≥ 3 metabolic equivalents, ≥ 10-min bouts), and adherence to the national physical activity (PA) recommendation for WL maintenance (≥ 250 min/wk) was assessed.

RESULTS

Independent of 1-year WL, 4-year MVPA (β = -0.003, SE = 0.002, P = 0.006), but not 1-year MVPA (β = 0.0001, SE = 0.001, P = 0.50), was significantly associated with 4-year WL. Compared with "nonmaintainers" (≥ 10% WL at year 1, but < 10% at year 4; n = 132), WL maintainers (≥ 10% WL at years 1 and 4; n = 103) had higher MVPA at year 1 (253.4 ± 251.8 vs. 163.9 ± 158.2 min/wk, P = 0.002) and year 4 (155.3 ± 180.6 vs. 111.4 ± 154.5 min/wk, P = 0.046). Although 38.8% and 22.3% of WL maintainers engaged in ≥ 250 min/wk at years 1 and 4, respectively, many engaged in < 150 min/wk (year 1: 41%, year 4: 61%).

CONCLUSIONS

Higher weekly MVPA is associated with greater long-term WL and weight maintenance; however, many individuals are able to maintain ≥ 10% WL while engaging in little MVPA.

Exercise Testing Reveals Everyday Physical Challenges of Bariatric Surgery Candidates

BACKGROUND

Few studies have quantified cardiorespiratory fitness among individuals seeking bariatric surgery. Treadmill testing allows researchers to determine exercise capacity through metabolic equivalents. These findings can assist clinicians in understanding patients' capabilities to carry out various activities of daily living. The purpose of this study was to determine exercise tolerance and the variables associated with fitness, among individuals seeking bariatric surgery.

METHODS

Bariatric surgery candidates completed submaximal treadmill testing and provided ratings of perceived exertion. Each participant also completed questionnaires related to history of exercise, mood, and perceived barriers/benefits of exercise.

RESULTS

Over half of participants reported that exercise was "hard to very hard" before reaching 70% of heart rate reserve, and one-third of participants reported that exercise was "moderately hard" at less than 3 metabolic equivalents (light activity). Body mass index and age accounted for the majority of the variance in exercise tolerance, but athletic history, employment status, and perceived health benefits also contributed. Perceived benefit scores were higher than barrier scores.

CONCLUSION

Categories commonly used to describe moderate-intensity exercise (3-6 metabolic equivalents) do not coincide with perceptions of intensity among many bariatric surgery candidates, especially those with a body mass index of 50 or more.

Four-Year Physical Activity Levels among Intervention Participants with Type 2 Diabetes

Physical activity (PA) has numerous health benefits, particularly for those with diabetes. However, rates of long-term PA participation are often poor.

PURPOSE

This study examined the effect of an intensive lifestyle intervention (ILI) on objectively assessed PA for a 4-yr period among older adults with type 2 diabetes.

METHODS

Data from 2400 participants (age = 59.3 ± 6.9 yr, body mass index = 36.1 ± 5.9 kg·m) with accelerometry data from the Look AHEAD trial were included in the analyses. Participants randomized to ILI were instructed to reduce caloric intake and progress to ≥175 min·wk of moderate-to-vigorous-intensity PA (MVPA), whereas those randomized to Diabetes Support and Education (DSE) served as the control group. PA was measured at baseline, year 1, and year 4 using an RT3 accelerometer, and bout-related MVPA (PA ≥3 METs, accumulated in bouts of ≥10 min in duration) was calculated.

RESULTS

Despite no differences at baseline (ILI = 93.4 ± 152.7 vs DSE = 88.4 ± 143.6 min·wk), bout-related MVPA was significantly greater in ILI compared with DSE at year 1 (151.0 ± 213.5 vs 87.5 ± 145.1 min·wk, P < 0.0001) and year 4 (102.9 ± 195.6 vs 73.9 ± 267.5 min·wk, P < 0.001), and more ILI participants achieved ≥175 min·wk at year 1 (29.1% vs 16.3%, P < 0.001) and year 4 (18.3% vs 10.0%, P < 0.001). Forty-one percent of ILI participants who achieved ≥175 min·wk at year 1 maintained this threshold of PA at year 4. However, the majority of ILI participants never achieved the ≥175 min·wk threshold.

CONCLUSIONS

When measured objectively and compared with DSE, ILI engaged in significantly more bout-related MVPA for a 4-yr period. However, future intervention strategies should target the large percentage of individuals who fail to reach the MVPA goal as result of a lifestyle intervention.

Effects of supervised and unsupervised physical activity programmes for weight loss

Objectives

Physical activity is important for weight management. However, it remains unclear what type of physical activity prescription/programme is optimal for increasing physical activity during a standard behavioural weight loss intervention. This study examined changes in physical activity after a 12‐week supervised programme prescribed in minutes per week (SUP‐PA), an unsupervised programme prescribed in minutes per week (UNSUP‐PA) and an unsupervised programme prescribed in steps per day (STEP).

Methods

Fifty‐two adults who were overweight or obese (age: 43.5 ± 10.1 years, BMI: 31.5 ± 3.5 kg·m⁻²) were randomized to STEP (n = 18), UNSUP‐PA (n = 17) and SUP‐PA (n = 17). Subjects attended weekly in‐person group intervention sessions and were prescribed a calorie‐restricted diet (1,200–1,800 kcals·day⁻¹) combined with increased physical activity (150 min·week⁻¹ or 10,000 steps·day⁻¹ with 2,500 brisk steps·day⁻¹).

Results

All three groups significantly increased moderate‐to‐vigorous physical activity (STEP: 80.6 ± 218.5 min·week⁻¹, UNSUP‐PA: 112.9 ± 180.4 min·week⁻¹ and SUP‐PA: 151.1 ± 174.0 min·week⁻¹, p < 0.001) with no differences between groups (p = 0.94) or group by time interaction (p = 0.81). In addition, there were no significant differences in weight loss between the groups (p = 0.81).

Conclusions

In this short‐term study, all three physical activity programmes increased physical activity and elicited modest weight loss when combined with a standard behavioural weight loss intervention.

Effect of Wearable Technology Combined With a Lifestyle Intervention on Long-term Weight Loss: The IDEA Randomized Clinical Trial

IMPORTANCE

Effective long-term treatments are needed to address the obesity epidemic. Numerous wearable technologies specific to physical activity and diet are available, but it is unclear if these are effective at improving weight loss.

OBJECTIVE

To test the hypothesis that, compared with a standard behavioral weight loss intervention (standard intervention), a technology-enhanced weight loss intervention (enhanced intervention) would result in greater weight loss.

DESIGN, SETTING, PARTICIPANTS

Randomized clinical trial conducted at the University of Pittsburgh and enrolling 471 adult participants between October 2010 and October 2012, with data collection completed by December 2014.

INTERVENTIONS

Participants were placed on a low-calorie diet, prescribed increases in physical activity, and had group counseling sessions. At 6 months, the interventions added telephone counseling sessions, text message prompts, and access to study materials on a website. At 6 months, participants randomized to the standard intervention group initiated self-monitoring of diet and physical activity using a website, and those randomized to the enhanced intervention group were provided with a wearable device and accompanying web interface to monitor diet and physical activity.

MAIN OUTCOMES AND MEASURES

The primary outcome of weight was measured over 24 months at 6-month intervals, and the primary hypothesis tested the change in weight between 2 groups at 24 months. Secondary outcomes included body composition, fitness, physical activity, and dietary intake.

RESULTS

Among the 471 participants randomized (body mass index [BMI], 25 to <40; age range, 18-35 years; 28.9% nonwhite, 77.2% women), 470 (233 in the standard intervention group, 237 in the enhanced intervention group) initiated the interventions as randomized, and 74.5% completed the study. For the enhanced intervention group, mean base line weight was 96.3 kg (95% CI, 94.2-98.5) and 24-month weight 92.8 kg (95% CI, 90.6- 95.0) [corrected]. For the standard intervention group, mean baseline weight was 95.2kg (95%CI,93.0-97.3)and24-month weight was 89.3 kg (95%CI, 87.1-91.5) [corrected]. Weight change at 24 months differed significantly by intervention group (estimated mean weight loss, 3.5 kg [95% CI, 2.6-4.5} in the enhanced intervention group and 5.9 kg [95% CI, 5.0-6.8] in the standard intervention group; difference, 2.4 kg [95% CI, 1.0-3.7]; P = .002). Both groups had significant improvements in body composition, fitness, physical activity, and diet, with no significant difference between groups.

CONCLUSIONS AND RELEVANCE

Among young adults with a BMI between 25 and less than 40, the addition of a wearable technology device to a standard behavioral intervention resulted in less weight loss over 24 months. Devices that monitor and provide feedback on physical activity may not offer an advantage over standard behavioral weight loss approaches.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01131871.

Relationship among physical activity, sedentary behaviors, and cardiometabolic risk factors during gastric bypass surgery-induced weight loss

BACKGROUND

The impact of daily physical activity (PA) on the cardiometabolic risk of bariatric surgery patients is not known.

OBJECTIVE

We examined the influence of physical activity and sedentary behavior on modifying cardiometabolic risk after Roux-en-Y gastric bypass (RYGB) surgery.

SETTING

University of Pittsburgh Medical Center and East Carolina University bariatric surgery centers.

METHODS

Data from 43 women and 7 men who completed testing at 1-3 months after RYGB surgery and again at 9 months postsurgery were analyzed. Outcomes measured included PA level (min/d), steps/d, sedentary time, and body composition. Insulin sensitivity was determined with an intravenous glucose tolerance test. Weight and blood lipid profiles also were obtained.

RESULTS

Patients reduced body mass index by a mean of -8.0±3.4 kg/m² (P<.001), increased moderate-to-vigorous PA by 17.0±47.0 min/d (P = .014), and decreased sedentary time (-47.9±101.0 min/d, P = .002). However, 24% of patients decreased overall PA (P<.001), and 39% increased sedentary behavior (P<.001). Changes in overall PA (rho = -.33, P = .006) and steps/d (rho = -.31, P = .0106) were related to weight loss. Insulin sensitivity was associated with light PA before (rho = .37, P<.001) and after (rho = .37, P = .015) intervention. Increasing overall PA also was related to higher levels of high-density lipoprotein cholesterol (rho = .33, P<.01). Decreasing sedentary time was related to decreased fat mass (rho = .35, P = .012) but not to other cardiometabolic risk factors.

CONCLUSIONS

The majority of patients increased PA (76%) and decreased sedentary time (61%) after RYGB surgery, but the amount of PA and sedentary time varied substantially. Higher PA, even at low intensity levels, was related to beneficial outcomes in body composition, insulin sensitivity, and high-density lipoprotein cholesterol.

Reliability of Physical Activity Measures During Free-Living Activities in People After Total Knee Arthroplasty

BACKGROUND

Few instruments that measure physical activity (PA) can accurately quantify PA performed at light and moderate intensities, which is particularly relevant in older adults. The evidence of their reliability in free-living conditions is limited.

OBJECTIVE

The study objectives were: (1) to determine the test-retest reliability of the Actigraph (ACT), SenseWear Armband (SWA), and Community Healthy Activities Model Program for Seniors (CHAMPS) questionnaire in assessing free-living PA at light and moderate intensities in people after total knee arthroplasty; (2) to compare the reliability of the 3 instruments relative to each other; and (3) to determine the reliability of commonly used monitoring time frames (24 hours, waking hours, and 10 hours from awakening).

DESIGN

A one-group, repeated-measures design was used.

METHODS

Participants wore the activity monitors for 2 weeks, and the CHAMPS questionnaire was completed at the end of each week. Test-retest reliability was determined by using the intraclass correlation coefficient (ICC [2,k]) to compare PA measures from one week with those from the other week.

RESULTS

Data from 28 participants who reported similar PA during the 2 weeks were included in the analysis. The mean age of these participants was 69 years (SD=8), and 75% of them were women. Reliability ranged from moderate to excellent for the ACT (ICC=.75-.86) and was excellent for the SWA (ICC=.93-.95) and the CHAMPS questionnaire (ICC=.86-.92). The 95% confidence intervals (95% CI) of the ICCs from the SWA were the only ones within the excellent reliability range (.85-.98). The CHAMPS questionnaire showed systematic bias, with less PA being reported in week 2. The reliability of PA measures in the waking-hour time frame was comparable to that in the 24-hour time frame and reflected most PA performed during this period.

LIMITATIONS

Reliability may be lower for time intervals longer than 1 week.

CONCLUSIONS

All PA measures showed good reliability. The reliability of the ACT was lower than those of the SWA and the CHAMPS questionnaire. The SWA provided more precise reliability estimates. Wearing PA monitors during waking hours provided sufficiently reliable measures and can reduce the burden on people wearing them.

Missing value imputation for physical activity data measured by accelerometer

An accelerometer, a wearable motion sensor on the hip or wrist, is becoming a popular tool in clinical and epidemiological studies for measuring the physical activity. Such data provide a series of activity counts at every minute or even more often and displays a person's activity pattern throughout a day. Unfortunately, the collected data can include irregular missing intervals because of noncompliance of participants and therefore make the statistical analysis more challenging. The purpose of this study is to develop a novel imputation method to handle the multivariate count data, motivated by the accelerometer data structure. We specify the predictive distribution of the missing data with a mixture of zero-inflated Poisson and Log-normal distribution, which is shown to be effective to deal with the minute-by-minute autocorrelation as well as under- and over-dispersion of count data. The imputation is performed at the minute level and follows the principles of multiple imputation using a fully conditional specification with the chained algorithm. To facilitate the practical use of this method, we provide an R package accelmissing. Our method is demonstrated using 2003-2004 National Health and Nutrition Examination Survey data.

Short-term weight loss with diet and physical activity in young adults: The IDEA study

OBJECTIVE

This study examined the effect of a behavioral weight loss intervention (BWLI) on young adults (age = 18-35 years).

METHODS

Participants (N = 470) enrolled in a 6-month BWLI that included weekly group sessions, a prescribed energy-restricted diet, and moderate to vigorous physical activity (MVPA). Assessments included weight, body composition, fitness, lipids, glucose, insulin, resting blood pressure and heart rate, physical activity, and dietary intake. Data are presented as median [25th, 75th percentiles].

RESULTS

Retention was 90% (N = 424; age: 30.9 [27.8, 33.7] years; BMI: 31.2 [28.4, 34.3] kg m(-2) ). Participants completed 87.5% [76.1%, 95.5%] of scheduled intervention contacts. Weight and body fat decreased while fitness increased (P < 0.0001). MVPA in bouts ≥10 min increased (P < 0.0001), though total MVPA did not change significantly. Sedentary time decreased (P = 0.03). Energy and percent fat intake decreased, while percent carbohydrate and protein intake increased (P < 0.0001). Systolic and diastolic blood pressure, total cholesterol, LDL cholesterol, triglycerides, glucose, and insulin decreased (P < 0.0001).

CONCLUSIONS

A 6-month BWLI produced favorable changes in dietary intake and physical activity and elicited favorable changes in weight and other health outcomes in young adults. MVPA performed in bouts of ≥10 min was associated with greater weight loss, but sedentary behavior was not.

Accelerometer-based physical activity levels among Mexican adults and their relation with sociodemographic characteristics and BMI: a cross-sectional study

Background

The objectives of this study were to describe the accelerometer based total and bout-specific PA levels for a representative sample of adults from Cuernavaca, Mexico, and to examine the relationships with sociodemographic characteristics and BMI status.

Methods

Cross sectional study of adults from Cuernavaca, Mexico (2011, n = 677). Participants wore Actigraph GT3X accelerometers for seven days and sociodemographic data was collected through a survey. Weight and height were objectively measured. Total minutes/week of moderate-to-vigorous PA (MVPA) and of MVPA occurring within bouts of at least ten minutes were obtained. Intensity-specific (moderate and vigorous) total PA and bouted-PA was also obtained. The relation of each PA variable with sex, age, socioeconomic status, education, marital status and BMI status was assessed using unadjusted and adjusted linear models.

Results

The mean total MVPA among adults from Cuernavaca was 221.3 ± 10.0 (median = 178.3 min/week). Average MVPA within bouts was 65.8 ± 4.7 min/week (median = 30.0 min/week). 9.7 % of total MVPA occurred within bouts. Significant associations were found for total and bout-specific MVPA with being male (positive) and owning a motor vehicle (negative). Additional associations were found for intensity-specific PA outcomes. Mexican adults were more active during weekdays than weekends, suggesting that PA may be more strongly driven by necessity (transport) than by choice (leisure).

Conclusions

This is the first study to objectively measure PA for a representative sample of Mexican adults in an urban setting. The sociodemographic correlates vary from those known from high income countries, stressing the need for more correlate studies from lower-to-middle income countries.

Electronic supplementary material

The online version of this article (doi:10.1186/s12966-015-0243-z) contains supplementary material, which is available to authorized users.

Exercise improves quality of life in bariatric surgery candidates: results from the Bari-Active trial

OBJECTIVE

To examine the impact of a pre-bariatric surgery physical activity intervention (PAI), designed to increase bout-related (≥10 min) moderate to vigorous PA (MVPA), on health-related quality of life (HRQoL).

METHODS

Analyses included 75 adult participants (86.7% female; BMI = 45.0 ± 6.5 kg m(-2)) who were randomly assigned to 6 weeks of PAI (n = 40) or standard pre-surgical care (SC; n = 35). PAI received 6 individual weekly counseling sessions to increase walking exercise. Participants wore an objective PA monitor for 7 days and completed the SF-36 Health Survey at baseline and post-intervention to evaluate bout-related MVPA and HRQoL changes, respectively.

RESULTS

PAI increased bout-related MVPA from baseline to post-intervention (4.4 ± 5.5 to 21.0 ± 21.4 min day(-1)) versus no change (7.9 ± 16.6 to 7.6 ± 11.5 min day(-1)) for SC (P = 0.001). PAI reported greater improvements than SC on all SF-36 physical and mental scales (P < 0.05), except role-emotional. In PAI, better baseline scores on the physical function and general health scales predicted greater bout-related MVPA increases (P < 0.05), and greater bout-related MVPA increases were associated with greater post-intervention improvements on the physical function, bodily pain, and general health scales (P < 0.05).

CONCLUSIONS

Increasing PA preoperatively improves physical and mental HRQoL in bariatric surgery candidates. Future studies should examine whether this effect improves surgical safety, weight loss outcomes, and postoperative HRQoL.

A sensitivity analysis on the variability in accelerometer data processing for monitoring physical activity

BACKGROUND

Accelerometers are gaining popularity for measuring physical activity, but there are many different ways to process accelerometer data. A sensitivity analysis was conducted to study the effect of varying accelerometer data processing protocols on estimating the association between PA level and socio-demographic characteristics using the National Health and Nutrition Examination Survey (NHANES) accelerometer data.

METHODS

The NHANES waves 2003-2004 and 2005-2006 accelerometer data (n=14,072) were used to investigate the effect of changing the accelerometer non-wearing time and valid day definitions on the demographic composition of the filtered datasets and the association between physical activity (PA) and socio-demographic characteristics (sex, age, race, educational level, marital status).

RESULTS

Under different filtering rules (minimum number of valid day and definition of non-wear time), the demographic characteristics of the final sample varied. The proportion of participants aged 20-29 decreased from 18.9% to 15.8% when the minimum number of valid days required increased from 1 to 4 (p for trend<0.001), whereas that for aged ≥70 years increased from 18.9% to 20.6% (p for trend<0.001). Furthermore, with different filters, the effect of these demographic variables and PA varied, with some variables being significant under certain filtering rules but becoming insignificant under some other rules.

CONCLUSIONS

The sensitivity analysis showed that the significance of the association between socio-demographic variables and PA could be varied with the definition of non-wearing time and minimum number of valid days.

A primary care nurse-delivered walking intervention in older adults: PACE (pedometer accelerometer consultation evaluation)-Lift cluster randomised controlled trial

BACKGROUND

Brisk walking in older people can increase step-counts and moderate to vigorous intensity physical activity (MVPA) in ≥10-minute bouts, as advised in World Health Organization guidelines. Previous interventions have reported step-count increases, but not change in objectively measured MVPA in older people. We assessed whether a primary care nurse-delivered complex intervention increased objectively measured step-counts and MVPA.

METHODS AND FINDINGS

A total of 988 60-75 year olds, able to increase walking and randomly selected from three UK family practices, were invited to participate in a parallel two-arm cluster randomised trial; randomisation was by household. Two-hundred-ninety-eight people from 250 households were randomised between 2011 and 2012; 150 individuals to the intervention group, 148 to the usual care control group. Intervention participants received four primary care nurse physical activity (PA) consultations over 3 months, incorporating behaviour change techniques, pedometer step-count and accelerometer PA intensity feedback, and an individual PA diary and plan. Assessors were not blinded to group status, but statistical analyses were conducted blind. The primary outcome was change in accelerometry assessed average daily step-counts between baseline and 3 months, with change at 12 months a secondary outcome. Other secondary outcomes were change from baseline in time in MVPA weekly in ≥10-minute bouts, accelerometer counts, and counts/minute at 3 months and 12 months. Other outcomes were adverse events, anthropometric measures, mood, and pain. Qualitative evaluations of intervention participants and practice nurses assessed the intervention's acceptability. At 3 months, eight participants had withdrawn or were lost to follow-up, 280 (94%) individuals provided primary outcome data. At 3 months changes in both average daily step-counts and weekly MVPA in ≥10-minute bouts were significantly higher in the intervention than control group: by 1,037 (95% CI 513-1,560) steps/day and 63 (95% CI 40-87) minutes/week, respectively. At 12 months corresponding differences were 609 (95% CI 104-1,115) steps/day and 40 (95% CI 17-63) minutes/week. Counts and counts/minute showed similar effects to steps and MVPA. Adverse events, anthropometry, mood, and pain were similar in the two groups. Participants and practice nurses found the intervention acceptable and enjoyable.

CONCLUSIONS

The PACE-Lift trial increased both step-counts and objectively measured MVPA in ≥10-minute bouts in 60-75 year olds at 3 and 12 months, with no effect on adverse events. To our knowledge, this is the first trial in this age group to demonstrate objective MVPA increases and highlights the value of individualised support incorporating objective PA assessment in a primary care setting.

TRIAL REGISTRATION

Controlled-Trials.com ISRCTN42122561.

Bari-Active: a randomized controlled trial of a preoperative intervention to increase physical activity in bariatric surgery patients

BACKGROUND

Habitual physical activity (PA) may help to optimize bariatric surgery outcomes; however, objective PA measures show that most patients have low PA preoperatively and make only modest PA changes postoperatively. Patients require additional support to adopt habitual PA. The objective of this study was to test the efficacy of a preoperative PA intervention (PAI) versus standard presurgical care (SC) for increasing daily moderate-to-vigorous PA (MVPA) in bariatric surgery patients.

METHODS

Outcomes analysis included 75 participants (86.7% women; 46.0±8.9 years; body mass index [BMI]=45.0±6.5 kg/m2) who were randomly assigned preoperatively to 6 weeks of PAI (n=40) or SC (n=35). PAI received weekly individual face-to-face sessions with tailored instruction in behavioral strategies (e.g., self-monitoring, goal-setting) to increase home-based walking exercise. The primary outcome, pre- to postintervention change in daily bout-related (≥10 min bouts) and total (≥1 min bouts) MVPA minutes, was assessed objectively via a multisensor monitor worn for 7 days at baseline- and postintervention.

RESULTS

Retention was 84% at the postintervention primary endpoint. In intent-to-treat analyses with baseline value carried forward for missing data and adjusted for baseline MVPA, PAI achieved a mean increase of 16.6±20.6 min/d in bout-related MVPA (baseline: 4.4±5.5 to postintervention: 21.0±21.4 min/d) compared to no change (-0.3±12.7 min/d; baseline: 7.9±16.6 to postintervention: 7.6±11.5 min/d) for SC (P=.001). Similarly, PAI achieved a mean increase of 21.0±26.9 min/d in total MVPA (baseline: 30.9±21.2 to postintervention: 51.9±30.0 min/d), whereas SC demonstrated no change (-0.1±16.3 min/d; baseline: 33.7±33.2 to postintervention: 33.6±28.5 minutes/d) (P=.001).

CONCLUSION

With behavioral intervention, patients can significantly increase MVPA before bariatric surgery compared to SC. Future studies should determine whether preoperative increases in PA can be maintained postoperatively and contribute to improved surgical outcomes.

A community health worker-led lifestyle behavior intervention for Latina (Hispanic) women: feasibility and outcomes of a randomized controlled trial

BACKGROUND

Low-income Latinas (Hispanics) face risk for cardiovascular disease due to high rates of overweight/obesity, sedentary lifestyle, and other factors. Limited access to health care and language barriers may prevent delivery of health promotion messages. Targeted approaches, including the integration of community health workers, may be required to promote healthy lifestyle and prevent chronic disease in underserved ethnic minority groups. The term commonly used to refer to female community health workers in Latino communities is "promotora(s)."

OBJECTIVES

This study evaluates the outcomes and feasibility of a promotora-led lifestyle behavior intervention for overweight, immigrant Latinas.

METHODS

A community prevention model was employed in planning and implementing this study. A randomized controlled trial design was used. A Community Advisory Board provided expertise in evaluating feasibility of study implementation in the community and other important guidance. The sample was comprised of 223 women aged 35-64 years, predominantly with low income and ≤8th grade education. The culturally tailored Lifestyle Behavior Intervention included group education (8 classes based upon Su Corazon, Su Vida), followed by 4 months of individual teaching and coaching (home visits and telephone calls). The control group received a comparable length educational program and follow-up contacts. Evaluations were conducted at baseline and at 6 and 9 months using a dietary habits questionnaire, accelerometer readings of physical activity, and clinical measures (body mass index, weight, waist circumference, blood pressure, lipids, blood glucose). Data were collected between January 2010 and August 2012.

RESULTS

Women in the intervention group improved significantly in dietary habits, waist circumference, and physical activity in comparison to those in the control group. A treatment dosage effect was observed for weight and waist circumference. Knowledge about heart disease increased. High attendance at classes and participation in the individual teaching and counseling sessions and high retention rates support the feasibility and acceptability of the promotora-led lifestyle behavior intervention.

CONCLUSIONS

Our findings demonstrate that lifestyle behaviors and other risk factors of overweight Latina women may be improved through a promotora-led lifestyle behavior intervention. Feasibility of implementing this intervention in community settings and engaging promotoras as facilitators is supported.

Impact of accelerometer data processing decisions on the sample size, wear time and physical activity level of a large cohort study

BACKGROUND

Accelerometers objectively assess physical activity (PA) and are currently used in several large-scale epidemiological studies, but there is no consensus for processing the data. This study compared the impact of wear-time assessment methods and using either vertical (V)-axis or vector magnitude (VM) cut-points on accelerometer output.

METHODS

Participants (7,650 women, mean age 71.4 y) were mailed an accelerometer (ActiGraph GT3X+), instructed to wear it for 7 days, record dates and times the monitor was worn on a log, and return the monitor and log via mail. Data were processed using three wear-time methods (logs, Troiano or Choi algorithms) and V-axis or VM cut-points.

RESULTS

Using algorithms alone resulted in "mail-days" incorrectly identified as "wear-days" (27-79% of subjects had >7-days of valid data). Using only dates from the log and the Choi algorithm yielded: 1) larger samples with valid data than using log dates and times, 2) similar wear-times as using log dates and times, 3) more wear-time (V, 48.1 min more; VM, 29.5 min more) than only log dates and Troiano algorithm. Wear-time algorithm impacted sedentary time (~30-60 min lower for Troiano vs. Choi) but not moderate-to-vigorous (MV) PA time. Using V-axis cut-points yielded ~60 min more sedentary time and ~10 min less MVPA time than using VM cut-points.

CONCLUSIONS

Combining log-dates and the Choi algorithm was optimal, minimizing missing data and researcher burden. Estimates of time in physical activity and sedentary behavior are not directly comparable between V-axis and VM cut-points. These findings will inform consensus development for accelerometer data processing in ongoing epidemiologic studies.

Objective physical activity and weight loss in adults: the step-up randomized clinical trial

OBJECTIVE

To examine the amount of objectively measured MVPA and LPA that is associated with long-term weight loss and the maintenance of clinically significant weight loss.

METHODS

Adults (N = 260; BMI: 25 to <40 kg/m(2) ; age: 18-55 years) participated in an 18-month behavioral weight loss intervention and were prescribed a low-calorie diet and increased physical activity. Change in weight and objectively measured physical activity were assessed. MVPA > 10 (MET-min/week) was computed from bouts >10 min and >3.0 METs and MVPA < 10 was computed from bouts <10 min in duration and >3.0 METs. LPA was computed from bouts between 1.5 to <3.0 METs.

RESULTS

When grouped on percent weight loss at 18 months, there was a significant group × time interaction effect (P < 0.0001) for both MVPA > 10 and LPA, with both measures being significantly greater at 18 months in those with >10% weight loss. Similar results were observed for MVPA > 10 and LPA with participants grouped on achieving >10% weight loss at 6 months and sustaining this at 18 months.

CONCLUSIONS

MVPA > 10 of 200-300 min per week, coupled with increased amounts of LPA, are associated with improved long-term weight loss. Interventions should promote engagement in these amounts and types of physical activity.

Physical activity and cardiometabolic characteristics in overweight Latina women

This community-based study examined physical activity (PA) in relation to cardiometabolic risk factors among 223 adult, immigrant Latina women who were overweight or obese. Participants were predominantly of Mexican descent, married and low-income. Data were obtained through accelerometer readings and clinical measures (e.g., BMI, waist circumference, blood pressure, lipid profile, fasting blood sugar). Findings showed that many women were active (mean step count = 8,575 ± 3,191); 27.6 % achieved 10,000 steps per day, and only 11 % were sedentary. They engaged in short bouts of moderate PA rather than long-sustained moderate-to-vigorous activity. Three or more MetS traits were present in 45.3 % of the women, raising concerns about risk for diabetes and cardiovascular disease. More active women had lower BMI, weight, waist circumference, and triglycerides levels. Results point to the importance of targeting maintenance of PA in active women and intervening with culturally tailored programs to promote healthier behavior in those who are sedentary or somewhat active.

Physical activity monitoring in extremely obese adolescents from the Teen-LABORATORIES study

BACKGROUND

The accuracy of physical activity (PA) monitors to discriminate between PA, sedentary behavior, and nonwear in extremely obese (EO) adolescents is unknown.

METHODS

Twenty-five subjects (9 male/16 female; age = 16.5 ± 2.0 y; BMI = 51 ± 8 kg/m2) wore 3 activity monitors (StepWatch [SAM], Actical [AC], Actiheart [AH]) during a 400-m walk test (400MWT), 2 standardized PA bouts of varying duration, and 1 sedentary bout.

RESULTS

For the 400MWT, percent error between observed and monitor-recorded steps was 5.5 ± 7.1% and 82.1 ± 38.6% for the SAM and AC steps, respectively (observed vs. SAM steps: -17.2 ± 22.2 steps; observed vs. AC steps: -264.5 ± 124.8 steps). All activity monitors were able to differentiate between PA and sedentary bouts, but only SAM steps and AH heart rate were significantly different between sedentary behavior and nonwear (P < .001). For all monitors, sedentary behavior was characterized by bouts of zero steps/counts punctuated by intermittent activity steps/counts; nonwear was represented almost exclusively by zero steps/counts.

CONCLUSION

Of all monitors tested, the SAM was most accurate in terms of counting steps and differentiating levels of PA and thus, most appropriate for EO adolescents. The ability to accurately characterize PA intensity in EO adolescents critically depends on activity monitor selection.

Standardizing the analysis of physical activity in patients with COPD following a pulmonary rehabilitation program

BACKGROUND

There is a wide variability in measurement methodology of physical activity. This study investigated the effect of different analysis techniques on the statistical power of physical activity outcomes after pulmonary rehabilitation.

METHODS

Physical activity was measured with an activity monitor armband in 57 patients with COPD (mean ± SD age, 66 ± 7 years; FEV1, 46 ± 17% predicted) before and after 3 months of pulmonary rehabilitation. The choice of the outcome (daily number of steps [STEPS], time spent in at least moderate physical activity [TMA], mean metabolic equivalents of task level [METS], and activity time [ACT]), impact of weekends, number of days of assessment, postprocessing techniques, and influence of duration of daylight time (DT) on the sample size to achieve a power of 0.8 were investigated.

RESULTS

The STEPS and ACT (1.6-2.3 metabolic equivalents of task) were the most sensitive outcomes. Excluding weekends decreased the sample size for STEPS (83 vs 56), TMA (160 vs 148), and METS (251 vs 207). Using 4 weekdays (STEPS and TMA) or 5 weekdays (METS) rendered the lowest sample size. Excluding days with < 8 h wearing time reduced the sample size for STEPS (56 vs 51). Differences in DT were an important confounder.

CONCLUSIONS

Changes in physical activity following pulmonary rehabilitation are best measured for 4 weekdays, including only days with at least 8 h of wearing time (during waking hours) and considering the difference in DT as a covariate in the analysis.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00948623; URL: www.clinicaltrials.gov.

Interruption in physical activity bout analysis: an accelerometry research issue

Background

The purpose of the present investigation was to clarify the impact of the treatment of interruptions on the durations and the frequency of the physical activity (PA) bouts under free-living conditions.

Methods

One hundred and forty adults (50 ± 7 years) wore an accelerometer (Lifecorder) for seven consecutive days under free-living conditions. According to the minutes by minutes metabolic equivalents (METs) value, the PA was divided into one of three intensity categories: light intensity PA (LPA, < 3 METs), moderate intensity PA (MPA, 3 to 6 METs), vigorous intensity PA (VPA, > 6 METs), and the sum of the MPA and VPA was defined as moderate to vigorous intensity PA (MVPA, > 3 METs). Thereafter, based on the time series data, we defined MVPA bouts as PA that was maintained at no less than 3 METs completely for 10 minutes or longer with or without allowing for a one-minute or a two-minute break (<3METs).

Results

The frequency and duration of the continuous MVPA bouts lasting longer than 10-min were significantly lower and shorter compared with that in the non-continuous MVPA bouts allowing a one- or two-minute interruption (4.11 ± 1.65, 6.58 ± 2.72 and 8.97 ± 3.55 bouts/day, 71.62 ± 33.66, 119.03 ± 49.35 and 169.75 ± 65.87 min/day, P < 0.05). The number of days with a total time of MVPA bouts of 30-min was significantly lower in the continuous MVPA bouts compared with that in the non-continuous MVPA bouts allowing a 1-min or 2-min interruption (5.36 ± 1.65, 6.39 ± 1.07 and 6.65 ± 0.85 days/week).

Conclusion

The treatment of interruptions for the setting of the accelerometer affects the estimation of the MVPA bouts under free-living conditions in middle-aged to older adults. The best analysis process with regard to the accelerometer quantifying the break to reflect the real behavioral pattern and the physiological stress in such subjects remains unclear.