Search

Background: Step-counting interventions with discrepant intensity emphases may elicit different effects. Methods: A total of 120 sedentary/low-active, postmenopausal women were randomly assigned to one of the following 3 groups: (1) 10,000 steps per day (with no emphasis on walking intensity/speed/cadence; basic intervention, 49 completers), (2) 10,000 steps per day and at least 30 minutes in moderate intensity (ie, at a cadence of at least 100 steps per minute; enhanced intervention, 47 completers), or (3) a control group (19 completers). NL-1000-determined steps and active minutes (a device-specific indicator of time at moderate+ intensity) were collected as process variables during the 12-week intervention. Outcome variables included systolic and diastolic blood pressure, anthropometric measurements, fasting blood glucose and insulin, flow-mediated dilation, gait speed, and ActiGraph GT3X+-determined physical activity and sedentary behavior. Results: The "basic group" increased 5173 to 9602 steps per day and 9.2 to 30.2 active minutes per day. The "enhanced group" similarly increased 5061 to 10,508 steps per day and 8.7 to 38.8 active minutes per day. The only significant change over time for clinical variables was body mass index. Conclusions: Interventions that use simple step-counters can achieve elevated volume and intensity of daily physical activity, regardless of emphasis on intensity. Despite this, few clinical outcomes were apparent in this sample of postmenopausal women with generally normal or controlled hypertension. [ABSTRACT FROM AUTHOR]

Background: Energy expenditure (EE) estimates for a broad age range of youth performing a variety of activities are needed. Methods: 106 participants (6–18 years) completed 6 free-living activities (seated rest, movie watching, coloring, stair climbing, basketball dribbling, jumping jacks) and up to 9 treadmill walking bouts (13.4 to 120.7 m/min; 13.4 m/min increments). Breath-by-breath oxygen uptake (VO2) was measured using the COSMED K4b2 and EE was quantified as youth metabolic equivalents (METy1:VO2/ measured resting VO2, METy2:VO2/estimated resting VO2). Age trends were evaluated with ANOVA. Results: Seated movie watching produced the lowest mean METy1 (6- to 9-year-olds: 0.94 ± 0.13) and METy2 values (13- to 15-year-olds: 1.10 ± 0.19), and jumping jacks produced the highest mean METy1 (13- to 15-year-olds: 6.89 ± 1.47) and METy2 values (16- to 18-year-olds: 8.61 ± 2.03). Significant age-related variability in METy1 and METy2 were noted for 8 and 2 of the 15 evaluated activities, respectively. Conclusions: Descriptive EE data presented herein will augment the Youth Compendium of Physical Activities. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to compare steps/day detected by the YAMAX SW-200 pedometer versus the Actigraph GT3X accelerometer in free-living adults. Methods: Daily YAMAX and GT3X steps were collected from a sample of 23 overweight and obese participants (78% female; age = 52.6 ± 8.4 yr.; BMI = 31.0 ± 3.7 m·kg-2). Because a pedometer is more likely to be used in a community-based intervention program, it was used as the standard for comparison. Percent difference (PD) and absolute percent difference (APD) were calculated to examine between-instrument agreement. In addition, days were categorized based on PD: a) under-counting (> -10 PD), b) acceptable counting (-10 to 10 PD), and c) over-counting (> 10 PD). Results: The YAMAX and GT3X detected 8,025 ± 3,967 and 7131 ± 3066 steps/day, respectively, and the outputs were highly correlated (r = .87). Average PD was -3.1% ± 30.7% and average APD was 23.9% ± 19.4%. Relative to the YAMAX, 53% of the days detected by the GT3X were classified as under-counting, 25% acceptable counting, and 23% over-counting. Conclusion: Although the output of these 2 instruments is highly correlated, caution is advised when directly comparing or using their output interchangeably. [ABSTRACT FROM AUTHOR]

Background: Analysis of the 2005-2006 National Health and Nutrition Examination Survey (NHANES) accelerometer data provides the descriptive epidemiology of peak 30-minute cadence (defined as the average steps/min recorded for the 30 highest, but not necessarily consecutive, minutes in a day) and peak 1-minute cadence (defined as the steps/min recorded for the highest single minute in a day) by sex, age, and body mass index (BMI). Methods: Minute-by-minute step data were rank ordered each day to identify the peak 30-minute and I -minute cadences for 3522 adults (20+ years of age) with complete sex, age, and BMI data and at least 1 valid day (ie, 10/24 hours of accelerometer wear) of accelerometer data. Peak values were averaged across days within participants by sex, age, and BMI-defined categories. Results: U.S. adults average a peak 30-minute cadence of 71.1 (men: 73.7, women: 69.6, P< .0001) steps/min and a peak 1-minute cadence of 100.7 (men: 100.9, women: 100.5, P = .54) steps/min. Both peak cadence indicators displayed significant and consistent declines with age and increasing levels of obesity. Conclusions: Peak cadence indicators capture the highest intensity execution of naturally occurring ambulatory activity. Future examination of their relationship with health parameters using cross-sectional, longitudinal, and intervention designs is warranted. [ABSTRACT FROM AUTHOR]

Supplemental digital content is available in the text. Purpose: To examine the impact of a community-based exercise training intervention on cardiometabolic outcomes in African American men who have a family history of type 2 diabetes. Methods: The Aerobic Plus Resistance Training and Insulin Sensitivity in African American Men (ARTIIS) study randomized participants into either an exercise training intervention or an information only control group for 5 months. The exercise training intervention consisted of 150 min of moderate intensity aerobic activity and 2 d of resistance training per week, consistent with the current federal physical activity guidelines. Participants in the control group received monthly newsletters featuring topics focused heavily on type 2 diabetes education and prevention. Outcome data were analyzed using repeated-measures ANCOVA models and incorporating both intention-to-treat and per-protocol principles. Results: Adherence to the aerobic and resistance training prescriptions were between 77% and 79%. Despite significant within group improvements in glucose and insulin levels (fasting, 2 h, 2 h minus baseline) and Homeostatic Model 2-Insulin Resistance, there were not significant between group differences. There was a marginally significant between group difference for Homeostatic Model 2-Beta (P < 0.06), and significant between group differences in peak cardiorespiratory fitness (P < 0.001) and waist circumference (P = 0.03). Conclusions: These findings suggest that exercise training in accordance with the current national recommendations is effective in improving some health parameters in middle-age African American men who have a family history of type 2 diabetes, but did not have a significant impact on glycemic status. [ABSTRACT FROM AUTHOR]

Background Exercise is recommended for weight management, yet exercise produces less weight loss than expected, which is called weight compensation. The mechanisms for weight compensation are unclear. Objective The aim of this study was to identify the mechanisms responsible for compensation. Methods In a randomized controlled trial conducted at an academic research center, adults (n  = 198) with overweight or obesity were randomized for 24 wk to a no-exercise control group or 1 of 2 supervised exercise groups: 8 kcal/kg of body weight/wk (KKW) or 20 KKW. Outcome assessment occurred at weeks 0 and 24. Energy intake, activity, and resting metabolic rate (RMR) were measured with doubly labeled water (DLW; with and without adjustments for change in RMR), armband accelerometers, and indirect calorimetry, respectively. Appetite and compensatory health beliefs were measured by self-report. Results A per-protocol analysis included 171 participants (72.5% women; mean ± SD baseline body mass index: 31.5 ± 4.7 kg/m2). Significant (P  < 0.01) compensation occurred in the 8 KKW (mean: 1.5 kg; 95% CI: 0.9, 2.2 kg) and 20 KKW (mean: 2.7 kg; 95% CI: 2.0, 3.5 kg) groups, and compensation differed significantly between the exercise groups (P  = 0.01). Energy intake by adjusted DLW increased significantly (P  < 0.05) in the 8 KKW (mean: 90.7 kcal/d; 95% CI: 35.1, 146.4 kcal/d) and 20 KKW (mean: 123.6 kcal/d; 95% CI: 64.5, 182.7 kcal/d) groups compared with control (mean: −2.3 kcal/d; 95% CI: −58.0, 53.5 kcal/d). Results were similar without DLW adjustment. RMR and physical activity (excluding structured exercise) did not differentially change among the 3 groups. Participants with higher compared with lower compensation reported increased appetite ratings and beliefs that healthy behaviors can compensate for unhealthy behaviors. Furthermore, they increased craving for sweet foods, increased sleep disturbance, and had worsening bodily pain. Conclusions Compensation resulted from increased energy intake and concomitant increases in appetite, which can be treated with dietary or pharmacological interventions. Compensation was not due to activity or metabolic changes. This trial was registered at clinicaltrials.gov as NCT01264406. [ABSTRACT FROM AUTHOR]

Background: We examined the effects of wear time on a population profile of time-stamped accelerometer outputs using the 2005-2006 National Health and Nutrition Examination Survey (NHANES) data representing 3744 adults ≥ 20 years of age. Methods: Outputs included activity counts, steps, and time variables: nonwear (macro-determined), sedentary behavior (<100 activity counts/minute), and time in low (100-499 activity counts/minute), light (500-2019 activity counts/minute), and moderate-to-vigorous physical activity (MVPA; ≥2020 activity counts/minute) intensities. We describe mean values according to a 24-hour clock. Analysis was repeated in a reduced data set with only those who wore the accelerometer for 60 minutes within each considered hour of the day. Results: Between 12:00 and 17:00, U.S. adults spend approximately 31 minutes each hour in sedentary behaviors, and approximately 14 minutes, 10 minutes, and 2 minutes in low, light, and MVPA intensity activity, respectively. Removing the effect of nonwear time, sedentary behaviors are reduced in the morning hours and increase in the evening hours. Conclusion: At either end of the day, nonwear time appears to distort population estimates of all accelerometer time and physical activity volume indicators, but its effects are particularly clear on population estimates of time spent in sedentary behavior. [ABSTRACT FROM AUTHOR]

Background: Objective physical activity data analyses focus on moderate-to-vigorous physical activity (MVPA) without considering lower intensity lifestyle-type activities (LA). We describe 1 ) quantity of LA (minutes and steps per day) across demographic groups, 2) proportion of LA to total physical activity, and 3) relationships between LA and MVPA using NHANES 2005-2006 accelerometer adult data (n = 3744). Methods: LA was defined as 760 to 2019 counts per minute (cpm) and MVPA as ≥2020 cpm. LA was compared within gender, ethnicity, age, and BMI groups. Regression analyses examined independent effects. Correlations were evaluated between LA and MVPA. All analyses incorporated sampling weights to represent national estimates. Results: Adults spent 110.4 ± 1.6 minutes and took 3476 ± 54 steps per day in LA. Similar to MVPA, LA was highest in men, Mexican Americans, and lowest in adults ≥60 years or obese. When LA was held constant, ethnic differences no longer predicted MVPA minutes, and age no longer predicted MVPA steps. LA and MVPA minutes (r = .84) and steps per day (r = .72) were significantly correlated, but attenuated with MVPA modified bouts (≥10 minutes sustained activity). Conclusions: LA accumulation differs between demographic subgroups and is related to MVPA: adults who spend more minutes and steps in MVPA also spend them in LA. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to examine the relationship between 2005-2006 National Health and Nutrition Examination Survey (NHANES) accelerometer-determined steps/day and activity counts/day, and between steps/day and estimates of nonwear time (as an indicator of the unmonitored day) and time spent in sedentary behaviors as well as a range of physical activity intensities. Methods: Linear regression models were used to characterize the relationship between steps/day, activity counts/day, estimates of wear time, and intensity categories. Results: 1781 males (mean age = 46.5 years) and 1963 females (mean age = 47.7 years) wore accelerometers 14.0 ± SEM0.06 hours/day. The relationship between steps/day and activity counts/day was positive and strong (R² = .87). The relationship between steps/day and time spent in sedentary behaviors was inverse and moderate (R² = .25). Stronger and positive relationships were apparent between steps/day and time in light (R² = .69) and moderate (R² = .63) intensity activities. There was no discernable relationship between steps/day and time spent in low or vigorous intensity activities or with wear time. Conclusions: Assessed by accelerometer, steps/day explains 87% of the variation in activity counts/day, 25% of the variation in time in sedentary behaviors, 69% of time in light intensity, and 63% of time in moderate intensity. [ABSTRACT FROM AUTHOR]

Objective: To examine the joint association of birth weight and physical activity/sedentary time with childhood obesity in 12 countries.Methods: A cross-sectional study of 5,088 children aged 9 to 11 years was conducted. Birth weight was recalled by parents or guardians. Moderate-to-vigorous physical activity (MVPA) and sedentary behavior were objectively measured using accelerometry.Results: The association of birth weight with the odds of obesity, central obesity, and high body fat was significant among children with either low MVPA or high sedentary time but not among children with either high MVPA or low sedentary time. In comparison with children with normal birth weight and high MVPA, children with high birth weight and low MVPA showed 4.48- to 5.18-fold higher odds of obesity, central obesity, and high body fat; children with normal birth weight and low MVPA showed 3.00- to 3.30-fold higher odds of obesity, central obesity, and high body fat, and children with high birth weight and high MVPA showed 1.16- to 1.68-fold higher odds of obesity, central obesity, and high body fat.Conclusions: High MVPA is more important than high birth weight as a correlate of obesity in children. [ABSTRACT FROM AUTHOR]

Objective The aim was to assess associations between lifestyle behaviors and obesity in a multinational study of children from 12 countries representing a wide range of human development. Methods The sample included 6,025 children 9-11 years of age. Behavioral risk factors included nocturnal sleep duration, moderate to vigorous physical activity (MVPA), television viewing (TV time), and healthy and unhealthy diet pattern scores. Multilevel analyses were used to obtain odds ratios for obesity expressed per standard deviation of each behavioral risk factor. Results The odds ratios (95% confidence intervals) for obesity from multilevel, multivariable models were 0.79 (0.71-0.90) for nocturnal sleep duration, 0.52 (0.45-0.60) for MVPA, 1.15 (1.05-1.27) for TV time, 1.08 (0.96-1.20) for healthy diet score, and 0.93 (0.83-1.04) for unhealthy diet score in boys and 0.71 (0.63-0.80) for nocturnal sleep duration, 0.43 (0.35-0.53) for MVPA, 1.07 (0.96-1.19) for TV time, 1.05 (0.93-1.19) for healthy diet score, and 0.96 (0.82-1.11) for unhealthy diet score in girls. Conclusions Behavioral risk factors are important correlates of obesity in children, particularly low MVPA, short sleep duration, and high TV viewing. [ABSTRACT FROM AUTHOR]

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Objectives: We used linked existing data from the 2006–2008 American Time Use Survey (ATUS), the Current Population Survey (CPS, a federal survey that provides on-going U.S. vital statistics, including employment rates) and self-reported body mass index (BMI) to answer: How does BMI vary across full time occupations dichotomized as sedentary/non-sedentary, accounting for time spent in sleep, other sedentary behaviors, and light, moderate, and vigorous intensity activities? Methods: We classified time spent engaged at a primary job (sedentary or non-sedentary), sleep, and other non-work, non-sleep intensity-defined behaviors, specifically, sedentary behavior, light, moderate, and vigorous intensity activities. Age groups were defined by 20–29, 30–39, 40–49, and 50–64 years. BMI groups were defined by 18.5–24.9, 25.0–27.4, 27.5–29.9, 30.0–34.9, and ≥35.0 kg/m2. Logistic and linear regression were used to examine the association between BMI and employment in a sedentary occupation, considering time spent in sleep, other non-work time spent in sedentary behaviors, and light, moderate, and vigorous intensity activities, sex, age race/ethnicity, and household income. Results: The analysis data set comprised 4,092 non-pregnant, non-underweight individuals 20–64 years of age who also reported working more than 7 hours at their primary jobs on their designated time use reporting day. Logistic and linear regression analyses failed to reveal any associations between BMI and the sedentary/non-sedentary occupation dichotomy considering time spent in sleep, other non-work time spent in sedentary behaviors, and light, moderate, and vigorous intensity activities, sex, age, race/ethnicity, and household income. Conclusions: We found no evidence of a relationship between self-reported full time sedentary occupation classification and BMI after accounting for sex, age, race/ethnicity, and household income and 24-hours of time use including non-work related physical activity and sedentary behaviors. The various sources of error associated with self-report methods and assignment of generalized activity and occupational intensity categories could compound to obscure any real relationships. [ABSTRACT FROM AUTHOR]

Objective The Lower Mississippi Delta (LMD) region of the United States is characterized by high levels of obesity and physical inactivity. The objective was to test the effectiveness of adapting the 2010 Dietary Guidelines for Americans (DG), with and without a physical activity (PA) component, for attenuating weight gain. Methods Overall, 121 white and African-American adults (35-64 years; body mass index 25-34.9 kg/m2) were randomized to a DG only group ( n = 61) or a DG + PA group ( n = 60). Both groups received a 12-week dietary education and behavior change intervention. The DG + PA group also received PA education and a pedometer. Changes in weight (kg), %weight, and waist circumference (WC; cm) were determined. Analyses considered all completers ( n = 99) and those who engaged with ≥80% of the intervention ( n = 83). General linear models compared mean changes between groups after adjustment for baseline values, race, and sex. Results Weight, %weight, and WC significantly decreased from baseline to follow-up in both groups ( p < 0.05; unadjusted values). Adjusted analysis showed a main effect of group for weight ( p = 0.041) and %weight ( p = 0.047) in the completers analysis, and WC ( p = 0.046) in the ≥80% attendance analysis, with the DG + PA group improving weight-related outcomes more. Conclusions Low-burden behavioral interventions could be effective strategies in attenuating unhealthy weight gain in the LMD. [ABSTRACT FROM AUTHOR]

Background Pedometer-based programs have elicited increased walking behaviors associated with improvements in blood pressure in sedentary/low active postmenopausal women, a population at increased risk of cardiovascular disease. Such programs typically encourage increasing the volume of physical activity with little regard for its intensity. Recent advances in commercially available pedometer technology now permit tracking of both steps/day and time in moderate (or greater) intensity physical activity on a daily basis. It is not known whether the dual message to increase steps/day while also increasing time spent at higher intensity walking will elicit additional improvements in blood pressure relative to a message to only focus on increasing steps/day. The purpose of this paper is to present the rationale, study design, and protocols employed in WalkMore, a 3-arm 3-month blinded and randomized controlled trial (RCT) designed to compare the effects of two community pedometer-based walking interventions (reflecting these separate and combined messages) relative to a control group on blood pressure in sedentary/low active post-menopausal women, a population at increased risk of cardiovascular disease. Methods/design 120 sedentary/low active post-menopausal women (45-74 years of age) will be randomly assigned (computer-generated) to 1 of 3 groups: A) 10,000 steps/day (with no guidance on walking intensity/speed/cadence; BASIC intervention, n = 50); B) 10,000 steps/day and at least 30 minutes in moderate intensity (i.e., a cadence of at least 100 steps/min; ENHANCED intervention, n = 50); or a Control group (n = 20). An important strength of the study is the strict control and quantification of the pedometer-based physical activity interventions. The primary outcome is systolic blood pressure. Secondary outcomes include diastolic blood pressure, anthropometric measurements, fasting blood glucose and insulin, flow mediated dilation, gait speed, and accelerometer-determined physical activity and sedentary behavior. Discussion This study can make important contributions to our understanding of the relative benefits that walking volume and/or intensity may have on blood pressure in a population at risk of cardiovascular disease. Trial registration ClinicalTrials.gov Record NCT01519583, January 18, 2012 [ABSTRACT FROM AUTHOR]

Background. Pedometers are more likely than accelerometers to be used in walking interventions and other applications, including wide spread adoption by lay people. The purpose of this article is to provide older adults’ sex-and-age-specific normative values for accelerometer-determined steps/day, adjusted to a pedometer-based scale. Methods. The data source was accelerometer data collected over multiple valid days (defined as ≥ 10 h/day; mean 5.8 ± SE 0.1 valid days) from 1,196 60+ year olds participating in the 2005–2006 National Health and Nutrition Examination Survey. Accelerometer data were adjusted to a pedometer scale using an established process of censoring steps counted during those minutes where activity counts totaled <500. Quintile-defined categories of adjusted steps/day (lowest, below average, average, above average, and highest) for six age groups (60–64, 65–69, 70–74, 75–79, 80–84, and 85+ years) were computed for the entire sample and separately for each sex. LMSChartmakerPro was used to create smoothed percentile curves corresponding to the 5th, 25th, 50th, 75th, and 95th percentiles. Results. Men aged 65–69 years defined the highest single category (>9,126 steps/day) and women aged 85+ years of age defined the lowest single category (<276 steps/day). In general, steps/day tended to decrease within each quintile-defined category as age increased. Similar patterns were apparent in the more detailed LMSChartmakerPro percentiles. Conclusions. These data represent the first presentation of a detailed population distribution of normative accelerometer-determined steps/day adjusted to pedometer scaling, an instrument more likely to be used in clinical and public health applications. [ABSTRACT FROM PUBLISHER]

Background: The primary aim of the International Study of Childhood Obesity, Lifestyle and the Environment (ISCOLE) was to determine the relationships between lifestyle behaviours and obesity in a multi-national study of children, and to investigate the influence of higher-order characteristics such as behavioural settings, and the physical, social and policy environments, on the observed relationships within and between countries. Methods/design: The targeted sample included 6000 10-year old children from 12 countries in five major geographic regions of the world (Europe, Africa, the Americas, South-East Asia, and the Western Pacific). The protocol included procedures to collect data at the individual level (lifestyle, diet and physical activity questionnaires, accelerometry), family and neighborhood level (parental questionnaires), and the school environment (school administrator questionnaire and school audit tool). A standard study protocol was developed for implementation in all regions of the world. A rigorous system of training and certification of study personnel was developed and implemented, including web-based training modules and regional in-person training meetings. Discussion: The results of this study will provide a robust examination of the correlates of adiposity and obesity in children, focusing on both sides of the energy balance equation. The results will also provide important new information that will inform the development of lifestyle, environmental, and policy interventions to address and prevent childhood obesity that may be culturally adapted for implementation around the world. ISCOLE represents a multi-national collaboration among all world regions, and represents a global effort to increase research understanding, capacity and infrastructure in childhood obesity. [ABSTRACT FROM AUTHOR]

Background: It remains unclear what people are attempting to communicate, in terms of objectively monitored behavior, when describing their physical activity and sedentary behavior through self-report. The purpose of this study was to examine various objectively monitored accelerometer variables (e.g., moderate-to-vigorous physical activity [MVPA], steps/day, sedentary time, etc.) across categories of self-reported MVPA (< 150 vs. ≥ 150 minutes/week), usual occupational/domestic activity (UODA; “mostly sitting” vs. “stand, walk, lift, or carry”), and leisure-time sedentary behavior (LTSB; ≥ 3 vs. < 3 hours/day) in a nationally representative sample of U.S. adults (≥ 20 years). Methods: This is a secondary analysis of 3,725 participants from the 2005–2006 National Health and Nutrition Examination Survey (NHANES) who provided relevant questionnaire responses and ≥ 1 day of valid accelerometer data. Descriptive statistics were computed for various objectively monitored accelerometer variables across categories of self-reported MVPA, UODA, and LTSB. Pairwise comparisons were conducted to examine differences in objectively monitored behavior between categories of self-reported MVPA, UODA, and LTSB. Results: On average, adults reporting compliance with physical activity guidelines (≥ 150 minutes/week of MVPA) accumulated more objectively measured physical activity and similar amounts of sedentary time relative to those reporting not achieving guidelines. Adults reporting their daily UODA as “mostly sitting” or accruing ≥3 hours/day of LTSB accumulated less objectively monitored physical activity and more sedentary time than those who described their UODA as “stand, walk, lift, or carry” or accrued < 3 hours/day of LTSB. The most active cross-classified category (7,935 steps/day; ≥ 150 minutes/week of self-reported MVPA, “stand, walk, lift, or carry” UODA, and < 3 hours/day of LTSB) accumulated more than twice as many daily steps as the least active cross-classified category (3,532 steps/day; < 150 minutes/week of self-reported MVPA, “mostly sitting” UODA, and ≥ 3 hours/day of LTSB). Conclusions: A number of objectively monitored physical activity indicators varied significantly between self-reported MVPA, UODA, and LTSB categories, while objectively monitored sedentary time only varied between UODA and LTSB categories. Cross-classifications of self-reported MVPA, UODA, and LTSB responses depict a greater range of physical activity than viewing dichotomous responses for these variables one-at-a-time. [ABSTRACT FROM AUTHOR]

Background: An evidence-based steps/day translation of U.S. federal guidelines for youth to engage in ≥60 minutes/day of moderate-to-vigorous physical activity (MVPA) would help health researchers, practitioners, and lay professionals charged with increasing youth's physical activity (PA). The purpose of this study was to determine the number of free-living steps/day (both raw and adjusted to a pedometer scale) that correctly classified children (6-11 years) and adolescents (12-17 years) as meeting the 60-minute MVPA guideline using the 2005-2006 National Health and Nutrition Examination Survey (NHANES) accelerometer data, and to evaluate the 12,000 steps/day recommendation recently adopted by the President's Challenge Physical Activity and Fitness Awards Program. Methods: Analyses were conducted among children (n = 915) and adolescents (n = 1,302) in 2011 and 2012. Receiver Operating Characteristic (ROC) curve plots and classification statistics revealed candidate steps/day cut points that discriminated meeting/not meeting the MVPA threshold by age group, gender and different accelerometer activity cut points. The Evenson and two Freedson age-specific (3 and 4 METs) cut points were used to define minimum MVPA, and optimal steps/day were examined for raw steps and adjusted to a pedometer-scale to facilitate translation to lay populations. Results: For boys and girls (6-11 years) with ≥ 60 minutes/day of MVPA, a range of 11,500-13,500 uncensored steps/day for children was the optimal range that balanced classification errors. For adolescent boys and girls (12-17) with ≥60 minutes/day of MVPA, 11,500-14,000 uncensored steps/day was optimal. Translation to a pedometer-scaling reduced these minimum values by 2,500 step/day to 9,000 steps/day. Area under the curve was ≥84% in all analyses. Conclusions: No single study has definitively identified a precise and unyielding steps/day value for youth. Considering the other evidence to date, we propose a reasonable 'rule of thumb' value of ≥ 11,500 accelerometer-determined steps/day for both children and adolescents (and both genders), accepting that more is better. For practical applications, 9,000 steps/day appears to be a more pedometer-friendly value. [ABSTRACT FROM AUTHOR]

Background: This study investigated the number of pedometer assessment occasions required to establish habitual physical activity in African American adults. Methods: African American adults (mean age 59.9 ± 0.60 years; 59 % female) enrolled in the Diet and Physical Activity Substudy of the Jackson Heart Study wore Yamax pedometers during 3-day monitoring periods, assessed on two to three distinct occasions, each separated by approximately one month. The stability of pedometer measured PA was described as differences in mean steps/day across time, as intraclass correlation coefficients (ICC) by sex, age, and body mass index (BMI) category, and as percent of participants changing steps/day quartiles across time. Results: Valid data were obtained for 270 participants on either two or three different assessment occasions. Mean steps/day were not significantly different across assessment occasions (p values>0.456). The overall ICCs for steps/day assessed on either two or three occasions were 0.57 and 0.76, respectively. In addition, 85 % (two assessment occasions) and 76 % (three assessment occasions) of all participants remained in the same steps/day quartile or changed one quartile over time. Conclusion: The current study shows that an overall mean steps/day estimate based on a 3-day monitoring period did not differ significantly over 4--6 months. The findings were robust to differences in sex, age, and BMI categories. A single 3-day monitoring period is sufficient to capture habitual physical activity in African American adults. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to determine if a short-term pedometer-based intervention results in immediate increases in time spent in moderate-to-vigorous physical activity (MVPA) compared to a minimal educational intervention. Methods: A sample of 43 overweight adults 35 to 64 years of age participated in a one week pedometer-based feasibility trial monitored by accelerometry. Participants were randomized into a one-week education-only group or a group that also wore a pedometer. Accelerometer-measured MVPA was measured over 7 days at baseline and again for 7 days immediately post-intervention. Results: Minutes of MVPA increased significantly in the overall sample (p = 0.02); however, the effect of adding the pedometer to the education program was not significant (p = 0.89). Mean (±SE) MVPA increased from 12.7±2.4 min/day to 16.2±3.6 min/day in the education-only group and from13.2±3.3 min/day to 16.3±3.9 min/day in the education+pedometer group. The correlation between change in steps/day and change in MVPA was 0.69 (p<0.0001). Conclusions: The results of this study suggest that the addition of a pedometer to a short-term education program does not produce added benefits with respect to increasing physical activity in the Lower Mississippi Delta. [ABSTRACT FROM AUTHOR]

The article presents a study on the accelerometer-determined steps of children and youth in the U.S., which aims to detect the low-force steps of the research-quality pedometers. It offers a descriptive epidemiology of an accelerometer-determined steps of children and youth. The study was conducted to 2610 children and youth who have an uncensored accelerometer-determined steps. It also mentions that the U.S. data has shown that a consistent decline of steps per day throughout childhood and youth.

Background: Knowing the most-frequently reported physical activities can inform intervention strategies, enhance questionnaire design, and inform objective monitor calibration studies. Purpose: To determine the 10 most-frequently reported nonwork and nonsleep activities by intensity (sedentary, light, moderate, vigorous) in American Time Use Survey (ATUS) adult respondents. Methods: The ATUS is a nationally representative telephone-based survey that captures activities that people recall doing during the preceding 24 hours. ATUS databases from 2003 to 2008 were combined and matched to previously published MET intensity values. Prevalences were rank ordered by weighted frequency within MET-defined intensity categories. Analyses took place in spring 2010. Results: Data from 79,652 ATUS respondents, all aged ≥20 years, were considered. Overall, the most-frequently reported nonwork, nonsleep sedentary (1.0≤MET<1.6) behavior was eating and drinking (95.6%), followed by watching TV/movies (80.1%); the most-frequently reported light activities (1.6≤MET<3.0) were washing, dressing, and grooming oneself (78.9%), followed by driving a car, truck, or motorcycle (71.4%); the most-frequently reported moderate activities (3.0≤MET<6.0) were food and drink preparation (25.7%) followed by lawn, garden, and houseplant care (10.6%); and the most-frequently reported vigorous activities were using cardiovascular equipment (2.2%) and running (1.1%). Conclusions: On any given day, most U.S. adults reported performing predominantly sedentary and light activities. The greatest prevalence for reported moderate activities was food and drink preparation for both men (12.8%) and women (37.63%), and overall only 5.07% report any vigorous-intensity activity. [Copyright &y& Elsevier]

The article reports on research which was conducted to investigate the free living cadence patterns and peak cadence indicators in children by sex, age and body mass index. Researchers evaluated information on cadence patterns and peak cadence which was derived from 2005-2006 National Health and Nutrition Examination Survey accelerometer data representing 2,610 U.S. children and adolescents. They found that U.S. children and adolescents seem to spend relatively few minutes in daily life engaged in activities that elicit step accumulation patterns indicative of normal walking speeds or those which are associated with higher intensity activities.

The article assesses the time spent physical activity on working day in sleep, work, sedentary behaviors, and light-moderate, and vigorous intensity behaviors by occupation intensity. The authors used data from 30,758 working respondents to the 2003-2009 American Time Use Survey. It revealed that about 32% of the 24-hour day was spent sleeping and about 31% was spent at work.

Abstract: Objective: Objective To assess the relationship between moderate intensity lifestyle activity (LA) and cardiometabolic health using accelerometer data from the National Health and Nutrition Examination Survey (NHANES) 2005–2006. Methods: One thousand three hundred and seventy-one adults (50% men; 71% non-Hispanic white) provided valid data to quantify time in LA [760–2019 counts per minute (CPM)] and moderate-to-vigorous physical activity (MVPA; ≥2020 CPM). Associations between LA [minutes per day (min/day); steps per day (steps/day)], and cardiometabolic risk factors [triglycerides, HDL-cholesterol (HDL-C), blood pressure, glucose, waist circumference], metabolic syndrome, self-reported hypertension and diabetes were investigated using logistic regression. Analyses were adjusted for age, gender, race/ethnicity, and MVPA categories. Results: Greater time in LA (min/day), independent from MVPA, was associated with lower odds of elevated triglycerides (OR,95% CI per 30 LA minutes: 0.89,0.83–0.97), low HDL-C (0.87,0.83–0.92), elevated waist circumference (0.88,0.83–0.94), metabolic syndrome (0.87,0.80–0.96), and diabetes (0.67,0.55–0.82). The same cardiometabolic risk factors were also significantly associated with LA steps/day. No significant association was found between LA (min/day or steps/day) and glucose or blood pressure. Conclusion: Accumulation of time or steps in LA is independently related to lower odds for certain cardiometabolic risk factors. Research should consider the effects of increasing LA, which could influence future physical activity recommendations. [Copyright &y& Elsevier]

Purpose: This study aimed to catalog the relationships between step-based accelerometer metrics indicative of physical activity volume (steps per day, adjusted to a pedometer scale), intensity (mean steps per minute from the highest, not necessarily consecutive, minutes in a day; peak 30-min cadence), and sedentary behavior (percent time at zero cadence relative to wear time; %TZC) and cardiometabolic risk factors. Methods: We analyzed data from 3388 participants, 20+ yr old, in the 2005-2006 National Health and Nutrition Examination Survey with ≥1 valid day of accelerometer data and at least some data on weight, body mass index, waist circumference, systolic and diastolic blood pressure, glucose, insulin, HDL cholesterol, triglycerides, and/or glycohemoglobin. Linear trends were evaluated for cardiometabolic variables, adjusted for age and race, across quintiles of steps per day, peak 30-min cadence, and %TZC. Results: Median steps per day ranged from 2247 to 12,334 steps per day for men and from 1755 to 9824 steps per day for women, and median peak 30-min cadence ranged from 48.1 to 96.0 steps per minute for men and from 40.8 to 96.2 steps per minute for women for the first and fifth quintiles, respectively. Linear trends were statistically significant (all P < 0.001), with increasing quintiles of steps per day and peak 30-min cadence inversely associated with waist circumference, weight, body mass index, and insulin for both men and women. Median %TZC ranged from 17.6% to 51.0% for men and from 19.9% to 47.6% for women for the first and fifth quintiles, respectively. Linear trends were statistically significant (all P < 0.05), with increasing quintiles of %TZC associated with increased waist circumference, weight and insulin for men, and insulin for women. Conclusions: This analysis identified strong linear relationships between step-based movement/nonmovement dimensions and cardiometabolic risk factors. These data offer a set of quantified access points for studying the potential dose-response effects of each of these dimensions separately or collectively in longitudinal observational or intervention study designs. [ABSTRACT FROM AUTHOR]

Purpose: To determine the relationships between moderate-to-vigorous physical activity (MVPA), vigorous physical activity (VPA), sedentary time, and obesity in children from 12 countries representing a wide range of human development. Methods: The sample included 6539 children age 9-11 yr. Times in MVPA, VPA, and sedentary behaviors were assessed by accelerometry. The body mass index (BMI; kg·m-2) was used to classify children as obese based on z-scores (> +2 SD) from World Health Organization reference data. Results: The mean (SD) times spent in MVPA, VPA, and sedentary behavior were 60 (25) min ·d-1, 18 (11) min ·d-1, and 513 (69) min ·d-1, respectively. The overall proportion of the sample that was obese ranged from 5.2% to 24.6% across sites. The odds ratios for obesity were significant for MVPA (0.49; 95% CI, 0.44-0.55), VPA (0.41; 0.37-0.46), and sedentary time (1.19; 1.08-1.30) in the overall sample. The associations of MVPA and VPA with obesity were significant in all 12 sites, whereas the association between sedentary time and obesity was significant in five of the 12 sites. There was a significant difference in BMI z-scores across tertiles of MVPA (P < 0.001) but not across tertiles of sedentary time in a mutually adjusted model. The results of receiver operating characteristic curve analyses for obesity indicated that the optimal thresholds for MVPA (area under the curve [AUC], 0.64), VPA (AUC, 0.67) and sedentary behavior (AUC, 0.57) were 55 (95% CI, 50-64) min ·d-1, 14 (11-16) min ·d-1, and 482 (455-535) min ·d-1, respectively. Conclusions: Greater MVPA and VPA were both associated with lower odds of obesity independent of sedentary behavior. Sedentary time was positively associated with obesity, but not independent of MVPA. Attaining at least 55 min·d-1 of MVPA is associated with lower obesity in this multinational sample of children, which supports current guidelines. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the effectiveness of a 3-month treadmill desk intervention in eliciting changes in physical activity and sedentary behavior among overweight/obese office workers. Methods: A randomized controlled trial was conducted among overweight/obese office workers (n = 41; mean age = 40.1 ± 10.1 years) at a private workplace. Participants were randomly assigned to a shared-treadmill desk intervention (n = 21) or a usual working condition control group (n = 20). Accelerometer-determined physical activity and sedentary behavior were measured before and after the intervention. Results: Compared with the control group, the intervention group increased daily steps (1622 steps/day; P = 0.013) and light physical activity (1.6 minutes/ hour; P = 0.008), and decreased sedentary time (−3.6 minutes/hour; P = 0.047) during working hours. Conclusions: Shared-treadmill desks in the workplace can be effective at promoting favorable changes in light physical activity (specifically 40 to 99 steps/minute) and sedentary behavior among overweight/obese office workers. [ABSTRACT FROM AUTHOR]

Background: Exercise training reduces adiposity and risk of cardiovascular disease. However, the combined effects of habitual free-living physical activity and aerobic training on waist circumference, weight, fitness, and blood pressure in postmenopausal women are unknown. Purpose: To evaluate the effects of habitual physical activity levels during aerobic training on weight, waist circumference, fitness, and blood pressure. Design: Secondary analysis of an RCT. Original data collected April 2001 to June 2005 and analyzed in 2012. Setting/participants: Postmenopausal women in a supervised exercise trial. Intervention: Women (n=325) were randomized to 4, 8, or 12 kcal/kg per week of aerobic training or a control group for 6 months. All outcome measures were collected at baseline and follow-up. Changes in dependent variables within each training group were evaluated across tertiles of pedometer-determined habitual physical activity outside exercise training sessions. Main outcome measures: Changes in waist circumference and weight. Results: Reductions in waist circumference were significantly greater with higher steps/day accumulated outside exercise training compared to lower levels in the 4 (high: −4.8 cm vs low: −1.4 cm, p=0.03); 8 (high: −4.2 cm vs low: −0.4 cm, p=0.03), and 12 kcal/kg per week groups (high: −4.1 cm vs low: −0.7 cm, p=0.05). For all groups, p-trend≤0.03. A trend was observed for greater weight reduction with higher steps/day in the 4 kcal/kg per week group (p-trend=0.04) but not for the other exercise doses. No effects were observed for blood pressure or fitness measures (all p>0.05). Conclusions: In postmenopausal women, higher habitual physical activity while participating in aerobic training was associated with greater reductions in central adiposity, and was supportive of weight loss compared to lower levels. [ABSTRACT FROM AUTHOR]

Purpose. Descriptive physical activity epidemiology of the U.S. population is critical for program development and resource allocation. The purpose of this project was to describe step-defined categories (as measured by accelerometer) of US. adults and to determine predictors of sedentary classification (<5000 steps/d). Design. The National Health and Nutrition Examination Survey (NHAIVES) is an annual nationally representative survey used to determine the health status of the US. populace. Setting. In-home interviews and physical examination components of NHANES. Participants. Overall, 4372 eligible adults wore accelerometers in the 2005-2006 NHANES; 628 were excluded, which yielded 3744 adults (of which 46.8% were men). Measures. Steps per day; body mass index (BMI,); demographic, household and behavioral variables. Analysis. Means and frequencies were calculated. Logistic regression was utilized to determine predictors of sedentary classification. Results. Overall, 36.1 % were sedentary (i.e., <5000 steps/d); 47.6% were low to somewhat active (5000-9999 steps/d); 16.3% were active to highly active (≥ 10,000 steps/d). Advancing age (odds ratio [OR], 1.95; confidence intervals [CIs], 1.78, 2.13), higher BMI (OR, 1.40; CIs, 1.23, 1.59), female sex (OR, 1.86; CIs, 1.46, 2.36), African-American versus European-American ethnicity (OR, 1.36; CIs, 1.13, 1.65), household income versus ≥ $45,000 (<$25,000: OR, 1.94; CIs, 1.40, 2.69; $25,000-$44,000: OR, 1.51; CIs, 1.23, 1.85), and current versus never smoker (OR, 1.53; CIs, 1.26, 1.86) variables had higher odds of sedentary classification. Usual daily occupational/domestic physical activity categories of standing/walking (OR, .51; CIs, .38, .69); lifting/climbing (OR, .26; CIs, .17, .38); and heavy loads/labor (OR, .16; CIs, .10, .26) had lower odds ofsedentary classification than sitting. Conclusions. Over one-third of the U.S. population was classified as sedentary by accelerometer-determined steps per day, and several characteristics predicted sedentary classification. [ABSTRACT FROM AUTHOR]