Are pedometers adequate instruments for assessing energy expenditure?

Latent profile analysis approach to the relationship between daily ambulatory activity patterns and metabolic syndrome in middle-aged and elderly Japanese individuals: The Toon Health Study

BACKGROUND

This cross-sectional study aimed to identify the accumulation patterns of objectively measured ambulatory activity (AA) variables in the Japanese middle-aged and elderly individuals and examine the relationship of these derivative patterns with metabolic syndrome (MetS).

METHODS

A total of 1850 participants (66.1% women, mean age: 57.7 years) provided objectively assessed AA data using a uniaxial accelerometer. The number of steps, time accumulated in light-intensity AA (LIAA) and moderate-to-vigorous intensity AA (MVAA), and the ratio of MVAA to total AA (LIAA + MVAA) were calculated. Latent profile analysis was used to identify groups of participants based on their distinct AA patterns. Logistic regression models were used to assess the association of groups with MetS after adjusting for age, sex, alcohol intake, and cigarette smoking.

RESULTS

Four distinct groups were identified: Group A had few steps and low levels of LIAA and MVAA; group B had a certain number of steps and recommended level of MVAA but low level of LIAA; group C had a certain number or more of steps, high level of LIAA, and recommended level of MVAA; group D had an extremely high number of steps and high levels of both LIAA and MVAA. The multivariate-adjusted odds ratio (95% CI) for MetS in groups B, C, and D relative to group A were 0.857 (0.611-1.201), 0.679 (0.500-0.922), and 0.434 (0.259-0.730), respectively. Groups C and D had significantly lower odds ratio of MetS compared to group A.

CONCLUSION

AA pattern involving a certain number or greater of steps accumulated through not only MVAA but also LIAA may help reduce the risk of MetS compared to inactive AA pattern.

Individual variations in steps per day for meeting physical activity guidelines in young adult women

Cross-sectional studies have found a correlation between the duration or volume of moderate-to-vigorous physical activity (MVPA) and steps per day (STEP), but there is little information on why this relationship varies among individuals. No previous research has established whether STEP can be used to estimate the duration of physical activity (PA) at or above lactate threshold (≥LT), such as for maintaining cardiorespiratory fitness. This study explored the association among STEP, MVPA indices, and ≥LT under free-living conditions. Seventy young adult women measured their PA for 7 days using a validated accelerometer. The mean LT measured by an exercise test was 5.8 ± 1.0 METs. STEP, MVPA, METs×h, and ≥LT were 9324 ± 2677 steps/day, 231.9 ± 101.5 min/week, 16.6 ± 7.4 METs×h/week and 24.0 ± 22.2 min/week, respectively. Significant correlations were found between STEP and MVPA duration and between STEP and METs×h/week (r = 0.81 and r = 0.81); however, approximately 1600 steps/day of the standard error of estimates in the regression equations were found. Multiple stepwise regression analysis revealed that the percentage of total time spent at light-intensity PA (LPA) and MVPA were significant determinants of the percent deviation of STEP from the linear relationships between STEP and MVPA indices. No significant relationship was observed between ≥LT and STEP. The association between STEP and MVPA fluctuated depending on individual daily LPA and MVPA. Thus, consideration of both STEP and the PA at specific intensities are necessary to ensure the PA guidelines are met and the health benefits gained. STEP alone would be not a sufficient indicator for assessing the ≥LT.

Academic-Based and Aerobic-Only Movement Breaks: Are There Differential Effects on Physical Activity and Achievement?

PURPOSE

This study investigated the academic achievement and physical activity differences between types of activity breaks implemented in elementary school classrooms. This study evaluated whether there was a difference between the impact of purely aerobic-based movement breaks and the impact of academic-based breaks on children's academic achievement outcomes.

METHOD

Participants included 460 children in 3rd grade through 5th grade at 4 elementary schools. There were 176 children in the schools that engaged in academic-based breaks and 284 in the schools that engaged in aerobic-only breaks. Schools were randomly assigned at the school level to implement either aerobic movement breaks with academic content infused within the breaks ("academic-based breaks") or aerobic-only movement breaks without the addition of academic material ("aerobic-only breaks") for approximately 10 min of activity per day. Math and reading achievement as well as children's step counts were measured before and after the intervention. A mixed-effects (multilevel-growth) model, in which the repeated measures of individuals nested within a classroom are analyzed, was used to answer all posited research questions.

RESULTS

Small to moderate effect sizes (ES) indicating gains in reading achievement (ES = .13) and steps (ES = .33) were found for classrooms that used aerobic-only movement breaks compared with those that used academic-based breaks.

CONCLUSIONS

The type of movement breaks that are implemented in classrooms may have differential outcomes for children's achievement and activity levels. Results from the present study indicate that children who were given aerobic-only movement breaks had slightly larger gains in reading achievement and physical activity levels than children who were given academic-based breaks.

Decline in objective physical activity over a 10-year period in a Japanese elementary school

Background

The purpose of this study was to examine the change in accelerometer-derived daily physical activity (PA) and activity record-derived daily activities over a 10-year period in urban elementary schoolchildren in Japan.

Methods

A total of 233 sixth-grade children (11–12 years old) in a same elementary school in Kyoto participated in the study (n = 125 and 108 in 1999 and 2009, respectively). The participant rate is 91.9 and 98.2 % in 1999 and 2009, respectively. The size and shape of the school district was not changed. The children were instructed to wear an accelerometer for 5 consecutive days of weekday and to keep minute-by-minute 24-h activity records with the assistance of their parents. The school-day scheduling was similar between 1999 and 2009 (29 and 27 sessions of 45-min class per week, respectively).

Results

From 1999 to 2009, step counts considerably decreased (20,832 vs. 12,237 steps per day in boys and 16,087 vs. 10,748 steps per day in girls; P < 0.001) with concomitant significant decreases in total energy expenditure (P = 0.011), activity energy expenditure (P < 0.001), and physical activity level (P < 0.001). Time spent playing outdoors and walking to school were also significantly less in 2009 than 1999 (P < 0.001). Accelerometer-measured PA was significantly associated with the amount of time spent playing outdoors and walking to school.

Conclusions

These results indicate that elementary schoolchildren in 2009 spend less time playing outdoors and walking to school, perform less PA, and take fewer steps than children of a decade ago.

An Overview of the Complexities in Obesity

A recent survey, even one limited to human studies, found considerable “publication scatter” in that more than 250 different professional journals publish articles on obesity. Over the years, and particularly since the 1970s and 1980s when the so-called obesity epidemic began, there has been an explosion of clinical interest in a field that encompasses general medicine, pediatrics, surgery, psychiatry, and almost every subspecialty. And rightly so, since even by 2008, there were an estimated 1.46 billion adults worldwide who were overweight, and of these, 502 million were in the obese category, all of which translate into major public health consequences. Despite many highly publicized studies, why do we not have a greater understanding about obesity than we do? It is certainly not from a lack of trying. This article presents an overview of the limitations and challenges, that is, complexities, due to discrepant frameworks and diverse conceptualizations of obesity; potential flaws inherent in its clinical studies; and particularly, impediments due to difficulties in the measurement of body composition (and particularly adipose accumulation), food intake, and physical activity, as well as to notoriously inaccurate self-reporting by subjects. As a result, clinicians remain limited in issuing recommendations to their patients.

An evaluation of energy expenditure estimation by three activity monitors

A comparative evaluation of the ability of activity monitors to predict energy expenditure (EE) is necessary to aid in the investigation of the effect of EE on health. The purpose of this study was to validate and compare the RT3, the SWA and the IDEEA at measuring EE in adults and children. Twenty-six adults and 22 children completed a resting metabolic rate (RMR) test and performed four treadmill activities at 3 km.h(-1), 6 km.h(-1), 6 km.h(-1) at a 10% incline, 9 km.h(-1). EE was assessed throughout the protocol by the RT3, the SWA and the IDEEA. Indirect calorimetry (IC) was used as a criterion measure of EE against which each monitor was compared. Mean bias was assessed by subtracting EE from IC from EE from each monitor for each activity. Limit of agreement plots were used to assess the agreement between each monitor and IC. Limits of agreement for resting EE were narrowest for the RT3 for adults and children. Although the IDEEA displayed the smallest mean bias between measures at 3 km.h(-1), 6 km.h(-1) and 9 km.h(-1) in adults and children, the SWA agreed closest with IC at 6 km.h(-1), 6 km.h(-1) at a 10% incline and 9 km.h(-1). Limits of agreement were closest for the SWA at 9 km.h(-1) in adults representing 42% of the overall mean EE. Although the RT3 provided the best estimate of resting EE in adults and children, the SWA provided the most accurate estimate of EE across a range of physical activity intensities.

Inconspicuous assessment of diet-induced thermogenesis using whole-body indirect calorimetry

We report a novel technique for computing diet-induced thermogenesis using data from 24-h respiration chamber measurements of 76 subjects. Physical activity (PA) was determined using a radar system to assess its duration and an accelerometer to evaluate its intensity. The regression line relating PA and energy expenditure facilitated calculation of the integrated thermogenic response to the total energy ingested (11.4% ± 3.8%), which is consistent with the values classically reported in the literature (10%) at the group level.

American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise

The purpose of this Position Stand is to provide guidance to professionals who counsel and prescribe individualized exercise to apparently healthy adults of all ages. These recommendations also may apply to adults with certain chronic diseases or disabilities, when appropriately evaluated and advised by a health professional. This document supersedes the 1998 American College of Sports Medicine (ACSM) Position Stand, "The Recommended Quantity and Quality of Exercise for Developing and Maintaining Cardiorespiratory and Muscular Fitness, and Flexibility in Healthy Adults." The scientific evidence demonstrating the beneficial effects of exercise is indisputable, and the benefits of exercise far outweigh the risks in most adults. A program of regular exercise that includes cardiorespiratory, resistance, flexibility, and neuromotor exercise training beyond activities of daily living to improve and maintain physical fitness and health is essential for most adults. The ACSM recommends that most adults engage in moderate-intensity cardiorespiratory exercise training for ≥30 min·d on ≥5 d·wk for a total of ≥150 min·wk, vigorous-intensity cardiorespiratory exercise training for ≥20 min·d on ≥3 d·wk (≥75 min·wk), or a combination of moderate- and vigorous-intensity exercise to achieve a total energy expenditure of ≥500-1000 MET·min·wk. On 2-3 d·wk, adults should also perform resistance exercises for each of the major muscle groups, and neuromotor exercise involving balance, agility, and coordination. Crucial to maintaining joint range of movement, completing a series of flexibility exercises for each the major muscle-tendon groups (a total of 60 s per exercise) on ≥2 d·wk is recommended. The exercise program should be modified according to an individual's habitual physical activity, physical function, health status, exercise responses, and stated goals. Adults who are unable or unwilling to meet the exercise targets outlined here still can benefit from engaging in amounts of exercise less than recommended. In addition to exercising regularly, there are health benefits in concurrently reducing total time engaged in sedentary pursuits and also by interspersing frequent, short bouts of standing and physical activity between periods of sedentary activity, even in physically active adults. Behaviorally based exercise interventions, the use of behavior change strategies, supervision by an experienced fitness instructor, and exercise that is pleasant and enjoyable can improve adoption and adherence to prescribed exercise programs. Educating adults about and screening for signs and symptoms of CHD and gradual progression of exercise intensity and volume may reduce the risks of exercise. Consultations with a medical professional and diagnostic exercise testing for CHD are useful when clinically indicated but are not recommended for universal screening to enhance the safety of exercise.