Patterns of physical activity in free-living adults in the Southern United States

Perceived Social Support and Sustained Physical Activity During the COVID-19 Pandemic

BACKGROUND

COVID-19 lockdown introduced substantial barriers to physical activity, providing a unique 'natural experiment' to understand the social factors associated with sustained physical activity. The objectives of this study were to identify the proportion of people who successfully sustained physical activity during lockdown and to explore whether social support, loneliness and social isolation were associated with maintenance of physical activity during COVID-19 lockdown.

METHOD

Longitudinal data from 16,980 participants, mean age 51.3 years (SD = 14.3) from the COVID-19 Social Study was used to identify a sample of participants who maintained their physical activity despite lockdown.

RESULTS

Seventeen percent were consistently active whilst 42% were completely inactive. After adjustment for multiple confounders, high social support was associated with a 64% (95% CI 50-80%) increased odds of sustaining physical activity and medium social support was associated with 32% (95% CI 20-44%) increased odds. Associations between physical activity and loneliness and social isolation were not found.

CONCLUSION

This study supports previous research showing the importance of social support for the long-term maintenance of physical activity behaviour but shows that such effects extend to contexts of social restrictions.

What Is the Impact of Energy Expenditure on Energy Intake?

Coupling energy intake (EI) to increases in energy expenditure (EE) may be adaptively, compensatorily, or maladaptively leading to weight gain. This narrative review examines if functioning of the homeostatic responses depends on the type of physiological perturbations in EE (e.g., due to exercise, sleep, temperature, or growth), or if it is influenced by protein intake, or the extent, duration, timing, and frequency of EE. As different measures to increase EE could convey discrepant neuronal or humoral signals that help to control food intake, the coupling of EI to EE could be tight or loose, which implies that some ways to increase EE may have advantages for body weight regulation. Exercise, physical activity, heat exposure, and a high protein intake favor weight loss, whereas an increase in EE due to cold exposure or sleep loss likely contributes to an overcompensation of EI, especially in vulnerable thrifty phenotypes, as well as under obesogenic environmental conditions, such as energy dense high fat—high carbohydrate diets. Irrespective of the type of EE, transient elevations in the metabolic rate seem to be general risk factors for weight gain, because a subsequent decrease in energy requirement is not compensated by an adequate adaptation of appetite and EI.

Gait Patterns and Mood in Everyday Life: A Comparison Between Depressed Patients and Non-depressed Controls

Background

Previous laboratory findings suggest deviant gait characteristics in depressed individuals (i.e., reduced walking speed and vertical up-and-down movements, larger lateral swaying movements, slumped posture). However, since most studies to date assessed gait in the laboratory, it is largely an open question whether this association also holds in more naturalistic, everyday life settings. Thus, within the current study we (1) aimed at replicating these results in an everyday life and (2) investigated whether gait characteristics could predict change in current mood.

Methods

We recruited a sample of patients (n = 35) suffering from major depressive disorder and a sample of age and gender matched non-depressed controls (n = 36). During a 2-day assessment we continuously recorded gait patterns, general movement intensity and repetitively assessed the participant’s current mood.

Results

We replicated previous laboratory results and found that patients as compared to non-depressed controls showed reduced walking speed and reduced vertical up-and-down movements, as well as a slumped posture during everyday life episodes of walking. Moreover, independent of clinical diagnoses, higher walking speed, and more vertical up-and-down movements significantly predicted more subsequent positive mood, while changes in mood did not predict subsequent changes in gait patterns.

Conclusion

In sum, our results support expectations that embodiment (i.e., the relationship between bodily expression of emotion and emotion processing itself) in depression is also observable in naturalistic settings, and that depression is bodily manifested in the way people walk. The data further suggest that motor displays affect mood in everyday life.

Padrão de utilização de espaços públicos abertos e nível de atividade física em São José dos Pinhais, Paraná

RESUMO O objetivo deste estudo foi analisar a associação entre o padrão de utilização de espaços públicos abertos (EPA) e o nível de atividade física (AF) de intensidade moderada a vigorosa (AFMV) em São José dos Pinhais, Paraná. Sexo, faixa etária e AF foram identificados com o System for Observing Play and Recreation in Communities (SOPARC). A AFMV foi analisada considerando as categorias de sexo, local, dia da semana, horário e período. Foram realizadas 2.591 observações de pessoas e a proporção de AFMV foi de 35%. O sexo feminino apresentou associação positiva com a AFMV (OR: 1,57; IC95%: 1,32-1,86), enquanto a utilização dos EPA no final de semana (OR: 0,55; IC95%: 0,46-0,65) e no período da tarde apresentou associação inversa com o desfecho (OR: 0,57; IC95%: 0,48-0,67). Conclui-se que mulheres e aqueles que utilizam os locais durante a semana ou pela manhã apresentam maiores chances de praticarem AFMV.

Relationship Between Weekly Patterns of Caloric Intake and Reported Weight Loss Outcomes: Retrospective Cohort Study

BACKGROUND

Although millions of overweight and obese adults use mobile phone apps for weight loss, little is known about the predictors of success.

OBJECTIVE

The objective of this study was to understand the relationship between weight loss outcomes and weekly patterns of caloric intake among overweight and obese adults using a mobile phone app for weight loss.

METHODS

We examined the relationship between weekly patterns of caloric intake and weight loss outcomes among adults who began using a weight loss app in January 2016 and continued consistent use for at least 5 months (N=7007). Unadjusted and adjusted linear regression analyses were used to evaluate the predictors of percentage of bodyweight lost for women and men separately, including age, body mass index category, weight loss plan, and difference in daily calories consumed on weekend days (Saturday and Sunday) versus Monday.

RESULTS

In adjusted linear regression, percentage of bodyweight lost was significantly associated with age (for women), body mass index (for men), weight loss plan, and differences in daily caloric intake on Mondays versus weekend days. Compared with women consuming at least 500 calories more on weekend days than on Mondays, those who consumed 50 to 250 calories more on weekend days or those with balanced consumption (±50 calories) lost 1.64% more and 1.82% more bodyweight, respectively. Women consuming 250 to 500 calories or more than 500 calories more on Mondays than on weekend days lost 1.35% more and 3.58% more bodyweight, respectively. Compared with men consuming at least 500 calories more on weekend days than on Mondays, those consuming 250 to 500 calories or more than 500 calories more on Mondays than on weekend days lost 2.27% and 3.42% less bodyweight, respectively.

CONCLUSIONS

Consistent caloric intake on weekend days and Mondays or consuming slightly fewer calories per day on Mondays versus weekend days was associated with more successful weight loss.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03136692; https://clinicaltrials.gov/ct2/show/NCT03136692 (Archived by WebCite at http://www.webcitation.org/6y9JvHya4).

Does replacing sedentary behaviour with light or moderate to vigorous physical activity modulate inflammatory status in adults?

BACKGROUND

Sedentary behaviour, obesity and insulin resistance are associated with pro-inflammatory status. Limited data on whether physical activity modulates inflammatory status and counteracts obesity and insulin resistance associated low-grade inflammation exist. Our objective was to investigate associations between objectively measured physical activity and inflammatory status, and specifically whether substituting daily sedentary behaviour with light activity or moderate to vigorous physical activity (MVPA), is associated with beneficial alterations to the inflammatory profile among middle-aged adults and those at increased cardiometabolic risk (obese and insulin resistant subjects).

METHODS

Data are from a sub-sample of the Mitchelstown cohort; a population-based cross-sectional sample of 2047 Irish adults. Physical activity intensity and duration were measured in 396 participants for 7-consecutive days using the GENEActiv accelerometer. Isotemporal regression analysis examined the associations between replacing 30 min per day of sedentary behaviour with equal amounts of light activity and MVPA on inflammatory factors (serum acute-phase reactants, adipocytokines, pro-inflammatory cytokines and white blood cells (WBC)).

RESULTS

Reallocating 30 min of sedentary time with MVPA was associated with a more favourable inflammatory profile characterized by higher adiponectin and lower complement component C3 (C3), leptin, interleukin 6 (IL-6) and WBC concentrations (P < 0.05). No significant effects were noted with substitution of sedentary time with light activity. Among the obese subjects replacing sedentary behaviour with an equivalent amount of MVPA was associated with lower WBC counts (P < 0.05); no associations were detected among the insulin resistant (HOMA-IR >75th percentile) subjects. Among the non-obese and non-insulin resistant subjects substituting 30 min of sedentary behaviour with MVPA was associated with decreased C3, IL-6 and WBC concentrations.

CONCLUSIONS

Replacing sedentary behaviour with MVPA modulates pro-inflammatory status. These findings, which highlight the need for the developing randomized trials aimed at lowering cardiometabolic risk, warrant further investigation.

One-year assessment of physical activity level in adult Qatari females: a pedometer-based longitudinal study

BACKGROUND

Physical inactivity is a growing health concern and has been identified as the fourth leading risk factor for global mortality. The Arab region includes countries with some of the world's highest physical inactivity levels, such as Qatar, more specifically the Qatari female population.

OBJECTIVE

The objective of this study is to assess the physical activity levels of Qatari national female adults during a 1-year pedometer-based program.

MATERIALS AND METHODS

A total of 549 Qatari national females aged between 18 years and 64 years were included. Data extracted from "Step into Health" program web database in Qatar were used for analyses. Daily habitual physical activity (daily total step count and aerobic steps) was assessed through the Omron HJ-324U pedometer. Step counts were classified as follows: <5,000 steps/d, sedentary; 5,000-7,499 steps/d, low active; and ≥7,500 steps/d, physically active. Statistical significance was set at P-value ≤0.05. Descriptive statistics were used, and habitual physical activity was calculated through repeated measures analysis of variance to determine the difference across the monitored days.

RESULTS

Mean age was 37.4±11.7 years, and median body mass index of 28.8 kg/m(2) (interquartile range 24.8-33.5). Daily steps for the overall population ranged from 3,505 steps/d to 10,010 steps/d, with a median of 6,008 steps/d. A total of 242 (44.1%) females were sedentary, 178 (32.4%) were low active, and 129 (23.5%) were physically active. The physically active group showed a median of 927 aerobic steps/d (interquartile range 0-4,248).

CONCLUSION

Based on the results of this study, Qatari females are not meeting the global recommendations of physical activity. Future research might need to consider barriers to physical activity as well as social, cultural, and environmental factors.

The Association of Physical Activity during Weekdays and Weekend with Body Composition in Young Adults

Physical activity (PA) is a key contributor in long-term weight management but there remains limited research on the association between weekly PA patterns and weight change. The purpose of the present study was to examine the prospective association between weekly PA patterns and weight change in generally healthy young adults. Anthropometric measurements, including dual X-ray absorptiometry, were obtained every 3 months over a period of one year in 338 adults (53% male). At each measurement time, participants wore a multisensor device for a minimum of 10 days to determine total daily energy expenditure and time spent sleeping, sedentary, in light PA (LPA), in moderate PA (MPA), and in vigorous PA (VPA). PA did not differ between weekdays and the weekend at baseline. Twenty-four-hour sleep time, however, was significantly longer during weekends compared to weekdays, which was associated with less time spent sedentary. Weight loss was associated with a significant increase in LPA at the expense of sedentary time during the weekend but not during weekdays. Regression analyses further revealed an inverse association between change in VPA during the weekend and body composition at 12-month follow-up. Taken together, these results suggest that weekend PA plays an important role in long-term weight management.

Socio-demographic correlates of leisure time physical activity among Portuguese adults

This study aimed to identify socio-demographic correlates of leisure time physical activity among Portuguese adults. Subjects aged 31-60 years (1,076 males, 1,383 females) were categorized into two groups according to recommended physical activities ranging from ≥ 10 or < 10 MET.hours.week-1. Leisure time physical activity data was self-reported, including activities, duration of each session and frequency. Chi-square and logistic regression analyses were applied to the results. Among men, having a high socioeconomic status (OR = 1.89; 95%CI: 1.30-2.76; p = 0.001) was associated with attaining the recommended level of physical activity. For women, middle education levels were associated with physical activity (OR = 1.36; 95%CI: 1.01-1.85). Moreover, middle socioeconomic status (OR = 1.45; 95%CI: 0.80-1.91; p = 0.009) was also positively associated with meeting physical activities recommendations in the unadjusted analysis. Men and women had different patterns of socio-demographic correlates. An intervention designed to improve the levels of physical activity among Portuguese adults may take these correlates into account.

Profile of energy expenditure in people with rheumatoid arthritis

BACKGROUND

No definitive conclusions have been made on the levels of physical activity in the rheumatoid arthritis (RA) population. Similarly no clear consensus has been reached on the correlates and predictors of physical activity in the population.

OBJECTIVE

To profile total energy expenditure (TEE), resting energy expenditure (REE) and physical activity related energy expenditure (PAEE) levels using a validated objective measurement tool and to determine demographic and health related factors which influence and predict TEE and PAEE levels in individuals with RA.

METHODS

Fifty nine (41 female, 18 male) individuals with RA were recruited to this cross sectional study. Energy expenditure was measured over seven days using SenseWear Armband. Correlational analysis and logistic regression were used to examine the relationship between demographic and health related factors and TEE, REE and PAEE.

RESULTS

A profile of energy expenditure in RA individuals was developed in terms of levels, differences between genders and differences between weekdays and weekend days. Median TEE, PAEE and REE were 2204.0, 409.5 and 1506.2 kcal/day respectively. Energy expenditure was associated with factors such as gender, age, body mass index, employment status, disease severity and smoking.

CONCLUSION

The findings add to the growing research assessing energy expenditure in the RA population and strengthen the position due to the use of an objective validated tool. Some recommendations on what factors are associated with energy expenditure in the RA population are made, thus unveiling ways to tailor physical activity type interventions in this group.

Separating bedtime rest from activity using waist or wrist-worn accelerometers in youth

Recent interest in sedentary behavior and technological advances expanded use of watch-size accelerometers for continuous monitoring of physical activity (PA) over extended periods (e.g., 24 h/day for 1 week) in studies conducted in natural living environment. This approach necessitates the development of new methods separating bedtime rest and activity periods from the accelerometer recordings. The goal of this study was to develop a decision tree with acceptable accuracy for separating bedtime rest from activity in youth using accelerometer placed on waist or wrist. Minute-by-minute accelerometry data were collected from 81 youth (10-18 years old, 47 females) during a monitored 24-h stay in a whole-room indirect calorimeter equipped with a force platform covering the floor to detect movement. Receiver Operating Characteristic (ROC) curve analysis was used to determine the accelerometer cut points for rest and activity. To examine the classification differences, the accelerometer bedtime rest and activity classified by the algorithm in the development group (n = 41) were compared with actual bedtime rest and activity classification obtained from the room calorimeter-measured metabolic rate and movement data. The selected optimal bedtime rest cut points were 20 and 250 counts/min for the waist- and the wrist-worn accelerometer, respectively. The selected optimal activity cut points were 500 and 3,000 counts/min for waist and wrist-worn accelerometers, respectively. Bedtime rest and activity were correctly classified by the algorithm in the validation group (n = 40) by both waist- (sensitivity: 0.983, specificity: 0.946, area under ROC curve: 0. 872) and wrist-worn (0.999, 0.980 and 0.943) accelerometers. The decision tree classified bedtime rest correctly with higher accuracy than commonly used automated algorithm for both waist- and wrist-warn accelerometer (all p<0.001). We concluded that cut points developed and validated for waist- and wrist-worn uniaxial accelerometer have a good power for accurate separation of time spent in bedtime rest from activity in youth.

Weight rhythms: weight increases during weekends and decreases during weekdays

BACKGROUND/AIMS

The week's cycle influences sleep, exercise, and eating habits. An accurate description of weekly weight rhythms has not been reported yet - especially across people who lose weight versus those who maintain or gain weight.

METHODS

The daily weight in 80 adults (BMI 20.0-33.5 kg/m(2); age, 25-62 years) was recorded and analysed to determine if a group-level weekly weight fluctuation exists. This was a retrospective study of 4,657 measurements during 15-330 monitoring days. Semi-parametric regression was used to model the rhythm.

RESULTS

A pattern of daily weight changes was found (p < 0.05), with higher weight early in the week (Sunday and Monday) and decreasing weight during the week. Increases begin on Saturday and decreases begin on Tuesday. This compensation pattern was strongest for those who lost or maintained weight and weakest for those who slowly gained weight.

CONCLUSION

Weight variations between weekends and weekdays should be considered as normal instead of signs of weight gain. Those who compensate the most are most likely to either lose or maintain weight over time. Long-term habits may make more of a difference than short-term splurges. People prone to weight gain could be counselled about the importance of weekday compensation.

Energy balance and obesity: a UK perspective on the gluttonyv.sloth debate

Obesity in the UK was assumed to have developed against a population decline in physical activity, with health messages focused on diet and exercise prevention strategies. Doubly-labelled water (DLW) studies of energy expenditure have indicated the alternative scenario that the increased obesity prevalence reflects excessive food energy intake with physical activity levels unchanged. This analysis is questionable, deriving in part from a weakness of the DLW methodology in identifying changing physical activity levels within populations of increasing body weight. This has resulted in an underestimation of the reduction in physical activity in the overweight and obese, as revealed by direct studies of such behaviour. Furthermore, a close examination of food energy supply, household food purchases and individual food energy consumption since 1955, in relation to likely estimates of current intakes indicated by simple modelling of predicted energy expenditure, identifies: (a) food energy supply as markedly overestimating energy intakes; (b) individual food energy consumption as markedly underestimating energy intakes; and (c) household food purchase data as the closest match to predicted current food energy intakes. Energy intakes indicated by this latter method have fallen by between 20 to 30 %, suggesting comparable falls in physical activity. Although unequivocal evidence for a matching UK trend in falling physical activity is limited, as is evidence that obesity follows reductions in physical activity, such a link has been recently suggested in a large prospective study in adolescents. Thus, for the UK, obesity has developed within a ‘move less–eat somewhat less but still too much’ scenario. A focus on both diet and exercise should remain the appropriate public health policy.

Physical activity in the lifestyle of Czech university students: Meeting health recommendations

The decline of physical activity (PA) in adults as well as children and youth is a worldwide phenomenon. The aim of this study is to analyse the amount of PA in Czech university students’ daily lives. The research on university students was conducted as part of nationwide research on PA in the adult population of the Czech Republic. A total of 906 students at eight selected universities were asked to participate in this study. The response rate was 79.5%. We analysed data from 641 university students: 318 male [mean age 21.63 ± 1.73; mean Body Mass Index (BMI) 23.50 ± 1.91] and 323 female (mean age 21.08 ± 1.53; mean BMI 21.23 ± 2.20). The students wore Yamax SW-701 pedometers continuously for seven days. With respect to BMI, the recommendation of 10,000 steps per day on an average day was met by 76% of men and 68% of women of normal weight, 67% of male students who were overweight or obese and 85% of female students who were overweight or obese. Of all monitored days, in both females and males, the number of steps taken on Sunday was significantly lower (p < 0.0001) in comparison to other days of a week. No significant differences were found in the number of steps taken among students of normal weight, students who were overweight and students who were obese on any of the monitored days. The majority of Czech male university students are of normal weight. Only 9% of students meet the criterion of 10,000 steps every day. Approximately two-thirds of students meet the 10,000 steps daily criterion on four or more days per week. The lowest number of steps is taken on Sundays; this finding supports the need for intervention programmes to enhance PA on weekends.

Assessment of wear/nonwear time classification algorithms for triaxial accelerometer

PURPOSE

The objective of this study is to assess the performance of existing wear/nonwear time classification algorithms for accelerometry data collected in the free-living environment using a wrist-worn triaxial accelerometer and a waist-worn uniaxial accelerometer in older adults.

METHODS

Twenty-nine adults age 76 to 96 yr wore wrist accelerometers for approximately 24 h per day and waist accelerometers during waking for approximately 7 d of free living. Wear and nonwear times were classified by existing algorithms (Alg([ActiLife]), Alg([Troiano]), and Alg([Choi])) and compared with wear and nonwear times identified by data plots and diary records. With the use of bias and probability of correct classification, the performance of the algorithms, two time windows (60 and 90 min), and vector magnitude (VM) versus vertical axis (V) counts from a triaxial accelerometer were compared.

RESULTS

Automated algorithms (Alg([Choi]) and Alg([Troiano])) classified wear/nonwear time intervals more accurately from VM than V counts. The use of the 90-min time window improved wear/nonwear classification accuracy when compared with the 60-min window. The Alg([Choi]) and Alg([Troiano]) performed better than the manufacturer-provided algorithm (Alg([ActiLife])), and the Alg([Choi]) performed better than the Alg([Troiano]) for wear/nonwear time classification using the data collected by both accelerometers.

CONCLUSIONS

Triaxial wrist-worn accelerometer can be used for an accurate wear/nonwear time classification in free-living older adults. The use of the 90-min window and the VM counts improves the performance of commonly used algorithms for wear/nonwear classification for both uniaxial and triaxial accelerometers.

Comparison of variations between percentage of body fat, body mass index and daily physical activity among young Japanese and Thai female students

Background

In our series of investigations concerning the causes of seasonal change in fat accumulation in young university students, we could not find any contribution of seasonal variation in the ratio of carbohydrate and fat metabolism to that of body fat percentage in Japanese and Thai participants. After our previous study, we examined the effect of daily physical activity on body fat percentage to look for the major causes of seasonal change in fat accumulation in young university students.

Findings

In this study, we measured participants’ (young Japanese and Thai university students) daily physical activity by a uniaxial accelerometer in addition to the measurements of body fat percentage and body mass index by a bioelectrical impedance meter. We found that there was significant and moderate negative correlation between body fat percentage and daily step counts among Japanese but not Thai participants. We observed significant, moderate and positive correlations between the percentage of body fat and body mass index among Japanese and Thai participants.

Conclusions

Daily physical activity plays an important role in the seasonal variation of body fat percentage of Japanese female students. Our present study also confirmed the importance of daily physical activity for controlling body mass index and for the prevention of obesity.

Variability in physical activity patterns as measured by the SenseWear Armband: how many days are needed?

To examine sources of variance in objectively measured physical activity and to determine the number of monitoring days needed to quantify physical activity patterns reliably, 394 Flemish adults (41.1 ± 9.9 years) were monitored during 7 days, using the SenseWear Armband. Differences between weekdays, Saturday and Sunday were examined with repeated measures ANOVA's. Variance components were estimated for subject, weekday and residual error using data from Mondays through Fridays and used to calculate the reliability of 1-5 monitoring weekdays. Saturday was more and Sunday less active than an average weekday. Inter-individual variability was the largest source of variance (54.4-67.9%) for physical activity level (PAL), energy expenditure, inactivity, light, moderate and total physical activity. Intra-individual variability accounted for 31.8-44.8% and weekday for 0.1-1.1% of total variance. Intra-individual variability was the largest source of variance for vigorous activity in both sexes and steps in women. At least, 3 monitoring weekdays were required to achieve a reliability of 0.80 for PAL, energy expenditure, inactivity, light, moderate and total physical activity. All 5 weekdays should be monitored to reach acceptable reliability for steps. Five weekdays resulted in a reliability of 0.58-0.60 for vigorous activity. Both Saturday and Sunday and at least 3 weekdays need to be monitored to obtain reliable measures of habitual physical activity.

Evaluation of a questionnaire to assess sedentary and active behaviors in the Southern Community Cohort Study

BACKGROUND

Low physical activity (PA) is linked to cancer and other diseases prevalent in racial/ethnic minorities and low-income populations. This study evaluated the PA questionnaire (PAQ) used in the Southern Cohort Community Study, a prospective investigation of health disparities between African-American and white adults.

METHODS

The PAQ was administered upon entry into the cohort (PAQ1) and after 12-15 months (PAQ2) in 118 participants (40-60 year-old, 48% male, 74% African-American). Test-retest reliability (PAQ1 versus PAQ2) was assessed using Spearman correlations and the Wilcoxon signed rank test. Criterion validity of the PAQ was assessed via comparison with a PA monitor and a last-month PA survey (LMPAS), administered up to 4 times in the study period.

RESULTS

The PAQ test-retest reliability ranged from 0.25-0.54 for sedentary behaviors and 0.22-0.47 for active behaviors. The criterion validity for the PAQ compared with PA monitor ranged from 0.21-0.24 for sedentary behaviors and from 0.17-0.31 for active behaviors. There was general consistency in the magnitude of correlations between the PAQ and PA-monitor between African-Americans and whites.

CONCLUSIONS

The SCCS-PAQ has fair to moderate test-retest reliability and demonstrated some evidence of criterion validity for ranking participants by their level of sedentary and active behaviors.

Validation of accelerometer wear and nonwear time classification algorithm

INTRODUCTION

the use of movement monitors (accelerometers) for measuring physical activity (PA) in intervention and population-based studies is becoming a standard methodology for the objective measurement of sedentary and active behaviors and for the validation of subjective PA self-reports. A vital step in PA measurement is the classification of daily time into accelerometer wear and nonwear intervals using its recordings (counts) and an accelerometer-specific algorithm.

PURPOSE

the purpose of this study was to validate and improve a commonly used algorithm for classifying accelerometer wear and nonwear time intervals using objective movement data obtained in the whole-room indirect calorimeter.

METHODS

we conducted a validation study of a wear or nonwear automatic algorithm using data obtained from 49 adults and 76 youth wearing accelerometers during a strictly monitored 24-h stay in a room calorimeter. The accelerometer wear and nonwear time classified by the algorithm was compared with actual wearing time. Potential improvements to the algorithm were examined using the minimum classification error as an optimization target.

RESULTS

the recommended elements in the new algorithm are as follows: 1) zero-count threshold during a nonwear time interval, 2) 90-min time window for consecutive zero or nonzero counts, and 3) allowance of 2-min interval of nonzero counts with the upstream or downstream 30-min consecutive zero-count window for detection of artifactual movements. Compared with the true wearing status, improvements to the algorithm decreased nonwear time misclassification during the waking and the 24-h periods (all P values < 0.001).

CONCLUSIONS

the accelerometer wear or nonwear time algorithm improvements may lead to more accurate estimation of time spent in sedentary and active behaviors.

Type of activity pacing instruction affects physical activity variability in adults with symptomatic knee or hip osteoarthritis

BACKGROUND

In a previous pilot study, the effect of 2 types of activity pacing instruction, general versus tailored, on osteoarthritis symptoms was examined and fatigue improved in the tailored group. Because activity pacing involves instruction on physical activity engagement, we undertook this secondary analysis to examine how pacing instruction affected physical activity patterns.

METHODS

Thirty-two adults with knee or hip osteoarthritis, stratified by age and gender, received either tailored or general activity pacing instruction. All participants wore an accelerometer for 5 days that measured physical activity and allowed for repeated symptom assessment at baseline and 10-week follow-up. Activity patterns were assessed by examining physical activity variability (standard deviation of 5-day average activity counts per minute), and average activity level (5-day average activity counts per minute).

RESULTS

Physical activity variability decreased in the tailored group and increased in the general group. No significant group changes in average activity from baseline to 10-week follow-up were found.

CONCLUSION

In this pilot study, type of activity pacing instruction affected objective physical activity patterns in adults with OA. Tailored activity pacing was more effective at reducing high and low activity bouts corresponding to the message of keeping a steady pace to reduce symptoms.

Metabolic normality in overweight and obese subjects. Which parameters? Which risks?

OBJECTIVES

The objective of this study was to define metabolic normality and to investigate the cardiometabolic profile of metabolically normal obese.

DESIGN

Cross-sectional study conducted at 21 research centers in Europe.

SUBJECTS

Normal body weight (nbw, n=382) and overweight or obese (ow/ob, n=185) subjects free from metabolic syndrome and with normal glucose tolerance, were selected among the Relationship between Insulin Sensitivity and Cardiovascular Disease study participants.

MAIN OUTCOME MEASURES

Insulin sensitivity was assessed by the clamp technique. On the basis of quartiles in nbw subjects, the limits of normal insulin sensitivity and of normal fasting insulinemia were established. Subjects with normal insulin sensitivity and fasting insulin were defined as metabolically normal.

RESULTS

Among ow/ob subjects, 11% were metabolically normal vs 37% among nbw, P<0.0001. Ow/ob subjects showed increased fasting insulin (P=0.0009), low-density lipoprotein cholesterol (LDL-cholesterol) (P=0.004), systolic (P=0.0007) and diastolic (P=0.001) blood pressure, as compared with nbw. When evaluating the contribution of body mass index (BMI), hyperinsulinemia and insulin resistance, BMI showed an isolated effect on high-density lipoprotein (P=0.007), high-sensitivity C-reactive protein (P<0.0001), systolic (P=0.002) and diastolic (P=0.008) blood pressures. BMI shared its influence with insulinemia on total cholesterol (P=0.04 and 0.003, respectively), LDL-cholesterol (P=0.003 and 0.006, respectively) and triglycerides (P=0.02 and 0.001, respectively).

CONCLUSION

In obese subjects, fasting insulin should be taken into account in the definition of metabolic normality. Even when metabolically normal, obese subjects could be at increased risk for cardiometabolic diseases. Increased BMI, alone or with fasting insulin, is the major responsible for the less favorable cardio-metabolic profile.

How children move: activity pattern characteristics in lean and obese chinese children

Physical activity and sedentary behavior are central components of lifetime weight control; however, our understanding of dimensions of these behaviors in childhood is limited. This study investigated free-living activity pattern characteristics and the individual variability of these characteristics in 84 lean and obese Chinese children (7-9 y) during the school day and over the weekend. Activity pattern characteristics were established from triaxial accelerometry (StayHealthy RT3). Results indicated that children's free-living activity is characterized by many short-duration, low-intensity bouts of movement. Obese children take longer rest intervals between bouts and engage in fewer activity bouts both at school and at home. Intraindividual variability in activity patterns was low during school days but high for the rest intervals between bouts and number of activity bouts per day at the weekend. Finding ways to reduce the rest time between bouts of movement and increase the number of movement bouts a child experiences each day is an important next step.

Physical activity and obesity gap between black and white women in the southeastern U.S

BACKGROUND

Differences between black and white women in the associations of sedentary and active behaviors and obesity are mostly unknown.

PURPOSE

To examine associations of sedentary and active behaviors with BMI, a marker of overall obesity, in a large group of black and white women and to determine whether there are differences by race in these associations.

METHODS

Associations between time spent in sedentary and active behaviors and BMI were examined using cross-sectional data collected from 2002 to 2006 at enrollment into the Southern Community Cohort Study (SCCS) from 22,948 black and 7830 white women living in the southeastern U.S. These associations were examined using linear and polytomous logistic regression models controlling for age, race, income, education, occupational status, tobacco use, marital status, and comorbidities.

RESULTS

Time spent in sedentary behaviors was directly related to BMI whereas time spent in active behaviors such as moderate and vigorous physical activity was inversely related to BMI, with stronger associations for whites than blacks. White women in the highest quartile of sedentary behaviors were more likely to be moderately (BMI=30-39) or severely (BMI>40) obese than women in the lowest quartile (OR=2.3, 95% CI=1.8, 2.9 for moderate, and OR=4.0, 95% CI=3.1, 5.3 for severe obesity), whereas the ORs among similarly sedentary black women were modestly elevated (ORs of 1.4, 95% CI=1.2, 1.6; and 1.6, 95% CI=1.4, 1.8).

CONCLUSIONS

There are significant differences in the association of physical activity patterns and obesity between black and white women living in the southeastern U.S. Although most guidelines for prevention of obesity and maintaining weight promote increased time in moderate and vigorous physical activity, these results indicate that a reduction in sedentary behavior time may represent another useful strategy in this population.

Seasonal changes in amount and patterns of physical activity in women

BACKGROUND

Environmental factors including seasonal changes are important to guide physical activity (PA) programs to achieve or sustain weight loss. The goal was to determine seasonal variability in the amount and patterns of free-living PA in women.

METHODS

PA was measured in 57 healthy women from metropolitan Nashville, TN, and surrounding counties (age: 20 to 54 years, body mass index: 17 to 48 kg/m2) using an accelerometer for 7 consecutive days during 3 seasons within 1 year. PA counts and energy expenditure (EE) were measured in a whole-room indirect calorimeter and used to model accelerometer output and to calculate daily EE and intensity of PA expressed as metabolic equivalents (METs).

RESULTS

PA was lower in winter than in summer (131+/-45 vs. 144+/-54x10(3) counts/d; P=.025) and in spring/fall (143+/-48x10(3) counts/d; P=.027). On weekends, PA was lower in winter than in summer by 22,652 counts/d (P=.008). In winter, women spent more time in sedentary activities than in summer (difference 35 min/d; P=.007) and less time in light activities (difference -29 min/d, P=.018) and moderate or vigorous activities (difference -6 min/d, P=.051).

CONCLUSIONS

Women living in the southeastern United States had lower PA levels in winter compared with summer and spring/fall, and the magnitude of this effect was greater on weekends than weekdays.

Physical activity and inactivity in an adult population assessed by accelerometry

INTRODUCTION

Strong evidence suggests a link between physical inactivity and chronic disease prevalence in the adult population. To target the right groups for interventions in a population, accurate assessment of physical activity is important. The objective of this study was to assess the levels and pattern of physical activity and inactivity in an adult population sample using an objective method.

METHODS

In total, 1114 adults (56% women, 45+/-15 yr), randomly recruited from the Swedish population across a year, used an accelerometer (Actigraph MTI) for seven consecutive days. Inactivity was defined as <100 counts per minute, and cutoff values for moderate and vigorous activity were 1952-5724 and >5724 counts per minute, respectively. Average intensity was measured as counts per minute.

RESULTS

The adults were active in at least moderate-intensity activity for a median (intraquartile range) of 31 (18-47) min.d(-1). Fifty-two percent accumulated 30 min.d(-1) of at least moderate-intensity physical activity. Only 1% achieved those 30 min from three or more bouts of at least 10 min. Average intensity, moderate and vigorous physical activity was lower with higher age or body mass index (BMI). Men spent more time than women in moderate and vigorous physical activity, but there was no gender difference in average intensity. The variation in inactivity could not be explained by gender, age, or BMI.

CONCLUSION

Objectively obtained estimates of physical activity yielded lower values and a different activity pattern compared with those obtained by commonly used self-reports. This highlights the need to better understand the nature and measurement issues of health-enhancing physical activity of adults.

A method to measure cervical spine motion over extended periods of time

STUDY DESIGN

System validation study.

OBJECTIVE

To develop and validate a motion sensor system for measuring cervical spine motion over extended time periods.

SUMMARY OF BACKGROUND DATA

Many studies using different methodologies have tried to estimate cervical spine motion. These have mostly been carried out in a laboratory setting performing active/passive range of motion or activities of daily living. However, cervical spine performance over extended periods of time in natural environments remains unknown.

METHODS

A novel motion sensor system, Wisconsin Analysis of Spine Motion Performance (WASP), was validated using 2 benchmarks: a materials testing machine (MTS) and optical motion tracking laboratory. Parameters tested included drift, frequency response, accuracy, effect of sensor orientation, and coupled motions. Applied motions from the MTS and measured motions in subject volunteers under various conditions were compared with WASP using correlation coefficients. Intersubject and intrasubject variability analyses for WASP were also performed.

RESULTS

The average WASP slopes for accuracy (compared with MTS) in flexion-extension, lateral bending, and axial rotation were 0.89, 0.93, and 0.38, respectively. The correlation coefficient was 0.99 in all cases. Compared with optical motion tracking, the WASP regression slopes were 1.1, 1.02, and 0.4 and the correlation coefficients were 0.98, 0.92, and 0.93 in the 3 axes of motion. Coupled motion was noted during all subject motions. WASP peak detection algorithm had a 0% error discounting boundary conditions.

CONCLUSION

WASP was accurate in flexion-extension and lateral bending. In axial rotation, WASP was less accurate. However, the system was highly reliable with low intersubject and intrasubject variability. WASP can be used in estimating cervical spine motion with high reliability while keeping in mind the decreased accuracy in measuring axial rotation.

Do children take the same number of steps every day?

The purpose of this study was to examine the day-to-day variability in pedometer-assessed physical activity (steps/day). A total of 1,443 children aged 6-12 years from the United States (195 boys, 254 girls), Sweden (257 boys, 252 girls), and Australia (229 boys, 256 girls) wore a pedometer for 4 consecutive weekdays. Repeated measures analysis of variance was used to examine daily differences in steps/day and the coefficient of variation (CV) was calculated for each individual to describe the day-to-day variability. Overall, mean steps/day were higher among boys (14,698 +/- 3,373 steps/day) than girls (12,086 +/- 2,929 steps/day). Significant differences were found between the 4 monitoring days for the entire sample; however, the absolute mean differences were small (55-958 steps) with an overall effect size of 0.01. This trend was apparent regardless of age, gender, and country. Individual CVs ranged from approximately 2 to 88% and the overall mean CV approximated 22%. An age-related increase in the mean CV was observed between 6- and 12-year-old children. The age x gender x country interaction was not significant (P > 0.05). These findings have implications toward the proper design, analysis, and interpretation of studies regarding physical activity among children. Beyond this aspect, our results lend insight into potential age-related biological mechanisms that may also influence daily levels and patterns of physical activity.

Profile of physical activity behaviors among Swedish women aged 56-75 years

The aim of this study was to assess profiles of physical activity (PA) behavior using accelerometers among middle-aged and elderly women in free-living conditions. A subset of 133 women aged 56-75 years from the population-based Swedish Mammography Cohort with valid accelerometer data was included in the analysis. The proportion of women who met the PA recommendation of accumulating 30 min of moderate-to-vigorous physical activity (MVPA), in either one continuous bout or several shorter bouts lasting 8-10 min, on five or more days/week was 31%. The precision of mean daily estimates of MVPA and of inactivity based on 7 days monitoring was 0.80 and 0.86, respectively. On average, participants spent 103 min/day on MVPA, but only about a third of that time was accumulated in the recommended pattern of bouts lasting at least 8-10 min. Obese women had, on average, one bout of MVPA less than normal-weight women (mean 3.6 bouts/day). The mean MVPA decreased 10 min/day with every 5-year increase in age. A low proportion of women accumulated MVPA in the pattern recommended for health benefits. The proportion would increase considerably if women maintained their current amount of MVPA but increased the duration of each bout of MVPA.

Physical activity patterns assessed by accelerometry in older people

Research into daily physical activity (PA) patterns of older adults (>or=70 years) has primarily relied on self-report. This study used accelerometry, an objective measure of minute-by-minute movement, to assess PA volume and intensity performed by older adults recruited to the Better Ageing project. Results were used to estimate the degree to which current health recommendations for PA were met. Participants [91 older females (OF) aged 76.0 +/- 4.0 years (mean +/- SD), 70 older males (OM) 76.3 +/- 3.9 years, 23 young females (YF) 26.8 +/- 4.1 years and 22 young males (YM) 27.0 +/- 4.2 years] wore an MTI actigraph model 7164 recording activity in 1-min epochs for 7 days. Only those with at least 5 days, and 10 h of actigraph data per day, were included in the analysis, using Caloric.Bas (CSA Inc. 1999) software and a tailored Microsoft Access 2000 macro. Mean counts min(-1) day(-1) were 37% lower for older adults than for young adults [OF 236.1 +/- 84.4 vs. YF 370.0 +/- 81.1 counts min(-1) day(-1) t(114) = -6.86, P < 0.001; OM 255.1 +/- 103.0 vs. YM 404.3 +/- 134.0 ct min(-1) day(-1), t(91) = -5.55, P < 0.001]. Older adults were more restricted in activity intensity range performing significantly fewer minutes of moderate to vigorous (MV) PA day(-1) than young adults [OF 16.7 +/- 12.2 vs. YF 38.4 +/- 18.4 MVPA min day(-1), t(114) = -6.90, P < 0.001; OM 23.8 +/- 20.0 vs. YM 40.4 +/- 19.2 MVPA min day(-1), t(91) = -3.47, P = 0.001]. Nearly half of older adults did not perform any sustained 10-min MVPA bouts (OF 48.4% vs. YF 13.0%, chi2 = 8.10, P = 0.004; OM 44.3% vs. YM 4.5%, chi2 = 9.97, P = 0.002), and none met current PA recommendations for health. This study is the first to provide objective data on a large sample of adults aged 70 years and over and indicates low levels of daily movement that are likely to be inadequate for optimal health benefit.

Within- and between-individual variability in estimated energy expenditure and habitual physical activity among young adults

OBJECTIVE

To examine the within- and between-individual variability in the estimated total energy expenditure (TEE) and habitual physical activity (PA) in free-living young adults. We were specifically interested in the day-to-day variation.

DESIGN

Cross-sectional.

SETTING

University.

SUBJECTS

A total of 277 (125 males, 152 females) participants aged 18-24 years.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Subjects recorded their daily PA with the Bouchard 3-day diary. Descriptive statistics for TEE, moderate-to-vigorous physical activity (MVPA), inactivity (IA), and activity energy expenditure (AEE) were calculated and presented as a frequency distribution. Within- and between-individual variability were tested by RMANOVA and also presented as the coefficient of variation (CV).

RESULTS

Mean values for TEE, MVPA, AEE, and IA were comparable between males and females; however, considerable between-individual variability existed. Only MVPA showed a significant difference between sexes (P<0.05), due to slightly greater vigorous PA in males compared to females (8.0 and 6.8 kcal/kg/day, respectively; P=0.12). Results from the RMANOVA revealed no significant day-to-day variability in any TEE or PA variable and the CVs were not significantly different between males and females. TEE and IA displayed mean CVs of approximately 12% while mean CVs for AEE and MVPA approximated 32 and 84%, respectively.

CONCLUSIONS

Results from this study suggest (1) a limited day-to-day variability in TEE and (2) a large degree of between-individual variation for TEE and PA exist. This study highlights the importance of understanding the variability associated with TEE, which is important for PA measurement and proper PA and nutritional recommendations.

SPONSORSHIP

None.

Accelerometer-Determined Physical Activity of Free-Living College Students

PURPOSE

This study was conducted to provide descriptive data of accelerometer-determined ambulatory physical activity in a sample of free-living college students and to examine college students' ambulatory physical activity patterns.

METHODS

All participants (245 females, age = 19.9 +/- 1.6 yr, body mass index (BMI) = 22.9 +/- 3.3 kg x m(-2); 209 males, age = 20.2 +/- 2.0 yr, BMI = 25.2 +/- 4.0 kg x m(-2)) wore an accelerometer for seven consecutive days. Accumulated physical activity (ct.d, ct x min(-1) x d(-1), and min x d(-1) spent at different intensities) and minutes per day spent in moderate or vigorous physical activity in sessions of at least 10 min were analyzed to describe the physical activity of the sample and examine physical activity patterns.

RESULTS

The entire sample accumulated 362,750.1 +/- 112,824.1 ct x d(-1) (males = 383,787.2 +/- 112,001.3 vs females = 344,804.1 +/- 110,619.5 ct x d(-1), P < 0.01) and 46.7 +/- 18.9 min x d(-1) in moderate physical activity (males = 51.7 +/- 19.8 vs females = 42.5 +/- 17.0 min x d(-1), P < 0.01). They were more active on weekdays than weekend days (P < 0.05), and they spent 13.6 +/- 12.7 min x d(-1) (males = 13.2 +/- 12.0 vs females = 13.8 +/- 13.3, P > 0.05) in moderate or vigorous physical activity sessions of at least 10 min.

CONCLUSION

Participants in this study accumulated a moderate amount of physical activity on most weekdays. Most participants, however, were not meeting the current moderate physical activity recommendation when moderate or vigorous physical activity sessions of at least 10 min were examined.

Planning to win: Health and lifestyles associated with physical activity amongst 15,423 adults

STUDY OBJECTIVE

To assess levels of physical activity in the general population and amongst the 'healthy', and to identify factors associated with this important health behaviour.

DESIGN

Population-based cross-sectional study.

SETTING

North-west England.

PARTICIPANTS

Adults (aged at least 18 years) registered with a general practitioner with a residential address within two local administrative districts (local authorities).

MAIN RESULTS

Less than one-third of adults performed adequate amounts of physical activity for health protection, and this differed little when analyses were restricted to 'healthy' people. Lower levels of physical activity were observed amongst women, older people, ethnic groups, those with obesity and in each increased quintile of social deprivation. Current smokers, but not previous smokers, were less likely to be physically active, as were those not eating at least five portions of fruit and vegetables per day. Lack of physical activity was associated with poor general health and a history of, or current, chronic disease.

CONCLUSIONS

Concerted efforts are required by the Government, society and individuals to overturn our predominantly physically inactive adult population. Interventions may be needed which specifically target certain groups, especially the most socially deprived, and that consider individuals and societal barriers to becoming physically active. Evidence of the effectiveness of individual and population-based interventions remains scant and this needs to be addressed urgently.

Accelerometer data reduction: a comparison of four reduction algorithms on select outcome variables

PURPOSE

Accelerometers are recognized as a valid and objective tool to assess free-living physical activity. Despite the widespread use of accelerometers, there is no standardized way to process and summarize data from them, which limits our ability to compare results across studies. This paper a) reviews decision rules researchers have used in the past, b) compares the impact of using different decision rules on a common data set, and c) identifies issues to consider for accelerometer data reduction.

METHODS

The methods sections of studies published in 2003 and 2004 were reviewed to determine what decision rules previous researchers have used to identify wearing period, minimal wear requirement for a valid day, spurious data, number of days used to calculate the outcome variables, and extract bouts of moderate to vigorous physical activity (MVPA). For this study, four data reduction algorithms that employ different decision rules were used to analyze the same data set.

RESULTS

The review showed that among studies that reported their decision rules, much variability was observed. Overall, the analyses suggested that using different algorithms impacted several important outcome variables. The most stringent algorithm yielded significantly lower wearing time, the lowest activity counts per minute and counts per day, and fewer minutes of MVPA per day. An exploratory sensitivity analysis revealed that the most stringent inclusion criterion had an impact on sample size and wearing time, which in turn affected many outcome variables.

CONCLUSIONS

These findings suggest that the decision rules employed to process accelerometer data have a significant impact on important outcome variables. Until guidelines are developed, it will remain difficult to compare findings across studies.