The association between accelerometer-measured patterns of sedentary time and health risk in children and youth: results from the Canadian Health Measures Survey

Sedentary Behavior and Cardiometabolic Markers in Adolescents: A 4-Year Longitudinal Study

PURPOSE

Analyzed the associations of sedentary behavior (SB) measured by questionnaire and accelerometer, with cardiometabolic markers in adolescents.

METHODS

Longitudinal study with 4 years of follow-up with adolescents from João Pessoa, Brazil. SB was measured using a questionnaire (305 adolescents: 54.5% females; age 11.7 [SD = 0.7]) and use of accelerometer (136 adolescents: 54.8% females; age 11.5 [SD = 0.7]). The cardiometabolic markers were body mass index, waist circumference, systolic and diastolic blood pressure, fasting glucose, total cholesterol, triglycerides, low-density lipoproteins and high-density lipoproteins (HDL-C), total cholesterol/HDL ratio, triglycerides/HDL ratio, and non-HDL-C. Generalized Estimating Equation analysis was used to for analyses.

RESULTS

The average time in SB by the accelerometer was greater (average 8.3 [SD = 1.5], 8.8 [SD = 1.6], and 8.4 [SD = 1.9] h/d/wk) than observed in the questionnaire (on average 6.0 [SD = 4.1], 7.2 [SD = 4.9], and 6.6 [SD = 5.4] h/d/wk), in all years of the study, but without a significant increasing trend (P > .05) over time for both measures. There was a significant and positive association between SB measured by the questionnaire and SBP (β = 0.148; 95% CI, 0.021-0.274).

CONCLUSIONS

The SB generally does not seem to contribute to significant changes in cardiometabolic markers in adolescents, despite it being associated with increased systolic blood pressure levels.

Device-measured sedentary behaviour and anxiety symptoms during adolescence: a 6-year prospective cohort study

BACKGROUND

Sedentary behaviour is potentially a modifiable risk factor for anxiety disorders, a major source of global disability that typically starts during adolescence. This is the first prospective study of associations between repeated, device-based measures of sedentary behaviour and anxiety symptoms in adolescents.

METHODS

A UK cohort with 4257 adolescents aged 12 at baseline (56% female). Main exposures were sedentary behaviour and physical activity measured using accelerometers for 7-days at ages 12, 14, and 16. Primary outcome was anxiety symptom scores at age 18 from a Clinical Interview Schedule-Revised. We used adjusted negative binomial regression and iso-temporal substitution methods to analyse the data.

RESULTS

We found a positive association between sedentary behaviour at ages 12, 14, and 16, with anxiety symptoms at age 18, independent of total physical activity volume. Theoretically replacing an hour of daily sedentary behaviour for light activity at ages 12, 14, and 16, was associated with lower anxiety symptoms by age 18 by 15.9% (95% CI 8.7-22.4), 12.1% (95% CI 3.4-20.1), and 14.7% (95% CI 4-24.2), respectively. Whereas, theoretically replacing an hour of sedentary behaviour with moderate-to-vigorous physical activity was not associated with differences in anxiety symptoms. These results were robust to a series of sensitivity analyses.

CONCLUSION

Sedentary behaviour is a possible risk factor for increasing anxiety symptoms during adolescence, independent of total physical activity volume. Instead of focusing on moderate-to-vigorous activity, replacing daily sedentary behaviour with light activity during adolescence could be a more suitable method of reducing future anxiety symptoms.

[Joint association of sedentary behavior and physical activity on anxiety tendency among occupational population in China]

OBJECTIVE

To investigate the status and influencing factors of anxiety tendency among occupational population in China and to examine the joint association between sedentary behavior and physical activity with anxiety tendency.

METHODS

The data were from the 2021 Asia Best Workplace (Chinese mainland) program. The Generalized Anxiety Tendency scale was used to assess employees' anxiety status, and Logistic regression was used to analyze the factors influencing anxiety tendency and calculate the odds ratio (OR) within different groups. The OR of sitting for each sitting-physical activity (PA) combination group and within PA strata were calculated to explore the joint association.

RESULTS

A total of 11 903 workers with an average age of 32.9 years were included in this study. Among them, 3 562 workers had anxiety tendency (29.9%) and the prevalence of those under 40 years old (30.6%) was significantly higher than the other age group (26.7%). 41.0% of the respondents had the moderated to vigorous physical activity. Their average daily sitting time was 9.4 h, and the percentage of those who exceeded 8 h sitting reached 73.9% in the past week. The analysis of Logistic regression showed that smoking (OR=1.24, 95%CI: 1.23-1.39), longer sedentary time and lower physical activity level were risk factors for anxiety tendency, and longer average daily sleep time (OR=0.56, 95%CI: 0.51-0.61) was a protective factor. The joint association analysis and stratified analysis of physical activity and sedentary behavior with anxiety tendency showed that increased sedentary time combined with decreased physical activity intensity was significantly associated with increased risk of anxiety tendency (range of OR: 1.64-3.14). The threshold for sedentary time in total as a risk factor for anxiety tendency gradually decreased as physical activity intensity increased.

CONCLUSION

The anxiety tendency and sedentary behavior among the occupational population should recieve more attention. Lack of physical activity and sedentary behavior are both risk factors for anxiety tendency, and strengthening the intensity of physical activity can attenuate the harmful effects of sedentary behavior on anxiety tendency.

[Joint association of sedentary behavior and physical activity on anxiety tendency among occupational population in China]

OBJECTIVE

To investigate the status and influencing factors of anxiety tendency among occupational population in China and to examine the joint association between sedentary behavior and physical activity with anxiety tendency.

METHODS

The data were from the 2021 Asia Best Workplace (Chinese mainland) program. The Generalized Anxiety Tendency scale was used to assess employees' anxiety status, and Logistic regression was used to analyze the factors influencing anxiety tendency and calculate the odds ratio (OR) within different groups. The OR of sitting for each sitting-physical activity (PA) combination group and within PA strata were calculated to explore the joint association.

RESULTS

A total of 11 903 workers with an average age of 32.9 years were included in this study. Among them, 3 562 workers had anxiety tendency (29.9%) and the prevalence of those under 40 years old (30.6%) was significantly higher than the other age group (26.7%). 41.0% of the respondents had the moderated to vigorous physical activity. Their average daily sitting time was 9.4 h, and the percentage of those who exceeded 8 h sitting reached 73.9% in the past week. The analysis of Logistic regression showed that smoking (OR=1.24, 95%CI: 1.23-1.39), longer sedentary time and lower physical activity level were risk factors for anxiety tendency, and longer average daily sleep time (OR=0.56, 95%CI: 0.51-0.61) was a protective factor. The joint association analysis and stratified analysis of physical activity and sedentary behavior with anxiety tendency showed that increased sedentary time combined with decreased physical activity intensity was significantly associated with increased risk of anxiety tendency (range of OR: 1.64-3.14). The threshold for sedentary time in total as a risk factor for anxiety tendency gradually decreased as physical activity intensity increased.

CONCLUSION

The anxiety tendency and sedentary behavior among the occupational population should recieve more attention. Lack of physical activity and sedentary behavior are both risk factors for anxiety tendency, and strengthening the intensity of physical activity can attenuate the harmful effects of sedentary behavior on anxiety tendency.

Physical activity and depressive symptoms among adolescents in a school-based sample

Objective:

To explore associations between self-reported weekly physical activity and depressive symptomatology among adolescents in a school-based sample from Brazil.

Methods:

We surveyed 7,405 adolescents aged 14 to 16 years in 101 public schools in Porto Alegre, Brazil. We assessed physical activity using an adapted version of the Patient-Centered Assessment and Counseling for Exercise Plus Nutrition – Adolescent Physical Activity Measure (PACE+), and depressive symptoms using the Brazilian Portuguese version of the Patient Health Questionnaire – Adolescent Version. We compared the depressive symptom scores among adolescents with varying levels of physical activity.

Results:

Of the overall sample, 84.4% exercised less than the recommended frequency of 60 minutes/day, at least 5 days/week, of moderate to intense physical activity (PACE+ score ≥ 5). Adolescents whose physical activity levels fell below that threshold had higher median depression scores (8 [IQR = 10] vs. 7 [IQR = 9], W = 4060461, p < 0.001). A similar pattern was observed for depression scores in those with PACE+ < 1 (median of 10 [IQR = 11]) and ≥ 1 (7 [IQR = 9], W = 7457608, p < 0.001).

Conclusion:

In this large sample of Brazilian adolescents, those who exercised less frequently and vigorously than their peers reported more depressive symptoms.

Investigating the influence of physical activity composition on arterial stiffness in youth

Physical activity is beneficial for arterial health in children but less is known about how all daily movement behaviours influence arterial stiffening. Compositional analysis can account for the co-dependent nature of these behaviours and therefore was employed to explore how the movement composition influences arterial health. Augmentation index (AIx) and pulse wave velocity were measured cross-sectionally in healthy children (n = 129; 12.4 ± 1.6 years). Time spent in sedentary, light physical activity (LPA), moderate-to-vigorous physical activity (MVPA) and asleep were derived from seven-day hip-worn accelerometry. The relative effects of individual behaviours and the overall movement composition on arterial stiffness were explored utilising compositional analysis, with predictive modelling used to predict effects of the substituting time between behaviours. Girls (n = 45, 12.1 ± 1.5yrs, 20.5 ± 3.6kg·m^-2) had a higher AIx (+ 3.94; p < 0.05) and accrued physical activity predominantly in LPA, whereas boys (n = 56, 12.6 ± 1.7yrs, 20.6 ± 4.0kg·m^-2) accrued physical activity predominantly in MVPA. Individual behaviours and the movement composition were not significant predictors of any measure of arterial stiffness (P > 0.05), and the reallocation of 20-minutes between behaviours did not elicit significant change in arterial stiffness, irrespective of sex (P > 0.05). The reallocation of time to MVPA from any other behaviour did not predict an improvement in arterial stiffness. This highlights the high potential dose of MVPA required to improve arterial health and the complex nature of the determinants of arterial stiffness. HighlightsMovement behaviours in isolation nor combination predicted arterial stiffness in youth.The reallocation of behaviours from any other behaviour to MVPA did not affect arterial stiffness in youth.Arterial stiffness is a complex, multidimensional health parameter that does not appear to be primarily determined by physical activity levels or intensity.

Impact of the COVID-19 Pandemic on Sedentary Time and Behaviour in Children and Adults: A Systematic Review and Meta-Analysis

The aim of this meta-analysis was to quantify the change in sedentary time during the COVID-19 pandemic and its effect on health outcomes in the general population. One thousand six hundred and one articles published after 2019 were retrieved from five databases, of which 64 and 40 were included in the systematic review and meta-analysis, respectively. Studies were grouped according to population: children (<18 years), adults (18–64 years) and older adults (>65 years). Average sedentary time was calculated, with sub-analyses performed by country, behaviour type and health outcomes. Children were most affected, increasing their sedentary time by 159.5 ± 142.6 min day⁻¹, followed by adults (+126.9 ± 42.2 min day⁻¹) and older adults (+46.9 ± 22.0 min day⁻¹). There were no sex differences in any age group. Screen time was the only consistently measured behaviour and accounted for 46.8% and 57.2% of total sedentary time in children and adults, respectively. Increases in sedentary time were negatively correlated with global mental health, depression, anxiety and quality of life, irrespective of age. Whilst lockdown negatively affected all age groups, children were more negatively affected than adults or older adults, highlighting this population as a key intervention target. As lockdowns ease worldwide, strategies should be employed to reduce time spent sedentary. Trial registration: PROSPERO (CRD42020208909).

Breaks in Sedentary Time and Cardiometabolic Markers in Adolescents

BACKGROUND

The interruption of the time spent in sedentary behavior (breaks) has been associated with better levels of cardiometabolic indicators in the adult population, but in adolescents, further investigations are still needed to confirm these findings.

OBJECTIVES

To analyze the association of the number of breaks per day in sedentary behaviors with cardiometabolic markers and whether it was moderated by nutritional status and excessive time on sedentary behavior in adolescents.

METHODS

This is a cross-sectional study of 537 adolescents (52.3% girls), aged between 10 and 14 years, enrolled in public schools in the city of João Pessoa, Paraíba state, Brazil. The number of daily breaks (>100 counts/minutes) in sedentary time was measured by Actigraph GT3X+ accelerometers. The following cardiometabolic markers were analyzed: systolic and diastolic blood pressure (mmHg), fasting blood glucose levels, total cholesterol, triglycerides, HDL-c, LDL-c (all in mg/dL) and body mass index (BMI) (kg/m2). Linear regression was used to analyze the association between the number of breaks and cardiometabolic markers and whether this association was moderated by nutritional status and excessive time in sedentary behavior. The significance level of p<0.05 was adopted for all analyses.

RESULTS

The number of daily breaks was negatively associated with BMI (boys - ß = -0.083; 95%CI: -0.132; -0.034 and girls - ß = -0.115; 95%CI: -0.169; -0.061), but not with the remaining cardiometabolic markers. The number of breaks per day was negatively associated with BMI (ß = -0.069; 95% CI: -0.102; -0.035), but not with the other cardiometabolic markers and this association was not moderated by the adolescents' nutritional status (p=0.221), or by excessive time in sedentary behavior (p=0.176).

CONCLUSIONS

Including breaks in sedentary time seems to contribute to lower BMI values in adolescents.

Recent Trends in Sedentary Time: A Systematic Literature Review

This paper systematically reviews and synthesizes the relevant literature on sedentary time research. A bibliometric analysis was conducted to evaluate the publications from 2010 to 2020 in the Web of Science (WoS) core collection database. Derwent Data Analyzer software was used for the cleaning, mining, and visualization of the data. Historical trends of the topics, main contributors, leading countries, leading institutions, leading research areas, and journals were explored. A total of 3020 publications were studied. The United States, the United Kingdom, and Australia are the three most productive countries. The Australian institution Baker Heart and Diabetes Institute led the list of productive institutions, and Ekelund U published the most papers. Sedentary time raised the concerns of scholars from 106 research areas, and public health was the dominant field. Physical activity, accelerometer, children, and obesity were the most frequently used keywords. The findings suggest that sedentary time is rapidly emerging as a global issue that has detrimental effects on public health. The hotspots shifted in the past 10 years, and COVID-19 was the most popular topic of sedentary time research.

Sedentary activity bout length was associated with BMI and waist circumference in Swedish children aged 5-7 years

AIM

This study examined the pattern of sedentary behaviour during the week and on weekends and associations with health outcomes among children aged 5-7 years in Sweden.

METHODS

This cross-sectional study used data from 342 children, many of whom had at least one parent born outside the Nordic region. Physical activity and sedentary time were measured by accelerometry. A sedentary bout was defined as 1-4 and 5-9 min. Diet, time in front of television or computer screen, sleep and physical activity behaviour were measured via parental reports, and anthropometric data by research staff.

RESULTS

The number of sedentary bouts was higher on weekends than on weekdays. Compared to girls, boys had more 1-4 min bouts on both weekdays and weekend days, and more 5-9 min bouts on weekends. A higher number of 5-9 min bouts was associated with a higher body mass index and waist circumference.

CONCLUSION

This study showed an association between sedentary activity and weight status in children as young as 5-7 years. Reducing time, especially longer bouts, spent in sedentary activities may encourage healthy weight development in children.

Comparison of Classroom-Based Sedentary Time and Physical Activity in Conventional Classrooms and Open Learning Spaces Among Elementary School Students

European children and adolescents spend most of their daily life and especially their school hours being sedentary which may increase their risk for chronic non-communicable diseases later in life. After the curriculum reform of Finnish basic education in 2014, most of the new or renovated comprehensive schools in Finland incorporate open and flexible classroom designs. Their open learning spaces may provide students opportunities to reduce sedentary behavior during school hours. Thus, waist-worn accelerometers were used to assess classroom-based sedentary time (ST), the number of breaks from sedentary time (BST), and physical activity (PA) among cross-sectional samples of 3rd and 5th grade students during two separate academic years in a school that underwent a renovation from conventional classrooms to open learning spaces. The cohort of 5th grade students before renovation had a smaller proportion of ST from total classroom time (56.97 ± 12.24%, n = 42 vs. 67.68 ± 5.61%, n = 28, mean difference = 10.71%-points, 95%CI = −15.65 to−5.77, p < 0.001), a greater number of BST per 60 min of classroom time (7.41 ± 1.16 breaks/h vs. 9.19 ± 1.59 breaks/h, mean difference = −1.78 breaks/h, 95%CI = −2.486 to −1.079, p < 0.001) and a greater proportion of light intensity PA (28.66 ± 9.99% vs. 22.56 ± 4.59%, mean difference = 6.10%, 95%CI = 2.56 to 9.64, p = 0.001) than the 5th grade cohort assessed after renovation. The cohort of 3rd grade student had a greater proportion of moderate-to-vigorous intensity PA (MVPA) after the renovation compared to the cohort assessed before the renovation [Mean Rank (Before) = 27.22, Mean Rank (After) = 37.58, U =524.0, p = 0.033]. Despite the greater ST found in 5th graders, schools with open learning spaces may facilitate BST or MVPA as observed in the 5th and 3rd grade cohorts in open learning spaces compared to the cohorts in conventional classrooms, respectively. Future studies should seek to investigate and develop teacher practices to capitalize the potential of open classrooms to reduce ST, since classroom renovation alone may not be a sufficient intervention as of itself. Longitudinal studies utilizing randomized controlled trials are warranted.

Relationship of Physical Activity and Sedentary Time with Metabolic Health in Children and Adolescents Measured by Accelerometer: A Narrative Review

The purpose of this study was to summarize the associations of physical activity (PA) and sedentary time (SED) with metabolic health and examine the effects of time reallocation on metabolic health in adolescents using accelerometer data. A literature search was conducted using PubMed, ScienceDirect, Web of Science, Cochran Library, and Google Scholar, and 27 articles were reviewed. Recent research generally confirms the associations of PA and SED with metabolic health. High PA levels and low SED levels had a positive relationship with metabolic health. Moreover, reallocating 10 min of daily SED to PA was associated with better metabolic health indicators. These results were stronger for moderate-to-vigorous physical activity than for light intensity PA. Thus, efforts to convert SED into PA of at least moderate intensity appear to be an effective strategy to prevent metabolic disease development in children and adolescents. However, some of the associations between PA and metabolic health indicators were inconsistent, depending on age, obesity degree, and PA intensity. Additionally, various accelerometer data collection and processing criteria impact the interpretation of the results. Therefore, consistent accelerometer data collection and analysis methods are needed in future studies. Further, intervention studies are required to verify the causality and effectiveness of the isotemporal substitution model.

What Happened Pre- and during COVID-19 in South Korea? Comparing Physical Activity, Sleep Time, and Body Weight Status

The purpose of the current study is to investigate the changes in physical activity (PA), sleep time (ST), and body weight (BW) Pre- and during COVID-19 in South Korea, and specifically, PA data were obtained during COVID-19 at three-time points based on the multilevel social distancing policies. All data were surveyed by questionnaires online and offline, and participants were required to fill in the monthly average of daily step counts were recorded an application on participants’ smartphone devices from Pre-COVID-19 (2019 year) and during COVID-19 (2020 year). Participants were 834 adults (males: 54.4%, female: 45.6%) and all statistical analyses were summarized by SPSS 25.0 program. The monthly average of daily step counts was 6747.09 during Pre-COVID-19, but the PA during COVID-19 was 5812.11 daily step counts per month. Also, there were significant pairwise differences between average PA Pre-COVID-19 and each level of social distancing (p < 0.001). After COVID-19, the participants who slept less than 7 h decreased by 3.6%, while those who slept more than 9 h increased by that much. As a result of BW, 269 participants responded their BW changed during COVID-19, and 199 of them reported they gained BW during COVID-19 (74.0%). Although self-reported questionnaires may have led to an under-or over-estimation of ST and BW, the present study found that the environment in which the COVID-19 is prevalent had adverse relationships on PA, ST, and BW. Therefore, it is important to identify strategies to motivate individuals for remaining physically active and getting adequate sleep while maintaining social distancing due to the presence of the COVID-19 global pandemic.

Which intensities, types, and patterns of movement behaviors are most strongly associated with cardiometabolic risk factors among children?

PURPOSE

The purpose of this study was to determine which intensities, patterns, and types of 24-h movement behaviors are most strongly associated with cardiometabolic risk factors among children.

METHODS

A total of 369 children aged 10-13 years were studied. Participants wore an Actical accelerometer and a Garmin Forerunner 220 Global Positioning System logger and completed an activity and sleep log for 7 days. Data from these instruments were combined to estimate average minute per day spent in 14 intensities, 11 types, and 14 patterns of movement. Body mass index, resting heart rate, and systolic blood pressure values were combined to create a cardiometabolic risk factor score. Partial least squares regression analysis was used to examine associations between the 39 movement behavior characteristics and the cardiometabolic risk factor score. The variable importance in projection (VIP) values were used to determine and rank important movement behavior characteristics. There was evidence of interaction by biological maturity, and the analyses were conducted separately in the 50% least mature and 50% most mature participants.

RESULTS

For the least biologically mature participants, fifteen of the 39 movement behavior characteristics had important VIP value scores; eight of these reflected movement intensities (particularly moderate and vigorous intensities), six reflected movement patterns, and one reflected a movement type. For the most mature participants, thirteen of the 39 movement behavior characteristics had important VIP value scores, with five reflecting intensities (particularly moderate and vigorous intensities), five reflecting patterns, and three reflecting types of movement.

CONCLUSION

More than 12 movement behavior characteristics were associated with cardiometabolic risk factors within both the most and least mature participants. Movement intensities within the moderate and vigorous intensity ranges were the most consistent correlates of these risk factors.

Replacing school and out-of-school sedentary behaviors with physical activity and its associations with adiposity in children and adolescents: a compositional isotemporal substitution analysis

BACKGROUND

Little is known on how context-specific sedentary behaviors (SB) affect adiposity. This study aimed to investigate compositional associations between context-specific SB and adiposity and estimate the differences in adiposity associated with replacing school and out-of-school SB with physical activity (PA).

METHODS

This study included 336 children and adolescents. Time spent in SB and PA was estimated using multi-day 24-hour raw accelerometer data. SB and PA were specified for school and out-of-school times. Fat mass percentage (FM%) and fat mass index (FMI) were used as adiposity indicators. A compositional isotemporal substitution model was used to estimate differences in adiposity associated with one-to-one reallocations of time from context-specific SB to PA.

RESULTS

Participants spent approximately two thirds of their school and out-of-school time being sedentary. Relative to the remaining 24-h movement behaviors, significant associations between out-of-school SB and adiposity were found in both boys (β_ilr1 = 0.63, 95% confidence interval [CI] = 0.03-1.22 for FM%; β_ilr1 = 0.76, 95% CI = 0.03-1.49 for FMI) and girls (β_ilr1 = 0.62, 95% CI = 0.25-0.98 for FM%; β_ilr1 = 0.80, 95% CI = 0.28-1.32 for FMI). Replacing 30 min/day of out-of-school SB with out-of-school light PA decreased FM% by 10.1% (95% CI = 3.3-17.9) and FMI by 14% (95% CI = 2.7-24) in girls. No significant associations were found for school SB.

CONCLUSIONS

A reduction of out-of-school SB in favor of light PA should be advocated as an appropriate target for interventions and strategies to prevent childhood obesity.

Effects of an Educational Hybrid Physical Education Program on Physical Fitness, Body Composition and Sedentary and Physical Activity Times in Adolescents: The Seneb's Enigma

Physical activity (PA), body composition and sedentary behavior may affect the health of children. Therefore, this study examined the effect of an educational hybrid physical education (PE) program on physical fitness (PF), body composition and sedentary and PA times in adolescents. A 9-month group-randomized controlled trial was conducted in 150 participants (age: 14.63 ± 1.38 years) allocated into the control group (CG, n = 37) and experimental group (EG, n = 113). Cardiorespiratory fitness, speed, strength, agility, flexibility and body mass index (BMI) were assessed through previously validated field tests. Sedentary time, PA at school and afterschool were evaluated with the Youth Activity Profile-Spain questionnaire. Significant differences were observed concerning to the CG in APA-weekend (p = 0.044), speed-agility (p = 0.005) and agility (p = 0.008). Regarding the intervention, cardiorespiratory fitness (p = 0.000), speed-agility (p = 0.000), strength (p = 0.000), flexibility (p = 0.000), agility (p = 0.000), PA in school (p = 0.011), APA-weekday (p = 0.001), APA-weekend (p = 0.000), APA-week (p = 0.000), and sedentary time (p = 0.000) increased significantly in the EG. The use of a hybrid program based on teaching personal and social responsibility and gamification strategies produced enhancements in cardiorespiratory fitness, agility, speed, APA-weekdays and APA-weekends, reducing the sedentary time.

The Association of Different Sedentary Patterns and Health-Related Physical Fitness in Pre-schoolers

Background: The results of sedentary time (ST) and health-related physical fitness (HPF) are not completely consistent and the studies concentrated on pre-schoolers are very limited. Methods: We measured ST and ST patterns (ST Bouts time, ST Breaks times) by accelerometer. The health-related physical fitness T-score (HPFT) was calculated by five indexes: height-weight standard score, 20 m shuttle-run test, grip strength, standing long jump and 2 × 10 m shuttle-run test. Results: We included 375 pre-schoolers (211 boys, 164 girls) in the final analysis. The total ST and ST Bouts times negatively correlated with HPFT in pre-schoolers. HPFT reduced by 1.69 and 0.70 points per 10 min increased in total ST and ST Bouts times, respectively. HPFT of the highest quartile group reduced by 9.85 points in total ST, and 10.54 points in ST Bouts time compared with the lowest quartile group. However, the HPFT increased by 0.09 points per 10 times increased in ST Breaks times; the HPFT increased by 16.21 and 15.59 points when moderate to vigorous physical activity (MVPA) replaced total ST and ST Bouts time. Conclusions: HPF negatively correlated with the Total ST and ST Bouts times, but positively correlated with ST Breaks times; and HPF significantly improved when MVPA replaced ST in pre-schoolers.

Patterns of Sedentary Time in the Hispanic Community Health Study/Study of Latinos (HCHS/SOL) Youth

BACKGROUND

Total sedentary time and prolonged sedentary patterns can negatively impact health. This study investigated rates of various sedentary pattern variables in Hispanic/Latino youth.

METHODS

Participants were 956 youths (50.9% female) in the Hispanic Community Health Study/Study of Latinos Youth, a population-based cohort study of Hispanic/Latino 8- to 16-year-olds from 4 geographic regions in the United States (2012-2014). Total sedentary time and 10 sedentary pattern variables were measured through 1 week of accelerometer wear. Differences were examined by sociodemographic characteristics, geographic location, weekdays versus weekends, and season.

RESULTS

On average, youth were sedentary during 67.3% of their accelerometer wear time, spent 24.2% engaged in 10- to 29-minute sedentary bouts, and 7.2% in ≥60-minute bouts. 8- to 12-year-olds had more favorable sedentary patterns (less time in extended bouts and more breaks) than 13- to 16-year-olds across all sedentary variables. Sedentary patterns also differed by Hispanic/Latino background, with few differences across sex, household income, season, and place of birth, and none between weekdays versus weekends.

CONCLUSIONS

Variables representing prolonged sedentary time were high among Hispanic/Latino youth. Adolescents in this group appear to be at especially high risk for unhealthy sedentary patterns. Population-based efforts are needed to prevent youth from engaging in increasingly prolonged sedentary patterns.

Physical behaviors and fundamental movement skills in British and Iranian children: An isotemporal substitution analysis

Although the relationship between fundamental movement skills (FMS) and physical behaviors has been established, differences between countries are scarcely explored. The impact of the whole physical behavior composition, in relation to FMS, has yet to be investigated in 9-11 y children. The aims were to investigate the associations of substitution of physical behaviors with FMS score and to compare traditional linear regression and compositional data analysis and compare between England and Iran. Measures included accelerometer-derived activity (sleep (SL), sedentary behavior (SB), light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) and FMS, using the TGMD-2, in 119 children (64 boys) from Iran (mean (±SD) age: 9.8 ± 0.3 y; BMI of 18.2 ± 3.3 kg/m² ) and 139 (61 boys) children from England (mean (±SD) age: 9.5 ± 0.6 y; BMI of 17.7 ± 3.1 kg/m² ). Isometric log-ratio multiple linear regression models were used to discern the association between FMS and the mean activity composition, and for new compositions, where fixed durations of time were reallocated from one behavior to another, while the remaining behaviors were unchanged. In physical behaviors as a composition, FMS was significantly associated in both ethnicities. English children responded significantly positively to adding 5 or more minutes LPA at the expense of SB (FMS unit change from 0.05 [0.01, 0.09] at 5 minutes to 0.72 [0.01, 1.34] at 60 minutes). Adding 10 minutes or more of SL, at the expense of SB, was associated with a significant, positive change in FMS in all children. Investigation is needed to understand the composition of SB and its potential influence on FMS development.

Effect of Children's Weight Status on Physical Activity and Sedentary Behavior during Physical Education, Recess, and After School

Children's body mass index may affect physical activity (PA) participation. Therefore, this study examined the effect of children's weight status on underserved elementary school children's PA and sedentary behavior (SB) throughout the segmented day. Participants were 138 children (X¯age = 8.14 years). Children's height and weight were measured with subsequent classification of children as healthy weight or overweight/obese. Durations of moderate-to-vigorous PA (MVPA), light PA (LPA), and SB during physical education (PE), morning recess, lunch recess, after school, and overall were assessed via accelerometry over three days. Independent t-tests evaluated differences in children's MVPA, LPA, and SB during each daily segment by weight status. Significantly higher MVPA was observed for children of healthy weight status versus children with overweight/obesity during morning recess, t(136) = 2.15, p = 0.03, after school, t(136) = 2.68, p < 0.01, and overall, t(136) = 2.65, p < 0.01. Interestingly, comparisons of children of healthy weight status and children with overweight/obesity's LPA and SB during the after-school segment revealed a trend wherein children with overweight/obesity participated in slightly greater LPA/less SB than children of healthy weight status. Higher MVPA was observed among children of healthy weight versus children with overweight/obesity during most daily segments. Concerted efforts should focus on increasing MVPA among children with overweight/obesity.

Comparing Cognitive Control Performance During Seated Rest and Self-Paced Cycling on a Desk Bike in Preadolescent Children

BACKGROUND

Although active workstations, such as desk bikes, have proven to be beneficial for health, there is limited information regarding their effects on children's acute cognitive performance during self-paced exercise.

METHODS

This study used a within-subjects, fully counterbalanced design with a sample of 38 preadolescent children (mean age = 12.50 y, SD = 0.62; 43% male), who performed cognitive tests while being seated or while cycling for 45 minutes with a 7-day interval. Effects of using a desk bike were evaluated on cognitive control: verbal and visuospatial working memory capacities were tested, and inhibition was assessed using a modified flanker task. In addition, subjective task experience was explored using self-report measures.

RESULTS

Cognitive control performance was not degraded but also not improved with the short-term use of desk bikes. Because of the null effects, there is no direction and magnitude of the outcomes to discuss.

CONCLUSIONS

These findings suggest that schools can successfully implement desk bikes to increase physical activity and reduce sedentary time among children without compromising cognitive control processes necessary for academic achievement.

Sedentary behavior patterns and adiposity in children: a study based on compositional data analysis

BACKGROUND

Between-person differences in sedentary patterns should be considered to understand the role of sedentary behavior (SB) in the development of childhood obesity. This study took a novel approach based on compositional data analysis to examine associations between SB patterns and adiposity and investigate differences in adiposity associated with time reallocation between time spent in sedentary bouts of different duration and physical activity.

METHODS

An analysis of cross-sectional data was performed in 425 children aged 7-12 years (58% girls). Waking behaviors were assessed using ActiGraph GT3X accelerometer for seven consecutive days. Multi-frequency bioimpedance measurement was used to determine adiposity. Compositional regression models with robust estimators were used to analyze associations between sedentary patterns and adiposity markers. To examine differences in adiposity associated with time reallocation, we used the compositional isotemporal substitution model.

RESULTS

Significantly higher fat mass percentage (FM%; β_ilr1 = 0.18; 95% CI: 0.01, 0.34; p = 0.040) and visceral adipose tissue (VAT; β_ilr1 = 0.37; 95% CI: 0.03, 0.71; p = 0.034) were associated with time spent in middle sedentary bouts in duration of 10-29 min (relative to remaining behaviors). No significant associations were found for short (< 10 min) and long sedentary bouts (≥30 min). Substituting the time spent in total SB with moderate-to-vigorous physical activity (MVPA) was associated with a decrease in VAT. Substituting 1 h/week of the time spent in middle sedentary bouts with MVPA was associated with 2.9% (95% CI: 1.2, 4.6), 3.4% (95% CI: 1.2, 5.5), and 6.1% (95% CI: 2.9, 9.2) lower FM%, fat mass index, and VAT, respectively. Moreover, substituting 2 h/week of time spent in middle sedentary bouts with short sedentary bouts was associated with 3.5% (95% CI: 0.02, 6.9) lower FM%.

CONCLUSIONS

Our findings suggest that adiposity status could be improved by increasing MVPA at the expense of time spent in middle sedentary bouts. Some benefits to adiposity may also be expected from replacing middle sedentary bouts with short sedentary bouts, that is, by taking standing or activity breaks more often. These findings may help design more effective interventions to prevent and control childhood obesity.

Tune out and turn in: the influence of television viewing and sleep on lipid profiles in children

BACKGROUND/OBJECTIVES

Physical activity is beneficial to lipid profiles; however, the association between sedentary behavior and sleep and pediatric dyslipidemia remains unclear. We aimed to investigate whether sedentary behavior or sleep predicted lipid profiles in children over a 2-year period.

SUBJECTS/METHODS

Six hundered and thirty children from the QUALITY cohort, with at least one obese parent, were assessed prospectively at ages 8-10 and 10-12 years. Measures of sedentary behavior included self-reported TV viewing and computer/video game use. Seven-day accelerometry was used to derive sedentary behavior and sleep duration. Adiposity was assessed using DEXA scans. Twenty-four-hour dietary recalls yielded estimates of carbohydrate and fat intake. Outcomes included fasting total cholesterol, triglycerides, HDL and LDL-cholesterol. Multivariable models were adjusted for adiposity and diet.

RESULTS

At both Visit 1 (median age 9.6 year) and Visit 2 (median age 11.6 year), children were of normal weight (55%), overweight (22%), or obese (22%). Every additional hour of TV viewing at Visit 1 was associated with a 7.0% triglyceride increase (95% CI: 3.5, 10.6; P < 0.01) and 2.6% HDL decrease (95% CI: -4.2, -0.9; P < 0.01) at Visit 2; findings remained significant after adjusting for adiposity and diet. Every additional hour of sleep at Visit 1 predicted a 4.8% LDL decrease (95% CI: -9.0, -0.5; P = 0.03) at Visit 2, after adjusting for fat intake; this association became nonsignificant once controlling for adiposity.

CONCLUSIONS

Longer screen time during childhood appears to deteriorate lipid profiles in early adolescence, even after accounting for other major lifestyle habits. There is preliminary evidence of a deleterious effect of shorter sleep duration, which should be considered in further studies.

Changes in the school and non-school sedentary time in youth: The UP&DOWN longitudinal study

The aims of this study were (i) to examine the sedentary time (ST) during different time periods [i.e., weekend, out-of-school weekdays hours, school hours, recess, physical education classes (PEC)] in children and adolescents; (ii) to identify 2-year longitudinal changes in the ST for these periods; and (iii) to examine if ST at baseline is associated with ST 2 years later. This was a 2-year follow-up study with 826 (51.9% boys) children and 678 (50.7% boys) adolescents. Accelerometers were used to assess ST. Students spent more than 60% of their weekend, out-of-school hours and school hours in ST. During these periods, girls and adolescents were more sedentary than boys and children, respectively (p < 0.05). Over 2-year follow-up, ST increased during the weekend, out-of-school hours, school hours and recess in all subgroups studied (p < 0.001). ST during PEC declined 2% per year in children (p < 0.001) but it increased in adolescents (p < 0.05). ST during the periods analysed at baseline was lowly associated with ST during these periods 2 years later (intraclass correlations from <0.001 to 0.364). Interventions in these settings may be adequate if the intention is to avoid ST increase in students.

Depressive symptoms and objectively measured physical activity and sedentary behaviour throughout adolescence: a prospective cohort study

BACKGROUND

Identifying modifiable risk factors is essential to reduce the prevalence adolescent depression. Self-report data suggest that physical activity and sedentary behaviour might be associated with depressive symptoms in adolescents. We examined associations between depressive symptoms and objectively measured physical activity and sedentary behaviour in adolescents.

METHODS

From a population-based cohort of adolescents whose mothers were invited to participate in the Avon Longitudinal Study of Parents and Children (ALSPAC) study, we included participants with at least one accelerometer recording and a Clinical Interview Schedule-Revised (CIS-R) depression score at age 17·8 years (reported as age 18 years hereafter). Amounts of time spent in sedentary behaviour and physical activity (light or moderate-to-vigorous) were measured with accelerometers at around 12 years, 14 years, and 16 years of age. Total physical activity was also recorded as count per minute (CPM), with raw accelerometer counts averaged over 60 s epochs. Associations between the physical activity and sedentary behaviour variables and depression (CIS-R) scores at age 18 years were analysed with regression and group-based trajectory modelling.

FINDINGS

4257 adolescents from the 14 901 enrolled in the ALSPAC study had a CIS-R depression score at age 18 years. Longitudinal analyses included 2486 participants at age 12 years, 1938 at age 14 years, and 1220 at age 16 years. Total follow-up time was 6 years. Total physical activity decreased between 12 years and 16 years of age, driven by decreasing durations of light activity (mean 325·66 min/day [SD 58·09] at 12 years; 244·94 min/day [55·08] at 16 years) and increasing sedentary behaviour (430·99 min/day [65·80]; 523·02 min/day [65·25]). Higher depression scores at 18 years were associated with a 60 min/day increase in sedentary behaviour at 12 years (incidence rate ratio [IRR] 1·111 [95% CI 1·051-1·176]), 14 years (1·080 [1·012-1·152]), and 16 years of age (1·107 [1·015-1·208]). Depression scores at 18 years were lower for every additional 60 min/day of light activity at 12 years (0·904 [0·850-0·961]), 14 years (0·922 [0·857-0·992]), and 16 years of age (0·889 [0·809-0·974]). Group-based trajectory modelling across 12-16 years of age identified three latent subgroups of sedentary behaviour and activity levels. Depression scores were higher in those with persistently high (IRR 1·282 [95% CI 1·061-1·548]) and persistently average (1·249 [1·078-1·446]) sedentary behaviour compared with those with persistently low sedentary behaviour, and were lower in those with persistently high levels of light activity (0·804 [0·652-0·990]) compared with those with persistently low levels of light activity. Moderate-to-vigorous physical activity (per 15 min/day increase) at age 12 years (0·910 [0·857-0·966]) and total physical activity (per 100 CPM increase) at ages 12 years (0·941 [0·910-0·972]) and 14 years (0·965 [0·932-0·999]), were negatively associated with depressive symptoms.

INTERPRETATION

Sedentary behaviour displaces light activity throughout adolescence, and is associated with a greater risk of depressive symptoms at 18 years of age. Increasing light activity and decreasing sedentary behaviour during adolescence could be an important target for public health interventions aimed at reducing the prevalence of depression.

FUNDING

Details of funding are provided in the Acknowledgments.

Associations between accelerometry measured physical activity and sedentary time and the metabolic syndrome: A meta-analysis of more than 6000 children and adolescents

BACKGROUND

Metabolic syndrome is increasingly prevalent in the pediatric population. To prevent an early onset, knowledge about its association with modifiable lifestyle factors is needed.

OBJECTIVES

To estimate the prevalence of the metabolic syndrome and examine its cross-sectional associations with physical activity and sedentary time.

METHODS

Participants were 6009 children and adolescents from 8 studies of the International Children's Accelerometry Database. Physical activity and sedentary time were measured by accelerometer. Metabolic syndrome was defined based on International Diabetes Federation criteria. Logistic regression models adjusted for sex, age and monitor wear time were used to examine the associations between physical activity, sedentary time and the metabolic syndrome in each study and effect estimates were combined using random-effects meta-analysis.

RESULTS

The overall prevalence of the metabolic syndrome was 2.9%. In crude models, a 10 min increase in moderate-to-vigorous intensity physical activity and vigorous-intensity physical activity were inversely associated with the metabolic syndrome [OR 0.88, 95% CI 0.82-0.94, OR 0.80, 95% CI 0.70-0.92]. One hour increase in sedentary time was positively associated with the metabolic syndrome [OR 1.28, 95% CI 1.13-1.45]. After adjustment for sedentary time, the association between moderate-to-vigorous-intensity physical activity and the metabolic syndrome remained significant [OR 0.91, 95% CI 0.84-0.99]. Sedentary time was not associated with the metabolic syndrome after adjustment for moderate-to-vigorous intensity physical activity [OR 1.14 95% CI 0.96-1.36].

CONCLUSIONS

Physical activity of at least moderate intensity but not sedentary time is independently associated with the metabolic syndrome.

Accelerometer-Measured Physical Activity and Sedentary Behavior Patterns in Taiwanese Adolescents

Levels of physical activity and sedentary behavior among adolescents seem to vary within different settings, but few Asian studies have compared physical activity and sedentary activity patterns in adolescents across weekdays/weekends and during-school time/after-school time. This study aimed to provide objectively measured data describing intensity-specific physical activity and sedentary behavior patterns in Taiwanese adolescents. The results were sorted by gender and divided between weekdays/weekends and during-school time/after-school time. A total of 470 Taiwanese students (49.6% boys, ages 12–15 y) were recruited and fitted with GT3X+ accelerometers for seven days. Intensity-specific physical activity, total sedentary time, and sedentary bouts (number and duration ≥30 min) were measured. The Mann-Whitney U test was used to examine the significant differences in physical activity and sedentary behavior patterns between the genders on weekdays/weekends and during school/after-school time. The results show that the adolescents’ overall activity levels were below recommended thresholds, with girls engaging in significantly less moderate to vigorous physical activity, having longer sedentary time, longer time spent in sedentary bouts, and more frequent sedentary bouts than boys. Similar results were observed in physical activities of each intensity as well as sedentary behavior variables, both on weekdays/weekends and during-school/after-school periods. These findings emphasize the importance of developing and implementing approaches to increase moderate to vigorous physical activity, as well as decrease prolonged sedentary time and long sedentary bouts, especially for Taiwanese girls.

Substituting prolonged sedentary time and cardiovascular risk in children and youth: a meta-analysis within the International Children's Accelerometry database (ICAD)

BACKGROUND

Evidence on the association between sitting for extended periods (i.e. prolonged sedentary time (PST)) and cardio-metabolic health is inconsistent in children. We aimed to estimate the differences in cardio-metabolic health associated with substituting PST with non-prolonged sedentary time (non-PST), light (LIPA) or moderate-to-vigorous physical activity (MVPA) in children.

METHODS

Cross-sectional data from 14 studies (7 countries) in the International Children's Accelerometry Database (ICAD, 1998-2009) was included. Accelerometry in 19,502 participants aged 3-18 years, together with covariate and outcome data, was pooled and harmonized. Iso-temporal substitution in linear regression models provided beta coefficients (95%CI) for substitution of 1 h/day PST (sedentary time accumulated in bouts > 15 min) with non-PST, LIPA or MVPA, for each study, which were meta-analysed.

RESULTS

Modelling substitution of 1 h/day of PST with non-PST suggested reductions in standardized BMI, but estimates were > 7-fold greater for substitution with MVPA (- 0.44 (- 0.62; - 0.26) SD units). Only reallocation by MVPA was beneficial for waist circumference (- 3.07 (- 4.47; - 1.68) cm), systolic blood pressure (- 1.53 (- 2.42; - 0.65) mmHg) and clustered cardio-metabolic risk (- 0.18 (- 0.3; - 0.1) SD units). For HDL-cholesterol and diastolic blood pressure, substitution with LIPA was beneficial; however, substitution with MVPA showed 5-fold stronger effect estimates (HDL-cholesterol: 0.05 (0.01; 0.10) mmol/l); diastolic blood pressure: - 0.81 (- 1.38; - 0.24) mmHg).

CONCLUSIONS

Replacement of PST with MVPA may be the preferred scenario for behaviour change, given beneficial associations with a wide range of cardio-metabolic risk factors (including adiposity, HDL-cholesterol, blood pressure and clustered cardio-metabolic risk). Effect estimates are clinically relevant (e.g. an estimated reduction in waist circumference of ≈1.5 cm for 30 min/day replacement). Replacement with LIPA could be beneficial for some of these risk factors, however with substantially lower effect estimates.

Associations of accelerometer-measured sedentary time, sedentary bouts, and physical activity with adiposity and fitness in children

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO₂max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO₂max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO₂max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO₂max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.

Characteristics of Canadian Youth Adhering to Physical Activity and Screen Time Recommendations

The purpose of the study was to describe adherence to screen time (ST) and physical activity (PA) recommendations among Canadian youth. The present study was based on a representative sample of Canadian students from Grades 7 through 12 (N = 47,203). ST and PA as well as demographic (gender, ethnicity, grade, and province of residence) and individual (alcohol, tobacco and cannabis usage, school connectedness) correlates were self-reported by youth. In total, 49.2% (99% confidence interval [CI] = [46.3%, 52.2%]) of participants respected none of the recommendations, while 40.2% (99% CI [37.0%, 43.3%]) and 20.8% (99% CI [19.2%, 22.4%]) respected PA or ST recommendations, respectively. In terms of the correlates of health-related behavior, White ethnicity, alcohol use, and feeling more connected to school were positively correlated with adherence. Attending school in Quebec and smoking cannabis increased risk of poor compliance. The present findings may help the design of school-based health promotion strategies designed to increase PA and reduce ST.

SEDENTARY BEHAVIOR AND CARDIOVASCULAR RISK IN CHILDREN: A SYSTEMATIC REVIEW

ABSTRACT In recognition of the increasing time spent in sedentary activities in modern life, an emerging area of study linking sedentary time to health has highlighted its role in the development of chronic diseases. Therefore, the objective of this systematic review was to investigate the indicators and characteristics of sedentary behavior associated with cardiovascular risk factors in children and adolescents. The databases SciVerse Scopus, MEDLINE®/PubMed and LILACS were selected as a source of reference, using the associated terms “sedentary lifestyle” or “sedentary behavior” or “sedentary” AND “cardiovascular diseases” AND “child or adolescent” to identify studies published from January 2006 to March 2019. The methodological quality of the studies was evaluated and a score was assigned. Fifty articles were included in this review at the end. Extensive sedentary time, especially greater screen and TV exposure time, were associated with cardiovascular risk factors. In addition, the accumulation of prolonged sedentary bouts with few breaks in sedentary time tended to compromise the cardiometabolic profile. These findings highlight the importance of differentiating and considering these various indicators and characteristics of sedentary behavior. Further studies are needed to elucidate the multiple and overlapping facets of sedentary behavior and their relationship with health, and to encourage the development of evidence-based recommendations for this population. Level of Evidence I; Systematic Review of Level I Studies.

Sedentary Behaviors in Today's Youth: Approaches to the Prevention and Management of Childhood Obesity: A Scientific Statement From the American Heart Association

This scientific statement is about sedentary behavior and its relationship to obesity and other cardiometabolic outcomes in youth. A deleterious effect of sedentary behavior on cardiometabolic health is most notable for screen-based behaviors and adiposity; however, this relation is less apparent for other cardiometabolic outcomes or when sedentary time is measured with objective movement counters or position monitors. Increasing trends of screen time are concerning; the portability of screen-based devices and abundant access to unlimited programming and online content may be leading to new patterns of consumption that are exposing youth to multiple pathways harmful to cardiometabolic health. This American Heart Association scientific statement provides an updated perspective on sedentary behaviors specific to modern youth and their impact on cardiometabolic health and obesity. As we reflect on implications for practice, research, and policy, what emerges is the importance of understanding the context in which sedentary behaviors occur. There is also a need to capture the nature of sedentary behavior more accurately, both quantitatively and qualitatively, especially with respect to recreational screen-based devices. Further evidence is required to better inform public health interventions and to establish detailed quantitative guidelines on specific sedentary behaviors in youth. In the meantime, we suggest that televisions and other recreational screen-based devices be removed from bedrooms and absent during meal times. Daily device-free social interactions and outdoor play should be encouraged. In addition, parents/guardians should be supported to devise and enforce appropriate screen time regulations and to model healthy screen-based behaviors.

Associations of Sitting Behavior Patterns With Cardiometabolic Risk in Children: The Sit Less for Health Cross-Sectional Study

BACKGROUND

The objective of this study was to investigate the associations between sedentary behavior patterns and cardiometabolic risk in children using a monitor that accurately distinguishes between different postures.

METHODS

In this cross-sectional study, 118 children (67 girls) aged 11-12 years had adiposity, blood pressure, lipids, and glucose measured, and then they wore an activPAL device to record sitting, standing, and stepping for 7 consecutive days. Data were analyzed using multiple linear regression.

RESULTS

After adjustment for potential confounders and moderate to vigorous physical activity, the number of breaks in sitting was significantly negatively associated with adiposity (standardized β ≥ -0.546; P ≤ .001) and significantly positively associated with high-density lipoprotein cholesterol (β = 0.415; P ≤ .01). Time in prolonged sitting bouts was significantly negatively associated with adiposity (β ≥ -0.577; P ≤ .001) and significantly positively associated with high-density lipoprotein cholesterol (β = 0.432; P ≤ .05). Standing time was significantly negatively associated with adiposity (β ≥ -0.270; P ≤ .05) and significantly positively associated with high-density lipoprotein cholesterol (β = 0.312; P ≤ .05).

CONCLUSIONS

This study suggests that increasing the number of breaks in sitting and increasing standing time are beneficially associated with cardiometabolic risk and should be considered in health promotion interventions in children.

Is occupational or leisure physical activity associated with low back pain? Insights from a cross-sectional study of 1059 participants

BACKGROUND

Low back pain is a highly prevalent and disabling musculoskeletal disorder. Physical activity is widely used as a prevention strategy for numerous musculoskeletal disorders; however, there is still conflicting evidence as to whether physical activity is a protective or risk factor for low back pain or whether activity levels differ between people with and without low back pain.

OBJECTIVE

To investigate the association between low back pain and different types (occupational and leisure) and intensities (moderate and vigorous) of physical activity.

METHODS

This is cross-sectional observational study. We included in this study a total of 1059 individuals recruited from a Spanish twin registry with data available on low back pain.

OUTCOME

Self-reported leisure and occupational physical activity were the explanatory variables. The low back pain outcome used in this study was recurrent low back pain.

RESULTS

Our results indicate that leisure physical activity is associated with a lower prevalence of recurrent low back pain. In contrast, occupational physical activity, such as carrying, lifting heavy weight while inclined, awkward postures (e.g. bending, twisting, squatting, and kneeling) are associated with a higher prevalence of recurrent low back pain. There was no statistically significant association between other occupational physical activities, such as sitting or standing, and low back pain.

CONCLUSION

Leisure and occupational physical activity are likely to have an opposed impact on low back pain. While leisure physical activity appears to be protective, occupational physical activity appears to be harmful to low back pain. Future longitudinal studies should assist in formulating guidelines addressing specific types and intensity of physical activity aimed at effectively preventing low back pain.

Associations of Accumulated Time in Bouts of Sedentary Behavior and Moderate-to-Vigorous Physical Activity With Cardiometabolic Health in 10- to 13-Year-Old Boys

BACKGROUND

Little is known about the impact of sedentary and moderate-to-vigorous physical activity (MVPA) bouts on cardiometabolic health. The aim was to examine how the accumulation of bouts of sedentary time and MVPA associates to cardiometabolic health in children independently of total sedentary and MVPA time.

METHODS

In a cross-sectional study with 123 boys (10-13 y), sedentary and MVPA bouts were determined using 7-day accelerometry. Each bout was compared with cardiometabolic risk factors and with the risk score that was calculated using standardized values of body mass index, waist circumference, homeostasis model assessment for insulin resistance, triglycerides, and total cholesterol/high-density cholesterol ratio.

RESULTS

Time in 10- to 14-minute sedentary bouts was negatively associated with continuous cardiometabolic risk score in weekdays and weekend days and with triglycerides in a weekend (P < .05). Time accumulated in ≥30-minute sedentary bouts was associated with higher insulin and homeostasis model assessment for insulin resistance values in weekend (P < .05). Weekday total MVPA and time accumulated in ≥10-minute MVPA bouts were negatively associated with continuous cardiometabolic risk score and body mass index in weekdays (P < .05). No associations were found between total sedentary time and metabolic health.

CONCLUSION

Significant associations between sedentary and MVPA bouts with cardiometabolic risk factors suggest the need of the more detailed analysis for sedentary behavior and its effects on health risks.

Duration and intensity of different types of physical activity among children aged 10-13 years

OBJECTIVES

To use a predominately objective measurement approach to assess and describe: (1) the amount of time that children aged 10-13 years spend participating in outdoor active play, active travel, curriculum-based physical activity at school, and organized sport; (2) the movement intensity composition of these four types of physical activity (i.e., % of time spent at a sedentary, light, or moderate-to-vigorous intensity); and (3) the proportion of each movement intensity obtained by participating in these four types of physical activity.

METHODS

Three hundred seventy-seven children aged 10-13 years from Kingston, Canada, were studied. Children wore an accelerometer and GPS watch for 7 days and recorded the start and end times of the school day, recess periods, and organized sport sessions on a log. These data were used to estimate time spent in the four types of physical activity and the movement intensity composition of these activities.

RESULTS

Time spent in outdoor active play (36 min/day) and organized sport (40 min/day) was higher than that for active travel (17 min/day) and curriculum-based physical activity (26 min/day). With the exception of organized sport, values were higher for boys than for girls. Older children accumulated less outdoor active play and more active travel than younger children. The greatest proportion of light- and moderate-to-vigorous-intensity movement was attributed to outdoor active play.

CONCLUSION

We used a primarily objective measurement approach to assess and describe the amount of time children aged 10-13 participate in four types of physical activity. These descriptive findings could be used to identify target areas for physical activity interventions and policies.

Association between breaks in sitting time and adiposity in Australian toddlers: Results from the GET-UP! study

BACKGROUND

In youth, research on the health benefits of breaking up sitting time is inconsistent. Our aim was to explore the association between the number of breaks in sitting time and adiposity in Australian toddlers.

METHODS

This study comprised 266 toddlers (52% boys), aged 19.6 ± 4.2 months from the GET-UP! Study, Australia. Body mass index (BMI) was calculated and z-scores by age and sex were computed for waist circumference (WC). Participants were classified as overweight according to the WHO criteria for BMI. For WC, participants with a z-score≥1SD were considered overweight. Sitting time was assessed with activPALs during childcare hours and participants were classified by tertiles of the number of breaks/h in sitting time: <26 breaks/h; 26-39 breaks/h, and >39 breaks/h. Logistic regression assessed odds ratios for non-overweight (BMI or waist circumference categories) by number of breaks in sitting time/h, controlling for age, sex, and socioeconomic status.

RESULTS

The number of breaks in sitting time significantly predicted a lower weight status (non-overweight) according to WC values (P for trend = 0.032) after adjustments.

CONCLUSIONS

Breaking up sitting time was positively associated with toddlers' waist circumference. Future studies are needed to determine whether breaking up sitting time is a protective for cardiometabolic health in toddlers.

Longitudinal associations of physical activity and sedentary time with cardiometabolic risk factors in children

BACKGROUND

There are few prospective studies on the associations of changes in objectively measured vigorous physical activity (VPA_∆ ), moderate-to-vigorous physical activity (MVPA_∆ ), light physical activity (LPA_∆ ), and sedentary time (ST_∆ ) with changes in cardiometabolic risk factors (_∆ ) in children. We therefore investigated these relationships among children.

METHODS

The participants were a population sample of 258 children aged 6-8 years followed for 2 years. We assessed PA and ST by a combined heart rate and movement sensor; computed continuous age- and sex-adjusted z-scores for waist circumference, blood pressure, and fasting insulin, glucose, triglycerides, and high-density lipoprotein (HDL) cholesterol; and constructed a cardiometabolic risk score (CRS) of these risk factors. Data were analyzed using linear regression models adjusted for age, sex, the explanatory and outcome variables at baseline, and puberty.

RESULTS

VPA_∆ associated inversely with CRS_∆ (β = -0.209, P = 0.001), body fat percentage (BF%)_∆ (β = -0.244, P = 0.001), insulin_∆ (β = -0.220, P = 0.001), and triglycerides_∆ (β = -0.164, P = 0.012) and directly with HDL cholesterol_∆ (β = 0.159, P = 0.023). MVPA_∆ associated inversely with CRS_∆ (β = -0.178, P = 0.012), BF%_∆ (β = -0.298, P = <0.001), and insulin_∆ (β = -0.213, P = 0.006) and directly with HDL cholesterol_∆ (β = 0.184, P = 0.022). LPA_∆ only associated negatively with CRS_∆ (β = -0.163, P = 0.032). ST_∆ associated directly with CRS_∆ (β = 0.218, P = 0.003), BF%_∆ (β = 0.212, P = 0.016), and insulin_∆ (β = 0.159, P = 0.049).

CONCLUSIONS

Increased VPA and MVPA and decreased ST were associated with reduced overall cardiometabolic risk and major individual risk factors. Change in LPA had weaker associations with changes in these cardiometabolic risk factors. Our findings suggest that increasing at least moderate-intensity PA and decreasing ST decrease cardiometabolic risk in children.

Not all sedentary behaviour is equal: Children's adiposity and sedentary behaviour volumes, patterns and types

OBJECTIVE

The importance of different constructs of sedentary behaviours in relation to childhood obesity is uncertain. Thus, this study aimed to investigate relationships between volume, patterns and types of sedentary behaviour and adiposity in children.

METHODS

A case-control study was undertaken involving 234 children aged 10-13years who were either of a healthy-weight (74 boys, 56 girls) or classified as obese (56 boys, 48 girls). Percent body fat (by dual-energy X-ray absorptiometry) and waist-to-height ratio were assessed. Time, type (television, videogame, computer, eating, passive transport) and bout length of sedentary behaviours were measured using accelerometry and the Multimedia Activity Recall for Children and Adolescents. Time use (total daily energy expenditure, sleep, physical activity), age, household income and Tanner stage were covariates in sex-stratified partial least squares analyses.

RESULTS

Daily energy expenditure and income were negatively associated with adiposity for both sexes. Television time was consistently positively associated with adiposity. In boys only, prolonged bouts of sedentary behaviour and time spent playing video games/computer were positively linked with adiposity. Non-screen sedentary behaviour was negatively associated with adiposity in girls. Independent of total energy expenditure, total sedentary time was only inconsistently associated with fatness.

CONCLUSIONS

These data suggest that (1) characteristics of sedentary time other than duration are associated with adiposity in children, and (2) associations may be sex-specific.

Associations between activity patterns and cardio-metabolic risk factors in children and adolescents: A systematic review

INTRODUCTION

Total volumes of physical activity and sedentary behaviour have been associated with cardio-metabolic risk profiles; however, little research has examined whether patterns of activity (e.g., prolonged bouts, frequency of breaks in sitting) impact cardio-metabolic risk. The aim of this review was to synthesise the evidence concerning associations between activity patterns and cardio-metabolic risk factors in children and adolescents aged 5-19 years.

MATERIALS AND METHODS

A systematic search of seven databases was completed in October 2017. Included studies were required to report associations between objectively-measured activity patterns and cardio-metabolic risk factors in children and/or adolescents, and be published between 1980 and 2017. At least two researchers independently screened each study, extracted data, and undertook risk of bias assessments.

RESULTS

From the 15,947 articles identified, 29 were included in this review. Twenty-four studies were observational (cross-sectional and/or longitudinal); five were experimental. Ten studies examined physical activity patterns, whilst 19 studies examined sedentary patterns. Only one study examined both physical activity and sedentary time patterns. Considerable variation in definitions of activity patterns made it impossible to identify which activity patterns were most beneficial to children's and adolescents' cardio-metabolic health. However, potential insights and current research gaps were identified.

DISCUSSION AND CONCLUSION

A consensus on how to define activity patterns is needed in order to determine which activity patterns are associated with children's and adolescents' cardio-metabolic risk. This will inform future research on the impact of activity patterns on children's and adolescents' short- and longer-term health.

Does the type of sedentary behaviors influence blood pressurein adolescents boys and girls? A cross-sectional study

Abstract The aim of this study was to analyze the association between different sedentary behaviors and high blood pressure in adolescent boys and girls. We conducted a cross-sectional study with 6,264 Brazilian adolescents (14 to 19 years old). Demographic data, obesity indicators and blood pressure, were evaluated. Time spent in the sedentary behaviors (television viewing, playing video games, using the computer, non-screen sitting and, total time sitting) were also assessed. The girls spent more time watching television than boys, whereas boys spent more time using computers and video games (12.7% vs. 7.4%, p < 0.001) than girls. Boys who watched more than four hours of television presented higher odds to give high blood pressure after adjustments for physical activity level, body mass index, age and educational level of mother (OR = 2.27, p < 0.001). In girls, we did not find a relation between sedentary behaviors and high blood pressure (p > 0.05). Television viewing time is associated with high blood pressure only boys. So, reduce this sedentary behavior, stimulating physical activities, might be essential to health, principally for male adolescents.

AEROBIC TRAINING IN OBESE ADOLESCENTS: A MULTIDISCIPLINARY APPROACH

ABSTRACT Introduction: The prevalence of excess weight/obesity in adolescence has increased, and physical training may be effective in combating this scenario. Objective: To analyze the effect of different intensities of aerobic training on the body composition of obese adolescents undergoing multidisciplinary intervention. Methods: In this study, 107 pubertal (Tanner 3 and 4), obese (BMI=34.72±4.10 kg/m²) adolescents (14.85±1.44 years) were randomly assigned to three groups: high intensity training (HITG – ventilatory threshold I (VTI)); low intensity training (LITG – 20% below the VTI) and control group (CG), without intervention. The adolescents in the HITG and LITG underwent nutritional and psychological (1x/week) and clinical (1 x/month) follow-up and physical training (3x/week) for 12 weeks. Results: Reductions in fat mass (FM) and body fat percentage (BFP) (p< 0.001) and an increase in fat-free mass (FFM) (p<0.001) were observed in all groups. There was a reduction in BMI only in the experimental groups (p<0.001). Conclusion: The effects of multidisciplinary treatment on the body composition of obese adolescents occur independently of the intensity of aerobic physical training. Level of Evidence I; High quality randomized clinical studies with or without statistically significant difference, but with narrow confidence intervals.

A comparison of 10 accelerometer non-wear time criteria and logbooks in children

BACKGROUND

There are many unresolved issues regarding data reduction algorithms for accelerometry. The choice of criterion for removal of non-wear time might have a profound influence on physical activity (PA) and sedentary time (SED) estimates. The aim of the present study was to compare 10 different non-wear criteria and a log of non-wear periods in 11-year-old children.

METHODS

Children from the Active Smarter Kids study performed 7-days of hip-worn accelerometer monitoring (Actigraph GT3X+) and logged the number of non-wear periods each day, along with the approximate duration and reason for non-wear. Accelerometers were analyzed using 10 different non-wear criteria: ≥ 10, 20, 30, 45, 60, and 90 min of consecutive zero counts without allowance for interruptions, and ≥60 and 90 min with allowance for 1 and 2 min of interruptions.

RESULTS

891 children provided 5203 measurement days, and reported 1232 non-wear periods ranging from 0 to 3 periods per day: on most days children reported no non-wear periods (77.1% of days). The maximum number of non-wear periods per day was 2 for the 90-min criterion, 3 to 5 for most criteria, 7 for the 20-min criterion, and 20 for the 10-min criterion. The non-wear criteria influenced overall PA (mean values across all criteria: 591 to 649 cpm; 10% difference) and SED time (461 to 539 min/day; 17% difference) estimates, especially for the most prolonged SED bouts. Estimates were similar for time spent in intensity-specific (light, moderate, vigorous, and moderate-to-vigorous) PA, but varied 6-9% among the non-wear criteria for proportions of time spent in intensity-specific PA (% of total wear time).

CONCLUSIONS

Population level estimates of PA and SED differed between different accelerometer non-wear criteria, meaning that non-wear time algorithms should be standardized across studies to reduce confusion and improve comparability of children's PA level. Based on the numbers and reasons for non-wear periods, we suggest a 45 or 60-min consecutive zero count-criterion not allowing any interruptions to be applied in future pediatric studies, at least for children older than 10 years.

TRIAL REGISTRATION

The study is registered in Clinicaltrials.gov with identification number NCT02132494 . Registered 7 April 2014.

Cross-sectional and prospective mediating effects of dietary intake on the relationship between sedentary behaviour and body mass index in adolescents

BACKGROUND

Cross-sectional evidence suggests TV viewing, but not objectively-measured sedentary time or bouts of sedentary time, is consistently associated with body mass index (BMI) in adolescents. However, it is unclear whether dietary intake is a potential mediator of these relationships. The aim of this study was to explore the cross-sectional and prospective mediating effects of dietary intake on the association of sedentary behaviour with BMI z-score (zBMI) in a cohort of Australian adolescents.

METHODS

Cross-sectional and prospective analyses were conducted in adolescents aged 12-15 years participating in the 2002/03 (baseline) and 2004/05 (follow-up) Nepean Growing Up Study. The independent variables were television (TV) viewing, an objective measure of total sedentary time and average sedentary bout duration, and the outcome variable zBMI. Using the Sobel-Goodman method with bootstrapping, mediation analyses were conducted examining three dietary components (discretionary foods, sugar-sweetened beverages [SSB] and takeaway foods) as mediators of associations between TV viewing and zBMI (n = 259) and between total sedentary time and average sedentary bout duration with zBMI (n = 140).

RESULTS

No significant cross-sectional or prospective total or direct associations were observed for TV viewing, total sedentary time and average sedentary bout duration with zBMI. However, TV viewing was positively associated with consumption of takeaway foods cross-sectionally (β = 0.06; 95% CI 0.01 to 0.12), prospectively at baseline (β = 0.07; 95% CI 0.01 to 0.12) and prospectively at follow-up (β = 0.10; 95% CI 0.04, 0.16), and average sedentary bout duration was inversely associated with SSB consumption both cross-sectionally (β = -0.36; 95% CI -0.69 to -0.02) and prospectively at baseline (β = -0.36; 95% CI -0.70 to -0.02). No mediation effects were identified.

CONCLUSIONS

TV viewing, total sedentary time and bouts of sedentary time were not associated cross-sectionally or prospectively with adolescents' zBMI, and three elements of dietary intake (e.g. intake of discretionary foods, SSB and takeaway foods) did not mediate this relationship. The role of dietary intake and sedentary behaviour in relation to adolescent health requires further clarification.

Isotemporal Substitution Analysis for Sedentary Behavior and Body Mass Index

PURPOSE

This study examined the prospective associations of reallocating time spent in different types of sedentary behavior, physical activity, and sleep with body mass index (BMI) in children using isotemporal substitution analysis.

METHODS

Chinese children in grades 1-3 were recruited to a cohort study in 2009 and were followed up over a 2-yr period. Reports were gathered from the parents on children's sedentary behavior, sleep duration, and sociodemographic variables. The reported sedentary behavior types were then grouped into three categories: screen time (e.g., watching TV), academic-related activities (e.g., doing homework), and other sedentary behaviors (e.g., sitting and talking). Moderate-to-vigorous physical activity (MVPA) and light-intensity physical activity were assessed by ActiGraph accelerometry (ActiGraph, Pensacola, FL). Isotemporal substitution models were performed to examine the effects of time allocation on BMI.

RESULTS

A total of 672 children (359 boys, mean age at recruitment = 7.6 yr) who had provided valid accelerometer data for at least one assessment time point were included in the analysis. Controlling for covariates and total behavior time, isotemporal substitution models indicated that the displacement of 30 min·d of other sedentary behaviors with equal amounts of screen time (B = 0.12; 95% confidence interval, 0.04-0.20) or academic-related activities (B = 0.13; 95% confidence interval, 0.04-0.21) was associated with higher BMI. Reallocating 30 min·d of MVPA with each of the sedentary behavior variables resulted in increased BMI.

CONCLUSIONS

The substitution of screen time or academic-related activities with other sedentary behaviors or MVPA was associated with lower BMI in Chinese children.

Objectively measured physical activity patterns, sedentary time and parent-reported screen-time across the day in four-year-old Swedish children

Background

Physical activity (PA) improves health outcomes accumulating evidence suggests that sedentary time (ST), especially parent-reported screen-time, is associated with negative health outcomes in children. The aim of the present study is to describe levels and patterns of PA and ST across the day and week and activity pattern differences between the sexes, across all weekdays and time spent in and outside the preschool in four-year old children.

Methods

In total 899 four-year old Swedish children who had both complete questionnaire data on screen-time behaviors and objective activity variables and at least 4 days, including one weekend day, with more than 10 h of GT3X+ Actigraph accelerometer wear time data were included in the study. Patterns of PA and ST across the day and week and differences between sexes, weekdays vs. weekend days and time in preschool vs. time spent outside preschool were assessed.

Results

Children engaged in 150 min (SD 73) and 102 min (SD 60) of screen-time on weekend days and weekdays, with 97% and 86% of children exceeding the 1 h guideline for screen-time on weekend days and weekdays, respectively. Accelerometer data showed that boys are more active and less sedentary compared with girls and both sexes were more active and less sedentary on weekdays compared with weekend days, while parent-reported data showed that boys engage in more screen-time compared with girls. Children accumulated 24.8 min (SD. 19) MVPA during preschool time and 26.6 min (SD. 16) outside preschool hours on weekdays, compared with 22.4 min (SD. 18) MVPA during preschool time and 25.3 min (SD. 22) outside preschool hours on weekend days.

Conclusions

Four-year old Swedish children display different activity patterns across the day on weekdays compared to weekend days, with preschool hours during weekdays being the most active segments and preschool hours during weekend days being the least active segments of the day.

Electronic supplementary material

The online version of this article (doi:10.1186/s12889-017-4600-5) contains supplementary material, which is available to authorized users.

Understanding differences between summer vs. school obesogenic behaviors of children: the structured days hypothesis

BACKGROUND

Although the scientific community has acknowledged modest improvements can be made to weight status and obesogenic behaviors (i.e., physical activity, sedentary/screen time, diet, and sleep) during the school year, studies suggests improvements are erased as elementary-age children are released to summer vacation. Emerging evidence shows children return to school after summer vacation displaying accelerated weight gain compared to the weight gained occurring during the school year. Understanding how summer days differ from when children are in school is, therefore, essential.

DISCUSSION

There is limited evidence on the etiology of accelerated weight gain during summer, with few studies comparing obesogenic behaviors on the same children during school and summer. For many children, summer days may be analogous to weekend days throughout the school year. Weekend days are often limited in consistent and formal structure, and thus differ from school days where segmented, pre-planned, restrictive, and compulsory components exist that shape obesogenic behaviors. The authors hypothesize that obesogenic behaviors are beneficially regulated when children are exposed to a structured day (i.e., school weekday) compared to what commonly occurs during summer. This is referred to as the 'Structured Days Hypothesis' (SDH). To illustrate how the SDH operates, this study examines empirical data that compares weekend day (less-structured) versus weekday (structured) obesogenic behaviors in U.S. elementary school-aged children. From 190 studies, 155 (~80%) demonstrate elementary-aged children's obesogenic behaviors are more unfavorable during weekend days compared to weekdays.

CONCLUSION

In light of the SDH, consistent evidence demonstrates the structured environment of weekdays may help to protect children by regulating obesogenic behaviors, most likely through compulsory physical activity opportunities, restricting caloric intake, reducing screen time occasions, and regulating sleep schedules. Summer is emerging as the critical period where childhood obesity prevention efforts need to be focused. The SDH can help researchers understand the drivers of obesogenic behaviors during summer and lead to innovative intervention development.