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BACKGROUND: This cross-sectional study analyzed the association of leisure-time physical activity (PA) and sedentary behavior (SB), nonleisure PA and SB, and total PA and SB in different time segments of the day with mental health among Dutch adolescents and young adults. METHODS: A total of 881 participants aged 16-25 years completed an online survey. Mental health was assessed using the Mental Health Inventory-5, and participants also reported sex, age, and income. They filled out a questionnaire of types of PA and SB for each hour of the day. Activities were categorized into nonleisure and leisure, during the morning, afternoon, evening, and for the whole day. RESULTS: Participants (52.8% female, on average 20.8 y) generally engaged in more leisure-time PA and SB during weekends compared with weekdays, and more nonleisure activities on weekdays. Associations varied between time segments and days of the week. Positive associations of leisure-time and total PA during the whole day and evenings with mental health were observed on weekdays. Total, leisure-time, and nonleisure-time SB were associated with worse mental health. Nonleisure PA was not associated with mental health. CONCLUSIONS: Leisure-time PA was found to have a favorable association with mental health, particularly in the evenings of weekdays and afternoons of weekend days. On the other hand, leisure SB was associated with poorer mental health in most of the time segments analyzed, and nonleisure SB in the evenings was also related to worse mental health. The type and timing of PA and SB behaviors play an important role in the relationship with mental health.
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Exercício Físico , Saúde Mental , Comportamento Sedentário , Adolescente , Feminino , Humanos , Masculino , Adulto Jovem , Estudos Transversais , Exercício Físico/psicologia , Exercício Físico/estatística & dados numéricos , Saúde Mental/estatística & dados numéricos , Fatores de Tempo , Adulto , Inquéritos Epidemiológicos , Países BaixosRESUMO
Traditional risk factors for obesity and the metabolic syndrome, such as excess energy intake and lack of physical activity, cannot fully explain the high prevalence of these conditions. Insufficient sleep and circadian misalignment predispose individuals to poor metabolic health and promote weight gain and have received increased research attention in the past 10 years. Insufficient sleep is defined as sleeping less than recommended for health benefits, whereas circadian misalignment is defined as wakefulness and food intake occurring when the internal circadian system is promoting sleep. This Review discusses the impact of insufficient sleep and circadian misalignment in humans on appetite hormones (focusing on ghrelin, leptin and peptide-YY), energy expenditure, food intake and choice, and risk of obesity. Some potential strategies to reduce the adverse effects of sleep disruption on metabolic health are provided and future research priorities are highlighted. Millions of individuals worldwide do not obtain sufficient sleep for healthy metabolic functions. Furthermore, modern working patterns, lifestyles and technologies are often not conducive to adequate sleep at times when the internal physiological clock is promoting it (for example, late-night screen time, shift work and nocturnal social activities). Efforts are needed to highlight the importance of optimal sleep and circadian health in the maintenance of metabolic health and body weight regulation.
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Ritmo Circadiano , Privação do Sono , Humanos , Privação do Sono/complicações , Privação do Sono/epidemiologia , Privação do Sono/metabolismo , Ritmo Circadiano/fisiologia , Sono/fisiologia , Obesidade/metabolismo , Aumento de Peso/fisiologiaRESUMO
Physical activity (PA) and sedentary behaviour (SED) have been linked to the mental health of children and adolescents, yet the timing of behaviours may play a role in this relationship and clarifying this could inform interventions. We explored cross-sectional associations of PA and SED in varying time segments throughout the school day with the mental health of school-aged children and adolescents from rural Northeastern Ontario, Canada. A total of 161 students (56% female, M = 10.3 years old) wore accelerometers for 8 days (7 nights) and completed a self-report survey (parent reported for children younger than 11). Mental health was measured using the Strengths and Difficulties Questionnaire. Accelerometer-measured SED, light PA (LPA), and moderate and vigorous PA (MVPA) were estimated in the time-segments before school (06:00-08:44), school time (08:45-15:04), after school (15:05-16:59), and evenings (17:00-21:59). Associations were tested with multilevel linear regressions while adjusting for confounding factors. Students spent 72.6 min in MVPA, 209.0 min in LPA, and 621.0 min in SED per day. Daily SED was associated with less conduct problems (ß = -0.27, p < 0.05). Evening LPA was inversely associated with hyperactivity (ß = -1.45, p < 0.05), while SED was associated with hyperactivity and with peer problems before school (ß = 1.70 and ß = 1.01, respectively, p < 0.05), and during school (ß = -0.83 and ß = -0.57, respectively, p < 0.05). No associations were observed for MVPA, emotional symptoms, or prosocial behaviour. In conclusion, displacing SED with LPA in some specific periods of the day may benefit the mental health of students; taking this into account could strengthen interventions.
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INTRODUCTION: To continue to inform sleep health guidelines and the development of evidence-based healthy sleep interventions for children and adolescents, it is important to better understand the associations between sleep timing (bedtime, wake-up time, midpoint of sleep) and various health indicators. The objective of this systematic review was to examine the associations between sleep timing and 9 health indicators in apparently healthy children and adolescents 5 to 18 years old. METHODS: Studies published in the 10 years preceding January 2021 were identified from searches in four electronic databases. This systematic review followed the guidelines prescribed in PRISMA 2020, the methodological quality and risk of bias were scored, and the summary of results used a best-evidence approach for accurate and reliable reporting. RESULTS: Forty-six observational studies from 21 countries with 208 992 unique participants were included. Sleep timing was assessed objectively using actigraphy in 24 studies and subjectively in 22 studies. The lack of studies in some of the health outcomes and heterogeneity in others necessitated using a narrative synthesis rather than a metaanalysis. Findings suggest that later sleep timing is associated with poorer emotional regulation, lower cognitive function/academic achievement, shorter sleep duration/ poorer sleep quality, poorer eating behaviours, lower physical activity levels and more sedentary behaviours, but few studies demonstrated associations between sleep timing and adiposity, quality of life/well-being, accidents/injuries, and biomarkers of cardiometabolic risk. The quality of evidence was rated as "very low" across health outcomes using GRADE. CONCLUSION: The available evidence, which relies on cross-sectional findings, suggests that earlier sleep timing is beneficial for the health of school-aged children and adolescents. Longitudinal studies and randomized controlled trials are needed to better advance this field of research. (PROSPERO registration no.: CRD42020173585).
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Qualidade de Vida , Sono , Adiposidade/fisiologia , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Humanos , Sono/fisiologia , Fatores de TempoRESUMO
BACKGROUND: The purpose of this systematic review was to examine the associations between school-related sedentary behaviours and indicators of health and well-being in children and youth (~ 5-18 years) attending school. METHODS: This review was conducted to inform the development of School-Related Sedentary Behaviour Recommendations. Peer-reviewed, published, or in-press articles in English were included. Reviews, meta-analyses, and case studies were excluded; all other study designs were eligible. Further, articles had to meet the a priori study criteria for population, intervention, comparator (PROSPERO ID: CRD42021227600). Embase, MEDLINE® ALL, and PsycINFO were searched. Risk of bias was assessed for individual experimental studies using the Cochrane risk of bias assessment tool, and in observational studies based on the GRADE framework and in line with previous systematic reviews examining sedentary behaviours in children. Overall quality of evidence was assessed using the GRADE framework for each outcome category and study design. Results were synthesized narratively, grouped by study design and outcome category. Further, several high-level summaries were conducted to help interpret results. RESULTS: Evidence was synthesized from 116 reports, including 1,385,038 participants and 1173 extracted associations. More school-related sedentary behaviour was favourably associated with nearly one-third of extracted associations for cognitive (33%) and social-emotional (32%) indicators (e.g., less anxiety), but unfavourably associated with other movement behaviours (e.g., less physical activity) (35%). Active lessons were favourable (72%), compared to more school-related sedentary behaviours, when examining associations for all health and well-being indicators. More homework was favourable across all health and well-being indicators in 4% of extracted associations for primary school children, and 25% of extracted associations for secondary school children. However, ≥2 h/day of homework appeared to be unfavourable for health and well-being. Limitations for synthesized studies included generally low quality of evidence and a lack of studies in South American, African, or low-middle income countries. CONCLUSIONS: Findings can help inform policy makers, schools, and teachers, regarding the amount of homework assigned and the introduction of active lessons into the classroom to enhance health and well-being of children. More research is needed examining school-related sedentary behaviours and indicators of health and well-being in low- and middle-income countries.
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Exercício Físico , Comportamento Sedentário , Adolescente , Criança , Humanos , Instituições AcadêmicasRESUMO
BACKGROUND: Existing sedentary behaviour guidelines for children and youth target overall sedentary behaviour and recreational screen time, without any specific recommendations regarding school-related sedentary behaviours (i.e., sedentary behaviours performed during the school day, or within the influence of school). The purpose of this paper is to describe the development of international evidence-based recommendations for school-related sedentary behaviours for children and youth, led by the Sedentary Behaviour Research Network (SBRN). METHODS: A panel of international experts was convened by SBRN in November 2020 to guide the development of these recommendations for children and youth aged ~ 5-18 years. The recommendations were informed by 1) age-relevant existing sedentary behaviour guidelines, 2) published research on the relationship between overall sedentary behaviour and health, 3) a de novo systematic review on the relationship between school-related sedentary behaviours and health and/or academic outcomes, and 4) a de novo environmental scan of the grey literature to identify existing recommendations for school-related sedentary behaviours. Draft recommendations were presented to the Expert Panel in June 2021. Following thorough discussion and modifications, updated recommendations were distributed for stakeholder feedback from July 9-26. Feedback was received from 148 stakeholders across 23 countries, leading to additional updates to the recommendations. Following further rounds of discussion and updates with the Expert Panel in August and September 2021, consensus was achieved on the final recommendations. RESULTS: A healthy day includes breaking up extended periods of sedentary behaviour and incorporating different types of movement into homework whenever possible, while limiting sedentary homework. School-related screen time should be meaningful, mentally or physically active, and serve a specific pedagogical purpose that enhances learning. Replacing sedentary learning activities with movement-based learning activities, and replacing screen-based learning activities with non-screen-based learning activities, can further support students' health and wellbeing. DISCUSSION: This paper presents the first evidence-based recommendations for school-related sedentary behaviours for children and youth. These recommendations will support the work of parents, caregivers, educators, school system administrators, policy makers, researchers and healthcare providers interested in promoting student health and academic success.
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Exercício Físico , Comportamento Sedentário , Adolescente , Idoso , Criança , Humanos , Instituições Acadêmicas , Tempo de Tela , EstudantesRESUMO
BACKGROUND: The energy-adjusted Dietary Inflammatory Index (E-DII™) has been associated with a high body mass index and markers of chronic diseases. Also, pro-inflammatory diets with a high E-DII have been positively associated with metabolic disturbances such as glucose intolerance and type II diabetes mellitus. However, it is unclear whether E-DII scores are positively associated with body fat percentage and visceral fat per se. This cross-sectional study aimed to evaluate whether the E-DII is associated with body fat content and metabolic health indicators in lean and obese young men. METHODS: The present study was conducted on 59 participants, without comorbidities, not using tobacco, medication and nutritional supplements. Dietary data were obtained by 3-day food records to calculate E-DII scores based on 28 food parameters. Body composition was assessed by dual X-ray absorptiometry (DXA). Blood samples were taken to measure fasting glucose, insulin, triacylglycerols, total cholesterol, and low- and high-density lipoprotein cholesterol. An oral glucose tolerance test also was performed. Associations were determined by mixed-effects linear regression. RESULTS: E-DII scores ranged from -3.48 to +3.10. Energy intake was similar across E-DII tertiles. After adjusting for covariates, the highest E-DII tertile was associated with increased body fat, visceral adipose tissue and waist circumference. There was no association between E-DII scores and glycaemic parameters. CONCLUSIONS: In young participants, a dietary pattern with a higher E-DII (i.e., pro-inflammatory) score was associated with high body fat and markers of central adiposity assessed by DXA, regardless of body mass.
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Diabetes Mellitus Tipo 2 , Gordura Intra-Abdominal , Adulto , Masculino , Humanos , Diabetes Mellitus Tipo 2/complicações , Estudos Transversais , Dieta , Índice de Massa Corporal , Obesidade/complicações , Tecido Adiposo , HDL-Colesterol , Biomarcadores , InflamaçãoRESUMO
Dry forests in the Caatinga biome of Brazil are seasonal ecosystems where diversity is driven by water availability. Understanding how the distribution of communities is driven by temporal climate changes has intrigued researchers for decades. However, temporal diversity patterns should be more evident in dry environments, since seasonality is characterized by being highly limiting to insect activities. Cerambycid beetles are considered good ecological indicators because they respond well to impacts of environmental changes. Thus, we asked two questions: (i) How do climatic changes affect the diversity of these insects across seasons? (ii) Are diversity components correlated with increasing air humidity, rainfall, and temperature? Our results showed a marked seasonality of cerambycid beetles, with higher abundance and richness in the wet season. The mean temperature and relative humidity were predictors of the composition of beetle assemblages. However, the variation of cerambycid assemblages between seasons is related mainly to species turnover. Our study demonstrates that the combined effect of temperature and humidity drives the temporal distribution of the cerambycids in dry forests. Although thermal sensitivity was low, the decrease in air moisture during the dry season was the limiting factor for these insects. Species turnover increased continuously with air moisture and temperature rise, creating temporal segregation among cerambycid species and maintaining the stability of the assemblage. Thus, our results are consistent with mechanisms invoking activity patterns, desiccation resistance, and physiologic constraints that predict a decrease in richness and abundance of the cerambycids from warmer and moister to colder and drier conditions.
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Besouros , Animais , Biodiversidade , Besouros/fisiologia , Ecossistema , Florestas , Estações do AnoRESUMO
BACKGROUND: Behavioral changes during adolescence are affected by biological and social aspects. However, environment aspects, which are beyond adolescents' control, also contribute to behavior adoption, and school may have a significant impact in these behaviors. This cross-sectional study aims to investigate how lifestyle behaviors are associated with the school shift attended by high school students. METHODS: The sample comprised 635 high school students (51.2% girls, 16.33 ± 1.0 years old) from Southern Brazil. Physical activities of different intensities (light and moderate-to-vigorous), sedentary behaviors, and sleep (duration, efficiency, and timing) were measured using accelerometers. Engagement in sport and non-sport activities, screen time indicators, and diet were self-reported. Linear models were fitted to compare each lifestyle behavior between the two school shifts. RESULTS: Students attending the afternoon shift slept (ß = 01:29 95%CI 01:13; 01:46) and woke up later (ß = 01.41 95%CI 01:27; 01:54), and had a longer sleep duration (ß = 00:12 95%CI 0:02; 00:21) than those attending the morning shift. However, the sleep efficiency of those in the afternoon shift was lower than their peers in the morning shift (ß = -1.89 95%CI -3.01; -0.77). CONCLUSIONS: School schedule was associated with sleep behaviors of adolescents, but not with other lifestyle behaviors.
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Ritmo Circadiano , Tempo de Tela , Adolescente , Estudos Transversais , Dieta , Exercício Físico , Feminino , Humanos , Masculino , Instituições Acadêmicas , Sono , Inquéritos e QuestionáriosRESUMO
Physical activity is influenced by an interplay of time and setting, thus, the role of psychosocial factors on behavior is expected to vary across the day. This cross-sectional study identified the psychosocial correlates of time spent in physical activity during in-school (i.e., 08:00-11:59) and out-of-school (i.e., 12:00-22:00) time segments. The sample consisted of adolescents (7th to 9th grade) of two public schools in Florianópolis, Brazil. Accelerometer measured light-intensity (LPA) and moderate-to-vigorous-intensity physical activity (MVPA) were estimated. Psychosocial correlates of physical activity (i.e., outcome expectations, attitude, self-efficacy, support from parents, and support from peers) were self-reported. Linear mixed models were applied and interaction effects of gender and age were also analyzed. From a total of 194 participants, 138 and 112 provided in-school and out-of-school valid data, respectively. Outcome expectations were associated with out-of-school MVPA (ß = 0.18; p = .006). Age interaction effects were observed for the associations between outcome expectations and out-of-school LPA (ß = 0.21; p = .009) and between self-efficacy and out-of-school MVPA (ß = 0.19; p = .009). In conclusion, psychosocial correlates were positively associated with out-of-school physical activity and the effects varied according to age. No psychosocial correlates were identified for LPA and MVPA performed during schooltime.
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Acelerometria , Comportamento Sedentário , Adolescente , Brasil/epidemiologia , Estudos Transversais , Exercício Físico/psicologia , Humanos , Instituições AcadêmicasRESUMO
It is shown that in the "Comment on 'Deformed Fokker-Planck equation: Inhomogeneous medium with a position-dependent mass,"' three crucial observations have gone unnoticed, thus restricting its conclusion on the legitimacy of the Langevin equation for a position-dependent mass, Eq. (46) of da Costa et al. [Phys. Rev. E 102, 062105 (2020)2470-004510.1103/PhysRevE.102.062105].
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Schools have been the main context for physical activity (PA) and sedentary behavior (SB) interventions among adolescents, but there is inconsistent evidence on whether they also improve dimensions of the health-related quality of life (HRQoL). The aim of this study was to evaluate the effects of a school-based active lifestyle intervention on dimensions of HRQoL. A secondary aim was to verify whether sex, age, and HRQoL at baseline were moderators of the intervention effect. A cluster-randomized controlled trial was conducted at three control and three intervention schools in Florianopolis, Brazil. All students from 7th to 9th grade were invited to participate. A school year intervention, designed primarily to increase PA and reduce SB, included strategies focused on (i) teacher training on PA, SB, and nutrition, and availability of teaching materials related to these contents; (ii) environmental improvements (i.e., creation and revitalization of spaces for the practice of PA in school); and (iii) education strategies, with the availability of folders and posters regarding PA, SB, and nutrition. Participants and the research staffs were not blinded to group assignment, but a standardized evaluation protocol was applied at baseline and after the intervention (March and November 2017) using the KIDSCREEN-27 to assess HRQoL across five dimensions. Mixed linear models were performed to evaluate the effect of the Movimente intervention on the five HRQoL dimensions. Of the 921 students who answered the questionnaire at baseline, 300 and 434 completed the study in control and intervention groups, respectively (dropouts: 20%). The results revealed no significant effects of the intervention on any HRQoL dimensions. A reduction of the school environment dimension was observed in both the control (-2.44; 95% CI: -3.41 to -1.48) and intervention groups (-2.09; 95% CI: -2.89 to -1.30). Sensitivity analyses showed that students in the highest baseline tertiles of HRQoL in any dimension had a reduction in their respective scores from pre- to post-intervention in both school groups. In conclusion, our results demonstrated no intervention effect on HRQoL dimensions and those students with the highest levels of HRQoL at baseline on all dimensions reduced from pre to post-intervention. CLINICAL TRIAL REGISTRATION: The trial is registered at the Clinical Trial Registry (Trial ID: NCT02944318; date of registration: October 18, 2016).
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Bacteria used in the production of fermented food products have been investigated for their potential role as modulators of inflammation in gastrointestinal tract disorders such as inflammatory bowel diseases (IBD) that cause irreversible changes in the structure and function of gut tissues. Ulcerative colitis (UC) is the most prevalent IBD in the population of Western countries, and it is marked by symptoms such as weight loss, rectal bleeding, diarrhea, shortening of the colon, and destruction of the epithelial layer. The strain Propionibacterium freudenreichii CIRM-BIA 129 recently revealed promising immunomodulatory properties that greatly rely on surface-layer proteins (Slp), notably SlpB. We, thus, cloned the sequence encoding the SlpB protein into the pXIES-SEC expression and secretion vector, and expressed the propionibacterial protein in the lactic acid bacterium Lactococcus lactis NCDO 2118. The probiotic potential of L. lactis NCDO 2118 harboring pXIES-SEC:slpB (L. lactis-SlpB) was evaluated in a UC-mice model induced by Dextran Sulfate Sodium (DSS). During colitis induction, mice receiving L. lactis-SlpB exhibited reduced severity of colitis, with lower weight loss, lower disease activity index, limited shortening of the colon length, and reduced histopathological score, with significant differences, compared with the DSS group and the group treated with L. lactis NCDO 2118 wild-type strain. Moreover, L. lactis-SlpB administration increased the expression of genes encoding tight junction proteins zo-1, cln-1, cln-5, ocln, and muc-2 in the colon, increased IL-10 and TGF-ß, and decreased IL-17, TNF-α, and IL-12 cytokines in the colon. Therefore, this work demonstrates that SlpB recombinant protein is able to increase the probiotic potential of the L. lactis strain to alleviate DSS-induced colitis in mice. This opens perspectives for the development of new approaches to enhance the probiotic potential of strains by the addition of SlpB protein.
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OBJECTIVE: To examine the association between physical activity, screen time, eating habits and daytime sleepiness among Brazilian adolescents. METHODS: Adolescents from three high schools (n = 876, 49.8% female, 16.4 ± 1.2 years) participated in this cross-sectional survey. Variables related to lifestyle behaviors (ie, physical activity, screen time, eating habits, sleep duration) were collected through an online questionnaire. Daytime sleepiness was assessed using the Pediatric Daytime Sleepiness Scale (PDSS). Excessive daytime sleepiness was defined as a PDSS score ≥20. RESULTS: The average PDSS score was 18.9 (SD ± 4.8) points and 46.8% of adolescents were classified as having excessive daytime sleepiness. Physical activity was inversely associated with PDSS score (ß = -0.29, 95% CI -0.47; -0.11). Consuming processed foods frequently (ß = 1.16, 95% CI 0.85; 1.47) and using social media (ß = 0.22, 95% CI 0.14; 0.30) were positively associated with PDSS score. Similar findings were observed for the odds of excessive daytime sleepiness. Physical activity was inversely associated (OR = 0.91, 95% CI 0.84; 0.99), while frequent consumption of processed foods (OR = 1.55, 95% CI 1.33; 1.82) and using social media (OR = 1.13, 95% CI 1.02; 1.24) were positively associated with excessive daytime sleepiness. CONCLUSIONS: Lower physical activity level, a higher consumption processed foods, and higher social media use were associated with daytime sleepiness in this sample of Brazilian adolescents.
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Distúrbios do Sono por Sonolência Excessiva , Tempo de Tela , Adolescente , Brasil , Criança , Estudos Transversais , Dieta , Distúrbios do Sono por Sonolência Excessiva/epidemiologia , Exercício Físico , Feminino , Humanos , Masculino , Inquéritos e QuestionáriosRESUMO
This study aimed to examine the clustering of 24-h movement behaviors (moderate to vigorous physical activity, screen time, and sleep duration) and their association with cardiorespiratory fitness among adolescents. We evaluated 561 adolescents (52.1% girls; mean age, 13.0 ± 1.0 years) from Florianópolis, Brazil. A 20-m shuttle run was used to assess cardiorespiratory fitness, while a questionnaire was used to measure 24-h movement behaviors. A latent class analysis was performed to identify the clustering of 24-h movement behaviors, while linear Bayesian mixed-effect regression models were applied to identify their association with cardiorespiratory fitness. Two classes were identified: unhealthy (10.4%), characterized as a high probability of practicing less than 300 min/week of moderate to vigorous physical activity, spending more than 4 h/day in front of screens, and sleeping less than 8 h/day; and healthy (89.6%), characterized by a high probability of practicing more than 420 min/week of moderate to vigorous physical activity, spending less than 2 h/day in front of screens, and sleeping 8-10 h/day. Adolescents in the healthy class had a higher cardiorespiratory fitness level than those in the unhealthy class. Most adolescents were grouped in the healthy class and had higher cardiorespiratory fitness levels than those in the unhealthy class. These results suggest that families and professionals should work toward creating healthier lifestyles for adolescents by increasing opportunities to practice moderate to vigorous physical activity, reduce screen time, and favor healthy sleep to increase their cardiorespiratory fitness levels. What is Known: ⢠Moderate to vigorous physical activity, screen time, and sleep duration are positively, negatively, and inconsistently associated with cardiorespiratory fitness, respectively, when analyzed separately. ⢠Little is known about the clustering of 24-h movement behaviors and how they are associated with cardiorespiratory fitness levels in adolescents. What is New: ⢠The 24-h movement behaviors clustered into almost opposite classes among adolescents (healthy and unhealthy classes). ⢠Adolescents in the healthy class had greater cardiorespiratory fitness levels than those in the unhealthy class.
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Aptidão Cardiorrespiratória , Adolescente , Teorema de Bayes , Brasil , Criança , Análise por Conglomerados , Estudos Transversais , Exercício Físico , Feminino , Humanos , Análise de Classes Latentes , Masculino , Aptidão Física , Comportamento SedentárioRESUMO
BACKGROUND: The present cross-sectional study aimed to determine the proportion of adolescents meeting the 24-hour movement guidelines, and investigate sociodemographic factors associated with meeting them. METHODS: Self-reported (average daily volume of MVPA, sleep duration, and time watching videos and playing videogames) and accelerometer-measured (MVPA and sleep duration) 24-hour movement behaviors were classified according to recommendations, and sex, age, socioeconomic status (SES), family structure, parental education, and number of people in the household were tested as correlates of meeting recommendations using multilevel logistic regressions. RESULTS: The proportion of adolescents (n = 867, mean age: 16.4 years, 50.3% girls) meeting the MVPA, ST, and sleep duration guidelines was of 25%, 28%, and 41%, respectively, for self-reported data. From accelerometer data (n = 688), 7.1% met MVPA and 31.7% met sleep duration recommendations. Adherence to all three recommendations was 3% with self-report and 0.2% with accelerometer data. Boys were more likely to meet MVPA, but not ST and sleep-duration recommendations. A positive relationship was observed between age and meeting the ST recommendation. CONCLUSIONS: Adherence to the sleep duration recommendation was higher than to the screen-time and MVPA recommendations and few in this sample of Brazilian adolescents achieved the 24-hour guidelines. Efforts are needed to improve 24-hour movement behaviors.
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Exercício Físico , Guias como Assunto , Comportamento Sedentário , Sono , Fatores Socioeconômicos , Adolescente , Brasil , Estudos Transversais , Feminino , Humanos , Estudos Longitudinais , Masculino , Prevalência , AutorrelatoRESUMO
PURPOSE: Sedentary behavior (SB) has been shown to be associated with unhealthy outcomes in children, and it is not clear whether children living with human immunodeficiency virus (HIV) engage in different patterns of SB compared with healthy children. This cross-sectional study aimed to compare patterns of SB between children living with HIV and a healthy control group. METHODS: A group of children with HIV and a paired control group wore accelerometers for 1 week and answered a questionnaire with items related to television viewing habits and computer usage. Accelerometer-derived and self-reported SB were compared between children living with HIV and controls and between treatment-based and viral load subgroups. RESULTS: A total of 130 children (of which 53% are girls with a mean age of 12.1 y) participated in the study with 65 in each group. Children in the control group exhibited significantly more objectively measured SB daily when compared with the HIV group (515 vs 490 min/d, respectively), but no differences were found between the treatment-based and viral load subgroups. Children with HIV watched more television on weekdays, compared with the control group (P < .05). No other differences were found in comparisons of self-reported SB between the control and HIV and the treatment-based or viral load subgroups. CONCLUSION: Children living with HIV spend less time being sedentary than those in the healthy control group. Future studies are important for clarifying the causes and consequences of these differences.
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Infecções por HIV , Comportamento Sedentário , Autorrelato , Acelerometria , Adolescente , Terapia Antirretroviral de Alta Atividade , Brasil , Criança , Estudos Transversais , Feminino , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Tempo de Tela , TelevisãoRESUMO
OBJECTIVES: To identify the association of clusters of screen time (ST) behaviours with waist circumference (WC) and cardiorespiratory fitness (CRF) among adolescents. DESIGN: Cross-sectional study of 574 adolescents (53% girls, 13 years), conducted in 2017. METHODS: Waist circumference was measured, a shuttle run was performed to assess CRF, and a questionnaire was applied. Sex, age, socioeconomic status was reported, and daily duration of ST indicators for television viewing, computer use, videogame playing, and cellphone use, in weekdays and weekend days. Latent class analysis was performed to identify typologies of ST behaviours. Mixed-effects linear regressions were used to test the association of ST clusters with WC and CRF. RESULTS: Participants' WC was 66.9±8cm and CRF was 39.5±4mlO2/kg/min. Four clusters were identified: "Low ST" (25%); "High ST" (20%); "Gamers" (17%); and "High cellphone" (39%). No significant associations were found between ST clusters and WC. Maximum oxygen uptake was higher in those in the "Low ST" cluster compared to the other clusters. No significant interactions for sex were observed. CONCLUSIONS: Typologies of ST behaviours do not seem to be related to WC; however, those in the Low ST cluster had higher CRF compared to their peers in the other clusters, suggesting that total ST may be more important for CRF than specific indicators.
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Aptidão Cardiorrespiratória , Tempo de Tela , Comportamento Sedentário , Circunferência da Cintura , Adolescente , Estudos Transversais , Feminino , Humanos , Masculino , Inquéritos e QuestionáriosRESUMO
We present the Fokker-Planck equation (FPE) for an inhomogeneous medium with a position-dependent mass particle by making use of the Langevin equation, in the context of a generalized deformed derivative for an arbitrary deformation space where the linear (nonlinear) character of the FPE is associated with the employed deformed linear (nonlinear) derivative. The FPE for an inhomogeneous medium with a position-dependent diffusion coefficient is equivalent to a deformed FPE within a deformed space, described by generalized derivatives, and constant diffusion coefficient. The deformed FPE is consistent with the diffusion equation for inhomogeneous media when the temperature and the mobility have the same position-dependent functional form as well as with the nonlinear Langevin approach. The deformed version of the H-theorem permits to express the Boltzmann-Gibbs entropic functional as a sum of two contributions, one from the particles and the other from the inhomogeneous medium. The formalism is illustrated with the infinite square well and the confining potential with linear drift coefficient. Connections between superstatistics and position-dependent Langevin equations are also discussed.
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BACKGROUND: Identifying factors associated with physical activity (PA) is useful in planning interventions and policies. The aim of this study was to identify sociodemographic, biological, and psychosocial factors associated with PA performed in school settings. METHODS: Data collected for the present study included gender, age, socioeconomic status, body fat percentage, aerobic fitness, self-efficacy, attitudes, peer and parental support, and perception of school environment. Dependent variables were light-intensity PA (LPA) and moderate-to-vigorous-intensity PA (MVPA) performed during school time, recesses, and physical education (PE) classes. Multiple regression analyses were performed. RESULTS: Participating adolescents (n = 567, 53% female, 12.9 ± 5.3 years) spent 5% of school time in MVPA and 27% in LPA, 15% of recesses in MVPA and 44% in LPA, and 16% of PE classes in MVPA and 41% in LPA. Boys engaged in more MVPA in all categories. Age was inversely related with MVPA and LPA in all periods, whereas body fat percentage was inversely related with MVPA in school time and PE classes. Attitude was inversely related with MVPA in all periods and with LPA in recesses. Considering PA to be good and enjoyable was positively associated with MVPA in school time. CONCLUSION: Adolescents spent little time in PA during school. Future interventions should implement enjoyable activities at school.