Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 226
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Int J Behav Nutr Phys Act ; 17(1): 55, 2020 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-32349761

RESUMO

BACKGROUND: Excessive sedentary behaviour (sitting) is a risk factor for poor health in children and adults. Incorporating sit-stand desks in the classroom environment has been highlighted as a potential strategy to reduce children's sitting time. The primary aim of this study was to examine the feasibility of conducting a cluster randomised controlled trial (RCT) of a sit-stand desk intervention within primary school classrooms. METHODS: We conducted a two-armed pilot cluster RCT involving 8 primary schools in Bradford, United Kingdom. Schools were randomised on a 1:1 basis to the intervention or usual practice control arm. All children (aged 9-10 years) in participating classes were eligible to take part. Six sit-stand desks replaced three standard desks (sitting 6 children) in the intervention classrooms for 4.5-months. Teachers were encouraged to use a rotation system to ensure all pupils were exposed to the sit-stand desks for > 1 h/day on average. Trial feasibility outcomes (assessed using quantitative and qualitative measures) included school and participant recruitment and attrition, intervention and outcome measure completion rates, acceptability, and preliminary effectiveness of the intervention for reducing sitting time. A weighted linear regression model compared changes in weekday sitting time (assessed using the activPAL accelerometer) between trial arms. RESULTS: School and child recruitment rates were 33% (n = 8) and 75% (n = 176). At follow-up, retention rates were 100% for schools and 97% for children. Outcome measure completion rates ranged from 63 to 97%. A preliminary estimate of intervention effectiveness revealed a mean difference in change in sitting of - 30.6 min/day (95% CI: - 56.42 to - 4.84) in favour of the intervention group, after adjusting for baseline sitting and wear time. Qualitative measures revealed the intervention and evaluation procedures were acceptable to teachers and children, except for some problems with activPAL attachment. CONCLUSION: This study provides evidence of the acceptability and feasibility of a sit-stand desk intervention and evaluation methods. Preliminary evidence suggests the intervention showed potential in reducing children's weekday sitting but some adaptations to the desk rotation system are needed to maximize exposure. Lessons learnt from this trial will inform the planning of a definitive trial. TRIAL REGISTRATION: ISRCTN12915848 (registered: 09/11/16).

3.
Transl Psychiatry ; 10(1): 128, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32366824

RESUMO

Interruptions to time spent sitting can ameliorate detrimental metabolic-health consequences of high volumes of sedentary time, but their potential mental health benefits have not been examined. We used the Swedish Health Profile Assessment database, a general health assessment offered to all employees working for companies or organisations connected to occupational and health services. Cross-sectional analyses examined data from 40,550 employees (60% male, mean age = 42 years), collected in 2017-2019. Participants reported the proportion of time (almost always; 75% of the time; 50% of the time; 25% of the time; and almost never) usually spent in leisure-time sedentary behaviours; and, separately, the frequency (never; rarely; sometimes; often; and very often) of interruptions (every 30 min) to sedentary time. Logistic regression models assessed associations of sedentary time, and the frequency of interruptions to sedentary time, with depression/anxiety symptoms. Fully adjusted models included physical exercise. Compared to those in the lowest sedentary time category, those in the medium and high categories had 1.52 (95% confidence interval (CI) = 1.40-1.66) and 3.11 (95% CI = 2.82-3.42) higher odds of frequent depression/anxiety symptoms, respectively. Compared to those who never/rarely interrupted their sedentary time, those who reported interruptions sometimes, often and very often had 0.72 (95% CI = 0.65-0.80), 0.59 (95% CI = 0.53-0.65), and 0.53 (95% CI = 0.46-0.59) lower odds of depression/anxiety symptoms, respectively. In stratified analyses, more frequent interruptions to sedentary time were associated with lower odds of depression/anxiety symptoms, except among those in the lowest interruptions categories (never/25% of the time). More regularly interrupting sitting during leisure-time may reduce the odds of experiencing symptoms of depression and anxiety.

4.
J Sport Health Sci ; 2020 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-32407803

RESUMO

BACKGROUND: While the relationship between sedentary time and adiposity markers may be independent of moderate-to-vigorous intensity physical activity (MVPA) among adolescents, little is known about the role of light-intensity physical activity (LIPA) in this relationship. The aim of this cross-sectional study was to examine whether device-measured LIPA and MVPA moderate the associations between objectively measured sitting time and adiposity markers (body mass index (BMI)) and waist circumference (WC)) among adolescents. METHODS: This study included accelerometer and inclinometer data obtained from 219 adolescents (age = 14.9 ± 1.6 years, mean ± standard deviation), collected during 2014 and 2015 in Melbourne, Australia. ActiGraph GT3X accelerometers were used to determine time spent in total-LIPA (101 counts/min to 3.99 metabolic equivalents), low-LIPA (101-799 counts/min), high-LIPA (800 counts/min to 3.99 metabolic equivalents), and MVPA (≥ 4 metabolic equivalents). The average time spent sitting was obtained from activPAL inclinometers. Anthropometric measures were assessed by trained staff. Interactions between sitting and total-LIPA, low-LIPA, high-LIPA, and MVPA on BMI z-score (zBMI) and WC z-score (zWC), respectively, were examined using linear regression, adjusting for age and sex; and moderation by total-LIPA, low-LIPA, high-LIPA, and MVPA were examined by adding interaction terms. Significant interaction effects were probed by comparing associations at the mean and at 1 standard deviation below and above the mean. RESULTS: Total-LIPA significantly moderated the association between sitting time and zBMI, and low-LIPA significantly moderated the association between sitting time and zBMI and zWC. No other associations were found for total-LIPA, high-LIPA, or MVPA. Specifically, at high levels of total-LIPA (+1 standard deviation), there is a negative association between sitting time and zBMI. In addition, at high levels of low-LIPA (+1 standard deviation), there is a negative association between sitting time and zBMI and zWC. CONCLUSION: Associations between sitting and adiposity depended on time spent in total-LIPA and low-LIPA, but not high-LIPA or MVPA. Results suggest that increasing time spent in LIPA may provide protection from the deleterious effects of sitting on adiposity markers among adolescents. Experimental evidence is needed to support these conclusions.

5.
JMIR Res Protoc ; 9(5): e15756, 2020 May 04.
Artigo em Inglês | MEDLINE | ID: mdl-32364513

RESUMO

BACKGROUND: The web-based BeUpstanding Champion Toolkit was developed to support work teams in addressing the emergent work health and safety issue of excessive sitting. It provides a step-by-step guide and associated resources that equip a workplace representative-the champion-to adopt and deliver the 8-week intervention program (BeUpstanding) to their work team. The evidence-informed program is designed to raise awareness of the benefits of sitting less and moving more, build a supportive culture for change, and encourage staff to take action to achieve this change. Work teams collectively choose the strategies they want to implement and promote to stand up, sit less, and move more, with this bespoke and participative approach ensuring the strategies are aligned with the team's needs and existing culture. BeUpstanding has been iteratively developed and optimized through a multiphase process to ensure that it is fit for purpose for wide-scale implementation. OBJECTIVE: The study aimed to describe the current version of BeUpstanding, and the methods and protocol for a national implementation trial. METHODS: The trial will be conducted in collaboration with five Australian workplace health and safety policy and practice partners. Desk-based work teams from a variety of industries will be recruited from across Australia via partner-led referral pathways. Recruitment will target sectors (small business, rural or regional, call center, blue collar, and government) that are of priority to the policy and practice partners. A minimum of 50 work teams will be recruited per priority sector with a minimum of 10,000 employees exposed to the program. A single-arm, repeated-measures design will assess the short-term (end of program) and long-term (9 months postprogram) impacts. Data will be collected on the web via surveys and toolkit analytics and by the research team via telephone calls with champions. The Reach, Effectiveness, Adoption, Implementation, and Maintenance Framework will guide the evaluation, with assessment of the adoption/reach of the program (the number and characteristics of work teams and participating staff), program implementation (completion by the champion of core program components), effectiveness (on workplace sitting, standing, and moving), and maintenance (sustainability of changes). There will be an economic evaluation of the costs and outcomes of scaling up to national implementation, including intervention affordability and sustainability. RESULTS: The study received funding in June 2018 and the original protocol was approved by institutional review board on January 9, 2017, with national implementation trial consent and protocol amendment approved March 12, 2019. The trial started on June 12, 2019, with 48 teams recruited as of December 2019. CONCLUSIONS: The implementation and multimethod evaluation of BeUpstanding will provide the practice-based evidence needed for informing the potential broader dissemination of the program. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry ACTRN12617000682347; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372843&isReview=true. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/15756.

6.
Artigo em Inglês | MEDLINE | ID: mdl-32243644

RESUMO

Elevated levels of cardiovascular disease (CVD) risk markers are highly prevalent in people with a spinal cord injury (SCI). Breaking up prolonged sedentary time with short, regular bouts of physical activity can reduce postprandial glucose and lipid levels in able-bodied individuals. The effects in people with paraplegia are unknown. The study aims were to examine the acute postprandial glucose (primary aim), lipid, blood pressure, and psychological responses (secondary aims) to breaking up prolonged sedentary time in individuals with paraplegia. This was a randomized crossover design trial. Fourteen participants with paraplegia (age 51 ± 9 years, trunk fat mass 44.3 ± 7.7%) took part in the following two, 5.5-hour conditions: (1) uninterrupted sedentary time (SED), and (2) sedentary time interrupted with 2 minutes of moderate-intensity arm crank ergometer physical activity every 20 minutes (SED-ACT). Standardized breakfast and lunch test meals were consumed during each condition. The outcomes were compared between conditions using linear mixed models. Glucose area under the curve (AUC) was significantly lower during the lunch postprandial period in SED-ACT vs SED (incremental AUC 1.9 [95% CI 1.0, 2.7) and 3.0 [2.1, 3.9] mmol/L∙2.5 hour, respectively, P = .015, f = 0.34). There were no differences between conditions for the breakfast or total 5.5 hours postprandial periods (P > .05). Positive affect was higher in SED-ACT than SED (P = .001). Breaking up prolonged sedentary time acutely attenuates lunch postprandial glucose and improves positive affect in people with paraplegia. This may have clinical relevance for reducing CVD risk and improving psychological well-being in this population.

7.
BMJ Open ; 10(3): e036607, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32193278

RESUMO

INTRODUCTION: Numerous studies have found associations between characteristics of urban environments and risk factors for dementia and cognitive decline, such as physical inactivity and obesity. However, the contribution of urban environments to brain and cognitive health has been seldom examined directly. This cohort study investigates the extent to which and how a wide range of characteristics of urban environments influence brain and cognitive health via lifestyle behaviours in mid-aged and older adults in three cities across three continents. METHODS AND ANALYSIS: Participants aged 50-79 years and living in preselected areas stratified by walkability, air pollution and socioeconomic status are being recruited in Melbourne (Australia), Barcelona (Spain) and Hong Kong (China) (n=1800 total; 600 per site). Two assessments taken 24 months apart will capture changes in brain and cognitive health. Cognitive function is gauged with a battery of eight standardised tests. Brain health is assessed using MRI scans in a subset of participants. Information on participants' visited locations is collected via an interactive web-based mapping application and smartphone geolocation data. Environmental characteristics of visited locations, including the built and natural environments and their by-products (e.g., air pollution), are assessed using geographical information systems, online environmental audits and self-reports. Data on travel and lifestyle behaviours (e.g., physical and social activities) and participants' characteristics (e.g., sociodemographics) are collected using objective and/or self-report measures. ETHICS AND DISSEMINATION: The study has been approved by the Human Research Ethics Committee of the Australian Catholic University, the Institutional Review Board of the University of Hong Kong and the Parc de Salut Mar Clinical Research Ethics Committee of the Government of Catalonia. Results will be communicated through standard scientific channels. Methods will be made freely available via a study-dedicated website. TRIAL REGISTRATION NUMBER: ACTRN12619000817145.

8.
Artigo em Inglês | MEDLINE | ID: mdl-32070034

RESUMO

This study conducted a cost and cost-benefit analysis of the Stand More AT (SMArT) Work workplace intervention, designed to reduce sitting time. The study was a cluster two-armed randomised controlled trial involving 37 office clusters (146 desk-based workers) in a National Health Service Trust. The intervention group received a height-adjustable workstation with supporting behaviour change strategies. The control group continued with usual practice. Self-report absenteeism, presenteeism and work productivity were assessed at baseline, 3, 6 and 12 months; and organisational sickness absence records 12 months prior to, and 12 months of the intervention. Mean per employee costs associated with SMArT Work were calculated. Absenteeism, presenteeism and work productivity were estimated, and employer-recorded absence data and employee wage-banding were used to provide a human-capital-based estimate of costs to the organisation. The return-on-investment (ROI) and incremental cost-efficacy ratios (ICER) were calculated. Intervention cost was £692.40 per employee. Cost-benefit estimates show a net saving of £1770.32 (95%CI £-354.40, £3895.04) per employee as a result of productivity increase. There were no significant differences in absence data compared to the control group. SMArT Work provides supporting evidence for policy-makers and employers on the cost benefits of reducing sitting time at work.

9.
Prev Med ; 133: 106021, 2020 Feb 08.
Artigo em Inglês | MEDLINE | ID: mdl-32044415

RESUMO

Sedentary behaviors (SB) can be associated with poorer mental health, but it remains unclear whether contexts for these behaviors may be important. We assessed relationships of SB in leisure-time and occupational contexts with frequent symptoms of depression and anxiety. Data originate from the Swedish Health Profile Assessment (HPA) database, a health assessment offered to employees working for companies or organizations connected to healthcare services. Analyses are based on data from 2017 onwards (N = 23,644; 57% male, mean age = 42 years). Two self-report questions assessed proportions of time spent in SB in leisure contexts and in the occupational setting. Logistic regressions examined relationships of SB in each context with the self-reporting of frequent symptoms of depression/anxiety. A separate model for the leisure plus occupational SB was also generated. Fully-adjusted models included exercise frequency. Compared to those reporting that they were 'almost never' sedentary in leisure-time contexts, a detrimental dose-response with frequent depression/anxiety symptoms was observed with increasing proportions of sedentary time: 50% of the time (OR = 1.44; 1.23-1.70), 75% (OR = 2.95; 2.45-3.54), almost always (OR = 3.85; 2.84-5.22). For occupational SB, the only associations were among those who reported being sedentary almost always, compared to almost never (OR = 1.47; 1.25-1.73). Associations of 'overall' SB with depression/anxiety symptoms mirrored the dose-response relationship for leisure-time SB. Exercise frequency attenuated the association for leisure-time SB only, but it remained statistically significant. Adults who spend ≥50% of their leisure-time in sedentary pursuits experience more frequent symptoms of depression and anxiety, compared to those who are less sedentary in that context.

10.
Trials ; 21(1): 171, 2020 Feb 12.
Artigo em Inglês | MEDLINE | ID: mdl-32051025

RESUMO

BACKGROUND: Patients with rheumatoid arthritis spend most of their daily hours in sedentary behavior (sitting), a predisposing factor to poor health-related outcomes and all-cause mortality. Interventions focused on reducing sedentary time could be of novel therapeutic relevance. However, studies addressing this topic remain scarce. We aim to investigate the feasibility and efficacy of a newly developed intervention focused on reducing sedentary time, and potential clinical, physiological, metabolic and molecular effects in rheumatoid arthritis. METHODS: The Take a STAND for Health study is a 4-month, parallel-group, randomized controlled trial, in which postmenopausal patients with rheumatoid arthritis will set individually tailored, progressive goals to replace their sedentary time with standing and light-intensity activities. Patients will be recruited from the Clinical Hospital (School of Medicine, University of Sao Paulo) and will be assessed at baseline and after a 4-month follow up. Outcomes will include objectively measured sedentary behavior (primary outcome) and physical activity levels, clinical parameters, anthropometric parameters and body composition; aerobic fitness, muscle function, blood pressure, cardiovascular autonomic function, vascular function and structure, health-related quality of life, and food intake. Blood and muscle samples will be collected for assessing potential mechanisms, through targeted and non-targeted approaches. DISCUSSION: Findings will be of scientific and clinical relevance with the potential to inform new prescriptions focused on reducing sedentary behavior, a modifiable risk factor that thus far has been overlooked in patients with rheumatoid arthritis. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03186924. Registered on 14 June 2017.

11.
Med Sci Sports Exerc ; 52(6): 1385-1393, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31895295

RESUMO

PURPOSE: To identify predictors of favorable changes to postprandial insulin and glucose levels in response to interrupting prolonged sitting time with standing or light-intensity physical activity. METHODS: Data were combined from four similarly designed randomized acute cross-over trials (n = 129; body mass index [BMI] range, 19.6-44.6 kg·m; South Asian = 31.0%; dysglycemia = 27.1%). Treatments included: prolonged sitting (6.5 h) or prolonged sitting broken-up with either standing or light-intensity physical activity (5 min every 30 min). Time-averaged postprandial responses for insulin and glucose were calculated for each treatment (mean ± 95% confidence interval). Mutually adjusted interaction terms were used to examine whether anthropometric (BMI), demographic (age, sex, ethnicity [white European vs South Asian]) and a cardiometabolic variable (Homeostatic Model Assessment of Insulin Resistance)-modified responses. RESULTS: Postprandial insulin and glucose were reduced when individuals interrupted prolonged sitting with bouts of light physical activity, but not with standing. Reductions in time-averaged postprandial insulin were more pronounced if individuals were South Asian compared with white European (-18.9 mU·L [-23.5%] vs -8.2 mU·L [-9.3%]), female compared with male (-15.0 mU·L [-21.2%] vs -12.1 mU·L [-17.6%]) or had a BMI ≥27.2 kg·m (-20.9 mU·L [-22.9%] vs -8.7 mU·L [-18.2%]). Similarly, being female (-0.4 mmol·L [-0.6 mmol·L, -0.2 mmol·L], -6.8% vs -0.1 mmol·L [-0.3 mmol·L, 1 mmol·L], -1.7%) or having a BMI ≥27.2 kg·m (-0.4 mmol·L [-0.6 mmol·L, -0.2 mmol·L], -6.7% vs -0.2 mmol·L [-0.4 mmol·L, 0.0 mmol·L], -3.4%) modified the postprandial glucose response. No significant interactions were found for Homeostatic Model Assessment of Insulin Resistance or age. CONCLUSIONS: Being female, South Asian, or having a higher BMI, all predicted greater reductions in postprandial insulin, whereas being female and having a higher BMI predicted greater reductions in postprandial glucose when sitting was interrupted with light physical activity. These results could help to guide personalized interventions in high-risk participants for whom breaking prolonged sitting time with light activity may yield the greatest therapeutic potential.

12.
Annu Rev Public Health ; 41: 265-287, 2020 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-31913771

RESUMO

In developed and developing countries, social, economic, and environmental transitions have led to physical inactivity and large amounts of time spent sitting. Research is now unraveling the adverse public health consequences of too much sitting. We describe improvements in device-based measurement that are providing new insights into sedentary behavior and health. We consider the implications of research linking evidence from epidemiology and behavioral science with mechanistic insights into the underlying biology of sitting time. Such evidence has led to new sedentary behavior guidelines and initiatives. We highlight ways that this emerging knowledge base can inform public health strategy: First, we consider epidemiologic and experimental evidence on the health consequences of sedentary behavior; second, we describe solutions-focused research from initiatives in workplaces and schools. To inform a broad public health strategy, researchers need to pursue evidence-informed collaborations with occupational health, education, and other sectors.

13.
Med Sci Sports Exerc ; 2020 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-31977636

RESUMO

INTRODUCTION: This cross-sectional study aimed to: i) identify and characterize youth according to distinct physical activity (PA) and sedentary (SED) accumulation patterns; and ii) investigate associations of these derived patterns with cardiometabolic risk factors. METHODS: ActiGraph accelerometer data from 7-13 year olds from two studies were pooled (n=1,219; 843 [69%] with valid accelerometry included in analysis). Time accumulated in ≥5-min and ≥10-min SED bouts, ≥1-min and ≥5-min bouts of light (LPA), and ≥1-min bouts of moderate (MPA) and vigorous (VPA) PA were calculated. Frequency of breaks in SED were also obtained. Latent profile analysis was used to identify groups of participants based on their distinct accumulation patterns. Linear and logistic regression models were used to test associations of group accumulation patterns with cardiometabolic risk factors, including adiposity indicators, blood pressure and lipids. Total PA and SED time were also compared between groups. RESULTS: Three distinct groups were identified: "Prolonged sitters" had the most time in prolonged SED bouts and the least time in VPA bouts; "Breakers" had the highest frequency of SED breaks and lowest engagement in sustained bouts across most PA intensities; "Prolonged movers" had the least time accumulated in SED bouts and the most in PA bouts across most intensities. Whilst "Breakers" engaged in less time in PA bouts compared to other groups, they had the healthiest adiposity indicators. No associations with the remaining cardiometabolic risk factors were found. CONCLUSION: Youth accumulate their daily activity in three distinct patterns (prolonged sitters, breakers and prolonger movers), with those breaking up sitting and most time in sporadic PA across the day having a lower adiposity risk. No relationships with other cardiometabolic risk factors were identified.

14.
Phys Ther ; 100(2): 332-345, 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-31588514

RESUMO

BACKGROUND: Physical activity is increasingly recognized as an important marker of functional recovery following fracture. OBJECTIVE: The objectives of this study were to measure sedentary behavior and physical activity 2 weeks and 6 months following fracture and to determine associated demographic and injury factors. DESIGN: This was an observational study. METHODS: Two weeks and 6 months following fracture, 83 adults who were 18 to 69 years old and had upper limb (UL) or lower limb (LL) fractures wore an accelerometer and an inclinometer for 10 days. We calculated sitting time, steps, moderate-intensity physical activity (MPA), and vigorous-intensity physical activity and conducted linear mixed-effects multivariable regression analyses to determine factors associated with temporal changes in activity. RESULTS: At 6 months versus 2 weeks after fracture, participants sat less, took more steps, and engaged in more MPA. Participants with LL fractures sat 2 hours more, took 66% fewer steps, and engaged in 77% less MPA than participants with UL fractures. Greater reductions in sitting time were observed for participants in the youngest age group and with LL fractures, participants with high preinjury activity, and participants who were overweight or obese. For steps, greater improvement was observed for participants in the youngest and middle-aged groups and those with LL fractures. For MPA, greater improvement was observed for middle-aged participants and those with LL fractures. LIMITATIONS: Although this study was sufficiently powered for the analysis of major categories, a convenience sample that may not be representative of all people with musculoskeletal trauma was used. CONCLUSIONS: Working-age adults with LL fractures had lower levels of physical activity 6 months after fracture than those with UL fractures. Older adults showed less improvement over time, suggesting that they are an important target group for interventions aimed at regaining preinjury activity levels.

15.
J Affect Disord ; 265: 538-544, 2020 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-31784118

RESUMO

BACKGROUND: As distinct from mentally-active sedentary behaviors (e.g. reading), passive sedentary behaviors (e.g. TV-viewing) have been linked to a higher risk of depression, but the underlying mechanisms are unclear. We examined the potential mediating role of sleep problems in prospective relationships of passive sedentary behaviors with major depressive disorder (MDD). METHOD: In 1997, 43 863 adults were surveyed and responses linked to clinician diagnoses of MDD until 2010. The questionnaire included items on sedentary behavior and sleep problems (Karolinska Sleep Questionnaire). Cox proportional hazard models and the 'counterfactual approach' were used to identify potential mediating effects of sleep problems in the association of passive sedentary behavior and MDD. RESULTS: Of the total sample, 3,065 (7.6%) were excluded for having indications of depression at baseline. Of 33,116 participants with complete data (mean age = 51.3 years, SD = 15.7, 64% female); 472 (1.4%) incident cases of MDD were identified during the 13-year follow-up. In Cox regression analyses, higher durations of passive sedentary behavior (≥3 h/day versus <3 h/day) were associated with greater hazards of developing MDD (HR = 1.27; 95% CI = 1.01, 1.58). This relationship remained after adjusting for confounders (HR = 1.29; 95% CI = 1.03, 1.63). Adding sleep problems into the analysis significantly attenuated these relationships (HR = 1.25; 95% CI = 0.99, 1.57). The excess MDD relative risk of passive sedentary behaviors due to sleep problems was statistically significant. LIMITATIONS: Measures of sedentary behavior, physical activity and sleep were self-reported. CONCLUSION: Sleep problems appear to mediate detrimental associations of passive sedentary behavior with depression. Findings require further confirmation using objective measures.

16.
Exerc Sport Sci Rev ; 48(1): 20-27, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31663866

RESUMO

Detrimental associations of sedentary behaviors with depression have been identified, but findings are inconsistent. We propose a novel approach to the classification and analysis of sedentary behaviors, which differentiates between those that are passive (e.g., television viewing) and mentally active (e.g., reading). Available evidence is summarized, and research questions relating to measurement, causal relationships, and mechanisms are considered.

17.
J Phys Act Health ; : 1-10, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31794961

RESUMO

BACKGROUND: Recent updates to physical activity guidelines highlight the importance of reducing sedentary time. However, at present, only general recommendations are possible (ie, "Sit less, move more"). There remains a need to investigate the strength, temporality, specificity, and dose-response nature of sedentary behavior associations with chronic disease, along with potential underlying mechanisms. METHODS: Stemming from a recent research workshop organized by the Sedentary Behavior Council themed "Sedentary behaviour mechanisms-biological and behavioural pathways linking sitting to adverse health outcomes," this paper (1) discusses existing challenges and scientific discussions within this advancing area of science, (2) highlights and discusses emerging areas of interest, and (3) points to potential future directions. RESULTS: A brief knowledge update is provided, reflecting upon current and evolving thinking/discussions, and the rapid accumulation of new evidence linking sedentary behavior to chronic disease. Research "action points" are made at the end of each section-spanning from measurement systems and analytic methods, genetic epidemiology, causal mediation, and experimental studies to biological and behavioral determinants and mechanisms. CONCLUSION: A better understanding of whether and how sedentary behavior is causally related to chronic disease will allow for more meaningful conclusions in the future and assist in refining clinical and public health policies/recommendations.

18.
Int J Behav Nutr Phys Act ; 16(1): 111, 2019 11 21.
Artigo em Inglês | MEDLINE | ID: mdl-31752916

RESUMO

BACKGROUND: There is now a body of evidence on the effectiveness of interventions to reduce workplace sitting time. However, there has been limited reporting of how such interventions may impact behaviour both during and outside of work. Sitting, standing and stepping changes following a workplace intervention were examined across five timeframes (work time on work days; non-work time on work days; work days; non-work days; overall (i.e. work and non-work time on all days)), and the relationships between changes during and outside of work was assessed. METHODS: The cluster-randomised controlled trial, 'Stand Up Victoria', delivered a multi-component workplace-delivered intervention that successfully reduced workplace and overall sitting time (relative to controls). Separately, over the five timeframes, changes in device (activPAL3)-assessed outcomes - sitting; prolonged sitting (≥30 min bouts); standing; and, stepping - were compared between intervention (n = 114) and controls (n = 84), along with the time-course of sitting changes during work hours, using mixed models. The potential relationships of changes during work with changes outside of work were examined using compositional data analysis. RESULTS: On workdays, intervention participants significantly (p < 0.05) improved their activity profile relative to controls, with reduced sitting (- 117 min/8-h workday, 95% CI: - 141, - 93) and prolonged sitting (- 77 min/8 h workday, 95% CI: - 101, - 52); increased standing (114 min/8 h workday, 95% CI: 92, 136) and maintenance of stepping (3 min/8 h workday, 95% CI: - 7, 11, p = 0.576). Effects were nearly identical for time at work; similar but slightly weaker for overall; and, small and non-significant outside of work on workdays and non-work days. Improvements occurred at all times, but not equally, during work hours (p < 0.001). Correlations between changes during and outside of work on workdays were very weak in both the intervention group (r = - 0.07) and controls (r = - 0.09). CONCLUSIONS: Sitting time was reduced almost exclusively during work hours (via replacement with standing), with reductions evident during all working hours, to varying degrees. There was no evidence of compensation, with minimal change in activity outside of work, in response to changes in activity at work. Future interventions may benefit from exploring how best to elicit change throughout the whole day, and across work and non-work domains. TRIAL REGISTRATION: This trial was prospectively registered with the Australian New Zealand Clinical Trials register (ACTRN12611000742976) on 15 July 2011.

19.
Curr Sports Med Rep ; 18(11): 421-422, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31702724
20.
Obesity (Silver Spring) ; 27(9): 1428-1433, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31441233

RESUMO

OBJECTIVE: This study aimed to examine the effects on postprandial glucose and insulin responses of interrupting sitting time with brief bouts of simple resistance activities (SRAs) in adults with overweight or obesity. METHODS: Participants (n = 19) were recruited for a randomized crossover trial involving the following two 6-hour conditions: (1) uninterrupted sitting or (2) sitting with 3-minute bouts of SRAs (half-squats, calf raises, gluteal contractions, and knee raises) every 30 minutes (total duration = 27 minutes). Incremental areas under the curve (iAUC) for glucose, insulin, and insulin:glucose ratio were analyzed as prespecified secondary outcomes using mixed-effects log-linear regression adjusted for sex, BMI, treatment order, and preprandial values. Results are reported as multiplicative change (exponentiated coefficient [EC] with 95% CI) relative to the control condition. RESULTS: Glucose iAUC during the SRA condition was not significantly different from the prolonged sitting condition (EC = 0.92; 95% CI: 0.73-1.16; P = 0.43). However, SRAs lowered the postprandial insulin response by 26% (EC = 0.74; 95% CI: 0.64-0.85; P < 0.001), and there was a 23% lowering of the iAUC for insulin:glucose (EC = 0.77; 95% CI: 0.67-0.89; P < 0.001). CONCLUSIONS: In adults with overweight or obesity, frequent interruptions to sitting time with SRAs lowered postprandial insulin responses and insulin:glucose. These findings may have implications for mitigating cardiometabolic risk in adults with overweight or obesity who engage in prolonged periods of sitting.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA