Sedentary behaviour (sitting time) has becoming a very popular topic for research and translation since early studies on TV viewing in children in the 1980s. The most studied area for sedentary ...behaviour health outcomes has been adiposity in young people. However, the literature is replete with inconsistencies.
We conducted a systematic review of systematic reviews and meta-analyses to provide a comprehensive analysis of evidence and state-of-the-art synthesis on whether sedentary behaviours are associated with adiposity in young people, and to what extent any association can be considered 'causal'. Searches yielded 29 systematic reviews of over 450 separate papers. We analysed results by observational (cross-sectional and longitudinal) and intervention designs.
Small associations were reported for screen time and adiposity from cross-sectional evidence, but associations were less consistent from longitudinal studies. Studies using objective accelerometer measures of sedentary behaviour yielded null associations. Most studies assessed BMI/BMI-z. Interventions to reduce sedentary behaviour produced modest effects for weight status and adiposity. Accounting for effects from sedentary behaviour reduction alone is difficult as many interventions included additional changes in behaviour, such as physical activity and dietary intake. Analysis of causality guided by the classic Bradford Hill criteria concluded that there is no evidence for a causal association between sedentary behaviour and adiposity in youth, although a small dose-response association exists.
Associations between sedentary behaviour and adiposity in children and adolescents are small to very small and there is little to no evidence that this association is causal. This remains a complex field with different exposure and outcome measures and research designs. But claims for 'clear' associations between sedentary behaviour and adiposity in youth, and certainly for causality, are premature or misguided.
BACKGROUND: The efficacy of high-intensity interval training for a broad spectrum of cardio-metabolic health outcomes is not in question. Rather, the effectiveness of this form of exercise is at ...stake. In this paper we debate the issues concerning the likely success or failure of high-intensity interval training interventions for population-level health promotion. DISCUSSION: Biddle maintains that high-intensity interval training cannot be a viable public health strategy as it will not be adopted or maintained by many people. This conclusion is based on an analysis of perceptions of competence, the psychologically aversive nature of high-intensity exercise, the affective component of attitudes, the less conscious elements of motivated behaviour that reflect our likes and dislikes, and analysis using the RE-AIM framework. Batterham argues that this appraisal is based on a constrained and outmoded definition of high-intensity interval training and that truly practical and scalable protocols have been - and continue to be - developed. He contends that the purported displeasure associated with this type of exercise has been overstated. Biddle suggests that the way forward is to help the least active become more active rather than the already active to do more. Batterham claims that traditional physical activity promotion has been a spectacular failure. He proposes that, within an evolutionary health promotion framework, high-intensity interval training could be a successful population strategy for producing rapid physiological adaptations benefiting public health, independent of changes in total physical activity energy expenditure. Biddle recommends that we focus our attention elsewhere if we want population-level gains in physical activity impacting public health. His conclusion is based on his belief that high-intensity interval training interventions will have limited reach, effectiveness, and adoption, and poor implementation and maintenance. In contrast, Batterham maintains that there is genuine potential for scalable, enjoyable high-intensity interval exercise interventions to contribute substantially to addressing areas of public health priority, including prevention and treatment of Type 2 diabetes and cardiovascular disease.
To review associations between the family environment and young people's fruit and vegetable consumption.
A systematic review. Published English-language (n 60) papers were identified using ...electronic databases and manual searches of personal files and reference lists. Observational research reporting a measure of fruit/vegetable intake for children (aged 6-11 years) and/or adolescents (aged 12-18 years) and at least one potential family correlate of dietary intake was included.
Parental modelling and parental intake were consistently and positively associated with children's fruit and fruit, juice and vegetable (FJV) consumption. There were also positive associations between home availability, family rules and parental encouragement and children's fruit and vegetable consumption. Parental intake was positively associated with adolescents' fruit and vegetable consumption. There were also positive associations between parental occupational status and adolescent fruit consumption and between parental education and adolescents' FJV consumption.
Our findings highlight the importance of targeting the family environment for the promotion of healthy eating behaviours among children and adolescents. Future interventions should encourage parents to be positive role models by targeting parental intake and to create a supportive home environment through increased encouragement and availability of fruits and vegetables and employing rules to govern eating behaviours. For adolescents, indicators of family circumstances (e.g. parental education) should be used to identify target groups for interventions aimed at promoting healthy eating.
Research examining sedentary behaviour as a potentially independent risk factor for chronic disease morbidity and mortality has expanded rapidly in recent years.
We present a narrative overview of ...the sedentary behaviour measurement literature. Subjective and objective methods of measuring sedentary behaviour suitable for use in population-based research with children and adults are examined. The validity and reliability of each method is considered, gaps in the literature specific to each method identified and potential future directions discussed.
To date, subjective approaches to sedentary behaviour measurement, e.g. questionnaires, have focused predominantly on TV viewing or other screen-based behaviours. Typically, such measures demonstrate moderate reliability but slight to moderate validity. Accelerometry is increasingly being used for sedentary behaviour assessments; this approach overcomes some of the limitations of subjective methods, but detection of specific postures and postural changes by this method is somewhat limited. Instruments developed specifically for the assessment of body posture have demonstrated good reliability and validity in the limited research conducted to date. Miniaturization of monitoring devices, interoperability between measurement and communication technologies and advanced analytical approaches are potential avenues for future developments in this field.
High-quality measurement is essential in all elements of sedentary behaviour epidemiology, from determining associations with health outcomes to the development and evaluation of behaviour change interventions. Sedentary behaviour measurement remains relatively under-developed, although new instruments, both objective and subjective, show considerable promise and warrant further testing.
Sedentary behaviour - i.e., low energy-expending waking behaviour while seated or lying down - is a health risk factor, even when controlling for physical activity. This review sought to describe the ...behaviour change strategies used within interventions that have sought to reduce sedentary behaviour in adults. Studies were identified through existing literature reviews, a systematic database search, and hand-searches of eligible papers. Interventions were categorised as 'very promising', 'quite promising', or 'non-promising' according to observed behaviour changes. Intervention functions and behaviour change techniques were compared across promising and non-promising interventions. Twenty-six eligible studies reported thirty-eight interventions, of which twenty (53%) were worksite-based. Fifteen interventions (39%) were very promising, eight quite promising (21%), and fifteen non-promising (39%). Very or quite promising interventions tended to have targeted sedentary behaviour instead of physical activity. Interventions based on environmental restructuring, persuasion, or education were most promising. Self-monitoring, problem solving, and restructuring the social or physical environment were particularly promising behaviour change techniques. Future sedentary reduction interventions might most fruitfully incorporate environmental modification and self-regulatory skills training. The evidence base is, however, weakened by low-quality evaluation methods; more RCTs, employing no-treatment control groups, and collecting objective data are needed.
The assessment of physical activity is an essential part of understanding patterns and influences of behaviour, designing interventions, and undertaking population surveillance and monitoring, but it ...is particularly problematic when using self-report instruments with young people. This study reviewed available self-report physical activity instruments developed for use with children and adolescents to assess their suitability and feasibility for use in population surveillance systems, particularly in Europe.
Systematic searches and review, supplemented by expert panel assessment.
Papers (n=437) were assessed as potentially relevant; 89 physical activity measures were identified with 20 activity-based measures receiving detailed assessment. Three received support from the majority of the expert group: Physical Activity Questionnaire for Children/Adolescents (PAQ-C/PAQ-A), Youth Risk Behaviour Surveillance Survey (YRBS), and the Teen Health Survey.
Population surveillance of youth physical activity is strongly recommended and those involved in developing and undertaking this task should consider the three identified shortlisted instruments and evaluate their appropriateness for application within their national context. Further development and testing of measures suitable for population surveillance with young people is required.
Sedentary behaviour and its association with dietary intake in young people and adults are important topics and were systematically reviewed in 2011. There is a need to update this evidence given the ...changing nature of sedentary behaviour and continued interest in this field. This review aims to assist researchers in better interpreting the diversity of findings concerning sedentary behaviour and weight status.
To provide an update of the associations between sedentary behaviour and dietary intake across the lifespan.
Electronic databases searched were MEDLINE, PsychInfo, Cochrane Library, Web of Science and Science Direct for publications between January 2010 and October 2013, thus updating a previous review. Included were observational studies assessing an association between at least one sedentary behaviour and at least one aspect of dietary intake in preschool children (<5 years), school-aged children (6-11 years), adolescents (12-18 years) and adults (>18 years).
27 papers met inclusion criteria (preschool k=3, school-aged children k=9, adolescents k=15, adults k=3). For all three groups of young people, trends were evident for higher levels of sedentary behaviour, especially TV viewing, to be associated with a less healthful diet, such as less fruit and vegetable and greater consumption of energy-dense snacks and sugar sweetened beverages. Data for the three studies with adults were less conclusive.
Sedentary behaviour continues to be associated with unhealthy diet in young people in mostly cross-sectional studies. More studies utilising a prospective design are needed to corroborate findings and more studies are needed with adults.
To investigate the association of running participation and the dose of running with the risk of all-cause, cardiovascular and cancer mortality.
Systematic review and meta-analysis.
Journal articles, ...conference papers and doctoral theses indexed in Academic Search Ultimate, CINAHL, Health Source: Nursing/Academic Edition, MasterFILE Complete, Networked Digital Library of Theses and Dissertations, Open Access Theses and Dissertations, PsycINFO, PubMed/MEDLINE, Scopus, SPORTDiscus and Web of Science.
Prospective cohort studies on the association between running or jogging participation and the risk of all-cause, cardiovascular and/or cancer mortality in a non-clinical population of adults were included.
Fourteen studies from six prospective cohorts with a pooled sample of 232 149 participants were included. In total, 25 951 deaths were recorded during 5.5-35 year follow-ups. Our meta-analysis showed that running participation is associated with 27%, 30% and 23% lower risk of all-cause (pooled adjusted hazard ratio (HR)=0.73; 95% confidence interval (CI) 0.68 to 0.79), cardiovascular (HR=0.70; 95% CI 0.49 to 0.98) and cancer (HR=0.77; 95% CI 0.68 to 0.87) mortality, respectively, compared with no running. A meta-regression analysis showed no significant dose-response trends for weekly frequency, weekly duration, pace and the total volume of running.
Increased rates of participation in running, regardless of its dose, would probably lead to substantial improvements in population health and longevity. Any amount of running, even just once a week, is better than no running, but higher doses of running may not necessarily be associated with greater mortality benefits.
Sit-to-stand workstations are becoming common in modern offices and are increasingly being implemented in sedentary behavior interventions. The purpose of this study was to examine whether the ...introduction of such a workstation among office workers leads to reductions in sitting during working hours, and whether office workers compensate for any reduction in sitting at work by increasing sedentary time and decreasing physical activity (PA) outside work.
Office workers (n = 40; 55% female) were given a WorkFit-S, sit-to-stand workstation for 3 months. Participants completed assessments at baseline (before workstation installation), 1 wk and 6 wk after the introduction of the workstation, and again at 3 months (postintervention). Posture and PA were assessed using the activPAL inclinometer and ActiGraph GT3X+ accelerometer, which participants wore for 7 d during each measurement phase.
Compared with baseline, the proportion of time spent sitting significantly decreased (75% ± 13% vs 52% ± 16% to 56% ± 13%), and time spent standing and in light activity significantly increased (standing: 19% ± 12% vs 32% ± 12% to 37% ± 15%, light PA: 14% ± 4% vs 16% ± 5%) during working hours at all follow-up assessments. However, compared with baseline, the proportion of time spent sitting significantly increased (60% ± 11% vs 66% ± 12% to 68% ± 12%) and light activity significantly decreased (21% ± 5% vs 19% ± 5%) during nonworking hours across the follow-up measurements. No differences were seen in moderate-to-vigorous activity during nonworking hours throughout the study.
The findings suggest that introducing a sit-to-stand workstation can significantly reduce sedentary time and increase light activity levels during working hours. However, these changes were compensated for by reducing activity and increasing sitting outside of working hours. An intervention of a sit-to-stand workstation should be accompanied by an intervention outside of working hours to limit behavior compensation.
The World Health Organization has released the first global public health guidelines on physical activity and sedentary behavior for people living with disability. This paper presents the guidelines, ...related processes, and evidence, and elaborates upon how the guidelines can support inclusive policy, practice, and research.
Methods were consistent with the World Health Organization protocols for developing guidelines. Systematic reviews of the evidence on physical activity for health for people living with disability were appraised, along with a consideration of the evidence used to inform the general 2020 World Health Organization guidelines.
Evidence supported the development of recommendations for people living with disability, stressing that there are no major risks to engaging in physical activity appropriate to an individual's current activity level, health status, and physical function, and that the health benefits accrued generally outweigh the risks. They also emphasize the benefits of limiting sedentary behavior.
The guidelines mark a positive step forward for disability inclusion, but considerable effort is needed to advance the agenda. This paper highlights key considerations for the implementation of the new recommendations for people living with disability, in line with the human rights agenda underpinning the Global Action Plan on Physical Activity 2018-2030 and allied policies.
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