Physiological and health implications of a sedentary lifestyle

Physical activity, sedentary behaviors and dietary habits among Saudi adolescents relative to age, gender and region

BACKGROUND

Few lifestyle factors have been simultaneously studied and reported for Saudi adolescents. Therefore, the purpose of the present study was to report on the prevalence of physical activity, sedentary behaviors and dietary habits among Saudi adolescents and to examine the interrelationships among these factors using representative samples drawn from three major cities in Saudi Arabia.

METHODS

This school-based cross-sectional study was conducted during the years 2009-2010 in three cities: Al-Khobar, Jeddah and Riyadh. The participants were 2908 secondary-school males (1401) and females (1507) aged 14-19 years, randomly selected using a multistage stratified sampling technique. Measurements included weight, height, sedentary behaviors (TV viewing, playing video games and computer use), physical activity using a validated questionnaire and dietary habits.

RESULTS

A very high proportion (84% for males and 91.2% for females) of Saudi adolescents spent more than 2 hours on screen time daily and almost half of the males and three-quarters of the females did not meet daily physical activity guidelines. The majority of adolescents did not have a daily intake of breakfast, fruit, vegetables and milk. Females were significantly (p < 0.05) more sedentary, much less physically active, especially with vigorous physical activity, and there were fewer days per week when they consumed breakfast, fruit, milk and diary products, sugar-sweetened drinks, fast foods and energy drinks than did males. However, the females' intake of French fries and potato chips, cakes and donuts, and candy and chocolate was significantly (p < 0.05) higher than the males'. Screen time was significantly (p < 0.05) correlated inversely with the intake of breakfast, vegetables and fruit. Physical activity had a significant (p < 0.05) positive relationship with fruit and vegetable intake but not with sedentary behaviors.

CONCLUSIONS

The high prevalence of sedentary behaviors, physical inactivity and unhealthy dietary habits among Saudi adolescents is a major public health concern. There is an urgent need for national policy promoting active living and healthy eating and reducing sedentary behaviors among children and adolescents in Saudi Arabia.

Potential contributors to the canadian pediatric obesity epidemic

As a group, Canadian children and youth are heavier than at any time in the recent past. However, to date there has been no critical examination of the factors which are likely to have contributed to these deleterious trends. A review of the evidence suggests that there is robust evidence supporting the role of reduced sleep, increased sedentary time, increased consumption of sugar-sweetened beverages, and secular increases in adult obesity as contributing factors to the current epidemic of childhood obesity. There is moderate evidence that these trends are related to changes in either total energy intake or physical activity, while there is very little evidence supporting the role of maternal age, breastfeeding, exposure to endocrine disrupters, or inadequate calcium intake. These findings suggest that targeting sleep, sedentary time, and sugar-sweetened beverage intake in Canadian children and youth may help to prevent future weight gain at the population level.

Adolescent predictors of objectively measured physical activity and sedentary behaviour at age 42: the Amsterdam Growth and Health Longitudinal Study (AGAHLS)

BACKGROUND

This study investigated the associations of physical characteristics and personality in adolescence with physical activity and sedentary behaviour in adulthood.

FINDINGS

Physical characteristics (i.e. objectively measured BMI, sum of skin folds, MOPER test battery performance), and personality (i.e. self-reported inadequacy, social inadequacy, rigidity, self-sufficiency/recalcitrance, dominance, achievement motivation, facilitating anxiety, debilitating anxiety, and social desirability) were assessed in 217 adolescent boys (Mean 13.0, SD 0.6) and girls (Mean 12.9, SD 0.6). Twenty-nine years later, at the age of 42, their physical activity and sedentary behaviour were assessed by means of accelerometry. Boys who scored lower on self-sufficiency/recalcitrance and higher on facilitating anxiety spent more time sedentary in adulthood. Girls with a superior standing high jump performance, and a lower score on social desirability spent more time sedentary in adulthood. In contrast with sedentary behaviour, physical activity at age 42 year could not be predicted by physical characteristics or personality in adolescence.

CONCLUSIONS

Sedentary behaviour in adulthood was partly explained by physical characteristics and/or personality in adolescence. Thus, our results suggest that it may be possible to identify people who are at risk of becoming sedentary at a rather young age.

Systematic review of sedentary behaviour and health indicators in school-aged children and youth

Accumulating evidence suggests that, independent of physical activity levels, sedentary behaviours are associated with increased risk of cardio-metabolic disease, all-cause mortality, and a variety of physiological and psychological problems. Therefore, the purpose of this systematic review is to determine the relationship between sedentary behaviour and health indicators in school-aged children and youth aged 5-17 years. Online databases (MEDLINE, EMBASE and PsycINFO), personal libraries and government documents were searched for relevant studies examining time spent engaging in sedentary behaviours and six specific health indicators (body composition, fitness, metabolic syndrome and cardiovascular disease, self-esteem, pro-social behaviour and academic achievement). 232 studies including 983,840 participants met inclusion criteria and were included in the review. Television (TV) watching was the most common measure of sedentary behaviour and body composition was the most common outcome measure. Qualitative analysis of all studies revealed a dose-response relation between increased sedentary behaviour and unfavourable health outcomes. Watching TV for more than 2 hours per day was associated with unfavourable body composition, decreased fitness, lowered scores for self-esteem and pro-social behaviour and decreased academic achievement. Meta-analysis was completed for randomized controlled studies that aimed to reduce sedentary time and reported change in body mass index (BMI) as their primary outcome. In this regard, a meta-analysis revealed an overall significant effect of -0.81 (95% CI of -1.44 to -0.17, p = 0.01) indicating an overall decrease in mean BMI associated with the interventions. There is a large body of evidence from all study designs which suggests that decreasing any type of sedentary time is associated with lower health risk in youth aged 5-17 years. In particular, the evidence suggests that daily TV viewing in excess of 2 hours is associated with reduced physical and psychosocial health, and that lowering sedentary time leads to reductions in BMI.

Health risks, correlates, and interventions to reduce sedentary behavior in young people

CONTEXT

Opportunities for young people to be sedentary have increased during leisure time, study time, and transportation time.

PURPOSE

This review paper focuses on sedentary behaviors among young people aged 2-18 years and includes evidence of the relationship between sedentary behavior and health risk indicators, an overview of public health recommendations, the prevalence of key sedentary behaviors, evidence of correlates of sedentary behavior and the effectiveness of interventions to reduce sedentary behaviors.

EVIDENCE ACQUISITION

Although this is a narrative style review and not systematic, where possible, findings from relevant review papers were summarized and a search of more recent literature was performed using computer-based databases such as PubMed, Google Scholar, ERIC, PsycINFO, Social Science Index, SportDiscus, and Health Reference Center - Academic.

EVIDENCE SYNTHESIS

Young people spend 2-4 hours per day in screen-based behaviors and 5-10 hours per day sedentary. Ethnicity, sociodemographic status, having a TV set in the bedroom, and parental behavior appear to be the most consistent correlates of TV viewing time; however, few recent studies aiming to reduce TV viewing or sedentary time among young people have been successful.

CONCLUSIONS

A growing body of evidence supports the development of public health recommendations to limit the time spent in screen-based behaviors. More research is needed to examine the prospective and experimental evidence of associations between overall sedentary time and health, determinants of sedentary behaviors other than screen-based behaviors, and interventions to reduce overall sedentary time or even alternative sedentary behaviors, such as transport- or education-related sitting time.

Enhancing the effectiveness of clearance for physical activity participation: background and overall process1This paper is one of a selection of papers published in the Special Issue entitled Evidence-based risk assessment and recommendations for physical activity clearance, and has undergone the Journal's usual peer-review process

Recent feedback from physical activity (PA) participants, fitness professionals, and physicians has indicated that there are limitations to the utility and effectiveness of the existing PAR-Q and PARmed-X screening tools for PA participation. The aim of this study was to have authorities in exercise and chronic disease management to work with an expert panel to increase the effectiveness of clearance for PA participation using an evidence-based consensus approach and the well-established Appraisal of Guidelines for Research and Evaluation (AGREE) Instrument. Systematic reviews were conducted to develop a new PA clearance protocol involving risk stratification and a decision-tree process. Evidence-based support was sought for enabling qualified exercise professionals to have a direct role in the PA participation clearance process. The PAR-Q+ was developed to use formalized probes to clarify problematic responses and to explore issues arising from currently diagnosed chronic disease or condition. The original PARmed-X tool is replaced with an interactive computer program (ePARmed-X+) to clear prospective PA participants for either unrestricted or supervised PA or to direct them to obtain medical clearance. Evidence-based validation was also provided for the direct role of highly qualified university-educated exercise professionals in the PA clearance process. The risks associated with exercise during pregnancy were also evaluated. The systematic review and consensus process, conforming to the AGREE Instrument, has provided a sound evidence base for enhanced effectiveness of the clearance process for PA participation of both asymptomatic populations and persons with chronic diseases or conditions.

A qualitative study of older adults' responses to sitting-time questions: do we get the information we want?

Background

In the last decade, there has been increasing interest in the health effects of sedentary behavior, which is often assessed using self-report sitting-time questions. The aim of this qualitative study was to document older adults' understanding of sitting-time questions from the International Physical Activity (PA) Questionnaire (IPAQ) and the PA Scale for the Elderly (PASE).

Methods

Australian community-dwelling adults aged 65+ years answered the IPAQ and PASE sitting questions in face-to-face semi-structured interviews. IPAQ uses one open-ended question to assess sitting on a weekday in the last 7 days 'at work, at home, while doing coursework and during leisure time'; PASE uses a three-part closed question about daily leisure-time sitting in the last 7 days. Participants expressed their thoughts out loud while answering each question. They were then probed about their responses. Interviews were recorded, transcribed and coded into themes.

Results

Mean age of the 28 male and 27 female participants was 73 years (range 65-89). The most frequently reported activity was watching TV. For both questionnaires, many participants had difficulties understanding what activities to report. Some had difficulty understanding what activities should be classified as 'leisure-time sitting'. Some assumed they were being asked to only report activities provided as examples. Most reported activities they normally do, rather than those performed on a day in the previous week. Participants used a variety of strategies to select 'a day' for which they reported their sitting activities and to calculate sitting time on that day. Therefore, many different ways of estimating sitting time were used. Participants had particular difficulty reporting their daily sitting-time when their schedules were not consistent across days. Some participants declared the IPAQ sitting question too difficult to answer.

Conclusion

The accuracy of older adults' self-reported sitting time is questionable given the challenges they have in answering sitting-time questions. Their responses to sitting-time questions may be more accurate if our recommendations for clarifying the sitting domains, providing examples relevant to older adults and suggesting strategies for formulating responses are incorporated. Future quantitative studies should include objective criterion measures to assess validity and reliability of these questions.

Clustering of children's activity behaviour: the use of self-report versus direct measures

While we concur with the objectives of the recent International Journal of Behavioural Nutrition and Physical Activity paper published by Jago and colleagues titled "Physical activity and sedentary behaviour typologies of 10-11 year olds", we feel that the results as currently presented do not support their conclusions. Though the authors created groups of children with dramatically different patterns of self-reported physical activity and sedentary behaviour, an inspection of the objectively measured accelerometry data shows little difference between the groups. Further, in at least one instance the difference between groups was of the opposite direction when using objective measures, as opposed to the self-report measures used in the published analysis. Thus, we caution the authors from making conclusions based on their self-report data, and propose that they re-analyze their data using their objectively measured data instead.

Canadian sedentary behaviour guidelines for children and youth

The Canadian Society for Exercise Physiology (CSEP), in partnership with the Healthy Active Living and Obesity Research Group (HALO) at the Children's Hospital of Eastern Ontario Research Institute, and in collaboration with ParticipACTION, and others, has developed the Canadian Sedentary Behaviour Guidelines for Children (aged 5-11 years) and Youth (aged 12-17 years). The guidelines include a preamble to provide context, followed by the specific recommendations for sedentary behaviour. The entire development process was guided by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument, which is the international standard for clinical practice guideline development. Thus, the guidelines have gone through a rigorous and transparent developmental process and the recommendations are based on evidence from a systematic review and interpretation of the research evidence. The final guidelines benefitted from an extensive online consultation process with 230 domestic and international stakeholders and key informants. The final guideline recommendations state that for health benefits, children (aged 5-11 years) and youth (aged 12-17 years) should minimize the time that they spend being sedentary each day. This may be achieved by (i) limiting recreational screen time to no more than 2 h per day - lower levels are associated with additional health benefits; and (ii) limiting sedentary (motorized) transport, extended sitting time, and time spent indoors throughout the day. These are the first evidence-based Canadian Sedentary Behaviour Guidelines for Children and Youth and provide important and timely recommendations for the advancement of public health based on a systematic synthesis, interpretation, and application of the current scientific evidence.

Study protocol of physical activity and sedentary behaviour measurement among schoolchildren by accelerometry--cross-sectional survey as part of the ENERGY-project

Background

Physical activity and sedentary behaviour among children should be measured accurately in order to investigate their relationship with health. Accelerometry provides objective and accurate measurement of body movement, which can be converted to meaningful behavioural outcomes. The aim of this study was to evaluate the best evidence for the decisions on data collection and data processing with accelerometers among children resulting in a standardized protocol for use in the participating countries.

Methods/Design

This cross-sectional accelerometer study was conducted as part of the European ENERGY-project that aimed to produce an obesity prevention intervention among schoolchildren. Five countries, namely Belgium, Greece, Hungary, Switzerland and the Netherlands participated in the accelerometer study. We used three different Actigraph models-Actitrainers (triaxial), GT3Xs and GT1Ms. Children wore the device for six consecutive days including two weekend days. We selected an epoch length of 15 seconds. Accelerometers were placed at children's waist at the right side of the body in an elastic belt.

In total, 1082 children participated in the study (mean age = 11.7 ± 0.75 y, 51% girls). Non-wearing time was calculated as periods of more than 20 minutes of consecutive zero counts. The minimum daily wearing time was set to 10 hours for weekdays and 8 hours for weekend days. The inclusion criterion for further analysis was having at least three valid weekdays and one valid weekend day. We selected a cut-point (count per minute (cpm)) of <100 cpm for sedentary behaviour, <3000 cpm for light, <5200 cpm for moderate, and >5200 cpm for vigorous physical activity. We also created time filters for school-time during data cleaning in order to explore school-time physical activity and sedentary behaviour patterns in particular.

Discussion

This paper describes the decisions for data collection and processing. Use of standardized protocols would ease future use of accelerometry and the comparability of results between studies.

Directives canadiennes en matière de comportement sédentaire à l’intention des enfants et des jeunes

La Société canadienne de physiologie de l’exercice (SCPE) en collaboration avec le groupe de recherche Healthy Active Living and Obesity Research Group (HALO) de l’Institut de recherche du Centre hospitalier pour enfants de l’est de l’Ontario, de ParticipACTION et d’autres organismes a élaboré les Directives canadiennes en matière de comportement sédentaire à l’intention des enfants âgés de 5 à 11 ans et des jeunes âgés de 12 à 17 ans. Les directives comprennent un préambule situant le contexte et des recommandations spécifiques en matière de comportement sédentaire. L’élaboration complète des directives a respecté la Grille II d’évaluation de la qualité des recommandations pour la pratique clinique (AGREE), un outil reconnu internationalement pour l’élaboration des lignes directrices en pratique clinique. L’élaboration des directives est donc le résultat d’un processus rigoureux et transparent, et les recommandations présentées dans cet article sont basées sur l’interprétation des données probantes relevées dans une analyse documentaire systématique. Les directives finales sont le fruit d’une vaste consultation en ligne auprès de 230 intervenants concernés et de sources de premier plan sur la scène nationale et internationale. Les directives finales énoncent ce qui suit : Afin de profiter des bienfaits pour leur santé, les enfants âgés de 5 à 11 ans et les jeunes âgés de 12 à 17 ans doivent diminuer chaque jour le temps consacré à des activités sédentaires. Ceci peut être accompli (i) en limitant le temps de loisir passé devant l’écran à moins de 2 h par jour; moins de temps passé devant l’écran est associé à des bienfaits supplémentaires pour la santé; (ii) en diminuant les déplacements en véhicule motorisé et en réduisant le temps passé assis à l’intérieur pendant la journée. Ces directives sont les premières Directives canadiennes en matière de comportement sédentaire à l’intention des enfants et des jeunes; elles résultent de la synthèse, de l’interprétation et de l’application des données probantes les plus récentes à ce jour et comportent des recommandations importantes qui arrivent à un moment opportun dans la promotion de la santé publique.

New Canadian Physical Activity Guidelines

The Canadian Society for Exercise Physiology (CSEP), in cooperation with ParticipACTION and other stakeholders, and with support from the Public Health Agency of Canada (PHAC), has developed the new Canadian Physical Activity Guidelines for Children (aged 5–11 years), Youth (aged 12–17 years), Adults (aged 18–64 years), and Older Adults (aged ≥65 years). The new guidelines include a preamble to provide context and specific guidelines for each age group. The entire guideline development process was guided by the Appraisal of Guidelines for Research Evaluation (AGREE) II instrument, which is the international standard for clinical practice guideline development. Thus, the guidelines have gone through a rigorous and transparent developmental process; we based the recommendations herein on evidence from 3 systematic reviews, and the final guidelines benefitted from an extensive online and in-person consultation process with hundreds of stakeholders and key informants, both domestic and international. Since 2006, the products of our efforts resulted in the completion of 21 peer-reviewed journal articles (including 5 systematic reviews) that collectively guided this work. The process that Canadian researchers undertook to update the national physical activity guidelines represents the most current synthesis, interpretation, and application of the scientific evidence to date.

Nouvelles Directives canadiennes en matière d’activité physique

La Société canadienne de physiologie de l’exercice (SCPE) en collaboration avec ParticipACTION et des parties prenantes et avec l’appui de l’Agence de santé publique du Canada (ASPC) a élaboré de nouvelles Directives canadiennes en matière d’activité physique à l’intention des enfants (âgés de 5 à 11 ans), des jeunes (âgés de 12 à 17 ans), des adultes (âgés de 18 à 64 ans) et des aînés (âgés de 65 ans et plus). Les nouvelles directives sont composées d’un préambule situant le contexte et de directives spécifiques à chaque tranche d’âge. L’élaboration complète des directives a respecté la Grille II d’évaluation de la qualité des recommandations pour la pratique clinique (AGREE), un outil reconnu internationalement pour l’élaboration des lignes directrices en pratique clinique. L’élaboration des directives résulte d’un processus rigoureux et transparent. Les recommandations présentées dans cet article sont basées sur les données probantes relevées dans trois analyses documentaires systématiques, et les directives finales ont bénéficié des fruits d’une vaste consultation en ligne et en personne auprès de centaines d’intervenants concernés et de sources de premier plan, sur la scène nationale et internationale. Depuis 2006, les résultats de nos efforts se retrouvent entre autres dans 21 articles (dont 5 analyses documentaires systématiques) sanctionnés par des pairs. La démarche entreprise par les chercheurs canadiens pour la mise à jour des directives en matière d’activité physique a abouti à la synthèse, l’interprétation et l’application des données probantes les plus récentes à ce jour.