Author Archive: Joel
The American Heart Association has released a Science Advisory on Sedentary Behaviour and health. The abstract is available below. The full paper is available here.
Epidemiological evidence is accumulating that indicates greater time spent in sedentary behavior is associated with all-cause and cardiovascular morbidity and mortality in adults such that some countries have disseminated broad guidelines that recommend minimizing sedentary behaviors. Research examining the possible deleterious consequences of excess sedentary behavior is rapidly evolving, with the epidemiology-based literature ahead of potential biological mechanisms that might explain the observed associations. This American Heart Association science advisory reviews the current evidence on sedentary behavior in terms of assessment methods, population prevalence, determinants, associations with cardiovascular disease incidence and mortality, potential underlying mechanisms, and interventions. Recommendations for future research on this emerging cardiovascular health topic are included. Further evidence is required to better inform public health interventions and future quantitative guidelines on sedentary behavior and cardiovascular health outcomes.
The French National Observatory of Physical Activity and Sedentary Behaviour (ONAPS) will be hosting a colloquium on sedentary behaviour in Paris on October 12, 2016. Speakers include Drs Angelo Tremblay and David Thivel, as well as many others. Full details on the colloquium can be found on the ONAPS website.
A new systematic review in Sports Medicine has been published on sedentary behaviour questionnaires for children. A brief author summary is found below. A full copy of the paper is available for free via the journal Sports Medicine.
This systematic review provides a summary of studies examining the measurement properties of self-report or proxy-report questionnaires assessing sedentary behavior in children and adolescents. In addition, an overview of the characteristics of the included questionnaires is provided. We performed systematic searches in three online databases: PubMed, EMBASE and SPORTDiscus. Studies had to report on at least one of the measurement properties of a self- or proxy-report questionnaire assessing sedentary behavior in a general population under the age of 18 years. Eventually, our searches resulted in 46 relevant studies on 46 questionnaires. Unfortunately, none of the included questionnaires was considered both valid and reliable, due to the lack of attention for content validity and methodological limitations of the included studies. Therefore, we recommend researchers to adopt standardized tools for the evaluation of measurement properties to improve the methodological quality of future studies and we emphasize the importance of assessing content validity.
The below job posting is from Professor Leon Straker in Perth, Australia. For more information, please contact Professor Straker directly.
LL-Today (Live Lighter Tailored Online Diet and Activity Study) PhD Opportunity
Interested in doing a high quality PhD that will make a difference to people’s health?
LL-Today is a randomised and controlled trial (n=600) evaluating the efficacy of computer-tailored feedback to change overweight adults’ diet and physical activity. This Healthway funded 3 year project is a multi-disciplinary collaboration between physical activity and nutrition researchers, technology experts and health promotion and translation practitioners drawn from universities, and Western Australian Cancer Council, Heart Foundation and Department of Health in Western Australia.
The successful physical activity doctoral candidate would be involved in formative work to refine the physical activity intervention including the choice of fitness tracker and messaging based on current theory, knowledge and technology, conducting the accelerometer-based sedentary time and physical activity assessments and, analysis and reporting on physical activity outcomes.
This is a full time only doctoral opportunity in Perth, Western Australia. A stipend of $32,500 per annum tax-free for 3 years will be provided.
The successful applicant is likely to have an Honours or Masters degree highly relevant to physical activity, an outstanding record of undergraduate achievement and publication experience and be eligible for an APA scholarship.
Expressions of interest including a curriculum vitae are due Friday 16th September 2016. For further details please contact Professor Leon Straker, L.Straker@curtin.edu.au.
On June 26 Canada released the Canadian 24 Hour Movement Guidelines for Children and Youth. These guidelines call for at least 60 minutes per day of moderate to vigorous physical activity, no more than two hours a day of recreational screen time, limited sitting for extended periods and at least 9-11 hours of sleep per night for children 5-13 years, and 8-10 hours for those aged 14-17 years. They were developed by the Canadian Society for Exercise Physiology, the Conference Board of Canada, HALO-CHEO, ParticipACTION and the Public Health Agency of Canada, with input from research experts and stakeholders across Canada and around the world.
The process was informed by 9 peer-reviewed publications, all available for free via the journal of Applied Physiology, Nutrition and Metabolism.
Three papers of particular relevance to sedentary behaviour:
New meta-analysis: the prospective relationship between childhood sedentary behaviour and biomedical health indicators
A new paper by van Ekris et al. examines the relationship between childhood sedentary behaviour and health indicators later in life. From the abstract:
Evidence for adverse health effects of excessive sedentary behaviour in children is predominantly based on cross-sectional studies, measuring TV viewing as proxy for sedentary behaviour. This systematic review and meta-analysis summarizes the evidence on the prospective relationshipbetween childhood sedentary behaviour and biomedical health indicators, overall and stratified by type of sedentary behaviour (TV viewing, computer use/games, screen time and objective sedentary time). PubMed, EMBASE, PsycINFO and Cochrane were systematically searched till January 2015. Methodological quality of all included studies was scored, and a best evidence synthesis was applied. We included 109 studies of which 19 were of high quality. We found moderate-to-strong evidence for a relationship of overall sedentary time with some anthropometrics (overweight/obesity, weight-for-height), one cardiometabolic biomarker (HDL-cholesterol) and some fitness indicators (fitness, being unfit). For other health indicators, we found no convincing evidence because of inconsistent or non-significant findings. The evidence varied by type ofsedentary behaviour. The meta-analysis indicated that each additional baseline hour of TV viewing (β = 0.01, 95%CI = [-0.002; 0.02]) or computer use (β = 0.00, 95%CI = [-0.004; 0.01]) per day was not significantly related with BMI at follow-up. We conclude that the evidence for a prospectiverelationship between childhood sedentary behaviour and biomedical health is in general unconvincing.
The full study is available via Obesity Reviews.
In May 2014, representatives from 15 countries gathered in Toronto, Canada, for the Global Summit on Physical Activity of Children. Experts reviewed available information and assigned a grade for 9 indicators in national Physical Activity Report Cards. Australia received a grade of “D minus(–)” for sedentary behaviors, with only 29% of 5- to 17-year-olds meeting screen time recommendations. A smaller group from the Australian Report Card Research Working group conducted a study to further review available evidence about sedentary behaviour in children (available here).
They asked the following 3 questions:
Question 1: What are the main sedentary behaviors of children?
Sedentary behavior can occur in 4 areas of children’s lives—education/school/child care, transport, self-care/domestic chores, and leisure/play. For school-aged children, a main “occupation” is being a student and the majority of the school day is spent sitting. Homework also contributes to additional sitting time. Transport time is usually highly sedentary with children sitting in buses, trains and cars to get to and from school and other destinations. Sedentary self-care tasks include eating and some grooming. Leisure and play sedentary behaviors include reading from a book or an electronic screen. Sedentary behaviors are often further classified as being either based around an electronic screen or not.
Question 2: What are the potential mechanisms for sedentary behaviors to impact child health and development?
There are a number of ways by which sedentary behaviors may influence child health and development, including disrupted metabolism, limited neuromuscular activity, prolonged/awkward postures or repetitive motions, socioemotional experiences, cognitive experiences, and other mechanisms such as influencing sleep quality.
Question 3: What are the effects of different types of sedentary behaviors on child health and development?
Research suggests that sedentary behaviors impact child health and development including cardiometabolic, neuromuscular, and psychosocial implications. However, most of the research is about the effects of watching TV, and there has been less of a focus on the effects of total screen time, screens other than TV, non-screen sedentary behaviours, and total sedentary time.
The available research, while incomplete, is sufficiently convincing that sedentary behaviors are important for child health and development. Nations therefore need to balance children’s healthy and unhealthy sedentary behaivours in order to improve their sedentary behaviour grade in future report cards.
Leon Straker, Erin Kaye Howie, Dylan Paul Cliff, Melanie T. Davern, Lina Engelen, Sjaan R. Gomersall, Jenny Ziviani, Natasha K. Schranz, Tim Olds, Grant Ryan Tomkinson. Australia and Other Nations Are Failing to Meet Sedentary Behaviour Guidelines for Children: Implications and a Way Forward. JPAH 13:177 – 188, 2016.
Glasgow Caledonian University is currently hiring a Research Fellow to work in the area of physical activity and sedentary behaviour. From the website:
The School of Health and Life Sciences is looking to appoint a fixed term Research Fellow for 36 months to the Healthy Ageing and Active Living Research Group in the Institute for Applied Health Research. The post holder will contribute to the high quality and impact of the group’s research. We seek an outstanding individual with the right combination of research, numerate and public engagement skills to be part of our vibrant team. The Research Fellow will be embedded within the research team under direction from Prof Dawn Skelton and Prof Jo Booth to specifically work on our portfolio of research and develop new projects on promoting physical activity and reducing sedentary behaviour in later life.
For more details, please visit the Glasgow Caledonian University website.
From the journal PLOS ONE:
Sedentary behaviour is increasingly recognized as an important health risk, but comparable data across Europe are scarce. The objective of this study was to explore the prevalence and correlates of self-reported sitting time in adults across and within the 28 European Union Member States.
This study reports data from the Special Eurobarometer 412. In 2013, 27,919 randomly selected Europeans (approximately 1000 per Member State) were interviewed face-to-face. Sitting time on a usual day was self-reported and dichotomised into sitting less- and more than 7.5 hours per day. Uni- and multivariate odds ratios of sitting more than 7.5 hours per day were assessed by country and socio-demographic variables using binary logistic regression analyses. The analyses were stratified by country to study the socio-demographic correlates of sitting time within the different countries.
A total of 26,617 respondents were included in the analyses. Median sitting time was five hours per day. Across Europe, 18.5 percent of the respondents reported to sit more than 7.5 hours per day, with substantial variation between countries (ranging from 8.9 to 32.1 percent). In general, northern European countries reported more sitting than countries in the south of Europe. ‘Current occupation’ and ‘age when stopped education’ were found to be the strongest correlates of sitting time, both across Europe and within most Member States. Compared to manual workers, the odds ratio of sitting more than 7.5 hours per day was 5.00 for people with white collar occupations, 3.84 for students, and 3.65 for managers.
There is substantial variation in self-reported sitting time among European adults across countries as well as socio-demographic groups. While regular surveillance of (objectively measured) sedentary behaviour is needed, the results of this study provide entry points for developing targeted interventions aimed at highly sedentary populations, such as people with sedentary occupations.
The full article is available for free here.
An updated Cochrane Review has examined the impact of workplace interventions to reduce sitting. From the plain language summary, available via the Cochrane Library.
Why is the amount of time spent sitting at work important?
Physical inactivity at work, particularly sitting has increased in recent years. Long periods of sitting increase the risk for obesity, heart disease, and overall mortality. It is unclear whether interventions that aim to reduce sitting at workplaces are effective at reducing the amount of time spent sitting.
The purpose of this review
We wanted to find out the effects of interventions aimed at reducing sitting time at work. We searched the literature in various databases up to 2 June 2015.
What trials did the review find?
We found twenty studies with a total of 2174 participants from high income nations. Nine studies evaluated physical changes in the workplace, four evaluated changes in workplace policy, seven studies evaluated information and counselling interventions and one study evaluated both physical workplace changes and information and counselling components.
Effect of sit-stand desks
Sit-stand desks alone decreased workplace sitting with about half an hour to two hours per day. When combined with information and counselling sit-stand desks reduced sitting at work in the same range. Sit-stand desks also reduced total sitting time (both at work and outside work) and the duration of sitting episodes that last 30 minutes or longer.
Effect of active workstations
Treadmill desks combined with counselling reduced sitting time at work compared to no intervention. Pedalling workstations combined with information did not reduce sitting at work compared to information alone.
Effect of walking during breaks
The introduction of walking during breaks in two studies with 443 participants did not change sitting time.
Effect of information and counselling
In two studies counselling decreased sitting time with 28 minutes and in another study mindfulness training did not have any effect on sitting at work. There was no considerable increase in work engagement with counselling.
Computer prompting software did not reduce sitting time in two studies. In another study computer prompts reduced sitting time with 55 minutes compared to no intervention. One study found that prompts to stand reduced sitting 14 minutes more than prompts to step. Computer prompts did not change the number of sitting episodes that last 30 minutes or longer.
Interventions from multiple categories
When multiple categories of interventions were combined to decrease sitting, there was reduction in workplace sitting time at 12 weeks’ and six months’ follow-up but there was no considerable difference between intervention and control group at 12 months’ follow-up.
The quality of evidence was very low to low for most interventions mainly because studies were very poorly designed and because they had very few participants. We conclude that at present there is very low quality evidence that sit-stand desks can reduce sitting at work at the short term. There is no evidence for other types of interventions. We need research to assess the effectiveness of different types of interventions for decreasing sitting at workplaces in the long term.