Showing papers by "David W. Dunstan published in 2014"
TL;DR: It is suggested that activity‐permissive workstations can be effective to reduce occupational sedentary time, without compromising work performance, and larger and longer‐term randomized‐controlled trials are needed to understand the sustainability of the sedentaryTime reductions and their longer-term impacts on health‐ and work‐related outcomes.
Abstract: Excessive sedentary time is detrimentally linked to obesity, type 2 diabetes, cardiovascular disease and premature mortality. Studies have been investigating the use of activity-permissive workstations to reduce sedentary time in office workers, a highly sedentary target group. This review systematically summarizes the evidence for activity-permissive workstations on sedentary time, health-risk biomarkers, work performance and feasibility indicators in office workplaces. In July 2013, a literature search identified 38 relevant peer-reviewed publications. Key findings were independently extracted by two researchers. The average intervention effect on sedentary time was calculated via meta-analysis. In total, 984 participants across 19 field-based trials and 19 laboratory investigations were included, with sample sizes ranging from n=2 to 66 per study. Sedentary time, health-risk biomarkers and work performance indicators were reported in 13, 23 and 23 studies, respectively. The pooled effect size from the meta-analysis was -77min of sedentary time/8-h workday (95% confidence interval=-120, -35min). Non-significant changes were reported for most health- and work-related outcomes. Studies with acceptability measures reported predominantly positive feedback. Findings suggest that activity-permissive workstations can be effective to reduce occupational sedentary time, without compromising work performance. Larger and longer-term randomized-controlled trials are needed to understand the sustainability of the sedentary time reductions and their longer-term impacts on health- and work-related outcomes.
264 citations
TL;DR: SITBRQ may be used for assessment of the frequency of sitting breaks within desk-based work settings with validity and reliability similar to other self-reports in the field of sedentary behaviour research, but until adequately improved and re-evaluated it should not be used to collect data about the duration of breaks in sitting time.
Abstract: Background
Breaks in prolonged sitting may have beneficial cardiometabolic and musculoskeletal health outcomes. Desk-based work settings are an important environment to promote and support breaks in sitting time. However, few studies have reported the psychometric properties of self-report measures to assess the frequency and duration of breaks from sitting. This study examined the concurrent validity and test-retest reliability of the Workplace Sitting Breaks Questionnaire (SITBRQ) designed to assess frequency and duration of breaks in sitting within desk-based work settings.
237 citations
TL;DR: A multi-component intervention was successful in reducing workplace sitting and may have important practical and financial implications for workplaces targeting sitting time reductions.
196 citations
TL;DR: Transitioning from a seated to a standing work posture every 30 min across the workday, relative to seated work, led to a significant reduction in fatigue levels and lower back discomfort in overweight/obese office workers, while maintaining work productivity.
Abstract: Objectives To examine whether the introduction of intermittent standing bouts during the workday using a height-adjustable workstation can improve subjective levels of fatigue, musculoskeletal discomfort and work productivity relative to seated work. Methods Overweight/obese office workers (n=23; age 48.2±7.9 years, body mass index 29.6±4 kg/m 2 ) undertook two, 5-day experimental conditions in an equal, randomised (1:1) order. In a simulated office environment, participants performed their usual occupational tasks for 8 h/day in a: seated work posture ( SIT condition ); or interchanging between a standing and seated work posture every 30 min using an electric, height-adjustable workstation ( STAND-SIT condition ). Self-administered questionnaires measuring fatigue, musculoskeletal discomfort and work productivity were performed on day 5 of each experimental condition. Results Participants’ total fatigue score was significantly higher during the SIT condition (mean 67.8 (95% CI 58.8 to 76.7)) compared with the STAND-SIT condition (52.7 (43.8 to 61.5); p Conclusions Transitioning from a seated to a standing work posture every 30 min across the workday, relative to seated work, led to a significant reduction in fatigue levels and lower back discomfort in overweight/obese office workers, while maintaining work productivity. Future investigations should be directed at understanding whether sustained use of height-adjustable workstations promote concentration and productivity at work. Trial Registration Number ACTRN12611000632998.
177 citations
TL;DR: Alternating standing and sitting in 30-min bouts results in modest beneficial effects on postprandial glucose responses in overweight/obese office workers.
Abstract: PurposeThis study aimed to examine whether reductions in sitting time through alternating 30-min bouts of sitting and standing can reduce postprandial glucose, insulin, and triglyceride responses.MethodsTwenty-three overweight/obese sedentary office workers (17 males and six females; mean ±
169 citations
TL;DR: Regularly breaking up prolonged sitting with light and moderate-intensity activity breaks may reduce systolic and diastolic blood pressure.
Abstract: Aim To compare the effect of 7 h of prolonged sitting on resting blood pressure with a similar duration of sitting combined with intermittent brief bouts of light-intensity or moderate-intensity physical activity. Methods and results Overweight/obese adults (n = 19; aged 45–65 years) were recruited for a randomized three-treatment crossover trial with a one-week washout between treatments: 1) uninterrupted sitting; 2) sitting with 2 min bouts of light-intensity walking at 3.2 km/h every 20 min; and, 3) sitting with 2 min bouts of moderate-intensity walking at between 5.8 and 6.4 km/h every 20 min. After an initial 2 h period seated, participants consumed a test meal (75 g carbohydrate, 50 g fat) and completed each condition over the next 5 h. Resting blood pressure was assessed oscillometrically every hour as a single measurement, 5 min prior to each activity bout. GEE models were adjusted for sex, age, BMI, fasting blood pressure and treatment order. After adjustment for potential confounding variables, breaking up prolonged sitting with light and moderate-intensity activity breaks was associated with lower systolic blood pressure [light: 120 ± 1 mmHg (estimated marginal mean ± SEM), P = 0.002; moderate: 121 ± 1 mmHg, P = 0.02], compared to uninterrupted sitting (123 ± 1 mmHg). Diastolic blood pressure was also significantly lower during both of the activity conditions (light: 76 ± 1 mmHg, P = 0.006; moderate: 77 ± 1 mmHg, P = 0.03) compared to uninterrupted sitting (79 ± 1 mmHg). No significant between-condition differences were observed in mean arterial pressure or heart rate. Conclusion Regularly breaking up prolonged sitting may reduce systolic and diastolic blood pressure. Trial registration number ACTRN12609000656235 ( http://www.anzctr.org.au ) Trial registration date August 4th 2009.
161 citations
TL;DR: A protein-enriched diet equivalent to ∼1.3 g · kg¹ · d⁻¹ achieved through lean red meat is safe and effective for enhancing the effects of PRT on LTM and muscle strength and reducing circulating IL-6 concentrations in elderly women.
159 citations
TL;DR: Recent observational and experimental evidence is discussed that makes a compelling case for reducing and breaking up prolonged sitting time in both the primary prevention and disease management contexts and the potential of population-wide initiatives designed to address too much sitting as a health risk is highlighted.
Abstract: Modern human environments are vastly different from those of our forebears. Rapidly advancing technology in transportation, communications, workplaces, and home entertainment confer a wealth of benefits, but increasingly come with costs to human health. Sedentary behavior—too much sitting as distinct from too little physical activity—contributes adversely to cardiometabolic health outcomes and premature mortality. Findings from observational epidemiology have been synthesized in meta-analyses, and evidence is now shifting into the realm of experimental trials with the aim of identifying novel mechanisms and potential causal relationships. We discuss recent observational and experimental evidence that makes a compelling case for reducing and breaking up prolonged sitting time in both the primary prevention and disease management contexts. We also highlight future research needs, the opportunities for developing targeted interventions, and the potential of population-wide initiatives designed to address too much sitting as a health risk.
143 citations
TL;DR: Stand Up Australia is an evidence-guided and systematically developed workplace intervention targeting reductions in office workers’ sitting time.
Abstract: Sitting, particularly in prolonged, unbroken bouts, is widespread within the office workplace, yet few interventions have addressed this newly-identified health risk behaviour. This paper describes the iterative development process and resulting intervention procedures for the Stand Up Australia research program focusing on a multi-component workplace intervention to reduce sitting time. The development of Stand Up Australia followed three phases. 1) Conceptualisation: Stand Up Australia was based on social cognitive theory and social ecological model components. These were operationalised via a taxonomy of intervention strategies and designed to target multiple levels of influence including: organisational structures (e.g. via management consultation), the physical work environment (via provision of height-adjustable workstations), and individual employees (e.g. via face-to-face coaching). 2) Formative research: Intervention components were separately tested for their feasibility and acceptability. 3) Pilot studies: Stand Up Comcare tested the integrated intervention elements in a controlled pilot study examining efficacy, feasibility and acceptability. Stand Up UQ examined the additional value of the organisational- and individual-level components over height-adjustable workstations only in a three-arm controlled trial. In both pilot studies, office workers’ sitting time was measured objectively using activPAL3 devices and the intervention was refined based on qualitative feedback from managers and employees. Results and feedback from participants and managers involved in the intervention development phases suggest high efficacy, acceptance, and feasibility of all intervention components. The final version of the Stand Up Australia intervention includes strategies at the organisational (senior management consultation, representatives consultation workshop, team champions, staff information and brainstorming session with information booklet, and supportive emails from managers to staff), environmental (height-adjustable workstations), and individual level (face-to-face coaching session and telephone support). Stand Up Australia is currently being evaluated in the context of a cluster-randomised controlled trial at the Department of Human Services (DHS) in Melbourne, Australia. Stand Up Australia is an evidence-guided and systematically developed workplace intervention targeting reductions in office workers’ sitting time.
78 citations
TL;DR: In this paper, the authors evaluated the effectiveness of a telephone-delivered behavioral weight loss and physical activity intervention targeting Australian primary care patients with type 2 diabetes and found that the intervention effect for MVPA remained statistically significant at 24 months.
Abstract: Free to read OBJECTIVE: To evaluate the effectiveness of a telephone-delivered behavioral weight loss and physical activity intervention targeting Australian primary care patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Pragmatic randomized controlled trial of telephone counseling (n = 151) versus usual care (n = 151). Reported here are 18-month (end-of-intervention) and 24-month (maintenance) primary outcomes of weight, moderate-to-vigorous-intensity physical activity (MVPA; via accelerometer), and HbA1c level. Secondary outcomes include dietary energy intake and diet quality, waist circumference, lipid levels, and blood pressure. Data were analyzed via adjusted linear mixed models with multiple imputation of missing data. RESULTS: Relative to usual-care participants, telephone counseling participants achieved modest, but significant, improvements in weight loss (relative rate [RR] -1.42% of baseline body weight [95% CI -2.54 to -0.30% of baseline body weight]), MVPA (RR 1.42 [95% CI 1.06-1.90]), diet quality (2.72 [95% CI 0.55-4.89]), and waist circumference (-1.84 cm [95% CI -3.16 to -0.51 cm]), but not in HbA1c level (RR 0.99 [95% CI 0.96-1.02]), or other cardio-metabolic markers. None of the outcomes showed a significant change/deterioration over the maintenance period. However, only the intervention effect for MVPA remained statistically significant at 24 months. CONCLUSIONS: The modest improvements in weight loss and behavior change, but the lack of changes in cardio-metabolic markers, may limit the utility, scalability, and sustainability of such an approach.
66 citations
TL;DR: Although the observed decrease in sitting time was not significant, a community-based, individually tailored, theory-based intervention program aimed at reducing sitting time may be effective for increasing standing and improving cardiometabolic health in sedentary adults.
01 May 2014
TL;DR: It is confirmed that this workplace intervention successfully modified sitting behaviour as intended (ie, fewer and shorter sitting bouts, with changes occurring throughout the day), and behavioural changes aligned with intervention aims.
Abstract: Objective
To investigate how and when changes in workplace sitting time occurred following a workplace intervention to inform evaluation of intervention success.
Method
The 4-week Stand Up Comcare study (June–September 2011) aimed to reduce workplace sitting time via regularly interrupting and replacing sitting time throughout the day. Activity monitor (activPAL3) workplace data from control (n=22) and intervention participants (n=21) were analysed. Differences in the number and usual duration of sitting bouts were used to evaluate how change occurred. To examine when change occurred, intervention effects were compared by hour since starting work and hour of the workday. Change in workplace activity (sitting, standing, stepping) was examined to further inform alignment with intervention messages. Individual variability was examined in how and when the change occurred.
Results
Overall, behavioural changes aligned with intervention aims. All intervention participants reduced total workplace sitting time, though there was wide individual variability observed (range −29 to −262 min per 8 h workday). On average, intervention participants reduced number of sitting bouts (−4.6 bouts (95% CI −10.1 to 1.0), p=0.106) and usual sitting bout duration (−5.6 min (95% CI −9.8 to −1.4, p=0.011)) relative to controls. Sitting time reductions were observed across the workday, though intervention effects varied by hour of the day (p=0.015). The intervention group successfully adopted the Stand Up and Sit Less intervention messages across the day.
Conclusion
These analyses confirmed that this workplace intervention successfully modified sitting behaviour as intended (ie, fewer and shorter sitting bouts, with changes occurring throughout the day).
TL;DR: In this paper, the authors investigated how and when changes in workplace sitting time occurred following a workplace intervention to inform evaluation of intervention success, and examined individual variability in how and how the change occurred.
Abstract: Objective To investigate how and when changes in workplace sitting time occurred following a workplace intervention to inform evaluation of intervention success. Method The 4-week Stand Up Comcare study (June–September 2011) aimed to reduce workplace sitting time via regularly interrupting and replacing sitting time throughout the day. Activity monitor (activPAL3) workplace data from control (n=22) and intervention participants (n=21) were analysed. Differences in the number and usual duration of sitting bouts were used to evaluate how change occurred. To examine when change occurred, intervention effects were compared by hour since starting work and hour of the workday. Change in workplace activity (sitting, standing, stepping) was examined to further inform alignment with intervention messages. Individual variability was examined in how and when the change occurred. Results Overall, behavioural changes aligned with intervention aims. All intervention participants reduced total workplace sitting time, though there was wide individual variability observed (range −29 to −262 min per 8 h workday). On average, intervention participants reduced number of sitting bouts (−4.6 bouts (95% CI −10.1 to 1.0), p=0.106) and usual sitting bout duration (−5.6 min (95% CI −9.8 to −1.4, p=0.011)) relative to controls. Sitting time reductions were observed across the workday, though intervention effects varied by hour of the day (p=0.015). The intervention group successfully adopted the Stand Up and Sit Less intervention messages across the day. Conclusion These analyses confirmed that this workplace intervention successfully modified sitting behaviour as intended (ie, fewer and shorter sitting bouts, with changes occurring throughout the day).
TL;DR: The findings suggest that increasing habitual sedentary behavior over time could increase breast cancer risk among postmenopausal women.
Abstract: Sedentary behavior has been previously shown, in a cross-sectional study, to have deleterious associations with biomarkers of postmenopausal breast cancer risk. We examined the associations of change in sedentary behavior [daily television (TV) viewing time, h/day] over a 5-year period with putative markers of postmenopausal breast cancer risk. The analytic cohort consisted of 1,001 postmenopausal women from the Australian Diabetes, Obesity and Lifestyle (AusDiab) study (1999–2005). Multivariate linear regression models were used to examine associations of change in TV viewing time with biomarkers of the following risk mechanisms: adiposity (body mass index [BMI], waist circumference); metabolic dysfunction (fasting plasma glucose, 2-h plasma glucose, fasting insulin, insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)]); and inflammation (high-sensitivity C-reactive protein (hs-CRP)). All analyses were adjusted for age, baseline TV viewing, and potential confounders. Hourly increments of change in TV viewing time were positively associated with BMI (β = 0.50, 95 % CI 0.20, 0.81; p = 0.001), waist circumference (β = 1.18, 95 % CI 0.49, 1.87; p = 0.001), fasting insulin (β = 38.13 %, 95 % CI 37.08, 39.20; p = 0.01) and HOMA-IR (β = 37.93 %, 95 % CI 36.92, 38.98; p = 0.03) in fully adjusted models. Significant associations with BMI, waist circumference, fasting insulin and HOMA-IR were also present in analyses using categories of change in TV viewing time (reduced, same, increased). The findings suggest that increasing habitual sedentary behavior over time could increase breast cancer risk among postmenopausal women. Further investigation into the role of sedentary behavior in breast cancer etiology is warranted.
TL;DR: TV viewing time is associated adversely with physical well-being, mental well- Being and vitality and further studies are required to better understand potential causal relationships and variations by gender and leisure-time physical activity.
TL;DR: The systems of work commonly observed in contemporary work environments demonstrate a high likelihood of excessive sitting hazard, and the degree of harm associated with this hazard is likely to be substantial; there are available ways to minimise the risk and the cost of these strategies is proportionate to the risk.
Abstract: Employers and doctors need to recognise and respond to the health hazards of too much sedentary time
TL;DR: In Australian adults there is heterogeneity in the age of onset, pattern and magnitude of changes in the different measures of muscle and fat mass derived from BIA, but overall the age-related losses were similar between men and women.
Abstract: Background
Bioelectrical impedance (BIA) represents a simple, inexpensive and non-invasive method that is often used to assess fat-mass (FM) and fat-free mass (FFM) in large population-based cohorts.
TL;DR: The findings from this study will provide new evidence on whether increased dietary protein achieved through the ingestion of a whey-protein drink combined with vitamin D supplementation can enhance the effects of PRT on glycaemic control, muscle mass and size, and cardiometabolic risk factors in older adults with type 2 diabetes.
Abstract: Background: While physical activity, energy restriction and weight loss are the cornerstone of type 2 diabetes management, less emphasis is placed on optimizing skeletal muscle mass. As muscle is the largest mass of insulin-sensitive tissue and the predominant reservoir for glucose disposal, there is a need to develop safe and effective evidence-based, lifestyle management strategies that optimize muscle mass as well as improve glycaemic control and cardiometabolic risk factors in people with this disease, particularly older adults who experience accelerated muscle loss. Methods/Design: Using a two-arm randomized controlled trial, this 6-month study builds upon the community-based progressive resistance training (PRT) programme Lift for Life® to evaluate whether ingestion of a whey-protein drink combined with vitamin D supplementation can enhance the effects of PRT on glycaemic control, body composition and cardiometabolic health in older adults with type 2 diabetes. Approximately 200 adults aged 50 to 75 years with type 2 diabetes, treated with either diet alone or oral hypoglycaemic agents (not insulin), will be recruited. All participants will be asked to participate in a structured, supervised PRT programme based on the Lift for Life® programme structure, and randomly allocated to receive a whey-protein drink (20 g daily of whey-protein plus 20 g after each PRT session) plus vitamin D supplements (2000 IU/day), or no additional powder and supplements. The primary outcome measures to be collected at baseline, 3 and 6 months will be glycated haemoglobin (HbA1c) and insulin sensitivity (homeostatic model assessment). Secondary outcomes will include changes in: muscle mass, size and intramuscular fat; fat mass; muscle strength and function; blood pressure; levels of lipids, adipokines and inflammatory markers, serum insulin-like growth factor-1 and 25-hydroxyvitamin D; renal function; diabetes medication; health-related quality of life, and cognitive function. (Continued on next page)
TL;DR: Insufficient PA was found to be associated with the development of T2D among adults with and without hypertension, and a role for promoting higher physical activity levels to lower T1D risk in both hypertensive and non-hypertensive individuals is supported.
Abstract: Background: Physical activity (PA) and hypertension (HTN) are important influences on the development of type 2 diabetes (T2D). However, the joint impact of PA and HTN on T2D development is unknown.
01 Jan 2014
TL;DR: Local government is admired for being ‘close to the people' as mentioned in this paper and respect from communities extends naturally to those institutions that claim to represent or serve them, as many local governments do.
Abstract: Local government is admired for being ‘close to the people’. Respect from communities extends naturally to those institutions that claim to represent or serve them, as many local governments do. Th...
TL;DR: In this article, Howie and Mierendorff discuss how the increasing recognition of the presence of Aboriginal people in national parks affected the balance between recreation and conservation, and leave unanswered the question posed in the introduction and left unanswered.
Abstract: alternatively, as a means of escaping modernity to reconnect with a longer human history. While the multi-author format provides a rich array of perspectives, it also leads to repetition of the basic trajectory of the foundation of parks and changes in their administration, some missed connections and a few omissions. Howie’s chapter on recreational facilities argues that visitors’ desire for continuity in national parks led to resistance to any changes, even those intended to provide better amenity and ecological sustainability. She mentions a new valuing of older structures as part of the cultural heritage of parks in the 1980s, but neither this chapter nor Mierendorff’s well-researched chapter on the halting efforts of NPWS to adequately provide for heritage tourism within parks takes up this point. How the increasing recognition of the presence of Aboriginal people in parks affected the balance between recreation and conservation is a question posed in the introduction and left unanswered. On a matter of great current interest in NSW, there are a few tantalising references to the early bans on hunting in national parks about which it would have been fascinating to read more. The images accompanying the text are somewhat disappointing for such a potentially stunningly visual topic. Most are presented in black and white and are informational rather than inspirational. The 14 colour plates of contemporary and archival photographs make up for this to some extent. The inclusion of dates with these photographs would have enhanced their historical value. I found Playing in the Bush to be a difficult book to read. This was not because of any shortcomings but because its evocative subject matter sent me off into reveries about my own experiences of campfires, romantic moments in sylvan glens and challenging canoe excursions, and then to the internet to investigate possibilities for future park visits. It will capture the imagination of the broad audience for which it is intended. For the serious historian, it is a reminder that while they are often valued for their sameness from generation to generation, national parks are dynamic sites of engagement with the natural world, which both shape our practices in relation to the environment and provide a stage on which deeply held beliefs are played out.