Laboratory head: Professor David Dunstan
The Physical Activity Laboratory is concerned with the primary prevention of chronic diseases, specifically diabetes, heart disease and cancer. Our research deals with:
- The health consequences of physical inactivity and sedentary behaviours
- The measurement and analysis of environmental, social and personal-level determinants of behavioral risk factors (e.g. television viewing, desk- and screen-bound work) and lack of physical activity.
The goal of our program is to contribute unique insights relevant to public health policy. We aim to identify environmental and social innovations that can increase physical activity and reduce sitting time.
The laboratory is building comprehensive scientific links between epidemiological evidence; clinical/experimental investigations; behavioural intervention trials on changing sitting time in real-world settings; and large-scale population studies of environment/behaviour relationships in key target settings such as workplaces and more recently, schools. This integration aims to provide much-needed evidence to inform new policy directions in public health in order to reduce Australia's disease burden from excessive sedentary time and physical inactivity.
Why focus on sitting time?
The ultimate goal of our program is to contribute unique insights relevant to public health policy. We aim to identify environmental and social innovations that can increase physical activity and reduce sitting time.
We work closely with the Behavioural Epidemiology Laboratory to build comprehensive scientific links between epidemiological evidence; clinical/experimental investigations; behavioural intervention trials on changing sitting time in real-world settings; and large-scale population studies of environment/behaviour relationships in key target settings such as workplaces and more recently, schools.
This integration aims to provide much-needed evidence to inform new policy directions in public health to reduce Australia's disease burden from excessive sedentary time and physical inactivity.
The program of studies on physical activity, sedentary behaviour and health conducted by the Physical Activity Laboratory includes:
- Cross-sectional and prospective epidemiologic observational studies.
- Measurement development studies using state-of-the-art accelerometer and inclinometer devices.
- Studies on the multiple levels of influence on physical activity and sedentary behaviour, focused on understanding environmental determinants.
- Field-based intervention trials on the feasibility and outcomes of changing physical activity and sedentary behaviour.
- The ongoing refinement of conceptual models to integrate the evidence and explain multiple levels of influence on physical activity and sedentary behaviour.
- Addressing research-translation implications.
- Informing clinical practice and public health policy.
Active ad breaks — offsetting the adverse glycaemic and vascular consequences of sitting watching TV
Australian adults spend an average of two hours per day watching television (TV). High amounts of TV viewing have been linked to an increased risk of obesity, diabetes, certain cancers, cardiovascular disease and premature mortality. A recent report suggests that life expectancy is reduced by 22 minutes for every single hour of TV viewed after the age of 25.
Interventions to reduce TV time have been effective in not only reducing the time spent sitting, but also in decreasing BMI and energy intake whilst watching TV. Recent findings from our laboratory indicate that compared to uninterrupted sitting, interrupting sitting time with short frequent light walking breaks attenuated post-meal glucose, insulin and blood pressure. Thus the aim of this study is to compare the acute effects of watching TV whilst sitting uninterrupted with sitting time interrupted by light-intensity stepping breaks (during TV commercials) on post-meal metabolites (glucose, lipids), vascular function and perceived hunger and fatigue.
Active Ad Breaks is generously supported by the Shepherd Foundation
Sitting time and chronic disease prevention – measurement, mechanisms and interventions
Project leaders: Professor Neville Owen with Professor Jo Salmon, Professor Stewart Trost, Professor David Dunstan, Professor Elizabeth Eakin, Dr Genevieve Healy, Professor Bronwyn Kingwell, Professor Gavin Lambert and Associate Professor Anna Timperio
The overall aims of the CRE are to:
- Generate new knowledge on sitting time and chronic disease risk, focused on measurement, mechanisms and interventions.
- Translate research outcomes to inform public health guidelines, policy and practice for chronic disease prevention.
- Build inter-disciplinary research capacities among early and mid-career researchers.
- Extend and enhance national and international research collaborations.
Together with our collaborators from the University of Queensland and Deakin University, we have established a multidisciplinary research team that is focused on the prevention of major chronic diseases, particularly cardio-metabolic diseases: type 2 diabetes, cardiovascular disease and breast and colon cancer.
Our expertise covers metabolic and vascular physiology, human neuroscience, exercise science, public health, epidemiology, psychology and human development. We conduct systematic laboratory studies to identify how variations in active and sedentary time influence mechanisms leading to increased chronic disease risk. Key emphases are to understand the determinants of behaviour change and maintenance, which we pursue through field-based intervention trials in real-world settings, and to address the translation of that knowledge into effective approaches to disease prevention.
A major focus of our research is on identifying effective primary prevention approaches that can be delivered on a large scale through evidence-based programs that have been developed through systematic randomised controlled trials; and building a knowledge base that can broadly inform population health policy and practice.
The CRE is generously supported by NHMRC
The REsistance and WAlking in Reducing Diabetes (REWARD) study
Breaking up prolonged sitting with walking and brief simple resistance activities for the management of type 2 diabetes (T2D)
While engagement in both aerobic and resistance exercise is a cornerstone in the management of T2D, many patients are often deconditioned, overweight/obese, or unable or insufficiently motivated to meet prescribed exercise recommendations. Furthermore, observational data suggests that those with T2D spend over 9 hr/day sitting — a lifestyle behaviour which is likely to predispose them to a greater risk of micro/macrovascular complications. Thus, there is a need for practical and innovative lifestyle strategies that can optimise daily metabolic function and ultimately reduce the risk of such complications. Our recent observational and experimental findings have demonstrated that the introduction of brief, light-intensity activity breaks during prolonged sitting time can lead to beneficial impacts on blood glucose control, insulin sensitivity, blood pressure, and blood viscosity parameters in individuals deemed at-risk of developing T2D. While these findings are promising, experimental studies are yet to establish the clinical relevance of breaking up sitting on glycaemic control in adults with T2D.
The proposed study represents an important 'next step' in gaining a better understanding of the extent to which novel, convenient and practical modes of activity (potentially incorporated into places where sitting is highly prevalent — such as the workplace or in the home), can help minimise the harmful effects of prolonged sitting in patients with T2D. Specifically, it will investigate the impact of breaks in prolonged sitting using brief (3 minute) bouts of walking or simple resistance activities on postprandial (post-meal) blood glucose in patients with T2D. Additionally, through collaborations with other laboratories within Baker IDI, we will assess candidate mechanisms to better understand the broader biological implications of such behaviours. The results of this study have the potential to provide more detailed and potentially prescriptive information to help shape clinical and public health approaches for the management of T2D.
Aim: To conduct a randomised crossover trial in adults with T2D to investigate the acute (1-day) effects of a single bout of prolonged sitting on postprandial blood glucose with and without intermittent bouts of light-intensity walking or simple resistance activities.
Hypothesis 1: Changes in postprandial glucose resulting from a single bout of prolonged sitting will be attenuated by incorporating brief intermittent bouts of physical activity in the form of either light-intensity walking bouts or simple resistance activities.
Hypothesis 2: Brief intermittent bouts of physical activity will reduce glycaemic variability and hyperglycaemic episodes (>10 mmol/L) over 22 hours compared to a bout of prolonged sitting.
Exploratory hypothesis: Modulation of postprandial glucose resulting from activity bouts will be mediated by both changes in insulin secretion/sensitivity and glucagon. Given the important role of the sympathetic nervous system and incretins (which potentiate post-meal insulin release in a glucose dependant manner) in modulating these factors, these mechanisms will be explored.
Taking a Break for Brain Health
Interacting effects of exercise bouts with breaks in sitting time on cognitive and cerebrovascular function in overweight adults
Maintaining optimal cognitive function through mid- and late-life is vital for independence, quality of life and productivity at work. Disease-modifying pharmacological approaches for the prevention of cognitive decline currently do not exist; however, there is substantial evidence supporting the use of regular physical activity or exercise training as an effective preventive or therapeutic strategy. Whilst a single bout of exercise can enhance several aspects of cognition in adults, it is not known whether such improvements persist in the face of prolonged sitting periods, characteristic of contemporary living.
The proposed research uniquely combines metabolic and vascular physiology and neuropsychological expertise in the first experimental trial to investigate the impacts of interrupting prolonged sitting on cognitive functioning in overweight adults. This study will determine whether combining moderate-intensity exercise with short light-intensity breaks from prolonged sitting improves cognitive and cerebrovascular function. It will provide crucial evidence that can inform recommendations on realistic lifestyle changes that could improve cognitive function.
Taking a break for brain health is generously supported by NHMRC
Identifying Health Consequences, and the Social and Environmental Determinants of Physical Activity and Sedentary Behaviour
Within an established program of observational-study research that uses large, multi-variable cross-sectional and prospective data sets, we conduct two main threads of investigation designed to inform population-based approaches to the primary prevention of cardiovascular disease and diabetes:
- What are the unique relationships of physical activity and sedentary behaviour with cardio-metabolic risk biomarkers and with morbidity and mortality outcomes?
- Identifying the environmental and social determinants of physical activity and sedentary behaviour — what needs to be changed in order to increase physical activity and reduce prolonged sitting time?
Data sets used for these studies include:
- AusDiab (the Australian Diabetes, Obesity and Lifestyle study), with data collected at three time points (AusDiab1 1999–2000; AusDiab2 2004–05; and AusDiab3 2011–12).
- NHANES (the National Health and Nutrition Examination Survey)
— a population-representative surveillance study of US civilians.
- PLACE (Physical Activity in Localities and Community Environments)
— a study with two observation points four years apart that includes objective measures of environmental attributes derived from Geographic Information Systems data sets.
- IPEN (International Physical Activity and the Environment Network study)
— a US National Cancer Institute funded study gathering accelerometer, survey and geographic information system data from 11 countries.
In identifying unique health consequences of physical activity and sedentary behaviour, in our work with AusDiab — for example, we are using device-derived measures to examine relationships with cardio-metabolic risk biomarkers of the patterns and accumulation of time spent sitting, standing, stepping and in light-intensity and moderate-to-vigorous intensity activity. AusDiab 3 is the first large population based study that has highly precise measures of sitting time (ActivPal inclinometer) together with an array of biological measures, including an oral glucose tolerance test. Compared to accelerometer-derived data, ActivPal data provide a much more precise indicator of sitting time, as it is able to measure posture and is thus an excellent tool to identify health consequences of too little physical activity and too much sitting.
In understanding the social and environmental determinants of physical activity and sedentary behaviour, we are working with data from AusDiab and the PLACE and IPEN studies to identify unique behavioural determinants with the potential to be addressed through large-scale policy initiatives to reduce chronic disease risk. For example, we have initially shown significant associations of objective and perceived indices of ‘neighbourhood walkability' with levels of physical activity and sedentary behaviour; ongoing studies are examining the influence of specific environmental attributes (including walking routes and local destinations).
The AusDiab project is generously supported by NHMRC
Student research opportunities
Dr Megan Grace (Postdoctoral Fellow)
Dr Robyn Larsen (Postdoctoral Fellow)
Paddy Dempsey (PhD Student)
Michael Wheeler (PhD Student)
Ruth Grigg (Program Manager)
Dr Rachel Climie (Research Assistant)
Jasmeen Oberoi (Research Assistant)
Parneet Sethi (Data Analyst)
Francis Dillon (Junior Data Analyst)
Ian Mullis (Research Assistant Nurse)
Kym Rickards (Research Assistant Nurse)