Mitigating the effects of sitting on vascular dysfunction in type 2 diabetes
Project leaders: Professor David Dunstan
Type 2 diabetes (T2D) is the fastest growing chronic health problem in Australia, and cardiovascular disease (CVD) accounts for 80 per cent of all deaths in those affected. Insulin resistance, raised blood glucose and dyslipidaemia render those with T2D susceptible to accelerated atherosclerosis and increased risk of CVD. Physical activity has well-recognised clinical and preventive benefits; recently, sedentary time (prolonged sitting as distinct from too little exercise) has also been linked to increased CVD risk. Patients with T2D can spend 70 per cent or more of their waking hours sitting, which in healthy populations, has been linked to decrements in vascular function and thus may contribute to CVD risk in patients with T2D. Acute experimental studies have shown that interrupting prolonged sitting has favourable effects on cardio-metabolic risk factors in healthy and at-risk populations, and on vascular function in healthy individuals; however, no studies have examined the direct effect on vascular function in patients with T2D. The proposed project aims to investigate the beneficial effects of breaking up prolonged sitting on vascular function and other markers of cardio-metabolic health in patients with T2D. This new evidence has the potential to inform new approaches to cardiovascular health, particularly in the prevention of vascular co-morbidities — which account for a substantial number of CVD deaths in this increasingly-large section of the middle-aged and older adult population.
No experimental studies have investigated the link between prolonged sitting and T2D with direct measures of vascular function. This study will be the first to test the effect of prolonged sitting with regular simple resistance activity (SRA) breaks (half squats and calf raises), using a direct measure of endothelial-mediated vascular function (flow mediated dilation [FMD], which is predictive of future cardiovascular events) in patients with T2D. Moreover, we will be the first to directly compare the effectiveness of different timing of activity breaks on cardiovascular health outcomes, in order to inform future large-scale trials.
This study has the potential to begin to build a base of prescriptive evidence regarding the optimal timing of activity breaks for cardiovascular health in a high-risk population, which will help to inform future trials as well as Australian clinical and preventive guidelines. This research has strong alignment with the Heart Foundation’s strategic goals to provide the community with simple but effective ways to reduce CVD risk.