Sedentary behaviour as a new behavioural target in the prevention and treatment of type 2 diabetes.

Our modern day society encompasses an ecological niche in which sedentary behaviour, labour-saving devices and energy dense foods have become the new reference of living. We now spend more time sedentary, defined as sitting, than in all other activities combined. It has recently been confirmed that the consequences of our modern chair dependency are substantial and a direct contributing factor to the ever increasing epidemic of chronic diseases witnessed within industrialized environments. Epidemiological evidence--from both cross-sectional and prospective observational studies--has indicated that the time spent in sedentary behaviour is a distinct risk factor for several health outcomes, including type 2 diabetes mellitus, insulin resistance, all-cause and cardiovascular disease mortality, depression and some types of cancer. Importantly, these detrimental associations remain even after accounting for time spent in moderate-to-vigorous physical activity, with the strongest and most persistent associations seen between sedentary time and type 2 diabetes mellitus. Importantly, experimental studies have started to confirm the observational associations, with mounting evidence showing that breaking prolonged sitting time with light ambulation is an effective strategy for improving postprandial glucose regulation. Indeed, there is even emerging evidence showing that simply substituting sitting for standing regularly throughout the day may be of sufficient stimulus to improve glucose regulation. We highlight some of the key definitions, issues and evidence underpinning the link between sedentary behaviour and chronic disease in order to better inform clinicians and patients about the importance of incorporating reduced sitting time into type 2 diabetes mellitus management and prevention pathways.