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 behaviour --too much sitting as distinct from too little physical activity -- contributes adversely to cardio metabolic health outcomes and premature mortality. Reducing time spent in sedentary behaviours is emerging as a novel and compelling public health strategy. There is now an empirical basis for advocating the reduction of overall sitting time as part of the treatment and management of type 2 diabetes patients. While explicit clinical recommendations regarding sedentary behaviours are yet to be refined, it now seems prudent for clinicians and others --in the interests of ‘doing no harm’-- to advise standing up more, sitting less, and taking every opportunity to move more, more often.