What's Your Poison? Is Sitting Always Health Hindering and Moving Always Health Promoting?

The clear public messaging from international health authorities is that individuals should "sit less and move more." While it is acknowledged that this guidance needs to be tailored to the age of people and also to their health, and abilities, the guidance is not tailored to their current level of physical behaviors. This opinion piece aims to highlight that although people with excessive sitting and insufficient moderate-to-vigorous physical activity should sit more and move less, for other people their health would be promoted by sitting more and moving less. Thus, physical behaviors are not always "poison" or "medicine," but rather the health impact of changes in physical behaviors depends on people's initial levels. Policy, research, and practice implications of this realization are presented. Only tailoring messaging to age and health status could be far from optimal for people with very different current levels of physical behaviors. Policy, research, and practice will be enhanced when the potential for physical behaviors to be either health hindering or health promoting is adequately considered.