(Re)Designing the built environment to support physical activity: Bringing public health back into urban design and planning

•Re-connecting urban design and planning and public health collaboration is a priority.•Optimal built environment scales and thresholds for promoting health are unknown.•Public health findings can inform and guide planning decisions.

While public health and urban planning fields worked closely to tackle communicable disease outbreaks in the 19th century, this collaboration faded during the 20th century. Over the last few decades, engagement in physical activity – even walking – has declined substantially, with serious impacts on population health. Recently there has been an emerging body of literature and guidance illustrating the role the built environment has in shaping health outcomes; much of this has focussed on physical activity behaviours. Associations between built environment attributes and physical activity have been reported by many studies, however the geographic scales at which these built environment attributes need to be measured and the magnitude of the built environment attributes required to support physical activity are not clear. Further studying these geographical scales and thresholds will facilitate development of specific guidance to urban designers and planners to create supportive built environments to facilitate physical activity engagement. This is an important addition for re-connecting the fields of public health and urban design and planning.