Investigators: Dr Thomas Astell-Burt (CI), Prof Karen Croteau, Prof Gregory Kolt, Dr Xiaoqi Feng. Using traditional and spatial modelling techniques, the investigators will investigate the spatial patterning of regular physical activity (PA), the declining propensity of regular PA with age, related health problems, and well-known social determinants among residents of NSW aged 45 years and over. Although it is widely known that regular physical activity (PA) can help to protect our health from a variety of problems, including (but not limited to) certain cancers, cardiovascular diseases, type 2 diabetes, depression and dementia, it is also well established that a substantive proportion of the population do not participate in enough regular PA. This is especially the case as people age, during which many of the aforementioned health problems begin to emerge. This study will aim to find ways to increase levels of regular PA at a population level in order to help prevent or postpone many of these health problems from occurring. The investigator’s focus on adults over 45 years is borne out of evidence suggesting an increased risk of withdrawal from regular PA with ageing. To shed additional new light on this association, a secondary aim of their study is to examine the extent that the decline in PA across this later stage of the life course varies spatially between different population subgroups (e.g. ethnic and gender groups) and in combination with other health-related behaviours (e.g. smoking and alcohol consumption).