BackgroundPromoting habitual physical activity (HPA; e.g. walking) may help decelerate dependency and disability in people with dementia (PwD). HPA refers to any movement the skeletal muscles make which requires energy expenditure, including daily tasks (e.g. gardening/housework). Research regarding physical activity in PwD mainly focuses on exercise‐based activities, which may not be feasible for people with chronic health conditions or frailty, or who cannot afford or travel to exercise classes. Promoting participation in HPA may be an inclusive, accessible strategy to support PwD to remain physically active and mobile. PwD participate in less HPA than recommended and disease‐specific factors (e.g. cognition) do not sufficiently explain this. In healthy ageing, HPA participation is associated with multiple socio‐ecological factors (e.g. psychosocial wellbeing/social support/environment) but this has not been explored in dementia. The ActivDem study aims to identify key socio‐ecological influences on HPA change over time in community‐dwellers with dementia. Figure 1 presents ActivDem’s core objectives.MethodPwD and their carers will be recruited from the ongoing cohort study, DETERMIND, they will participate in a continuous seven‐day HPA assessment. This involves wearing an inertial measurement unit on their lower back at baseline and one‐year follow up. Digital mobility outcomes relating to volume (e.g. steps per day), pattern (e.g. mean ambulatory bout length), and variability (i.e. of bout length) will be derived via validated algorithms. PwD will also complete the LASA Physical Activity Questionnaire and Falls Efficacy Scale. Carers will complete the Dementia Management Strategies Scale. Demographic, clinical and psychosocial characteristics and information on care support will be assessed as part of the DETERMIND study (1).ResultLongitudinal statistical methods will identify key predictors of HPA change in PwD, and examine the relationship between HPA and independenceConclusionThe ActivDem study will identify key socio‐ecological predictors of HPA change, these will inform key interventional components to support PwD to remain physically active and mobile following diagnosis of dementia.References1. Farina et al., 2020. DETERMinants of quality of life, care and costs, and consequences of INequalities in people with Dementia and their carers (DETERMIND): A protocol paper. Int. J. Geriatr.