RecruitingBehavioural interventionDigital Intervention for Physical ActivityThe present study will assess the effects of a four-week digitally delivered intervention on physical activity and depressive symptoms among adults experiencing at least moderate depressive symptoms. The main questions this research aims to answer are: * Does a digitally-delivered intervention increase physical activity levels? * Does a digitally-delivered intervention reduce symptoms of depression? Researchers will compare an intervention promoting physical activity to a passive control (does not receive the intervention) group to see if the intervention reduces depressive symptoms and increases physical activity levels. Participants will: * Visit the laboratory at two separate time points before group assignment, separated by one week of physical activity monitoring * Be randomly assigned to complete four weeks of a digital intervention prompting engagement in physical activity or have their mental health symptoms monitored over four weeks (i.e., passive control group) * Visit the laboratory at two separate time points after the intervention, separated by one week of physical activity monitoring