The 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

Procedures include four laboratory visits: two visits before the intervention and two visits after the intervention.

Participants will be randomly assigned to either four weeks of a digital intervention that prompts participants to engage in physical activity or a waitlist (passive) control condition. Participants will be randomized using a stratified approach using depressive symptoms and physical activity measured at pre-intervention as strata.

The digital intervention group will be instructed to download a Pathverse mobile application on their Apple or Android smartphone device. The Pathverse mobile application will be used as a research delivery platform that can send participants daily push notifications to engage in physical activity of their choice. During the second pre-intervention visit, each participant will select approximately five types of physical activity they find enjoyable that they would like to engage in over the four-week intervention. Participants will report on the physical activity they completed, along with the duration and intensity of each activity. Participants will have the choice of time of day as to when they would like to receive daily notifications on their device.

Members of the passive control group will be informed that their mental health will be monitored over four weeks as a control condition. After the study, they will be offered the digital PA intervention, if desired.

Inclusion Criteria:

• Between the ages of 19 and 40 years
• Verbally fluent in English (i.e., must be able to speak or understand English)
• No uncorrected visual or hearing impairment
• Moderate depressive symptoms or greater of at least 10 or higher on the Patient Health Questionnaire-8 screening instrument
• Eligible to participate in physical activity
• Physically inactive (i.e., engaging in less than 150 min of weekly moderate-to-vigorous physical activity)
• Owns an Apple or Android mobile device, willing to download the Pathverse app , and willing to keep the device on during the study period
• Not currently pregnant

Exclusion Criteria:

- Participants will not qualify for the current study if they do not meet the above inclusion criteria.

The investigator and outcomes assessor will be unaware of group assignment; research staff working for the investigator will perform randomization. Participants will know whether they are assigned to the digital physical activity or passive control arm.