Brief Summary: The purpose of this study is to examine whether nature-based activities provide benefits for breast cancer survivors. The investigators want to know whether a nature-based exercise program is feasible. Women who were diagnosed with breast cancer and have completed cancer treatment will be recruited for the main study. The main study will enroll up to 20 breast cancer subjects in total. This intervention will also include a sub-study examining the same outcomes among adolescents and young adult (AYA) subjects who were diagnosed with cancer (any type) and have completed cancer treatment. The sub-study will enroll up to 20 AYA (ages 18-39) subjects.

Detailed Description: This is a single-arm pilot study MAIN STUDY Breast cancer survivors (n=20) will engage in three months of moderate intensity walking sessions three times a week in a nature and park conservation area. All walks will be supervised by certified clinical Exercise Physiologists (EP). Participants will be encouraged to keep the same days and walk session times throughout the intervention. Sessions will be 50-minutes in total (5-minute warm-up, 40 minute walk, 5 minute cool-down and stretch). Session intensity will be tracked with Fitbits. Participants will be asked to reach a moderate intensity heart rate, defined as 40%-59% heart rate reserve. Participants will complete surveys, physical assessments and collection of biomarkers at baseline and at end of study. Participants also have the option to participate in a 1 hr qualitative exit interview about their participation experiences. Note. Based on any COVID pandemic restrictions at the time of a walk, sessions will be socially distanced one-on-one with an EP. When no restrictions are in place, they will take place in small groups (3-5 participants). SUB-STUDY Adolescent and young adult (AYA) (ages 18-39) survivors (n=20) will complete all of the components of the Main-Study described above.