Physical Activity Promotion for Breast and Endometrial Cancer Survivors

Inclusion Criteria:

* Female adult (≥18 years of age)
* Diagnosis of Stage I-III breast or Stage I-II Type 1 endometrial cancer within the past 5 years.
* At least 3 months past completion of primary active treatment (i.e., surgery, chemotherapy, and/or radiation). May still be undergoing endocrine or Human epidermal growth factor receptor 2 (Her2) therapies.
* Insufficiently active, defined as ≤60 min/week of MVPA, performed in bouts of ≥10 minutes.This is 40% of the recommended amount of MVPA based on the 2008 Federal Guidelines and the American Cancer Society's guidelines for cancer survivors. The 7-Day Recall will be used to screen for physical activity; eligibility will be confirmed prior to randomization using the ActiGraph accelerometer.
* Able to access high-speed Internet daily at home on a computer, smartphone, or tablet. Internet access may be through a household connection or a wireless provider (e.g., Verizon, AT\&T). For compatibility with the Fitbit, the device must run a Windows, Apple, or Android operating system.
* Have a MyChart account or be willing to create one.
* Fluent in spoken and written English language.
* For safety, participants will be screened using the Physical Activity Readiness Questionnaire (PAR-Q) and the Falls Risk Screener, which address joint and cardiovascular problems, balance issues, and other concerns. Physician consent will be obtained for all participants who meet the following criteria:

  * Answer yes to ≥1 question on the PAR-Q OR
  * Answer yes to ≥4 questions on the Falls Risk Screener
* Willing and able to attend study visits at the University of Wisconsin, Madison or Northwestern University, Chicago
* Own and can use a smartphone

Exclusion Criteria:

* Any absolute contraindications to exercise (i.e. acute myocardial infarction, severe orthopedic conditions), metastatic disease or planned elective surgery during intervention/ follow-up.
* Self-reported difficulty transitioning walking 1 block (as a proxy measure of basic physical functioning), or inability to work towards the intervention goals
* Plans to become pregnant or to move from the area within the next two years
* Current enrollment in another dietary or physical activity trial