Excessive sitting time (sedentary time) has been associated with risk of insulin resistance and other factors which may be relevant to breast cancer prognosis. This 8-week study tests different strategies for helping breast cancer survivors to modify their levels of sitting time. Participants will be assigned with equal likelihood to one of three groups (1) overall reduction in sitting time, (2) interruption of sitting time with standing breaks, and (3) usual care.

Inclusion Criteria:

1. diagnosed with Stage 0-III breast cancer. Bilateral or multiple primary breast cancers are permitted.
2. Completed primary treatment defined as definitive surgery, (neo)adjuvant chemotherapy and/or (neo)adjuvant radiation. Participants still receiving adjuvant endocrine or HER2 targeted therapies are eligible.
3. Report sitting for ≥8 accumulated waking hours on a typical day,
4. Willing and able to attend 3 study visits at the UW,
5. Willing to attempt reduction of sitting time,
6. Use the internet on a regular basis,
7. Willing and able to complete study requirements, and
8. Currently considered postmenopausal (no menstrual periods in past 12 months), even if pre-menopausal at diagnosis.

Exclusion Criteria:

1. Evidence of recurrence or metastatic disease,
2. Unable to move from sitting to standing without difficulty and to walk 1 block.