 This study will include two phases: a pilot phase to test the procedures and a test phase to assess self-worth and PA. During the test phase, Women will receive text message prompts in the morning, afternoon, and evening for 28 days on their cell phones. Each prompt will include a link to an 11-item mobile Internet-based survey assessing momentary PA, self-worth, and self-efficacy. Women will also concurrently wear an activity monitor GENEActiv to objectively measure their activity levels throughout the study. 