Text messages and an activity tracker to increase physical activity in mothers and grandmothers

Heart disease is the leading cause of death for women in the United States, and many women find it hard to prioritize their own health while caring for family. This randomized control trial pilot aims to test whether linking heart-healthy habits to a woman's role as a mother or grandmother can increase physical activity and improve other heart-healthy behaviors. The study will enroll mothers and grandmothers of young children, who may join as a mother-grandmother pair or on their own. All participants will complete a baseline questionnaire (self-reported cardiovascular health including physical activity), followed by 4 weeks of wearing an activity tracker (such as a Fitbit) and a post-study period questionnaire (repeating baseline measures). After the first baseline week, participants will be randomly assigned, with pairs assigned together, to an intervention or comparison group. The intervention group will complete a short online writing activity about their caregiving role and personal values, then receive 2 weeks of daily text messages linking their health and physical activity to the health of their children and family, followed by a fourth observational week where no messaging is delivered. The comparison group will also wear the tracker for 4 weeks, but will receive 2 weeks of general daily messages (a greeting + device use reminder). The main question is whether the intervention group is more engaged in the study activities during the text message period.