Background <p>Prior research has shown that multi-component behavior change technique (BCT) interventions can potentially increase physical activity (PA) in middle-aged and older adults and thereby reduce risk of cardiovascular disease (CVD) and mortality. However, habit formation theory suggests that the PA is most likely to be sustained when the behavior involves high levels of automaticity for walking. Therefore, PA behavior such as walking must be automatic to be sustainable. The current National Institutes of Health (NIH) Stage Model of Behavioral Intervention Stage 1B trial examines the feasibility of a digital, personalized, multi-component BCT intervention to increase the automaticity with which participants execute a walking routine to ultimately reduce likelihood of future CVD and mortality.</p> Methods <p>A personalized, single-arm, in 44 participants involving digital recruitment and intervention delivery was delivered to adults ages 45 to 75 who worked in Northwell Health system. Participants continuously wore a Fitbit activity tracker during a 2-week baseline and a 10-week intervention. During intervention, participants received five daily BCT associated with habit formation (i.e., goal-setting, action-planning, self-monitoring of behavior, behavioral practice/rehearsal, and behavioral repetition) to follow to execute a walking plan. Participants rated their satisfaction with personalized trial components at the conclusion of the intervention and made ratings of the walking plan’s hypothesized mechanism of action—automaticity—over the course of the intervention phase. Step counts, adherence to the walking plan, adherence to step-count monitoring of step count, and attitudes about personalized trial implementation were also collected.</p> Results <p>Half of the participants acquired automaticity of their daily walking routine in this virtual trial, but there was considerable heterogeneity across participants. Satisfaction with personalized trial elements was consistently high (rated as “satisfied” to “very satisfied” for most items). Adherence to the walking routine and self-monitoring of steps was moderate to good, with participants adhering to their walking plan for 55% of days. Eight of 34 participants achieved an increase of 2000 steps from baseline.</p> Conclusions <p>This stage 1b study found that patients were satisfied with personalized trial components and implementation. Furthermore, half of the participants in the trial reached the hypothesized automaticity criterion over the course of intervention (albeit at different rates). This preliminary evidence suggests that personalized BCT interventions to initiate a walking habit among middle-aged and older adults are both feasible and acceptable.</p>