TranSITion: Ecological Momentary Determinants of Sedentary Behavior

Phase 1: This is an observational study that will utilized Ecological Momentary Assessment, to determine which personal (e.g. fatigue, mood, and stress level), behavioral (e.g. watching TV, working at desk, and eating meals), environmental (e.g. being at home or work, time of the day, and weather) and contextual factors were associated with sedentary behavior. Three EMAs per day will be sent randomly sent to participants on weekdays (Monday to Friday), for four consecutive weeks (total of 20 days). During these days, participants will also wear an activPAL device to objectively measure sedentary behavior. The purpose of the study is to identify the combination of factors most likely to precede and proceed short (<30 min) and long (≥30 min) bouts of sedentary behavior.

Phase 2: A micro-randomized trial will be used to evaluate the efficacy of an email-based prompt to elicit a proximal effect (e.g., a postural response defined as a transition from seated to standing or seated to moving within 5 minutes to interrupt prolonged sitting) compared to a no prompt condition. A secondary aim of this study is to determine whether prompts that encourage standing are more likely to elicit a response than those that encourage moving. An exploratory aim is to examine whether varying the content of the stand or move prompt to include combinations of short term goals and employer approval, influence the magnitude of response.