Responses to Physical Activity Messages Among Midlife Adults
Condition: Exercise; Sedentary Behavior; Motivation
Study type: Observational

Summary: 
      The purpose of this study is to test the short-term effects of physical activity promotion
      messages designed for midlife adults. These messages are designed to provide information and
      motivation for physical activity by engaging key social processes, such as social comparison
      (i.e., self-evaluations relative to others).
    

Detailed description: 
      This study will employ an intensive assessment procedure, in which participants are asked to
      complete several brief surveys per day via mobile device. On some days, as described below,
      survey content will be assigned with an embedded experimental design, administered via
      "micro-randomization" (i.e., randomization to receive one of multiple types of content at
      each momentary report). These methods allow for insight into the immediate effects of
      different types of content and their accumulated effects over the study period, as
      participants go about their normal activities.

      Participants will complete an initial survey to assess their global and recent experiences
      (e.g., demographic information, social media use). Participants then will be asked to engage
      in 7 days of ambulatory data collection (i.e., as they go about their normal daily
      activities). This includes wearing pedometers to capture PA behavior (steps per day and
      aerobic-intensity PA) and completing 4 surveys per day via their smartphone.

      A. For the first 3 days, surveys will assess each participant's preferences and responses to
      potential message content as they naturally occur. Content has been pre-tested in preliminary
      work. This will establish participants' baseline behaviors.

      B. For the following 2 days, participants will be randomized at each survey to either: 1)
      make an upward PA comparison (to someone engaging in a lot of activity), 2) make a downward
      PA comparison (to someone engaging in very little activity), or 3) assess a different
      experience (e.g., received social support).

      C. For the final 2 days, participants will be randomized at each survey to either: 1)
      informational messages about ways to increase activity, 2) encouragement to increase their
      activity in healthy ways, or 3) reminders about their activity goals.

      Phases B and C will be counterbalanced, such that half of participants will receive prompts
      described in Phase B before Phase C, and half will receive prompts described in Phase C
      before Phase B.
    

Intervention name(s): Encouragement/Support; Social Comparison
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Messages that focus on improving self-efficacy and motivation for physical activity; Messages that provide exposure to another person's physical activity engagement data (for comparison)
Observational model: Case-Only
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Adults in midlife with elevated risk for cardiovascular disease (as defined by one or more
        of the following: smoking, diagnoses of obesity. prediabetes/type 2 diabetes,
        prehypertension/ hypertension, high cholesterol, or metabolic syndrome)