ADAPT Micro-Randomized Trial (ADAPT MRT)

The goal of this study is to collect quantitative and qualitative data that can be used to optimize the HeartSteps mHealth intervention for physical activity. The current version of the intervention is intended to help patients with heart disease increase and maintain their physical activity long-term. To accomplish this goal, a 3-month pilot micro-randomized trial (MRT) will be conducted with 60 patients who are currently completing or have recently completed phase II cardiac rehabilitation (CR).

The core of the study participation is the use of the HeartSteps intervention over the course of 3 months. This includes wearing the Fitbit Charge activity tracker during waking hours and using the HeartSteps intervention to support their efforts to be active. The HeartSteps intervention consists of two sets of intervention components: (1) components intended to improve participants' affective associations with physical activity, including activity suggestions designed to to trigger positive feelings and associate them with being active, and prompts to bring their awareness to intrinsically motivating aspects of being active; and (2) components that target reflective self-regulatory processes, including graphs for self-monitoring, prompts to plan activity, and weekly activity goals. How exactly, and how much, participants will use HeartSteps will not be prescribed since our goal is to understand naturalistic trajectory of engagement with the intervention.

Study Overview

• Status: Recruiting
• Conditions: Cardiovascular Diseases
• Intervention / Treatment: Behavioral: mobile health app

• Study Type: Interventional
• Enrollment (Estimated): 60
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Pedja Klasnja, Ph.D. in Information Science; Phone Number: 734-763-3581; Email: klasnja@umich.edu

Study Locations

• United States
  • Michigan
    • Ann Arbor, Michigan, United States, 48109
      • Recruiting
      • University of Michigan
      • Contact: Pedja Klasnja, Ph.D.; Phone Number: 734-763-3581; Email: klasnja@umich.edu
      • Sub-Investigator: Jessica Golbus, M.D.
      • Sub-Investigator: Brahmajee Nallamothu, M.D.
      • Sub-Investigator: Mark Newman, Ph.D.

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Must be a patient within the Michigan Medicine clinical system with data available in the electronic health record after January 1, 2020.
• Age > 18
• Owns and is a daily user of an Android or iPhone smartphone with study supported operating software.
• Understands English to enable informed consent, completion of study-related surveys, and compliance with study notifications.

• Will be completing within 30 days or have completed in the last 30 days the cardiac rehabilitation program at Michigan Medicine based on one of the following indications:

  • Coronary artery disease (including acute coronary syndromes and stable angina) following percutaneous coronary intervention (PCI)
  • Coronary artery disease following coronary artery bypass surgery (CABG)]
  • Valve repair or replacement (either surgical or percutaneous)
  • Coronary artery disease or an acute coronary syndrome not requiring revascularization

Exclusion Criteria:

• Orthopedic or neurological condition limiting ability to actively engage in moderate intensity physical activity (e.g., brisk walking)
• Greater than mild cognitive impairment
• Wrist too large to wear an activity tracker comfortably. This will be assessed by asking participants "If they have ever had difficulty wearing a watch in the past due to the band being too small."
• Currently receiving palliative care and/or in hospice care
• Severe valvular stenosis or regurgitation
• Unrevascularized left main coronary artery disease (> 50% obstruction on angiography) or proximal left anterior descending disease (>70% obstruction on angiography).
• Exercise-induced ventricular tachycardia
• Cardiac arrest within the prior 6 months
• New York Heart Association (NYHA) class III or IV heart failure
• Pulmonary arterial hypertension treated with inhaled or intravenous pulmonary hypertension-specific therapy
• Ejection fraction <40%
• Determined to be unsafe for participation in this program as assessed by a clinical nurse or investigative team.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Supportive Care
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Intervention; Participants receive the HeartSteps mHealth intervention for 3 months to support and increase physical activity. Components include: Activity Suggestions: Push notifications encouraging walks, randomized twice daily (probability 0.5).; Morning Salience Messages: Notifications highlighting positive aspects of activity, randomized daily (probability 0.5).; Planning Prompts: Notifications to plan next day's activity, randomized daily (probability 0.5).; Weekly Reflection: Prompts each Sunday to reflect on past activity, set goals, and plan for the next week.; Pull Interventions: In-app features like activity dashboards and planning tools.; Ecological Momentary Assessments (EMA): Daily and weekly surveys on psychosocial constructs related to physical activity. Participants wear a Fitbit Charge tracker to monitor activity, synced to their MyDataHelps account. The intervention aims to optimize engagement and physical activity levels.

Behavioral: mobile health app; HeartSteps is an innovative mobile health (mHealth) app designed for cardiac rehabilitation patients. The app features dynamic push notifications, daily and weekly surveys to capture psychosocial data, and an in-app dashboard that provides feedback on activity levels, goal progress, and reminders. Integrated with a Fitbit Charge tracker, HeartSteps emphasizes behavioral changes through engaging features. The intervention is personalized to meet individual needs and preferences, enhancing patient engagement and promoting sustained physical activity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Weekly number of minutes of moderate to vigorous physical activity	The primary outcome of the study is number of weekly minutes of moderate to vigorous physical activity (MVPA), as assessed by the Fitbit Charge 6 activity tracker. Primary analysis will assess the difference in MVPA between the baseline week and the last (i.e. 12th) week of the study.	Baseline, 12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
3-hour step count	Number of steps, as assessed by the Fitbit Charge 6 activity tracker, measured in the three-hour window following the randomization of activity suggestions. This outcome will be assessed after each decision point for the micro-randomized activity suggestions. Each participant will have two decision points per day for the duration of the study.	12 weeks
Daily step count	Number of steps per day, assessed by the Fitbit Charge 6 activity tracker.	12 weeks
Affective exercise experiences (AFFEXX) scale	A validated 36-item self-report instrument that assesses participants' affective associations with physical activity. AFFEXX scale will be administered weekly for the duration of the study. The main analysis of this outcome will assess pre-post differences in the AFFEXX score between baseline and 12th week.	Baseline, 12 weeks

Collaborators and Investigators

• Sponsor: University of Michigan
• Collaborators: National Heart, Lung, and Blood Institute (NHLBI)

Study record dates

Study Major Dates

• Study Start (Actual): May 20, 2025
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): October 1, 2026

Study Registration Dates

• First Submitted: April 1, 2025
• First Submitted That Met QC Criteria: April 1, 2025
• First Posted (Actual): April 8, 2025

Study Record Updates

• Last Update Posted (Actual): June 1, 2026
• Last Update Submitted That Met QC Criteria: May 27, 2026
• Last Verified: August 1, 2025

More Information

Terms related to this study

• Keywords: Physical activity; Cardiac Rehabilitation; mobile health intervention
• Additional Relevant MeSH Terms: Behavior; Cardiovascular Diseases; Motor Activity
• Other Study ID Numbers: HUM00269831; 5R01HL125440-07 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No