A Text Messaging Intervention for Priming the Affective Rewards of Exercise in Adults: Protocol for a Microrandomized...

Area of Science:

• Behavioral science
• Digital health interventions
• Exercise psychology

Background:

• Effective physical activity interventions are needed.
• Affective attitudes, particularly anticipated positive feelings, show promise for sustained behavior change.
• Current interventions often focus on cognitive factors, with limited long-term success.

Purpose of the Study:

• To evaluate an SMS text messaging intervention manipulating anticipated affective response to exercise.
• To test if pre-exercise reminders of positive post-exercise feelings increase physical activity.
• To explore the impact of different message designs (low-reflection vs. high-reflection) on affective attitudes and motivation.

Main Methods:

• A 9-week microrandomized trial with 120 participants.
• Intervention arms: affective messages (positive post-exercise feelings), control reminders, or no message.
• SMS message types: read-only (self-written) and high-reflection (requiring response).
• Outcome measures: calories burned (Apple Watch), step count, active minutes, affective attitudes, and intrinsic motivation.
• Qualitative interviews for intervention acceptability.

Main Results:

• Enrollment is ongoing, with 57 of 120 participants enrolled as of July 2023.
• The study is designed to provide early evidence on the efficacy of repeated affective message manipulation.
• Analysis will focus on calories burned, with secondary analyses on other physical activity metrics and psychological constructs.

Conclusions:

• This study will offer initial insights into the effectiveness of manipulating anticipated affective responses to exercise.
• Findings will inform the design of digital health interventions aimed at improving affective attitudes and promoting long-term physical activity.
• The comparison of two message types will identify optimal strategies for engaging users in exercise interventions.