JMIR Publications

ABSTRACT

Background:

Physical activity is a critical target for health interventions, but effective interventions remain elusive. A growing body of work suggests that interventions targeting affective attitudes towards physical activity may be more effective for sustaining activity long-term than those that rely on cognitive constructs alone like goal-setting and self-monitoring. Anticipated affective response in particular is a promising target for intervention.

Objective:

We will evaluate the efficacy of a text-based intervention that manipulates anticipated affective response to exercise to promote physical activity.

Methods:

100 individuals will be enrolled in a micro-randomized trial testing (1) affective messages reminding users about feeling good after exercise (2) control reminders or (3) no message. Two types of affective messages will be deployed: one type requiring a response, the other read-only. The weighted and centered least squares method will be used to analyze the effect of delivering the intervention vs. not on calories burned over four hours around the time of planned activity, measured by the Apple Watch; secondary analyses will include investigation of the effects of the intervention on affective attitudes towards exercise. Participants will be interviewed to gain qualitative insights into intervention impact and acceptability.

Results:

Enrollment has not yet begun as of February 2023. We anticipate enrolling 100 participants beginning in the spring of 2023.

Conclusions:

This study will provide early evidence about the effect of repeated manipulation of anticipated affective response to exercise and insight into optimal design strategies for improving affective attitudes towards exercise. Clinical Trial: ClinicalTrials.gov #NCT05582369