An extension of the extended parallel process model to promote heart-healthy exercise behavior: An experimental study.

Background: The prevalence of heart disease has increased and is a leading cause of death in the U.S. Despite the importance of physical activity, only one-third of adults in the United States meet the amount of physical activity recommended by the Centers for Disease Control and Prevention (CDC). The purpose of this study was to extend the extended parallel process model (EPPM) by adding a 'barrier' (a construct from Health Belief Model) and exploring the roles of threat, efficacy, and barrier on participants' self-efficacy, attitudes, and intentions toward exercise. Methods: A between-subject experimental design was conducted online in 2018 in the U.S. A total of 446 participants were recruited from the Amazon Mechanical Turk age 18 or above. The participants were first provided with stimuli messages about physical activity behaviors. Then participants' responses to self-efficacy, intention, and attitudes toward exercise were assessed. Results: The results found an interaction between efficacy and barrier to participants' attitudes toward exercise [F(1,435)=4.35, P=0.038, η² _part=0.01]. The results also showed that there was a statistically significant effect of barriers on participants' self-efficacy regarding exercise behavior [F(1,442)=4.21, P=0.04, η² _part=0.009]. However, three-way interactions of threat, efficacy, and barrier were not found in attitudes or intentions to exercise. Conclusion: The findings suggested that addressing an individual's perceived barrier regarding a health behavior may lead to an increase in self-confidence ensuing in higher physical activity. Future studies should further explore how addressing barriers may influence other health behaviors to design unique and effective health messages.