Mediators of exercise maintenance after cardiac rehabilitation.
PURPOSE
Exercise maintenance after completing phase II cardiac rehabilitation (CR) is challenging for many patients. A telephone-based maintenance intervention improved exercise participation compared with a control group at 12 months post-CR discharge. We examined the 6-month mediators of intervention effects on exercise.


METHODS
In a randomized controlled trial, 130 patients who had completed CR (mean age: 63.6 [SD = 9.7] years, 20.8% female) were randomized to Maintenance Counseling (n = 64) or Contact Control (n = 66). Putative mediators examined the following: self-efficacy, behavioral processes of change, decisional balance index, social support for exercise, and enjoyment of exercise.


RESULTS
Multiple mediation analyses showed that the intervention significantly increased social support from friends at 6 months but not the other constructs. Decreasing support from friends mediated greater exercise participation in Maintenance Counseling than in Contact Control at 12 months.


CONCLUSIONS
Social support from friends functioned as a suppressor mediator for exercise maintenance among cardiac patients.