Physical Activity After Cardiac Rehabilitation: Explicit and Implicit Attitudinal Components and Ambivalence

Objective: Physical activity is crucial in the treatment of cardiac disease. In addition to sociocognitive theories of behavior change, attitudinal ambivalence and nonconscious factors have also been demonstrated to predict physical activity. We propose an extension to the theory of planned behavior with a dual-systems approach including explicit and implicit attitudes, and different types of attitudinal ambivalence as moderators to predict the physical activity of patients after discharge from inpatient cardiac rehabilitation. Method: The sample comprised N= 111 cardiac patients who provided daily diary reports of intention, cognitive, affective, and implicit attitudes for 21 days after discharge (86% male. M-age = 62, SDage = 11, n = 2,017 days). Daily moderate-to-vigorous (MVPA) and light (IPA) physical activity were measured using accelerometers. Five types of ambivalence were calculated. Analyses included Bayesian multilevel modeling. Results: Patients with more positive affective attitudes and more positive implicit attitudes had a higher intention. Higher ambivalence weakened the affective attitudes-intention relationship. On days with more positive implicit attitudes than usual, intention was lower, but only when ambivalence was low. Patients with higher ambivalence engaged in less MVPA. On days with extremely low ambivalence, implicit attitudes were negatively associated with tomorrow's MVPA. Patients with more positive affective auitudes engaged in more LPA, but only when their ambivalence was very low. On days with higher ambivalence than usual, the next day's LPA was shorter. However, another type of ambivalence showed the opposite effect. Conclusions: The results emphasise the importance of affective and implicit attitudes and ambivalence for the physical activity of cardiac patients.