Measures
Shortness of breath
The following measures, which include exercise behavior, perceived benefits, self-efficacy, perceived barriers, and perceived threats represented core model constructs that were collected during the study at baseline and at month 12. Shortness of breath and social support were collected at baseline, and these variables functioned as covariates that controlled for model effects. The HF-ACTION study was not designed to test the HBM, but the original investigators employed standardized measurements that assessed behavioral-level variables. Some of the administered scales were congruent with HBM constructs such as exercise behavior, and self-efficacy. Other model constructs that include perceived benefits, barriers, and threats were measured by selecting items from other validated scales. Reliability tests (internal consistency) was performed where applicable. Additional details are described below.