Background. Adherence to cardiac rehabilitation remains a challenge despite established evidence that engaging in regular exercise is a strong preventive measure to experiencing a second cardiac event. A recent study found a six-month cardiac rehabilitation program to be effective for facilitating regular exercise behavior among patients diagnosed with acute coronary syndrome. The purpose of this study was to conduct a phenomenological investigation using Colaizzi's descriptive technique to understand mechanisms responsible for behavior change. Methods. Data were collected and analyzed among patients with acute coronary syndrome at a cardiac rehabilitation using semi-structured interviews that were conducted over the phone across three months. Conclusion. Thematic analysis of 15 semi-structured interviews resulted in 124 statements that were analyzed. The data yielded seven themes that included "motivation to follow prescribed exercise program", "volitional decision", "capability of performing exercise", "connectedness to peers", "planning", "habit formation", and "adopting healthy behaviors beyond exercise". The emerged themes align with construct definitions of the self-determination theory, which include the three psychological needs (autonomy, competence, and relatedness), in addition to autonomous motivation, which represents internally driven reasons to participate in exercise. Planning and habit formation themes support contemporary research that identifies these constructs responsible for behavioral maintenance. While these themes help explain exercise participation, the final theme, adopting healthy behaviors beyond exercise, reflects the impact of the program on having a change towards a healthier lifestyle. The findings highlight the complexity of exercise behavior, and that long-term participation is likely explained by amalgamating the self-determination theory.
Keywords: autonomous; cardiac rehabilitation; exercise; motivation; phenomenology; physical activity; qualitative; self-determination; theory.