This study aims to evaluate the feasibility and effectiveness of a sedentary behavior intervention based on the Integrated Theory of Health Behavior Change (ITHBC) in older adults with coronary heart disease and frailty. Participants will be randomly assigned to an intervention group or a control group. The intervention is designed around the three core components of ITHBC-knowledge and beliefs, self-regulation skills and abilities, and social facilitation-to help participants reduce sedentary behavior, improve physical activity, and enhance their ability to manage health-related behaviors. The study will include a 1-month intervention period followed by a 2-month follow-up period, with a total study duration of 3 months for each participant. Changes in sedentary behavior and other health-related outcomes will be assessed throughout the study period.