The study monitored 168 middle-aged patients with chronic obstructive pulmonary disease (COPD) with a mean age of 50.91 years over 7 days using ecological momentary assessment. Patients assessed dyspnea, irritability, and active exercise behavior three times daily via mobile devices. Results showed that dyspnea and irritability significantly predicted lower levels of active exercise behavior. Self-efficacy positively predicted active exercise behavior and significantly buffered the negative effect of irritability on exercise behavior. The conclusion highlights a close relationship between exercise behavior and symptoms, with self-efficacy showing promising potential to improve patients' active exercise behavior.