Purpose: This study was conducted in order to measure fatigue as an objective index, depression and health-related quality of life of patients with COPD in daily life, to understand the correlation between them, and to present reasons for using the results clinically. Methods: This study is intended to evaluate and compare depression, the health-related quality of life of each group after measuring lactic acid levels of 39 male patients with COPD, and dividing those with measurement values than the normal value into the experimental group, and those with normal values into the control group. Results: When comparing depression between the experimental group and the control group, it was measured at 10.38 in the experimental group, and at 7.00 in the control group (p<0.05). Health-related quality of life between the experimental group and the control group was measured at 51.8 in the experimental group, and at 48.67 in the control group (p>0.05). Conclusion: According to the results described above, it appears that patients with COPD have adapted to their disease in some degree for a long period of time, and they are physically and psychologically adjusting to the fatigue they experience, in their own ways of adapting. These results imply that improving physical activity is associated with relief of fatigue and improvement of the quality of life. Thus, there is a need for developing and researching an exercise program and a physical therapy intervention for enhancement of physical activity.