In the present study, the postoperative FVC and FEV1 values were significantly worse than their preoperative values in all patients: the patients who had undergone lung resection lost 33% of FVC and 28% of FEV1 2 weeks after surgery (Table 2). Neural depression due to pain causes a decrease in respiratory muscle power, which results in a decrease in FVC and FEV1. In addition, resected lung parenchyma is a direct cause of the decline of pulmonary function [9]. The FVC_A value in the systemic PR group 6 months after the operation was not different from the preoperative value (p=0.558). The FVC value of the experimental group improved significantly 6 months after the surgery (p=0.030), demonstrating that a 6-month systemic PR program improved FVC more than self-exercise program and the improvement matched the preoperative level in patients who underwent lung resection.