ObjectiveTo observe the effect of comorbidity for patients with non-small cell lung cancer (NSCLC) on exercise tolerance and cardiopulmonary function. MethodsNSCLC patients who underwent cardiopulmonary exercise testing (CPET) before surgery were retrospectively included. According to the Charlson comorbidity index (CCI) score, patients were divided into two groups: a CCI≥3 group and a CCI＜3 group. The patients were matched with a ratio of 1 : 1 by propensity score matching according to the age, body mass index, sex, smoking histology, exercise habits, pathological stage and type of surgery. After matching, CPET indexes were compared between the two groups to explore the differences in exercise tolerance and cardiopulmonary function. ResultsA total of 276 patients were included before matching. After matching, 56 patients were enrolled with 28 patients in each group, including 38 (67.9%) males and 18 (32.1%) females with an average age of 70.7±6.8 years. Compared with the CCI＜3 group, work rate at peak (WR peak), WR peak/predicted (WR peak%), kilogram oxygen uptake at anaerobic threshold (VO2/kg AT), VO2/kg peak, VO2/kg peak%, peak carbon dioxide output (VCO2 peak), the minute ventilation to carbon dioxide production slope (VE/VCO2 slope), O2 pulse peak and O2 pulse peak% of CCI≥3 group were statistically different (P＜0.05). Among them, the rate of postoperative pulmonary complication in the CCI≥3 group was higher than that in the CCI＜3 group (60.7% vs. 32.1%, P=0.032). ConclusionIn the NSCLC patients, exercise tolerance and cardiopulmonary function decreased in patients with CCI≥3 compared with those with CCI<3. CPET can provide an objective basis for risk assessment in patients with comorbidity scored by CCI for pulmonary resection.