Takahashi K, Uchida M, Kato G, et al. - Researchers undertook this prospective, multicenter, randomized, open-labeled, and parallel interventional study to compare the alterations in physical activity prior to and following tiotropium and tiotropium/olodaterol treatment in treatment-naïve chronic obstructive pulmonary disease (COPD) patients. Eighty Japanese patients were randomly assigned to either tiotropium or tiotropium/olodaterol treatment for 12 weeks. Compared with tiotropium treatment, tiotropium/olodaterol treatment afforded greater changes in FEV1 (forced expiratory volume in 1 second) and transient dyspnea index (TDI) before and after the treatment. In a multiple regression model adjusted for cofounding factors such as age, FEV1, total COPD assessment test scores, 6-minute walk distance, and TDI, tiotropium/olodaterol treatment was shown to attenuate the duration of physical activity with 1.0– 1.5 metabolic equivalents. For the first time ever, the effect of dual bronchodilator on physical activity in treatment-naïve COPD patients of Japanese with low BMI was documented.