['Field exercise tests have been increasingly used for pulmonary risk assessment. The 6-min walking distance (6MWD) is a field test commonly employed in clinical practice; however, there is limited evidence supporting its use as a risk assessment method in abdominal surgery. The aim was to assess if the 6MWD can predict the development of post-operative pulmonary complications (PPCs) in patients having upper abdominal surgery (UAS).', "This prospective cohort study included 137 consecutive subjects undergoing elective UAS. Subjects performed the 6MWD on the day prior to surgery, and their performance were compared with predicted values of 6MWD (p6MWD) using a previously validated formula. PPCs (including pneumonia, tracheobronchitis, atelectasis with clinical repercussions, bronchospasm and acute respiratory failure) were assessed daily by a pulmonologist blinded to the 6MWD results. 6MWD and p6MWD were compared between subjects who developed PPC (PPC group) and those who did not (no PPC group) using Student's t-test.", 'Ten subjects experienced PPC (7.2%) and no significant difference was observed between the 6MWD obtained in the PPC group and no PPC group (466.0\u2003±\u200397.0\u2003m vs. 485.3\u2003±\u2003107.1\u2003m; P\u2003=\u20030.57, respectively). There was also no significant difference observed between groups for the p6MWD (100.7\u2003±\u200329.1% vs. 90.6\u2003±\u200320.9%; P\u2003>\u20030.05).'] Does preoperative 6-min walking distance predict pulmonary complications in upper abdominal surgery?