Introduction: Chronic obstructive pulmonary disease (COPD) is associated with ventilatory limitation, dyspnea, and reduced exercise tolerance, negatively affecting functional capacity and quality of life. High-flow nasal oxygen therapy (HFNOT) has been proposed as an adjunct during exercise to improve oxygenation and ventilatory efficiency. Materials and Methods: A literature review was conducted including articles published between January 2016 and December 2025, using the PubMed, Web of Science, and PEDro databases. MeSH terms related to COPD, oxygen therapy, exercise, and pulmonary rehabilitation were used. Ten studies were included and organized according to exercise protocol and outcome measures. Results: In constant-load exercise tests at 75% of maximal capacity, HFNOT was associated with improvements in time to exhaustion of 20 to 50%, corresponding to 2 to 6 minutes. Dyspnea, assessed using the Borg scale, was reduced in two studies by 1 to 2 points, while no differences were observed compared with control conditions in the remaining studies. Peripheral oxygen saturation increased significantly in two studies by 1 to 4%, whereas no significant changes were reported in the others. In studies evaluating interventions over multiple sessions, no significant differences in dyspnea were found. The COPD Assessment Test showed clinically relevant improvements of at least 2 points in both groups, with no clear superiority of HFNOT. A greater proportion of responders was observed in the high-flow group for the 6-minute walk test and exercise duration in one study. Physiological studies demonstrated reduced respiratory muscle workload with HFNOT, partly explained by anatomical dead space washout. In the 6-minute walk test, the mean increase in walking distance was 24 m, which is below the threshold for clinical relevance, with no significant differences in dyspnea or transcutaneous carbon dioxide. Conclusions: HFNOT during exercise improves exercise tolerance and physiological parameters in individuals with COPD. However, functional benefits are inconsistent and do not consistently reach clinical relevance.
Sacadura et al. (Wed,) studied this question.