We would like to thank M.R. Schaeffer and colleagues for their correspondence regarding our recently published systematic review of oxygen for interstitial lung disease (ILD) [1]. In this review, we found no consistent evidence that oxygen therapy administered during exercise tests reduced the primary outcome of dyspnoea, although randomised crossover trials demonstrated improvements in exercise performance. We also reported that the quality of evidence was very poor, due to the retrospective nature of many studies, the potential for selection bias and lack of blinding.