Patients with fibrotic interstitial lung disease (fILD) often face an unpredictable clinical course marked by progressive lung function decline and an elevated risk of death or lung transplantation. The researchers looked to determine whether recovery time from exertional oxygen desaturation was associated with disease severity and future outcomes. They developed a recovery index that integrates three factors: the degree of oxygen desaturation during the 6MWT, the time required to recover to within 3% of baseline oxygen saturation, and the use of supplemental oxygen. For instance, higher RI values were significantly associated with lower percent predicted FVC at baseline and higher ILD-GAP scores in both cohorts. Even so, the findings add an important new dimension to the interpretation of the six-minute walk test in fibrotic interstitial lung disease.