IPF: idiopathic pulmonary fibrosis; 6MWD: 6-min walk distance; N: no; SSc: systemic sclerosis; FVC: forced vital capacity; NSIP: nonspecific idiopathic pneumonia; PVRI: pulmonary vascular resistance index; SGRQ: St George's Respiratory Questionnaire; IIP: idiopathic interstitial pneumonia; PF: pulmonary fibrosis; NO: nitric oxide; Y: yes; MVPA: moderate/vigorous physical activity. ^#: a decrease of FVC from baseline in FVC ≥10% and diffusing capacity of the lung for carbon monoxide (D_LCO) ≥15% or acute exacerbation of idiopathic pulmonary fibrosis or death. ^¶: the first occurrence of either a decrease of ≥10% in FVC and a decrease of ≥5% in D_LCO or a decrease of ≥5% in FVC and a decrease of ≥15% in D_LCO; respiratory hospitalisation (hospitalisation involving worsening of, or deterioration in respiratory symptoms, gas exchange/hypoxaemia or radiographic findings on chest radiograph or high-resolution computed tomography scan; all-cause mortality. ⁺: study terminated early because of increased severe side-effects and mortality in the treated arm. ^§: MVPA measured via actigraphy through a wrist-worn medical-grade physical activity monitoring device. ^ƒ: disease progression, defined as either a relevant decline in 6MWD, respiratory-related admission to hospital or all-cause mortality.