Interstitial Lung Diseases (ILDs)Idiopathic Interstitial Pneumonias (IIPs)Idiopathic Pulmonary Fibrosis (IPF)SarcoidosisPulmonary Function Test (PFT)HypoxiaHypoxia Inducible Factors (HIF)Intermittent Hypoxia (IH)Chronic Intermittent Hypoxia (CIH)Alveolar Epithelial Cell (AEC)Alveolar Fluid Clearance (AFC)Epithelial Sodium Channel (ENaC)Pulmonary Function Test (PFT)Cardiopulmonary Exercise Test (CPET)Sleep ApneaSleep Breathing DisordersDyspneaExercise PhysiologyLung PhysiologyLung Pathophysiology