Ambulatory Oxygen Therapy for Individuals With Mild-to-moderate Interstitial Lung Disease

The investigators plan to conduct a study to find out if giving portable oxygen therapy (during physical activity) to patients with interstitial lung disease will improve quality of life, exercise tolerance, shortness of breath, and blood vessel function. Oxygen will be provided for a period of 8 weeks. Additionally, the investigators plan to investigate if it is helpful to deliver individualized support when providing oxygen therapy, through check-in phone calls with a respiratory therapist and by providing additional educational material.

Inclusion Criteria: * Individuals with fibrotic ILD (all sub-groups of ILD) who have normal oxygen saturation at rest (SpO2 \> 90%) but develop exertional hypoxemia as demonstrated by a SpO2 = 80-89% with activity (measured during 6MWT). Exclusion Criteria: * Use of home oxygen therapy within the previous year for the management of ILD, co-morbid conditions that may require oxygen therapy (such as COPD, cardiovascular disease, or other illnesses), or individuals that require the use of non-invasive ventilation. Additionally, individuals with significant cardiovascular, metabolic, neuromuscular or any other disease that could contribute to dyspnea or abnormal cardiopulmonary responses to exercise will be excluded. Individuals with musculoskeletal injuries that prevent them from completing cycle ergometry exercise trials and ambulation will also be excluded. Individuals with peripheral vascular disease will be excluded from measurement of vascular function (flow mediated dilation).