Can oxygen or moderate altitude improve Exercise Capacity during rehabilitation in COPD? Study Protocol

Background Up to 47% of patients referred to pulmonary rehabilitation (PR) experience a drop in oxygen saturation (SpO₂) below 90% during field walking tests, indicating exercise-induced oxygen desaturation (EID). Hypoxemia can diminish gains in exercise tolerance, thereby limiting the effectiveness of exercise training and potentially accelerate deconditioning. The aim of the study is to determine, in people with chronic obstructive pulmonary disease (COPD) who desaturate during exercise, whether supplemental oxygen during a three-week inpatient pulmonary rehabilitation program is more effective than medical air (sham intervention) or exercise training conducted at moderate altitude (approximately 1,600 m) without supplemental oxygen, where the lower ambient oxygen pressure may further exacerbate hypoxemia but may improve exercise capacity at the completion of the program returning at low altitude and at three-month follow-up.

Methods This is a prospective, randomized controlled three-arm parallel trial with concealed allocation, blinding of participants, therapists and assessors. 51 patients with chronic obstructive pulmonary disease experiencing resting oxygen saturation (SpO₂)≥88% and exercise induced hypoxemia defined by a fall in SpO₂ by≥4% and/or below 90% during a 6-minute walking test (6MWT) will be enrolled into a three-weeks inpatient pulmonary rehabilitation program in Kyrgyzstan with supervised cycle exercise training for six times per week. Patients with severe daytime resting hypoxemia (SpO₂<88%) and receiving long-term oxygen therapy will be excluded. After inclusion, participants will be randomly assigned to one of three groups: the Oxygen Group, receiving supplemental oxygen during exercise; the Air Group, receiving medical air; or the Altitude Group, exercising at altitude while breathing ambient air. The primary outcome will be endurance exercise capacity measured by the constant work rate exercise test (CWRET). Secondary outcomes will be alongside others the 6-minute walk distance (6MWD) evaluating walking capacity, oxygen saturation during exercise and symptoms of COPD measured by the COPD assessment test (CAT) and the Modified Medical Research Council (mMRC). All outcomes will be measured at baseline, completion of training and at three-month follow-up.

Publication History

Article published online:
23 October 2025