Currently submitted to: JMIR Research Protocols
Date Submitted: Aug 21, 2026
Open Peer Review Period: Aug 21, 2026 - Oct 16, 2026
(currently open for review)
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Effect of Supplemental Oxygen Therapy on Exercise Tolerance in COPD Patients with Exercise-Induced Desaturation During In-Patient Pulmonary Rehabilitation at two different Altitudes: Protocol for a Randomized Three-Arm Trial
ABSTRACT
ABSTRACT
Background:
Exercise-induced oxygen desaturation (EID) is common in people with chronic obstructive pulmonary disease (COPD) and can diminish gains in exercise tolerance particularly at moderate altitude (1,600 m). Supplemental oxygen therapy (SOT) during exercise may enhance training tolerance. Nevertheless, evidence supporting either approach during inpatient pulmonary rehabilitation remains limited. This study aims to evaluate whether SOT during inpatient pulmonary rehabilitation improves exercise capacity more effectively than with medical air (sham) or rehabilitation at moderate altitude with room air (approximately 1,600 m) in COPD patients with EID. Methods/Design: This is a prospective, randomized controlled, three-arm, parallel-group trial conducted at two sites in Kyrgyzstan: Bishkek (760 m) and Issyk-Kul (1,600 m). Participants with COPD who desaturate during 6-minute walk test (6MWT) (transcutaneous SpO₂ drop ≥ 4% and/or < 90% during the 6MWT) will be randomly assigned to one of three groups: the hyperoxia group (SOT during exercise training at 760 m, representing hyperoxia), the normoxia group (medical air during exercise training at 760 m, representing normoxia), or the hypoxia group (room air during exercise training at 1,600 m, representing hypoxia). All groups will complete a three-week supervised cycling-based exercise training program. The primary outcome is change in endurance time during constant work rate exercise testing (CWRET) from baseline to post-rehabilitation. Secondary outcomes include 6-minute walk distance (6MWD), health-related quality of life (Chronic Respiratory Disease Questionnaire; CRQ), symptom burden (COPD Assessment Test, CAT; modified Medical Research Council scale, mMRC), and psychological status (Hospital Anxiety and Depression Scale, HADS). Outcomes will be measured at baseline, post-intervention, and three-month follow-up under normoxic, sea-level conditions. Discussion: This trial will be the first to investigate the effectiveness of SOT during inpatient PR at different altitudes in patients with COPD and EID. Findings are expected to clarify the clinical role of oxygen supplementation and altitude exposure during rehabilitation, and to support the development of individualized training strategies for this population. Trial registration: ClinicalTrials.gov identifier: NCT07044843.
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