Effect of supplemental oxygen therapy on 6-min walk distance in patients with pulmonary arterial hypertension living at 2850 m: a randomised, crossover trial
In brief
Portable oxygen did not improve walking distance in high-altitude pulmonary hypertension
In a randomized crossover trial of 28 people with pulmonary arterial hypertension living at 2,850 meters, low-flow portable oxygen changed six-minute walk distance by an average of -5 meters versus ambient air, with no improvement in breathlessness. It did raise oxygen levels at rest; whether higher oxygen flow could help during exertion remains unknown.
- Journal
- ERJ open research (Q1)
- Published
- 28 September 2026
- Study design
- Randomized controlled trial
- Evidence level
- Level 1, High (CEBM 1b)
- Authors
- Dinah Hertig, Michael Furian, Mona Lichtblau, Julian Müller, Simon R Schneider, Stéphanie Saxer, et al.
- PMID
- 42807797
- DOI
- 10.1183/23120541.01671-2025
Why clinicians should know about it
- Picked for Pulmonary and Respiratory Medicine (top studies of the week, 4 October 2026): Low‑dose oxygen did not improve 6MWD
Abstract
BACKGROUND: Patients with pulmonary arterial hypertension (PAH) who permanently live at high altitude (>2500 m) face particular challenges due to hypobaric hypoxia, which may exacerbate pulmonary hypertension and impair exercise capacity. We therefore investigated the effect of low-dose supplemental oxygen therapy (SOT) on 6-min walk distance (6MWD) in high-altitude residents diagnosed with PAH. METHODS: Adults diagnosed with PAH who permanently live at >2500 m performed two 6MWD tests, once with SOT (1-2 L·min-1 via nasal cannula provided by a portable back-packed concentrator) and once while breathing ambient air (air) at 2850 m according to a randomised, controlled, crossover trial. The primary outcome was the difference in 6MWD between SOT and air. Secondary outcomes were effects of SOT on heart rate, blood pressure and peripheral oxygen saturation (S pO2 ) and Borg scale. RESULTS: 28 patients (86% women, mean±sd age 45±12 years, resting S pO2 93±3%, mean pulmonary artery pressure 52±16 mmHg, 6MWD at 2850 m 462±100 m) were included. SOT compared to hypoxic air at 2850 m did not improve 6MWD (mean difference -5 m, 95% CI: -24 to 14 m, p=0.576), dyspnoea, leg discomfort or end-exercise S pO2 , but did increase resting S pO2 . CONCLUSION: In high-altitude residents diagnosed with PAH, low-dose SOT as commonly prescribed via portable concentrator did not improve 6MWD nor dyspnoea perception, most likely due to insufficient flow provided by the concentrator during exercise, further lowered by exertional mouth breathing and the weight of the backpacked concentrator.
Abstract as published, via PubMed.
For healthcare professionals. The summary is generated by AI from the published abstract, and the evidence level is assigned automatically from the study design on the Oxford CEBM hierarchy. Neither is medical advice. Read the full paper before changing practice.