Low-Dose CO 2 Inhalation to Improve Oxygenation and Exercise Capacity at High Altitude: A Double-Blind Pilot Study.
RespirologyJul 10, 2026 (epub)
Clinical ResearchPulmonology
Shanfeng Liang, Peter Catcheside, Andrew Wellman et al.
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In 30 seconds
This randomized controlled trial investigated the effects of 2.5% CO2 inhalation on oxygenation and exercise capacity in 28 healthy lowlanders at high altitude (4505 m). Results indicated that CO2 inhalation significantly increased both arterial oxygen (PaO2) and exercise performance, with ESWT distances of 960.0 m compared to 677.0 m for ambient air (p < 0.001).
Key findings
- PaCO2 was significantly higher during CO2 inhalation (33.5 ± 4.0 mmHg) compared to ambient air (31.4 ± 3.5 mmHg, p < 0.001).
- PaO2 levels increased significantly with CO2 inhalation (42.3 ± 5.8 mmHg) versus ambient air (34.9 ± 5.1 mmHg, p < 0.001).
- The ESWT distance was significantly longer during CO2 inhalation (960.0 m) compared to ambient air (677.0 m, p < 0.001).
Why it matters
Improving oxygenation and exercise capacity at high altitudes is crucial for individuals exposed to hypoxic conditions. This study suggests that CO2 inhalation may be a viable strategy to enhance performance and mitigate hypoxia-related issues.