Abstract
Background To study the overall and differential effect of breathing hyperoxia (FiO2 0.5) versus placebo (ambient air, FiO2 0.21) to enhance exercise performance in healthy people, patients with pulmonary vascular disease (PVD) with precapillary pulmonary hypertension (PH), chronic obstructive pulmonary disease (COPD), PH due to heart failure with preserved ejection fraction (HFpEF) and cyanotic congenital heart disease (CHD) using data of five RCTs performed with identical protocols.
Methods 91 subjects (32 healthy, 22 PVD with pulmonary arterial or distal chronic thromboembolic PH, 20 with COPD, 10 with PH in HFpEF and 7 with CHD) performed 2 cycle incremental (IET) and 2 constant work-rate exercise tests (CWRET) at 75% of maximal load (Wmax), each with ambient air and hyperoxia in single blinded, randomized-controlled cross-over trials. The main outcomes were differences in Wmax (IET) respectively cycling time (CWRET) with hyperoxia versus ambient air.
Results Overall, hyperoxia increased Wmax by +12 W (95%CI: 9 to 16, p<0.001) and cycling time by +6:13 min (4:50 to 7:35, p<0.001), with improvements being highest in patients with PVD: (Wmax/min: +18%/+118% versus COPD: +8%/+60%, healthy: +5%/+44%, HFpEF: +6%/+28%, CHD: +9%/+14%).
Conclusion This large collective of healthy and patients with various cardiopulmonary disease confirms that hyperoxia significantly prolongs cycling exercise with improvements being highest in endurance CWRET and patients with PVD. These results call for studies investigating optimal oxygen levels to prolong exercise time and effects on training.
Footnotes
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- Received October 24, 2022.
- Accepted December 6, 2022.
- Copyright ©The authors 2023
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