High altitude medicine & biology · 2025
The Physiological and Altitude Lowering Effects of Different Supplemental Oxygen Flow Rates at Extreme Simulated Altitude: A Pilot Study.
СтатьяНазвание и аннотация: Перевод пока не подготовлен
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Wakeham Denis J, Tomlinson Andrew R, Manferdelli Giorgio, Howrey Matthew M, Geib Anna K, Ramanathan Murugappan, Payne Marcus, Guilliod Renie, Berry James, Babb Tony G, Hackett Peter, Levine Benjamin D, Hearon Christopher M
Аннотация
UNLABELLED: Wakeham, Denis J., Andrew R. Tomlinson, Giorgio Manferdelli, Matthew M. Howrey, Anna K. Geib, Murugappan Ramanathan, Marcus Payne, Renie Guilliod, James Berry, Tony G. Babb, Peter Hackett, Benjamin D. Levine, and Christopher M. Hearon, Jr. The physiological and altitude lowering effects of different supplemental oxygen flow rates at extreme simulated altitude: a pilot study. High Alt Med Biol. 27:143-151, 2026.
BACKGROUND: Approximately 80% of high-altitude climbers use supplemental oxygen >8,000 meters, yet optimal dosing strategies have not been established.
METHODOLOGY: Therefore, in six unacclimatized individuals (34 ± 8 years; 2 F/4 M), we quantified the effects of supplemental oxygen flow rates (6, 4, 2, 1 and 0 L/min) using the SUMMIT Oxygen mask at 282 mmHg (rest and cycle ergometry: 60 and 120 Watts) and 253 mmHg (rest only) barometric pressure in a hypobaric chamber. We measured oxygen saturation (SpO2) and gas fractions in the mask during 4-minute exposures to each flow rate.
RESULTS: Resting at 282 mmHg, SpO2 (6 L/min: 99% ± 0%; 0 L/min: 70% ± 8%, p < 0.001) and mean inspired oxygen fraction decreased (6 L/min: 65.87% ± 14.11%; 0 L/min: 21.50% ± 0.44%, p < 0.001) with lowering of supplemental oxygen. Exercise further decreased SpO2 and oxygen fractions across all flow rates at 282 mmHg. At 253 mmHg, SpO2 followed a similar trend to data collected at 282 mmHg (6 L/min: 96% ± 2%; 4 L/min: 93% ± 3%; 2 L/min: 87% ± 3%; 1 L/min: 71% ± 0%; 0 L/min: 66% ± 9%). Furthermore, at rest at 253 mmHg, 2 L/min of supplemental oxygen lowered the equivalent altitude to 4,489 meters.
CONCLUSION: All unacclimatized participants were able to tolerate 253 mmHg at rest on as little as 2 L/min of supplemental oxygen.
BACKGROUND: Approximately 80% of high-altitude climbers use supplemental oxygen >8,000 meters, yet optimal dosing strategies have not been established.
METHODOLOGY: Therefore, in six unacclimatized individuals (34 ± 8 years; 2 F/4 M), we quantified the effects of supplemental oxygen flow rates (6, 4, 2, 1 and 0 L/min) using the SUMMIT Oxygen mask at 282 mmHg (rest and cycle ergometry: 60 and 120 Watts) and 253 mmHg (rest only) barometric pressure in a hypobaric chamber. We measured oxygen saturation (SpO2) and gas fractions in the mask during 4-minute exposures to each flow rate.
RESULTS: Resting at 282 mmHg, SpO2 (6 L/min: 99% ± 0%; 0 L/min: 70% ± 8%, p < 0.001) and mean inspired oxygen fraction decreased (6 L/min: 65.87% ± 14.11%; 0 L/min: 21.50% ± 0.44%, p < 0.001) with lowering of supplemental oxygen. Exercise further decreased SpO2 and oxygen fractions across all flow rates at 282 mmHg. At 253 mmHg, SpO2 followed a similar trend to data collected at 282 mmHg (6 L/min: 96% ± 2%; 4 L/min: 93% ± 3%; 2 L/min: 87% ± 3%; 1 L/min: 71% ± 0%; 0 L/min: 66% ± 9%). Furthermore, at rest at 253 mmHg, 2 L/min of supplemental oxygen lowered the equivalent altitude to 4,489 meters.
CONCLUSION: All unacclimatized participants were able to tolerate 253 mmHg at rest on as little as 2 L/min of supplemental oxygen.