Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedules
Abstract This study aimed to quantify the effect of two consecutive prolonged, intermittent exposures to high and very high altitudes on oxygen saturation (SpO2) and acute mountain sickness (AMS). For this, healthy lowlanders (N = 21), aged 18–30 years, underwent two 7-day sojourns at the ALMA obser...
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2025-04-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-025-97554-7 |
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| author | Nina F. Waldner Sara E. Hartmann Lara Muralt Mona Lichtblau Patrick R. Bader Jean M. Rawling Ivan Lopez Silvia Ulrich Marc J. Poulin Konrad E. Bloch Michael Furian |
| author_facet | Nina F. Waldner Sara E. Hartmann Lara Muralt Mona Lichtblau Patrick R. Bader Jean M. Rawling Ivan Lopez Silvia Ulrich Marc J. Poulin Konrad E. Bloch Michael Furian |
| author_sort | Nina F. Waldner |
| collection | DOAJ |
| description | Abstract This study aimed to quantify the effect of two consecutive prolonged, intermittent exposures to high and very high altitudes on oxygen saturation (SpO2) and acute mountain sickness (AMS). For this, healthy lowlanders (N = 21), aged 18–30 years, underwent two 7-day sojourns at the ALMA observatory, Chile (6 h/day at 5050 m, 18 h/day at 2900 m), separated by 1-week at 520 m. SpO2 (pulse oximetry) and AMS severity (AMSc, Environmental Symptom Questionnaire cerebral score) diagnosing AMS (AMSc ≥ 0.7) were assessed daily at both altitudes. The study was registered at www.ClinicalTrials.gov: NCT02730143. SpO2 at 2900 m and 5050 m on arrival was mean ± SD 93.6 ± 0.5% and 79.9 ± 1.0% (P < 0.05 between altitudes), whereas the AMSc scores were 0.43 ± 0.08 and 0.97 ± 0.11 (P < 0.05 between altitudes), respectively. At 2900 m during a 7-day intermittent hypoxic exposure, SpO2 increased by a mean (95% CI) 0.3 %/day (0.1;0.4) and by 0.9 %/day (0.4;1.3) at 5050 m. Similarly, AMSc decreased by 0.05 points/day (0.01;0.08) at 2900 m and by 0.16 points/day (0.11;0.21) at 5050 m. During the second sojourn (vs. 1st sojourn), day 1, SpO2 at 2900 m was unchanged but higher at 5050 m by 2.9% (0.6;5.3). AMSc was lower at 2900 m and 5050 m by 0.37 (0.16;0.59) and 0.37 (0.11;0.63) (P < 0.05 both comparisons vs 1st sojourn), respectively. Acclimatization with the 2nd sojourn increased SpO2 at 2900 m by 0.3%/day (0.1;0.4) and 5050 m by 0.5%/day (0.1;0.8). AMSc remained unchanged with acclimatization at 2900 m but decreased at 5050 m by 0.08 points/day (0.04;0.11). In conclusion, in healthy lowlanders, a 7-day intermittent hypobaric hypoxic exposure improved SpO2 and AMS severity at 2900 m, with larger improvements at 5050 m. During a second identical sojourn, initial AMS severity was reduced despite comparable SpO2 at 2900 m compared to the 1st sojourn. No further acclimatization effects were observed in SpO2 but in AMS symptoms at 2900 m. In contrast, re-exposure to 5050 m showed higher initial SpO2 and lower AMSc values with further improvement with intermittent re-exposures. These findings highlight altitude-dependent acclimatization patterns and confirm pre-conditioning’s effectiveness in preventing AMS. |
| format | Article |
| id | doaj-art-95c388e548db45bd884cb871acd7f34e |
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| language | English |
| publishDate | 2025-04-01 |
| publisher | Nature Portfolio |
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| spelling | doaj-art-95c388e548db45bd884cb871acd7f34e2025-08-20T02:17:50ZengNature PortfolioScientific Reports2045-23222025-04-0115111210.1038/s41598-025-97554-7Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedulesNina F. Waldner0Sara E. Hartmann1Lara Muralt2Mona Lichtblau3Patrick R. Bader4Jean M. Rawling5Ivan Lopez6Silvia Ulrich7Marc J. Poulin8Konrad E. Bloch9Michael Furian10Pulmonary Division and Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of ZurichDepartment of Physiology and Pharmacology and Hotchkiss Brain Institute, Cumming School of Medicine, University of CalgaryPulmonary Division and Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of ZurichPulmonary Division and Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of ZurichPulmonary Division and Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of ZurichDepartment of Family Medicine, Cumming School of Medicine, University of CalgarySafety Group, Atacama Large Millimeter Submillimeter ArrayPulmonary Division and Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of ZurichDepartment of Physiology and Pharmacology and Hotchkiss Brain Institute, Cumming School of Medicine, University of CalgaryPulmonary Division and Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of ZurichPulmonary Division and Sleep Disorders Center, Department of Respiratory Medicine, University Hospital of ZurichAbstract This study aimed to quantify the effect of two consecutive prolonged, intermittent exposures to high and very high altitudes on oxygen saturation (SpO2) and acute mountain sickness (AMS). For this, healthy lowlanders (N = 21), aged 18–30 years, underwent two 7-day sojourns at the ALMA observatory, Chile (6 h/day at 5050 m, 18 h/day at 2900 m), separated by 1-week at 520 m. SpO2 (pulse oximetry) and AMS severity (AMSc, Environmental Symptom Questionnaire cerebral score) diagnosing AMS (AMSc ≥ 0.7) were assessed daily at both altitudes. The study was registered at www.ClinicalTrials.gov: NCT02730143. SpO2 at 2900 m and 5050 m on arrival was mean ± SD 93.6 ± 0.5% and 79.9 ± 1.0% (P < 0.05 between altitudes), whereas the AMSc scores were 0.43 ± 0.08 and 0.97 ± 0.11 (P < 0.05 between altitudes), respectively. At 2900 m during a 7-day intermittent hypoxic exposure, SpO2 increased by a mean (95% CI) 0.3 %/day (0.1;0.4) and by 0.9 %/day (0.4;1.3) at 5050 m. Similarly, AMSc decreased by 0.05 points/day (0.01;0.08) at 2900 m and by 0.16 points/day (0.11;0.21) at 5050 m. During the second sojourn (vs. 1st sojourn), day 1, SpO2 at 2900 m was unchanged but higher at 5050 m by 2.9% (0.6;5.3). AMSc was lower at 2900 m and 5050 m by 0.37 (0.16;0.59) and 0.37 (0.11;0.63) (P < 0.05 both comparisons vs 1st sojourn), respectively. Acclimatization with the 2nd sojourn increased SpO2 at 2900 m by 0.3%/day (0.1;0.4) and 5050 m by 0.5%/day (0.1;0.8). AMSc remained unchanged with acclimatization at 2900 m but decreased at 5050 m by 0.08 points/day (0.04;0.11). In conclusion, in healthy lowlanders, a 7-day intermittent hypobaric hypoxic exposure improved SpO2 and AMS severity at 2900 m, with larger improvements at 5050 m. During a second identical sojourn, initial AMS severity was reduced despite comparable SpO2 at 2900 m compared to the 1st sojourn. No further acclimatization effects were observed in SpO2 but in AMS symptoms at 2900 m. In contrast, re-exposure to 5050 m showed higher initial SpO2 and lower AMSc values with further improvement with intermittent re-exposures. These findings highlight altitude-dependent acclimatization patterns and confirm pre-conditioning’s effectiveness in preventing AMS.https://doi.org/10.1038/s41598-025-97554-7 |
| spellingShingle | Nina F. Waldner Sara E. Hartmann Lara Muralt Mona Lichtblau Patrick R. Bader Jean M. Rawling Ivan Lopez Silvia Ulrich Marc J. Poulin Konrad E. Bloch Michael Furian Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedules Scientific Reports |
| title | Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedules |
| title_full | Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedules |
| title_fullStr | Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedules |
| title_full_unstemmed | Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedules |
| title_short | Oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high-altitude working schedules |
| title_sort | oxygen saturation and acute mountain sickness during repeated altitude exposures simulating high altitude working schedules |
| url | https://doi.org/10.1038/s41598-025-97554-7 |
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