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Berger MM, Luks AM. High Altitude. Semin Respir Crit Care Med 2023; 44:681-695. [PMID: 37816346 DOI: 10.1055/s-0043-1770063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/12/2023]
Abstract
With ascent to high altitude, barometric pressure declines, leading to a reduction in the partial pressure of oxygen at every point along the oxygen transport chain from the ambient air to tissue mitochondria. This leads, in turn, to a series of changes over varying time frames across multiple organ systems that serve to maintain tissue oxygen delivery at levels sufficient to prevent acute altitude illness and preserve cognitive and locomotor function. This review focuses primarily on the physiological adjustments and acclimatization processes that occur in the lungs of healthy individuals, including alterations in control of breathing, ventilation, gas exchange, lung mechanics and dynamics, and pulmonary vascular physiology. Because other organ systems, including the cardiovascular, hematologic and renal systems, contribute to acclimatization, the responses seen in these systems, as well as changes in common activities such as sleep and exercise, are also addressed. While the pattern of the responses highlighted in this review are similar across individuals, the magnitude of such responses often demonstrates significant interindividual variability which accounts for subsequent differences in tolerance of the low oxygen conditions in this environment.
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Affiliation(s)
- Marc Moritz Berger
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - Andrew M Luks
- Division of Pulmonary, Critical Care and Sleep Medicine, University of Washington, Seattle, Washington
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2
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Seiler T, Nakas CT, Brill AK, Hefti U, Hilty MP, Perret-Hoigné E, Sailer J, Kabitz HJ, Merz TM, Pichler Hefti J. Do cardiopulmonary exercise tests predict summit success and acute mountain sickness? A prospective observational field study at extreme altitude. Br J Sports Med 2023:bjsports-2022-106211. [PMID: 36898769 DOI: 10.1136/bjsports-2022-106211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2023] [Indexed: 03/12/2023]
Abstract
OBJECTIVE During a high-altitude expedition, the association of cardiopulmonary exercise testing (CPET) parameters with the risk of developing acute mountain sickness (AMS) and the chance of reaching the summit were investigated. METHODS Thirty-nine subjects underwent maximal CPET at lowlands and during ascent to Mount Himlung Himal (7126 m) at 4844 m, before and after 12 days of acclimatisation, and at 6022 m. Daily records of Lake-Louise-Score (LLS) determined AMS. Participants were categorised as AMS+ if moderate to severe AMS occurred. RESULTS Maximal oxygen uptake (V̇O2max) decreased by 40.5%±13.7% at 6022 m and improved after acclimatisation (all p<0.001). Ventilation at maximal exercise (VEmax) was reduced at 6022 m, but higher VEmax was related to summit success (p=0.031). In the 23 AMS+ subjects (mean LLS 7.4±2.4), a pronounced exercise-induced oxygen desaturation (ΔSpO2exercise) was found after arrival at 4844 m (p=0.005). ΔSpO2exercise >-14.0% identified 74% of participants correctly with a sensitivity of 70% and specificity of 81% for predicting moderate to severe AMS. All 15 summiteers showed higher V̇O2max (p<0.001), and a higher risk of AMS in non-summiteers was suggested but did not reach statistical significance (OR: 3.64 (95% CI: 0.78 to 17.58), p=0.057). V̇O2max ≥49.0 mL/min/kg at lowlands and ≥35.0 mL/min/kg at 4844 m predicted summit success with a sensitivity of 46.7% and 53.3%, and specificity of 83.3% and 91.3%, respectively. CONCLUSION Summiteers were able to sustain higher VEmax throughout the expedition. Baseline V̇O2max below 49.0 mL/min/kg was associated with a high chance of 83.3% for summit failure, when climbing without supplemental oxygen. A pronounced drop of SpO2exercise at 4844 m may identify climbers at higher risk of AMS.
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Affiliation(s)
- Thomas Seiler
- Department of Pulmonary Medicine, Inselspital,Bern University Hospital, University of Bern, Bern, Switzerland
| | - Christos T Nakas
- Institute of Clinical Chemistry, Inselspital University Hospital, University of Bern, Bern, Switzerland.,Laboratory of Biometry, University of Thessaly, Volos, Greece
| | - Anne-Kathrin Brill
- Department of Pulmonary Medicine, Inselspital,Bern University Hospital, University of Bern, Bern, Switzerland
| | - Urs Hefti
- Swiss Sportclinic, Bern, Switzerland
| | - Matthias Peter Hilty
- Department of Intensive Care Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Eveline Perret-Hoigné
- Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Jannis Sailer
- Swiss Sportclinic, Bern, Switzerland.,Orthopedics and Traumatology, Hospital Nidwalden, Stans, Switzerland
| | - Hans-Joachim Kabitz
- Department of Internal Medicine II Pneumology Cardiology Intensive Care Medicine, Klinikum Konstanz, Konstanz, Germany
| | - Tobias M Merz
- Cardiovascular Intensive Care Unit, Auckland City Hospital, Auckland, New Zealand.,Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, University of Bern, Bern, Switzerland
| | - Jacqueline Pichler Hefti
- Department of Pulmonary Medicine, Inselspital,Bern University Hospital, University of Bern, Bern, Switzerland .,Swiss Sportclinic, Bern, Switzerland
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Ortiz-Prado E, Encalada S, Mosquera J, Simbaña-Rivera K, Gomez-Barreno L, Duta D, Ochoa I, Izquierdo-Condoy JS, Vasconez E, Burgos G, Calvopiña M, Viscor G. A comparative analysis of lung function and spirometry parameters in genotype-controlled natives living at low and high altitude. BMC Pulm Med 2022; 22:100. [PMID: 35313848 PMCID: PMC8939107 DOI: 10.1186/s12890-022-01889-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 02/25/2022] [Indexed: 12/15/2022] Open
Abstract
Background The reference values for lung function are associated to anatomical and lung morphology parameters, but anthropometry it is not the only influencing factor: altitude and genetics are two important agents affecting respiratory physiology. Altitude and its influence on respiratory function has been studied independently of genetics, considering early and long-term acclimatization. Objective The objective of this study is to evaluate lung function through a spirometry study in autochthonous Kichwas permanently living at low and high-altitude. Methodology A cross-sectional study of spirometry differences between genetically matched lowland Kichwas from Limoncocha (230 m) at Amazonian basin and high-altitude Kichwas from Oyacachi (3180 m) in Andean highlands. The sample size estimates permitted to recruited 118 patients (40 men and 78 women) from Limoncocha and 95 (39 men and 56 women) from Oyacachi. Chi-square method was used to analyze association or independence of categorical variables, while Student’s t test was applied to comparison of means within quantitative variables. ANOVA, or in the case that the variables didn’t meet the criteria of normality, Kruskal Wallis test were used to compare more than two groups. Results The FVC and the FEV1 were significantly greater among highlanders than lowlanders (p value < 0.001), with a proportion difference of 15.2% for men and 8.5% for women. The FEV1/FVC was significantly higher among lowlanders than highlanders for men and women. A restrictive pattern was found in 12.9% of the participants. Conclusion Residents of Oyacachi had greater FVC and FEV1 than their peers from Limoncocha, a finding physiologically plausible according to published literature. Lung size and greater ventilatory capacities could be an adaptive mechanism developed by the highlander in response to hypoxia. Our results support the fact that this difference in FVC and FEV1 is a compensatory mechanism towards lower barometric and alveolar partial pressure of oxygen pressure.
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Affiliation(s)
- Esteban Ortiz-Prado
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador. .,Department of Cell Biology, Physiology and Immunology, Universidad de Barcelona, Barcelona, Spain.
| | - Sebastián Encalada
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador
| | - Johanna Mosquera
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador
| | - Katherine Simbaña-Rivera
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador
| | - Lenin Gomez-Barreno
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador
| | - Diego Duta
- Limoncocha Community Health Unit, Limoncocha, Ecuador
| | - Israel Ochoa
- Oyacachi Community Health Unit, Oyacachi, Ecuador
| | - Juan S Izquierdo-Condoy
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador
| | - Eduardo Vasconez
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador
| | - German Burgos
- Faculty of Medicine, Universidad de las Américas, Quito, Ecuador
| | - Manuel Calvopiña
- One Health Research Group, Faculty of Medicine, Universidad de las Américas, Calle de los Colimes y Avenida De los Granados, 170137, Quito, Ecuador
| | - Ginés Viscor
- Department of Cell Biology, Physiology and Immunology, Universidad de Barcelona, Barcelona, Spain
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Netzer NC, Rausch LK, Frieß M, Strohl KP, Schilz R, Decker M, Pramsohler S. Expiratory Peak Flow and Minute Ventilation Are Significantly Increased at High Altitude versus Simulated Altitude in Normobaria. Life (Basel) 2022; 12:life12020306. [PMID: 35207593 PMCID: PMC8875033 DOI: 10.3390/life12020306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 01/17/2022] [Accepted: 02/06/2022] [Indexed: 11/16/2022] Open
Abstract
Simulated altitude (normobaric hypoxia, NH) is used to study physiologic hypoxia responses of altitude. However, several publications show differences in physiological responses between NH and hypobaric conditions at altitude (hypobaric hypoxia, HH). The causality for these differences is controversially discussed. One theory is that the lower air density and environmental pressure in HH compared to NH lead to lower alveolar pressure and therefore lower oxygen diffusion in the lung. We hypothesized that, if this theory is correct, due to physical laws (Hagen-Poiseuille, Boyle), resistance respectively air compression (Boyle) at expiration should be lower, expiratory flow higher, and therefore peak flow and maximum expiratory flow (MEF) 75–50 increased in hypobaric hypoxia (HH) vs. normobaric hypoxia (NH). To prove the hypothesis of differences in respiratory flow as a result of lower alveolar pressure between HH and NH, we performed spirography in NH at different simulated altitudes and the corresponding altitudes in HH. In a cross over study, 6 healthy subjects (2 f/4 m, 28.3 ± 8.2 years, BMI: 23.2 ± 1.9) performed spirography as part of spiroergometry in a normobaric hypoxic room at a simulated altitude of 2800 m and after a seven-hour hike on a treadmill (average incline 14%, average walking speed 1.6 km/h) to the simulated summit of Mauna Kea at 4200 m. After a two-month washout, we repeated the spirometry in HH on the start and top of the Mauna Kea hiking trail, HI/USA. Comparison of NH (simulated 4200 m) and HH at 4200 m resulted in increased pulmonary ventilation during exercise (VE) (11.5%, p < 0.01), breathing-frequency (7.8%, p < 0.01), peak expiratory flow PEF (13.4%, p = 0.028), and MEF50 (15.9%, p = 0.028) in HH compared to NH, whereas VO2max decreased by 2%. At 2800 m, differences were only trendy, and at no altitude were differences in volume parameters. Spirography expresses higher mid expiratory flows and peak flows in HH vs. NH. This supports the theory of lower alveolar and small airway pressure due to a lower air density resulting in a lower resistance.
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Affiliation(s)
- Nikolaus C. Netzer
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Institute of Sport Science, University Innsbruck, 83043 Bad Aibling, Germany; (L.K.R.); (M.F.); (S.P.)
- Institute of Mountain Emergency Medicine, Eurac Research, 39100 Bozen, Italy
- Department of Medicine, Division of Sport Medicine and Rehabilitation, University Hospitals, 89070 Ulm, Germany
- Correspondence:
| | - Linda K. Rausch
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Institute of Sport Science, University Innsbruck, 83043 Bad Aibling, Germany; (L.K.R.); (M.F.); (S.P.)
| | - Matthias Frieß
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Institute of Sport Science, University Innsbruck, 83043 Bad Aibling, Germany; (L.K.R.); (M.F.); (S.P.)
| | - Kingman P. Strohl
- Department of Pulmonary and Critical Care Medicine, University Hospitals, Case Western Reserve University, Cleveland, OH 44106, USA; (K.P.S.); (R.S.)
| | - Robert Schilz
- Department of Pulmonary and Critical Care Medicine, University Hospitals, Case Western Reserve University, Cleveland, OH 44106, USA; (K.P.S.); (R.S.)
| | - Michael Decker
- Department of Physiology, Institute for Aerospace Physiology, Case Western Reserve University, Cleveland, OH 44106, USA;
| | - Stephan Pramsohler
- Hermann Buhl Institute for Hypoxia and Sleep Medicine Research, Institute of Sport Science, University Innsbruck, 83043 Bad Aibling, Germany; (L.K.R.); (M.F.); (S.P.)
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de Carvalho M, Fernandes SR, Pereira M, Gromicho M, Santos MO, Alves I, Pinto S, Swash M. Respiratory function tests in amyotrophic lateral sclerosis: The role of maximal voluntary ventilation. J Neurol Sci 2022; 434:120143. [PMID: 35030382 DOI: 10.1016/j.jns.2022.120143] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Revised: 12/29/2021] [Accepted: 01/01/2022] [Indexed: 12/11/2022]
Abstract
BACKGROUND Pulmonary function tests are routinely used to measure progression in ALS. This study aimed to assess the change of various respiratory tests, in particular maximal voluntary ventilation (MVV), which evaluates respiratory endurance. METHODS A group of 51 patients were assessed 3 times (T1, T2, T3, separated by 5.4 months), including slow (SVC) and forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), peak expiratory flow (PEF), maximal inspiratory (MIP) and expiratory (MEP) pressures, MVV, and sniff nasal inspiratory pressure (SNIP). In addition, body mass index (BMI), ALSFRS-R and phrenic nerve responses were obtained 4 times. Patients with dementia and marked bulbar involvement were excluded. RESULTS Mean ALSFRS-R was high at entry (42.9) and its decline was moderately slow at 0.4/month. FVC and FEV1 declined significantly in the three time frames analysed. MVV reduced significantly only between T1-T3 and SVC between T2-T3, and MIP, MEP, PEF and SNIP did not change significantly. The amplitude and the latency of the motor response of the phrenic nerve changed significantly, and BMI declined significantly in most time periods, and ALSFRS-R changed significantly in the 4 time periods. We found a strong correlation between MVV, and FVC, SVC, FEV1, SNIP, phrenic nerve amplitude/area (p < 0.001), and markedly with PEF (rho = 0.821) and ALSFRS-R (rho = 0.713). CONCLUSIONS Our study of early affected patients supports the use of a set of volitional and non-volitional respiratory tests to assess disease progression, rather than any single test. We found MVV a potentially useful marker of pulmonary function in ALS.
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Affiliation(s)
- Mamede de Carvalho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Department of Neurosciences and Mental Health, Hospital de Santa Maria, Centro Hospitalar Universitário de Lisboa Norte, Lisbon, Portugal.
| | - Sofia R Fernandes
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Instituto de Biofísica e Engenharia Biomédica, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
| | - Mariana Pereira
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Marta Gromicho
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Miguel Oliveira Santos
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Department of Neurosciences and Mental Health, Hospital de Santa Maria, Centro Hospitalar Universitário de Lisboa Norte, Lisbon, Portugal
| | - Inês Alves
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Susana Pinto
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal
| | - Michael Swash
- Instituto de Fisiologia, Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisbon, Portugal; Departments of Neurology and Neuroscience, Barts and the London School of Medicine, Queen Mary University of London, United Kingdom
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Schrutka L, Slama A, Muehlbacher J, Bessa V, Lichtenegger P, Ghimessy Á, Ebenbichler G, Winkler R, Faybik P, Nachbaur E, Aigner C, Hoetzenecker K, Jaksch P, Benazzo A. Cardiopulmonary response to high-altitude mountaineering in lung transplant recipients-The Jebel Toubkal experience. Scand J Med Sci Sports 2021; 31:1941-1948. [PMID: 34170580 DOI: 10.1111/sms.14008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 07/25/2021] [Accepted: 05/20/2021] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Only a small proportion of lung transplant recipients achieve a physical status comparable to healthy individuals in the long term. It is reasonable to hypothesize that the necessary cardiopulmonary adaptation required for strenuous physical exercise may be impaired. Exposure to high altitude provides an optimal platform to study the physiological cardiopulmonary adaptation in lung transplant recipients under aerobic conditions. To gain a deeper understanding, 14 healthy lung transplant recipients and healthcare professionals climbed the highest peak in North Africa (Mount Jebel Toubkal; 4167 m) in September 2019. METHODS Monitoring included daily assessment of vital signs, repeated transthoracic echocardiography, pulmonary function tests, and capillary blood sampling throughout the expedition. RESULTS Eleven out of fourteen lung transplant recipients reached the summit. All recipients showed a stable lung function and vital parameters and physiological adaptation of blood gases. Similar results were found in healthy controls. Lung transplant recipients showed worse results in the 6-minute walk test at low and high altitude compared to controls (day 1: 662 m vs. 725 m, p < 0.001, day 5: 656 m vs. 700 m, p = 0.033) and a lack of contractile adaptation of right ventricular function with increasing altitude as measured by tricuspid plane systolic excursion on echocardiography (day 2: 22 mm vs. 24 mm, p = 0.202, day 5: 23 mm vs. 26 mm, p = 0.035). CONCLUSIONS Strenuous exercise in healthy lung transplant recipients is safe. However, the poorer cardiopulmonary performance in the 6-minute walk test and the lack of right ventricular cardiac adaptation may indicate underlying autonomic dysregulation.
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Affiliation(s)
- Lore Schrutka
- Department of Internal Medicine II, Division of Cardiology, Medical University of Vienna, Vienna, Austria
| | - Alexis Slama
- Department of Thoracic Surgery, West German Center for Lung Transplantation, University Medicine Essen - Ruhrlandklinik, Essen, Germany
| | - Jakob Muehlbacher
- Division of Visceral Surgery, Department of Surgery, Medical University of Vienna, Vienna, Austria
| | - Vasiliki Bessa
- Department of Pneumology, West German Center for Lung Transplantation, University Medicine Essen - Ruhrlandklinik, Essen, Germany
| | - Paul Lichtenegger
- Department of Anesthesia, Intensive Care Medicine and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Áron Ghimessy
- Department of Thoracic Surgery, Semmelweis University, Budapest, Hungary
| | - Gerold Ebenbichler
- Department of Physical Medicine and Rehabilitation, Medical University of Vienna, Vienna, Austria
| | | | - Peter Faybik
- Department of Anesthesia, Intensive Care Medicine and Pain Medicine, Medical University of Vienna, Vienna, Austria
| | - Edith Nachbaur
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Pulmonology, Allergology and Endocrinology, Medical University of Vienna, Vienna, Austria
| | - Clemens Aigner
- Department of Thoracic Surgery, West German Center for Lung Transplantation, University Medicine Essen - Ruhrlandklinik, Essen, Germany
| | - Konrad Hoetzenecker
- Department of Thoracic Surgery, Medical University of Vienna, Vienna, Austria
| | - Peter Jaksch
- Department of Thoracic Surgery, Medical University of Vienna, Vienna, Austria
| | - Alberto Benazzo
- Department of Thoracic Surgery, Medical University of Vienna, Vienna, Austria
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Small E, Juul N, Pomeranz D, Burns P, Phillips C, Cheffers M, Lipman GS. Predictive Capacity of Pulmonary Function Tests for Acute Mountain Sickness. High Alt Med Biol 2021; 22:193-200. [PMID: 33601996 DOI: 10.1089/ham.2020.0150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Small, Elan, Nicholas Juul, David Pomeranz, Patrick Burns, Caleb Phillips, Mary Cheffers, and Grant S. Lipman. Predictive capacity of pulmonary function tests for acute mountain sickness. High Alt Med Biol. 22: 193-200, 2021. Background: Pulmonary function as measured by spirometry has been investigated at altitude with heterogenous results, though data focused on spirometry and acute mountain sickness (AMS) are limited. The objective of this study was to investigate the capacity of pulmonary function tests (PFTs) to predict the development of AMS. Materials and Methods: This study was a blinded prospective observational study run during a randomized controlled trial comparing acetazolamide, budesonide, and placebo for AMS prevention on White Mountain, CA. Spirometry measurements of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow were taken at a baseline altitude of 1,250 m, and the evening of and morning after ascent to 3,810 m. Measurements were assessed for correlation with AMS. Results: One hundred three participants were analyzed with well-matched baseline demographics and AMS incidence of 75 (73%) and severe AMS of 48 (47%). There were no statistically significant associations between changes in mean spirometry values on ascent to high altitude with incidence of AMS or severe AMS. Lake Louise Questionnaire scores were negatively correlated with FVC (r = -0.31) and FEV1 (r = -0.29) the night of ascent. Baseline PFT had a predictive accuracy of 65%-73% for AMS, with a receiver operating characteristic of 0.51-0.65. Conclusions: Spirometry did not demonstrate statistically significant changes on ascent to high altitude, nor were there significant associations with incidence of AMS or severe AMS. Low-altitude spirometry did not accurately predict development of AMS, and it should not be recommended for risk stratification.
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Affiliation(s)
- Elan Small
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Nicholas Juul
- Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | | | - Patrick Burns
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Caleb Phillips
- Department of Computational Science, University of Colorado, Boulder, Colorado, USA
| | - Mary Cheffers
- Department of Emergency Medicine, Keck School of Medicine, Los Angeles, California, USA
| | - Grant S Lipman
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
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8
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Hinde KL, Low C, Lloyd R, Cooke CB. Inspiratory muscle training at sea level improves the strength of inspiratory muscles during load carriage in cold-hypoxia. ERGONOMICS 2020; 63:1584-1598. [PMID: 32812837 DOI: 10.1080/00140139.2020.1807613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 07/13/2020] [Indexed: 06/11/2023]
Abstract
Inspiratory muscle training (IMT) and functional IMT (IMTF: exercise-specific IMT activities) has been unsuccessful in reducing respiratory muscle fatigue following load carriage. IMTF did not include load carriage specific exercises. Fifteen participants split into two groups (training and control) walked 6 km loaded (18.2 kg) at speeds representing ∼50%V̇O2max in cold-hypoxia. The walk was completed at baseline; post 4 weeks IMT and 4 weeks IMTF (five exercises engaging core muscles, three involved load). The training group completed IMT and IMTF at a higher maximal inspiratory pressure (Pimax) than controls. Improvements in Pimax were greater in the training group post-IMT (20.4%, p = .025) and post-IMTF (29.1%, p = .050) compared to controls. Respiratory muscle fatigue was unchanged (p = .643). No other physiological or subjective measures were improved by IMT or IMTF. Both IMT and IMTF increased the strength of respiratory muscles pre-and-post a 6 km loaded walk in cold-hypoxia. Practitioner Summary: To explore the interaction between inspiratory muscle training (IMT), load carriage and environment, this study investigated 4 weeks IMT and 4 weeks functional IMT on respiratory muscle strength and fatigue. Functional IMT improved inspiratory muscle strength pre-and-post a loaded walk in cold-hypoxia but had no more effect than IMT alone. Abbreviations: ANOVA: analysis of variance; BF: breathing frequency; CON: control group; EELV: end-expiratory lung volume; EXP: experimental group; FEV1: forced expiratory volume in one second; FiO2: fraction of inspired oxygen; FVC: forced vital capacity; HR: heart rate; IMT: inspiratory muscle training; IMTF: functional inspiratory muscle training; Pemax: maximal expiratory pressure; Pimax: maximal inspiratory pressure; RMF: respiratory muscle fatigue; RPE: rate of perceived exertion; RWU: respiratory muscle warm-up; SaO2: arterial oxygen saturation; SpO2: peripheral oxygen saturation; V̇E: minute ventilation; V̇O2: rate of oxygen uptake.
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Affiliation(s)
- K L Hinde
- Defence Science and Technology Laboratory, Salisbury, UK
- Carnegie School of Sport, Leeds Beckett University, Leeds, UK
| | - C Low
- Carnegie School of Sport, Leeds Beckett University, Leeds, UK
| | - R Lloyd
- School of Social and Health Sciences, Leeds Trinity University, Leeds, UK
| | - C B Cooke
- School of Social and Health Sciences, Leeds Trinity University, Leeds, UK
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9
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Scultetus AH, Jefferson MA, Haque A, Hubbell JN, Arnaud FG, Moon-Massat P, McCarron RM, Malone DL. Histopathological Evidence of Multiple Organ Damage After Simulated Aeromedical Evacuation in a Swine Acute Lung Injury Model. Mil Med 2020; 185:57-66. [PMID: 32074309 DOI: 10.1093/milmed/usz248] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
INTRODUCTION Rapid aeromedical evacuation (AE) is standard of care in current conflicts. However, not much is known about possible effects of hypobaric conditions. We investigated possible effects of hypobaria on organ damage in a swine model of acute lung injury. METHODS Lung injury was induced in anesthetized swine via intravenous oleic acid infusion. After a stabilization phase, animals were subjected to a 4 hour simulated AE at 8000 feet (HYPO). Control animals were kept at normobaria. After euthanasia and necropsy, organ damage was assessed by combined scores for hemorrhage, inflammation, edema, necrosis, and microatelectasis. RESULTS Hemodynamic, neurological, or hematologic measurements were similar prior to transport. Hemodynamic instability became apparent during the last 2 hours of transport in the HYPO group. Histological injury scores in the HYPO group were higher for all organs (lung, kidney, liver, pancreas, and adrenal glands) except the brain, with the largest difference in the lungs (P < 0.001). CONCLUSIONS Swine with mild acute lung injury subjected to a 4 hour simulated AE showed more injury to most organs and, in particular, to the lungs compared with ground transport. This may exacerbate otherwise subclinical pathology and, eventually, manifest as abnormalities in gas exchange or possibly end-organ function.
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Affiliation(s)
- Anke H Scultetus
- Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.,Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814
| | - Michelle A Jefferson
- Department of Pathology, Walter Reed Army Institute of Research, 503 Robert Grant Avenue, Silver Spring, MD 20910
| | - Ashraful Haque
- Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.,Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817
| | - Jordan N Hubbell
- Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.,Parsons, 100 West Walnut Street, Pasadena, CA 91124.,Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817
| | - Francoise G Arnaud
- Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.,Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814.,Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817
| | - Paula Moon-Massat
- Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.,Henry M. Jackson Foundation for the Advancement of Military Medicine, 6720A Rockledge Drive, Bethesda, MD 20817
| | - Richard M McCarron
- Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.,Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814
| | - Debra L Malone
- Neuro Trauma Department, Naval Medical Research Center, 503 Robert Grant Avenue, Silver Spring, MD 20910.,Department of Surgery, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, MD 20814.,Department of Surgery, Walter Reed National Military Medical Center, 4494 North Palmer Road, Bethesda, MD 20889
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10
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Ruzycki CA, Martin AR, Vehring R, Finlay WH. AnIn VitroExamination of the Effects of Altitude on Dry Powder Inhaler Performance. J Aerosol Med Pulm Drug Deliv 2018; 31:221-236. [DOI: 10.1089/jamp.2017.1417] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Conor A. Ruzycki
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Andrew R. Martin
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Reinhard Vehring
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
| | - Warren H. Finlay
- Department of Mechanical Engineering, University of Alberta, Edmonton, Canada
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11
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Cross TJ, Wheatley C, Stewart GM, Coffman K, Carlson A, Stepanek J, Morris NR, Johnson BD. The influence of thoracic gas compression and airflow density dependence on the assessment of pulmonary function at high altitude. Physiol Rep 2018; 6:e13576. [PMID: 29595881 PMCID: PMC5875542 DOI: 10.14814/phy2.13576] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 12/14/2017] [Accepted: 12/17/2017] [Indexed: 11/27/2022] Open
Abstract
The purpose of this report was to illustrate how thoracic gas compression (TGC) artifact, and differences in air density, may together conflate the interpretation of changes in the forced expiratory flows (FEFs) at high altitude (>2400 m). Twenty-four adults (10 women; 44 ± 15 year) with normal baseline pulmonary function (>90% predicted) completed a 12-day sojourn at Mt. Kilimanjaro. Participants were assessed at Moshi (Day 0, 853 m) and at Barafu Camp (Day 9, 4837 m). Typical maximal expiratory flow-volume (MEFV) curves were obtained in accordance with ATS/ERS guidelines, and were either: (1) left unadjusted; (2) adjusted for TGC by constructing a "maximal perimeter" MEFV curve; or (3) adjusted for both TGC and differences in air density between altitudes. Forced vital capacity (FVC) was lower at Barafu compared with Moshi camp (5.19 ± 1.29 L vs. 5.40 ± 1.45 L, P < 0.05). Unadjusted data indicated no difference in the mid-expiratory flows (FEF25-75% ) between altitudes (∆ + 0.03 ± 0.53 L sec-1 ; ∆ + 1.2 ± 11.9%). Conversely, TGC-adjusted data revealed that FEF25-75% was significantly improved by sojourning at high altitude (∆ + 0.58 ± 0.78 L sec-1 ; ∆ + 12.9 ± 16.5%, P < 0.05). Finally, when data were adjusted for TGC and air density, FEFs were "less than expected" due to the lower air density at Barafu compared with Moshi camp (∆-0.54 ± 0.68 L sec-1 ; ∆-10.9 ± 13.0%, P < 0.05), indicating a mild obstructive defect had developed on ascent to high altitude. These findings clearly demonstrate the influence that TGC artifact, and differences in air density, bear on flow-volume data; consequently, it is imperative that future investigators adjust for, or at least acknowledge, these confounding factors when comparing FEFs between altitudes.
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Affiliation(s)
- Troy J. Cross
- Division of Cardiovascular DiseasesMayo ClinicRochesterMinnesota
- Menzies Health Institute QueenslandGriffith UniversitySouthportQueenslandAustralia
| | | | - Glenn M. Stewart
- Division of Cardiovascular DiseasesMayo ClinicRochesterMinnesota
- Menzies Health Institute QueenslandGriffith UniversitySouthportQueenslandAustralia
| | - Kirsten Coffman
- Division of Cardiovascular DiseasesMayo ClinicRochesterMinnesota
| | - Alex Carlson
- Division of Cardiovascular DiseasesMayo ClinicRochesterMinnesota
| | - Jan Stepanek
- Preventive, Occupational and Aerospace MedicineMayo ClinicScottsdaleArizona
| | - Norman R. Morris
- Menzies Health Institute QueenslandGriffith UniversitySouthportQueenslandAustralia
- Allied Health Research CollaborativeThe Prince Charles HospitalBrisbaneQueenslandAustralia
| | - Bruce D. Johnson
- Division of Cardiovascular DiseasesMayo ClinicRochesterMinnesota
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12
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Diaphragm Muscle Weakness Following Acute Sustained Hypoxic Stress in the Mouse Is Prevented by Pretreatment with N-Acetyl Cysteine. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:4805493. [PMID: 29670681 PMCID: PMC5836441 DOI: 10.1155/2018/4805493] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 10/29/2017] [Accepted: 12/12/2017] [Indexed: 12/18/2022]
Abstract
Oxygen deficit (hypoxia) is a major feature of cardiorespiratory diseases characterized by diaphragm dysfunction, yet the putative role of hypoxic stress as a driver of diaphragm dysfunction is understudied. We explored the cellular and functional consequences of sustained hypoxic stress in a mouse model. Adult male mice were exposed to 8 hours of normoxia, or hypoxia (FiO2 = 0.10) with or without antioxidant pretreatment (N-acetyl cysteine, 200 mg/kg i.p.). Ventilation and metabolism were measured. Diaphragm muscle contractile function, myofibre size and distribution, gene expression, protein signalling cascades, and oxidative stress (TBARS) were determined. Hypoxia caused pronounced diaphragm muscle weakness, unrelated to increased respiratory muscle work. Hypoxia increased diaphragm HIF-1α protein content and activated MAPK, mTOR, Akt, and FoxO3a signalling pathways, largely favouring protein synthesis. Hypoxia increased diaphragm lipid peroxidation, indicative of oxidative stress. FoxO3 and MuRF-1 gene expression were increased. Diaphragm 20S proteasome activity and muscle fibre size and distribution were unaffected by acute hypoxia. Pretreatment with N-acetyl cysteine substantially enhanced cell survival signalling, prevented hypoxia-induced diaphragm oxidative stress, and prevented hypoxia-induced diaphragm dysfunction. Hypoxia is a potent driver of diaphragm weakness, causing myofibre dysfunction without attendant atrophy. N-acetyl cysteine protects the hypoxic diaphragm and may have application as a potential adjunctive therapy.
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13
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Rębacz-Maron E. The multi-ethnic global lung initiative 2012 and Third National Health and Nutrition Examination Survey reference values do not reflect spirometric measurements in Black boys and men from Tanzania. Clin Physiol Funct Imaging 2016; 38:76-86. [DOI: 10.1111/cpf.12386] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/11/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Ewa Rębacz-Maron
- Department of Vertebrate Zoology and Anthropology; University of Szczecin; Szczecin Poland
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14
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Vernillo G, Rinaldo N, Giorgi A, Esposito F, Trabucchi P, Millet GP, Schena F. Changes in lung function during an extreme mountain ultramarathon. Scand J Med Sci Sports 2014; 25:e374-80. [PMID: 25262823 DOI: 10.1111/sms.12325] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2014] [Indexed: 11/28/2022]
Abstract
This study aimed to assess the effects of an extreme mountain ultramarathon (MUM, 330 km, 24,000 D+) on lung function. Twenty-nine experienced male ultramarathon runners performed longitudinally [before (pre), during (mid), and immediately after (post) a MUM] a battery of pulmonary function tests. The tests included measurements of forced vital capacity, forced expiratory volume in 1 s, peak flow, inspiratory capacity, and maximum voluntary ventilation in 12 s (MVV12). A significant reduction in the running speed was observed (-43.0% between pre-mid and mid-post; P < 0.001). Expiratory function declined significantly at mid (P < 0.05) and at post (P < 0.05). A similar trend was observed for inspiratory function (P < 0.05). MVV12 declined at mid (P < 0.05) and further decreased at post (P < 0.05). Furthermore, there are significant negative correlations between performance time and MVV12 pre-race (R = -0.54, P = 0.02) as well as changes in MVV12 between pre- and post-race (R = -0.53, P = 0.009). It is concluded that during an extreme MUM, a continuous decline in pulmonary function was observed, likely attributable to the high levels of ventilation required during this MUM in a harsh mountainous environment.
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Affiliation(s)
- G Vernillo
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy.,CeRiSM, Research Center "Sport, Mountain and Health", University of Verona, Rovereto, Italy
| | - N Rinaldo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - A Giorgi
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - F Esposito
- Department of Biomedical Sciences for Health, Università degli Studi di Milano, Milan, Italy
| | - P Trabucchi
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| | - G P Millet
- ISSUL, Institute of Sport Sciences, Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - F Schena
- CeRiSM, Research Center "Sport, Mountain and Health", University of Verona, Rovereto, Italy.,Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
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15
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Swenson ER. CON: Most Climbers Do Not Develop Subclinical Interstitial Pulmonary Edema. High Alt Med Biol 2011; 12:125-8; discussion 129-30. [DOI: 10.1089/ham.2011.0005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Erik R. Swenson
- VA Puget Sound Health Care System, University of Wasington, Seattle, Washington
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16
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Lalande S, Anderson PJ, Miller AD, Ceridon ML, Beck KC, O’Malley KA, Johnson JB, Johnson BD. Variability in pulmonary function following rapid altitude ascent to the Amundsen–Scott South Pole station. Eur J Appl Physiol 2011; 111:2221-8. [DOI: 10.1007/s00421-011-1864-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 02/01/2011] [Indexed: 11/29/2022]
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17
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Orhan O, Bilgin U, Cetin E, Oz E, Dolek BE. The effect of moderate altitude on some respiratory parameters of physical education and sports' students. J Asthma 2010; 47:609-13. [PMID: 20653497 DOI: 10.3109/02770901003725676] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES Analysis of the effects of moderate altitude on some respiratory functions of students enrolled in School of Physical Education and Sports. METHODS The study group comprised of 9 female and 10 male volunteers who were attending a 5-day skiing training camp. All participants were enrolled in School of Physical Education and Sports at Gazi University. The male students had an age range of 22.2 +/- 1.7 years, height of 175.0 +/- 4.3 cm, and body weight of 71.0 +/- 10.4 kg; the female students had an age range of 21.2 +/- 1.7 years, height of 167.1 +/- 4.9 cm, and body weight of 53.7 +/- 4.8 kg. Respiratory tests were performed on the 1st and 5th days (the first and second measurements) at an altitude of 1880 m (in Ilgaz Mountain); 10 days after being exposed to high altitude, further tests were performed at an altitude of 856 m (in Ankara) (the third measurement). Data were analyzed using SPSS software (version 10.0). Intragroup differences were analyzed using repeated measures analysis of variance (ANOVA). According to the results of normality test results, an independent-sample t test was used in comparisons between the groups. A significance level of p < .05 was used in analysis. RESULTS Statistical analysis indicated that there was no significant difference between the intragroup comparisons of female and male students. Intergroup comparisons showed significant differences in forced vital capacity (FVC), forced expiratory volume (FEV), peak expiratory flow (PEF), maximal voluntary ventilation (MVV), and VC parameters (p < .05). CONCLUSION The authors conclude that moderate altitude does not have any effect on some respiratory parameters after 5 days of skiing camp.
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Affiliation(s)
- O Orhan
- Gazi University, School of Physical Education and Sports, Ankara, Turkey.
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18
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Mountaineering experience decreases the net oxygen cost of climbing Mont Blanc (4,808 m). Eur J Appl Physiol 2009; 108:1209-16. [DOI: 10.1007/s00421-009-1334-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2009] [Indexed: 11/27/2022]
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19
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Napoli AM, Milzman DP, Damergis JA, Machan J. Physiologic affects of altitude on recreational climbers. Am J Emerg Med 2009; 27:1081-4. [DOI: 10.1016/j.ajem.2008.09.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2008] [Revised: 09/11/2008] [Accepted: 09/13/2008] [Indexed: 10/20/2022] Open
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20
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Resnick SM, Hall GL, Simmer KN, Stick SM, Sharp MJ. The Hypoxia Challenge Test Does Not Accurately Predict Hypoxia in Flight in Ex-Preterm Neonates. Chest 2008; 133:1161-6. [DOI: 10.1378/chest.07-2375] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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