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Bhattachar S, Malhotra VK, Yanamandra U, Singh S, Sikri G, Patrikar S, Kotwal A. Ibuprofen Compared to Acetazolamide for the Prevention of Acute Mountain Sickness: A Randomized Placebo-Controlled Trial. Cureus 2024; 16:e55998. [PMID: 38606209 PMCID: PMC11007448 DOI: 10.7759/cureus.55998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2024] [Indexed: 04/13/2024] Open
Abstract
INTRODUCTION Acetazolamide is recommended for the prevention of acute mountain sickness (AMS); however, its use is limited in some areas because of side effects. Previous studies report ibuprofen to be similar to or slightly inferior to acetazolamide. This randomized, triple-blinded, parallel-group, placebo-controlled trial was designed to compare ibuprofen with acetazolamide for the prevention of AMS. METHODS Four hundred forty-three healthy Asian Indian men with a mean age of 29 (range: 20-49) years were randomized into three groups A, B, and P at 350m (SL). Acetazolamide (A): 85 mg; ibuprofen (B): 600 mg; or placebo (P): calcium carbonate was administered thrice daily, starting one day prior and continuing for three days after arrival at 3500m (HA). Participants were evaluated for AMS using the Lake Louise Questionnaire and for pulse, BP, SpO2, and respiratory rate twice daily for the first two days during rest and once a day for days three to six at HA. RESULTS Of the 443 participants recruited at SL, 139 could not be airlifted due to logistical limitations, and 304 were available for follow-up at HA. Among these, 254 had ascended as per protocol. By intent to treat (IT) (N = 304; A = 99, B = 102, P = 103), the incidence of AMS (LLQS>/=3) was 12%, 5%, and 13%, and the incidence of severe AMS was 1%, 2%, and 6%, in groups A, B, and P, respectively. Using per protocol analysis (PP) (N = 254; A = 83, B = 87, P = 84), the incidence of AMS was 12%, 6%, and 13% in groups A, B, and P, respectively. The relative risk for developing AMS vs. placebo was A-0.96 (CI:0.46-2.0, p=0.91), B-0.39 (CI:0.14-1.04, p=0.06), A-0.94 (CI:0.42-2.1, p=0.88), and B-0.45 (0.16-1.24, p=0.12) by IT and PP, respectively. CONCLUSION Ibuprofen is effective in males for the prevention of AMS with rapid ascent to 3500 m-rest for the first two days. Acetazolamide was superior to ibuprofen in the prevention of moderate-to-severe AMS.
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Affiliation(s)
- Srinivasa Bhattachar
- Physiology, High Altitude Medical Research Centre, Leh, IND
- Space and Environmental Physiology, Institute of Aerospace Medicine, Bengaluru, IND
| | - Vineet K Malhotra
- Space and Environmental Physiology, Institute of Aerospace Medicine, Bengaluru, IND
| | | | | | - Gaurav Sikri
- Physiology, Armed Forces Medical Services, New Delhi, IND
| | - Seema Patrikar
- Community Medicine, Armed Forces Medical College, Pune, IND
| | - Atul Kotwal
- Community Medicine, National Health Systems Resource Centre, New Delhi, IND
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McKenna ZJ, Bellovary BN, Ducharme JB, Deyhle MR, Wells AD, Fennel ZJ, Specht JW, Houck JM, Mayschak TJ, Mermier CM. Circulating markers of intestinal barrier injury and inflammation following exertion in hypobaric hypoxia. Eur J Sport Sci 2023; 23:2002-2010. [PMID: 37051668 DOI: 10.1080/17461391.2023.2203107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
Hypoxia induced intestinal barrier injury, microbial translocation, and local/systemic inflammation may contribute to high-altitude associated gastrointestinal complications or symptoms of acute mountain sickness (AMS). Therefore, we tested the hypothesis that six-hours of hypobaric hypoxia increases circulating markers of intestinal barrier injury and inflammation. A secondary aim was to determine if the changes in these markers were different between those with and without AMS. Thirteen participants were exposed to six hours of hypobaric hypoxia, simulating an altitude of 4572 m. Participants completed two 30-minute bouts of exercise during the early hours of hypoxic exposure to mimic typical activity required by those at high altitude. Pre- and post-exposure blood samples were assessed for circulating markers of intestinal barrier injury and inflammation. Data below are presented as mean ± standard deviation or median [interquartile range]. Intestinal fatty acid binding protein (Δ251 [103-410] pg•mL-1; p = 0.002, d = 0.32), lipopolysaccharide binding protein (Δ2 ± 2.4 μg•mL-1; p = 0.011; d = 0.48), tumor necrosis factor-α (Δ10.2 [3-42.2] pg•mL-1; p = 0.005; d = 0.25), interleukin-1β (Δ1.5 [0-6.7] pg•mL-1 p = 0.042; d = 0.18), and interleukin-1 receptor agonist (Δ3.4 [0.4-5.2] pg•mL-1p = 0.002; d = 0.23) increased from pre- to post-hypoxia. Six of the 13 participants developed AMS; however, the pre- to post-hypoxia changes for each marker were not different between those with and without AMS (p > 0.05 for all indices). These data provide evidence that high altitude exposures can lead to intestinal barrier injury, which may be an important consideration for mountaineers, military personnel, wildland firefighters, and athletes who travel to high altitudes to perform physical work or exercise.
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Affiliation(s)
- Zachary J McKenna
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
| | - Bryanne N Bellovary
- Kinesiology Departments, State University of New York at Cortland, Cortland, New York
| | - Jeremy B Ducharme
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
| | - Michael R Deyhle
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
| | - Andrew D Wells
- Department of Health & Exercise, Wake Forest University, Winston-Salem, NC, USA
| | - Zachary J Fennel
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
| | - Jonathan W Specht
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
| | | | - Trevor J Mayschak
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
- Department of Emergency Medicine, University of New Mexico, Albuquerque, NM, USA
| | - Christine M Mermier
- Department of Health, Exercise and Sports Sciences, University of New Mexico, Albuquerque, NM, USA
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Beidleman BA, Figueiredo PS, Landspurg SD, Femling JK, Williams JD, Staab JE, Buller MJ, Karl JP, Reilly AJ, Mayschak TJ, Atkinson EY, Mesite TJ, Hoyt RW. Active ascent accelerates the time course but not the overall incidence and severity of acute mountain sickness at 3,600 m. J Appl Physiol (1985) 2023; 135:436-444. [PMID: 37318986 PMCID: PMC10538982 DOI: 10.1152/japplphysiol.00216.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Revised: 05/30/2023] [Accepted: 06/13/2023] [Indexed: 06/17/2023] Open
Abstract
Acute mountain sickness (AMS) typically peaks following the first night at high altitude (HA) and resolves over the next 2-3 days, but the impact of active ascent on AMS is debated. To determine the impact of ascent conditions on AMS, 78 healthy Soldiers (means ± SD; age = 26 ± 5 yr) were tested at baseline residence, transported to Taos, NM (2,845 m), hiked (n = 39) or were driven (n = 39) to HA (3,600 m), and stayed for 4 days. AMS-cerebral (AMS-C) factor score was assessed at HA twice on day 1 (HA1), five times on days 2 and 3 (HA2 and HA3), and once on day 4 (HA4). If AMS-C was ≥0.7 at any assessment, individuals were AMS susceptible (AMS+; n = 33); others were nonsusceptible (AMS-; n = 45). Daily peak AMS-C scores were analyzed. Ascent conditions (active vs. passive) did not impact the overall incidence and severity of AMS at HA1-HA4. The AMS+ group, however, demonstrated a higher (P < 0.05) AMS incidence in the active vs. passive ascent cohort on HA1 (93% vs. 56%), similar incidence on HA2 (60% vs. 78%), lower incidence (P < 0.05) on HA3 (33% vs. 67%), and similar incidence on HA4 (13% vs. 28%). The AMS+ group also demonstrated a higher (P < 0.05) AMS severity in the active vs. passive ascent cohort on HA1 (1.35 ± 0.97 vs. 0.90 ± 0.70), similar score on HA2 (1.00 ± 0.97 vs. 1.34 ± 0.70), and lower (P < 0.05) score on HA3 (0.56 ± 0.55 vs. 1.02 ± 0.75) and HA4 (0.32 ± 0.41 vs. 0.60 ± 0.72). Active compared with passive ascent accelerated the time course of AMS with more individuals sick on HA1 and less individuals sick on HA3 and HA4.NEW & NOTEWORTHY This research demonstrated that active ascent accelerated the time course but not overall incidence and severity of acute mountain sickness (AMS) following rapid ascent to 3,600 m in unacclimatized lowlanders. Active ascenders became sicker faster and recovered quicker than passive ascenders, which may be due to differences in body fluid regulation. Findings from this well-controlled large sample-size study suggest that previously reported discrepancies in the literature regarding the impact of exercise on AMS may be related to differences in the timing of AMS measurements between studies.
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Affiliation(s)
- Beth A Beidleman
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Peter S Figueiredo
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Steven D Landspurg
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Jon K Femling
- Department of Emergency Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Jason D Williams
- Department of Emergency Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Janet E Staab
- Military Performance Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Mark J Buller
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - J Philip Karl
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Aaron J Reilly
- Department of Emergency Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Trevor J Mayschak
- Department of Emergency Medicine, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States
| | - Emma Y Atkinson
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Timothy J Mesite
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
| | - Reed W Hoyt
- Military Nutrition Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts, United States
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Burtscher J, Swenson ER, Hackett PH, Millet GP, Burtscher M. Flying to high-altitude destinations: Is the risk of acute mountain sickness greater? J Travel Med 2023; 30:taad011. [PMID: 36694981 PMCID: PMC10289512 DOI: 10.1093/jtm/taad011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 12/31/2022] [Accepted: 01/17/2023] [Indexed: 01/26/2023]
Abstract
BACKGROUND Altitude sojourns increasingly attract individuals of all ages and different health statuses due to the appeal of high-altitude destinations worldwide and easy access to air travel. The risk of acute mountain sickness (AMS) when flying to high-altitude destinations remains underemphasized. Thus, this review aims to evaluate the altitude-dependent AMS incidence depending on the mode of ascending, e.g. by air vs terrestrial travel. METHODS A literature search was performed to identify the observational studies assessing AMS incidence after acute ascent of primarily healthy adults to real high altitude. In addition, placebo arms of interventional trials evaluating the prophylactic efficacy of various drugs have been separately analysed to confirm or refute the findings from the observational studies. Linear regression analyses were used to evaluate the altitude-dependent AMS incidence. RESULTS Findings of 12 observational studies, in which the AMS incidence in 11 021 individuals ascending to 19 different altitudes (2200-4559 m) was evaluated, revealed an impressive 4.5-fold steeper increase in the AMS incidence for air travel as compared with slower ascent modes, i.e. hiking or combined car and/or air travel and hiking. The higher AMS incidence following transportation by flight vs slower means was also confirmed in placebo-treated participants in 10 studies of drug prophylaxis against AMS. CONCLUSIONS Due to the short time span in going from low to high altitude, reduced acclimatization likely is the main reason for a higher AMS risk when travelling to high-altitude destinations by flight. To avoid frustrating travel experiences and health risks, appropriate and timely medical advice on how to prepare for air travel to high altitude is of vital importance. Effective preparation options include the use of modern pre-acclimatization strategies and pharmacological prophylaxis by acetazolamide or dexamethasone, or even considering alternate itineraries with more gradual ascent.
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Affiliation(s)
- Johannes Burtscher
- Institute of Sport Sciences, University of Lausanne, Lausanne 1015, Switzerland
- Department of Biomedical Sciences, University of Lausanne, Lausanne 1005, Switzerland
| | - Erik R Swenson
- VA Puget Health Care System, University of Washington, Seattle, WA, USA
| | - Peter H Hackett
- Altitude Research Center, Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Grégoire P Millet
- Institute of Sport Sciences, University of Lausanne, Lausanne 1015, Switzerland
- Department of Biomedical Sciences, University of Lausanne, Lausanne 1005, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, Innsbruck A-6020, Austria
- Austrian Society for Alpine and High-Altitude Medicine, Innsbruck A-6020, Austria
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Subedi S, Regmi P, Bhandari SS, Dawadi S. Three rare presentations of high-altitude pulmonary edema at a high-altitude clinic in the Everest region (4371 m): A case series. Clin Case Rep 2023; 11:e7236. [PMID: 37113640 PMCID: PMC10126756 DOI: 10.1002/ccr3.7236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Revised: 03/22/2023] [Accepted: 04/04/2023] [Indexed: 04/29/2023] Open
Abstract
Diagnosis of HAPE can be challenging when the presentation deviates from usual natural history. Point of care ultrasonography serves as a great diagnostic tool in such settings. An umbrella treatment could be beneficial during such scenarios.
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Affiliation(s)
- Sachin Subedi
- Institute of Medicine, Tribhuvan UniversityMaharajgunjNepal
- Himalayan Rescue Association of NepalKathmanduNepal
| | | | - Sanjeeb S. Bhandari
- Himalayan Rescue Association of NepalKathmanduNepal
- Department of Emergency MedicineWestern Maryland Medical CenterCumberlandMarylandUSA
| | - Suvash Dawadi
- Himalayan Rescue Association of NepalKathmanduNepal
- CIWEC HospitalKathmanduNepal
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Bellovary BN, Wells AD, Fennel ZJ, Ducharme JB, Houck JM, Mayschak TJ, Gibson AL, Drum SN, Mermier CM. Could Orthostatic Stress Responses Predict Acute Mountain Sickness Susceptibility Prior to High Altitude Travel? A Pilot Study. High Alt Med Biol 2023; 24:19-26. [PMID: 36473199 DOI: 10.1089/ham.2021.0177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bellovary, Bryanne N., Andrew D. Wells, Zachary J. Fennel, Jeremy B. Ducharme, Jonathan M. Houck, Trevor J. Mayschak, Ann L. Gibson, Scott N. Drum, and Christine M. Mermier. Could orthostatic stress responses predict acute mountain sickness susceptibility before high altitude travel? A pilot study. High Alt Med Biol. 24:19-26, 2023. Purpose: This study assessed head-up tilt (HUT) responses in relation to acute mountain sickness (AMS)-susceptibility during hypoxic exposure. Materials and Methods: Fifteen participants completed three lab visits: (1) protocol familiarization and cycle maximal oxygen consumption (VO2max) test; (2) HUT test consisting of supine rest for 20 minutes followed by 70° tilting for ≤40 minutes; and (3) 6 hours of hypobaric hypoxic exposure (4,572 m) where participants performed two 30-minute cycling bouts separated by 1 hour at a 50% VO2max workload within the first 3 hours and rested when not exercising. During HUT, systolic blood pressure (SBP), diastolic blood pressure, heart rate (HR), and variability (blood pressure variability [BPV] and HR variability [HRV]) were measured continuously. The AMS scores were determined after 6 hours of exposure. Correlations determined relationships between HUT cardiovascular responses and AMS scores. Repeated-measures analysis of variance (ANOVA) assessed differences between those with and without AMS symptoms during HUT. Results: Higher AMS scores correlated with greater change in SBP variability (r = 0.52, p = 0.048) and blunted changes in HRV (root mean square of successive differences between normal heartbeats r = 0.81, p = 0.001, percentage of adjacent normal sinus intervals that differ by more than 50 milliseconds [pNN50] r = 0.87, p < 0.001) during HUT. A pNN50 interaction (p = 0.02) suggested elevated cardiac sympathetic activity at baseline and a blunted increase in cardiac sympathetic influence throughout HUT in those with AMS (pNN50 baseline: AMS = 26.2% ± 15.3%, no AMS = 51.0% ± 13.5%; first 3 minutes into HUT: AMS = 17.2% ± 19.1%, no AMS = 17.1% ± 10.9%; end of HUT: AMS = 6.2% ± 9.1%, no AMS 11.0% ± 10.0%). Conclusions: The results suggest autonomic responses via HUT differ in AMS-susceptible individuals. Changes in HRV and BPV during HUT may be a promising predictive measurement for AMS-susceptibility, but further research is needed for confirmation.
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Affiliation(s)
- Bryanne N Bellovary
- Kinesiology Department, State University of New York at Cortland, Cortland, New York, USA
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Andrew D Wells
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Health and Exercise Science, Wake Forest University, Winston-Salem, North Carolina, USA
| | - Zachary J Fennel
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA
| | - Jeremy B Ducharme
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Jonathan M Houck
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Science, Husson University, Bangor, Maine, USA
| | - Trevor J Mayschak
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
- Department of Emergency Medicine, University of New Mexico, Albuquerque, New Mexico, USA
| | - Ann L Gibson
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
| | - Scott N Drum
- Department of Health Sciences, Northern Arizona University, Flagstaff, Arizona, USA
| | - Christine M Mermier
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, New Mexico, USA
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Mallet RT, Burtscher J, Pialoux V, Pasha Q, Ahmad Y, Millet GP, Burtscher M. Molecular Mechanisms of High-Altitude Acclimatization. Int J Mol Sci 2023; 24:ijms24021698. [PMID: 36675214 PMCID: PMC9866500 DOI: 10.3390/ijms24021698] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 01/11/2023] [Accepted: 01/13/2023] [Indexed: 01/17/2023] Open
Abstract
High-altitude illnesses (HAIs) result from acute exposure to high altitude/hypoxia. Numerous molecular mechanisms affect appropriate acclimatization to hypobaric and/or normobaric hypoxia and curtail the development of HAIs. The understanding of these mechanisms is essential to optimize hypoxic acclimatization for efficient prophylaxis and treatment of HAIs. This review aims to link outcomes of molecular mechanisms to either adverse effects of acute high-altitude/hypoxia exposure or the developing tolerance with acclimatization. After summarizing systemic physiological responses to acute high-altitude exposure, the associated acclimatization, and the epidemiology and pathophysiology of various HAIs, the article focuses on molecular adjustments and maladjustments during acute exposure and acclimatization to high altitude/hypoxia. Pivotal modifying mechanisms include molecular responses orchestrated by transcription factors, most notably hypoxia inducible factors, and reciprocal effects on mitochondrial functions and REDOX homeostasis. In addition, discussed are genetic factors and the resultant proteomic profiles determining these hypoxia-modifying mechanisms culminating in successful high-altitude acclimatization. Lastly, the article discusses practical considerations related to the molecular aspects of acclimatization and altitude training strategies.
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Affiliation(s)
- Robert T. Mallet
- Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, TX 76107, USA
| | - Johannes Burtscher
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
- Institute of Sport Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
| | - Vincent Pialoux
- Inter-University Laboratory of Human Movement Biology EA7424, University Claude Bernard Lyon 1, University of Lyon, FR-69008 Lyon, France
| | - Qadar Pasha
- Institute of Hypoxia Research, New Delhi 110067, India
| | - Yasmin Ahmad
- Defense Institute of Physiology & Allied Sciences (DIPAS), Defense Research & Development Organization(DRDO), New Delhi 110054, India
| | - Grégoire P. Millet
- Department of Biomedical Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
- Institute of Sport Sciences, University of Lausanne, CH-1005 Lausanne, Switzerland
| | - Martin Burtscher
- Department of Sport Science, University of Innsbruck, A-6020 Innsbruck, Austria
- Austrian Society for Alpine and High-Altitude Medicine, A-6020 Innsbruck, Austria
- Correspondence:
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Contribution of Adenosine in the Physiological Changes and Injuries Secondary to Exposure to Extreme Oxygen Pressure in Healthy Subjects. Biomedicines 2022; 10:biomedicines10092059. [PMID: 36140160 PMCID: PMC9495509 DOI: 10.3390/biomedicines10092059] [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: 07/16/2022] [Revised: 08/04/2022] [Accepted: 08/16/2022] [Indexed: 12/05/2022] Open
Abstract
Climbers and aviators are exposed to severe hypoxia at high altitudes, whereas divers are exposed to hyperoxia at depth. The aim of this study was to report changes in the adenosinergic system induced by exposure to extreme oxygen partial pressures. At high altitudes, the increased adenosine concentration contributes to brain protection against hypoxia through various mechanisms such as stimulation of glycogenolysis for ATP production, reduction in neuronal energy requirements, enhancement in 2,3-bisphosphoglycerate production, and increase in cerebral blood flow secondary to vasodilation of cerebral arteries. In the context of mountain illness, the increased level of A2AR expression leads to glial dysfunction through neuroinflammation and is involved in the pathogenesis of neurological disorders. Nonetheless, a high level of adenosine concentration can protect against high-altitude pulmonary edema via a decrease in pulmonary arterial pressure. The adenosinergic system is also involved in the acclimatization phenomenon induced by prolonged exposure to altitude hypoxia. During hyperoxic exposure, decreased extracellular adenosine and low A2A receptor expression contribute to vasoconstriction. The resulting decrease in cerebral blood flow is considered a preventive phenomenon against cerebral oxygen toxicity through the decrease in oxygen delivery to the brain. With regard to lung oxygen toxicity, hyperoxia leads to an increase in extracellular adenosine, which acts to preserve pulmonary barrier function. Changes in the adenosinergic system induced by exposure to extreme oxygen partial pressures frequently have a benefit in decreasing the risk of adverse effects.
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Pathophysiology and Therapy of High-Altitude Sickness: Practical Approach in Emergency and Critical Care. J Clin Med 2022; 11:jcm11143937. [PMID: 35887706 PMCID: PMC9325098 DOI: 10.3390/jcm11143937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 06/21/2022] [Accepted: 06/24/2022] [Indexed: 12/26/2022] Open
Abstract
High altitude can be a hostile environment and a paradigm of how environmental factors can determine illness when human biological adaptability is exceeded. This paper aims to provide a comprehensive review of high-altitude sickness, including its epidemiology, pathophysiology, and treatments. The first section of our work defines high altitude and considers the mechanisms of adaptation to it and the associated risk factors for low adaptability. The second section discusses the main high-altitude diseases, highlighting how environmental factors can lead to the loss of homeostasis, compromising important vital functions. Early recognition of clinical symptoms is important for the establishment of the correct therapy. The third section focuses on high-altitude pulmonary edema, which is one of the main high-altitude diseases. With a deeper understanding of the pathogenesis of high-altitude diseases, as well as a reasoned approach to environmental or physical factors, we examine the main high-altitude diseases. Such an approach is critical for the effective treatment of patients in a hostile environment, or treatment in the emergency room after exposure to extreme physical or environmental factors.
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10
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Hennis PJ, Cumpstey AF, O'Doherty AF, Fernandez BO, Gilbert-Kawai ET, Mitchell K, Moyses H, Cobb A, Meale P, Pöhnl H, Mythen MG, Grocott MPW, Levett DZH, Martin DS, Feelisch M. Dietary Nitrate Supplementation Does Not Alter Exercise Efficiency at High Altitude - Further Results From the Xtreme Alps Study. Front Physiol 2022; 13:827235. [PMID: 35295581 PMCID: PMC8918982 DOI: 10.3389/fphys.2022.827235] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
Introduction Nitrate supplementation in the form of beetroot juice (BRJ) ingestion has been shown to improve exercise tolerance during acute hypoxia, but its effect on exercise physiology remains unstudied during sustained terrestrial high altitude exposure. We hypothesized that performing exercise at high altitude would lower circulating nitrate and nitrite levels and that BRJ ingestion would reverse this phenomenon while concomitantly improving key determinants of aerobic exercise performance. Methods Twenty seven healthy volunteers (21 male) underwent a series of exercise tests at sea level (SL, London, 75 m) and again after 5-8 days at high altitude (HA, Capanna Regina Margherita or "Margherita Hut," 4,559 m). Using a double-blind protocol, participants were randomized to consume a beetroot/fruit juice beverage (three doses per day) with high levels of nitrate (∼0.18 mmol/kg/day) or a nitrate-depleted placebo (∼11.5 μmoles/kg/day) control drink, from 3 days prior to the exercise trials until completion. Submaximal constant work rate cycle tests were performed to determine exercise efficiency and a maximal incremental ramp exercise test was undertaken to measure aerobic capacity, using breath-by-breath pulmonary gas exchange measurements throughout. Concentrations of nitrate, nitrite and nitrosation products were quantified in plasma samples collected at 5 timepoints during the constant work rate tests. Linear mixed modeling was used to analyze data. Results At both SL and HA, plasma nitrate concentrations were elevated in the nitrate supplementation group compared to placebo (P < 0.001) but did not change throughout increasing exercise work rate. Delta exercise efficiency was not altered by altitude exposure (P = 0.072) or nitrate supplementation (P = 0.836). V̇O2peak decreased by 24% at high altitude (P < 0.001) and was lower in the nitrate-supplemented group at both sea level and high altitude compared to placebo (P = 0.041). Dietary nitrate supplementation did not alter other peak exercise variables or oxygen consumption at anaerobic threshold. Circulating nitrite and S-nitrosothiol levels unexpectedly rose in a few individuals right after cessation of exercise at high altitude. Conclusion Whilst regularly consumed during an 8 days expedition to terrestrial high altitude, nitrate supplementation did not alter exercise efficiency and other exercise physiological variables, except decreasing V̇O2peak. These results and those of others question the practical utility of BRJ consumption during prolonged altitude exposure.
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Affiliation(s)
- Philip J Hennis
- Centre for Altitude Space and Extreme Environment Medicine, University College London Hospital NIHR Biomedical Research Centre, Institute of Sport, Exercise and Health, London, United Kingdom.,SHAPE Research Group, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Andrew F Cumpstey
- Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Alasdair F O'Doherty
- Department of Sport, Exercise and Rehabilitation, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Bernadette O Fernandez
- Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry, United Kingdom
| | - Edward T Gilbert-Kawai
- Centre for Altitude Space and Extreme Environment Medicine, University College London Hospital NIHR Biomedical Research Centre, Institute of Sport, Exercise and Health, London, United Kingdom
| | - Kay Mitchell
- Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Helen Moyses
- Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom
| | - Alexandra Cobb
- Centre for Altitude Space and Extreme Environment Medicine, University College London Hospital NIHR Biomedical Research Centre, Institute of Sport, Exercise and Health, London, United Kingdom
| | - Paula Meale
- Centre for Altitude Space and Extreme Environment Medicine, University College London Hospital NIHR Biomedical Research Centre, Institute of Sport, Exercise and Health, London, United Kingdom
| | - Helmut Pöhnl
- AURAPA Würzungen GmbH, Bietigheim-Bissingen, Germany
| | - Monty G Mythen
- Centre for Altitude Space and Extreme Environment Medicine, University College London Hospital NIHR Biomedical Research Centre, Institute of Sport, Exercise and Health, London, United Kingdom
| | - Michael P W Grocott
- Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Denny Z H Levett
- Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Daniel S Martin
- Centre for Altitude Space and Extreme Environment Medicine, University College London Hospital NIHR Biomedical Research Centre, Institute of Sport, Exercise and Health, London, United Kingdom.,Peninsula Medical School, University of Plymouth, Plymouth, United Kingdom
| | - Martin Feelisch
- Perioperative and Critical Care Theme, NIHR Southampton Biomedical Research Centre, University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom.,Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom.,Division of Metabolic and Vascular Health, Warwick Medical School, University of Warwick, Coventry, United Kingdom
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11
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Georges T, Menu P, Le Blanc C, Ferreol S, Dauty M, Fouasson-Chailloux A. Contribution of Hypoxic Exercise Testing to Predict High-Altitude Pathology: A Systematic Review. Life (Basel) 2022; 12:life12030377. [PMID: 35330129 PMCID: PMC8950822 DOI: 10.3390/life12030377] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/01/2022] [Accepted: 03/03/2022] [Indexed: 11/20/2022] Open
Abstract
Altitude travelers are exposed to high-altitude pathologies, which can be potentially serious. Individual susceptibility varies widely and this makes it difficult to predict who will develop these complications. The assessment of physiological adaptations to exercise performed in hypoxia has been proposed to help predict altitude sickness. The purpose of this review is to evaluate the contribution of hypoxic exercise testing, achieved in normobaric conditions, in the prediction of severe high-altitude pathology. We performed a systematic review using the databases PubMed, Science Direct and Embase in October 2021 to collect studies reporting physiological adaptations under hypoxic exercise testing and its interest in predicting high-altitude pathology. Eight studies were eligible, concerning 3558 patients with a mean age of 46.9 years old, and a simulated mean altitude reaching of 5092 m. 597 patients presented an acute mountain sickness during their altitude travels. Three different protocols of hypoxic exercise testing were used. Acute mountain sickness was defined using Hackett’s score or the Lake Louise score. Ventilatory and cardiac responses to hypoxia, desaturation in hypoxia, cerebral oxygenation, core temperature, variation in body mass index and some perceived sensations were the highlighted variables associated with acute mountain sickness. A decision algorithm based on hypoxic exercise tests was proposed by one team. Hypoxic exercise testing provides promising information to help predict altitude complications. Its interest should be confirmed by different teams.
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Affiliation(s)
- Thomas Georges
- CHU Nantes, Service de Médecine Physique et Réadapatation Locomotrice et Respiratoire, 44093 Nantes, France; (T.G.); (P.M.); (C.L.B.); (S.F.); (M.D.)
| | - Pierre Menu
- CHU Nantes, Service de Médecine Physique et Réadapatation Locomotrice et Respiratoire, 44093 Nantes, France; (T.G.); (P.M.); (C.L.B.); (S.F.); (M.D.)
- CHU Nantes, Service de Médecine du Sport, 44093 Nantes, France
- Institut Régional de Médecine du Sport (IRMS), 44093 Nantes, France
- Inserm, UMR 1229, RMeS, Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France
| | - Camille Le Blanc
- CHU Nantes, Service de Médecine Physique et Réadapatation Locomotrice et Respiratoire, 44093 Nantes, France; (T.G.); (P.M.); (C.L.B.); (S.F.); (M.D.)
| | - Sophie Ferreol
- CHU Nantes, Service de Médecine Physique et Réadapatation Locomotrice et Respiratoire, 44093 Nantes, France; (T.G.); (P.M.); (C.L.B.); (S.F.); (M.D.)
| | - Marc Dauty
- CHU Nantes, Service de Médecine Physique et Réadapatation Locomotrice et Respiratoire, 44093 Nantes, France; (T.G.); (P.M.); (C.L.B.); (S.F.); (M.D.)
- CHU Nantes, Service de Médecine du Sport, 44093 Nantes, France
- Institut Régional de Médecine du Sport (IRMS), 44093 Nantes, France
- Inserm, UMR 1229, RMeS, Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France
| | - Alban Fouasson-Chailloux
- CHU Nantes, Service de Médecine Physique et Réadapatation Locomotrice et Respiratoire, 44093 Nantes, France; (T.G.); (P.M.); (C.L.B.); (S.F.); (M.D.)
- CHU Nantes, Service de Médecine du Sport, 44093 Nantes, France
- Institut Régional de Médecine du Sport (IRMS), 44093 Nantes, France
- Inserm, UMR 1229, RMeS, Regenerative Medicine and Skeleton, Université de Nantes, ONIRIS, F-44042 Nantes, France
- Correspondence:
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12
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Figueiredo PS, Sils IV, Staab JE, Fulco CS, Muza SR, Beidleman BA. Acute mountain sickness and sleep disturbances differentially influence cognition and mood during rapid ascent to 3000 and 4050 m. Physiol Rep 2022; 10:e15175. [PMID: 35133088 PMCID: PMC8822873 DOI: 10.14814/phy2.15175] [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: 10/29/2021] [Revised: 01/03/2022] [Accepted: 01/04/2022] [Indexed: 12/04/2022] Open
Abstract
The impact of acute mountain sickness (AMS) and sleep disturbances on mood and cognition at two altitudes relevant to the working and tourist population is unknown. Twenty unacclimatized lowlanders were exposed to either 3000 m (n = 10; 526 mmHg) or 4050 m (n = 10; 460 mmHg) for 20 h in a hypobaric chamber. AMS prevalence and severity was assessed using the Environmental Symptoms Questionnaire (ESQ) and an AMS‐C score ≥ 0.7 indicated sickness. While sleeping for one night both at sea level (SL) and high altitude (HA), a wrist motion detector was used to measure awakenings (Awak, events/h) and sleep efficiency (Eff, %). If Eff was ≥85%, individuals were considered a good sleeper (Sleep+). Mood and cognition were assessed using the Automated Neuropsychological Assessment Metric and Mood Scale (ANAM‐MS). The ESQ and ANAM‐MS were administered in the morning both at SL and after 20 h at HA. AMS severity (mean ± SE; 1.82 ± 0.27 vs. 0.20 ± 0.27), AMS prevalence (90% vs. 10%), depression (0.63 ± 0.23 vs. 0.00 ± 0.24) Awak (15.6 ± 1.6 vs. 10.1 ± 1.6 events/h), and DeSHr (38.5 ± 6.3 vs. 13.3 ± 6.3 events/h) were greater (p < 0.05) and Eff was lower (69.9 ± 5.3% vs. 87.0 ± 5.3%) at 4050 m compared to 3000 m, respectively. AMS presence did not impact cognition but fatigue (2.17 ± 0.37 vs. 0.58 ± 0.39), anger (0.65 ± 0.25 vs. 0.02 ± 0.26), depression (0.63 ± 0.23 vs. 0.00 ± 0.24) and sleepiness (4.8 ± 0.4 vs. 2.7 ± 0.5) were greater (p < 0.05) in the AMS+ group. The Sleep− group, compared to the Sleep+ group, had lower (p < 0.05) working memory scores (50 ± 7 vs. 78 ± 9) assessed by the Sternberg 6‐letter memory task, and lower reaction time fatigue scores (157 ± 17 vs. 221 ± 22), assessed by the repeated reaction time test. Overall, AMS, depression, DeSHr, and Awak were increased (p < 0.05) at 4050 m compared to 3000 m. In addition, AMS presence impacted mood while poor sleep impacted cognition which may deteriorate teamwork and/or increase errors in judgement at HA.
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Affiliation(s)
- Peter S. Figueiredo
- Biophysics and Biomedical Modeling Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Ingrid V. Sils
- Thermal and Mountain Medicine Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Janet E. Staab
- Military Performance Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Charles S. Fulco
- Thermal and Mountain Medicine Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Stephen R. Muza
- Strategic Science and Development Office U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
| | - Beth A. Beidleman
- Biophysics and Biomedical Modeling Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts USA
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13
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McKenna ZJ, Gorini Pereira F, Gillum TL, Amorim FT, Deyhle MR, Mermier CM. High altitude exposures and intestinal barrier dysfunction. Am J Physiol Regul Integr Comp Physiol 2022; 322:R192-R203. [PMID: 35043679 DOI: 10.1152/ajpregu.00270.2021] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Gastrointestinal complaints are often reported during ascents to high altitude (> 2500 m), though their etiology is not known. One potential explanation is injury to the intestinal barrier which has been implicated in the pathophysiology of several diseases. High altitude exposures can reduce splanchnic perfusion and blood oxygen levels causing hypoxic and oxidative stress. These stressors might injure the intestinal barrier leading to consequences such as bacterial translocation and local/systemic inflammatory responses. The purpose of this mini review is to 1) discuss the impact of high-altitude exposures on intestinal barrier dysfunction, and 2) present medications and dietary supplements which may have relevant impacts on the intestinal barrier during high-altitude exposures. There is a small but growing body of evidence which shows that acute exposures to high altitudes can damage the intestinal barrier. Initial data also suggests that prolonged hypoxic exposures can compromise the intestinal barrier through alterations in immunological function, microbiota, or mucosal layers. Exertion may worsen high-altitude related intestinal injury via additional reductions in splanchnic circulation and greater hypoxemia. Collectively these responses can result in increased intestinal permeability and bacterial translocation causing local and systemic inflammation. More research is needed to determine the impact of various medications and dietary supplements on the intestinal barrier during high-altitude exposures.
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Affiliation(s)
- Zachary J McKenna
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, NM, United States
| | - Felipe Gorini Pereira
- Department of Kinesiology, Indiana University Bloomington, Bloomington, IN, United States
| | - Trevor L Gillum
- Department of Kinesiology, California Baptist University, Riverside, CA, United States
| | - Fabiano Trigueiro Amorim
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, NM, United States
| | - Michael R Deyhle
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, NM, United States
| | - Christine M Mermier
- Department of Health, Exercise, and Sport Sciences, University of New Mexico, Albuquerque, NM, United States
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14
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Bärtsch P. The Impact of Nocebo and Placebo Effects on Reported Incidence of Acute Mountain Sickness. High Alt Med Biol 2021; 23:8-17. [PMID: 34964659 DOI: 10.1089/ham.2021.0078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Bärtsch Peter. The impact of nocebo and placebo effects on reported incidence of acute mountain sickness. High Alt Med Biol 00:000-000, 2021. Well comparable studies reporting acute mountain sickness (AMS) in nonacclimatized, acutely exposed individuals performed at 3,450-3,650 m (9 studies) and 4,559-4,675 m (18 studies) at real altitude or in hypobaric or in normobaric hypoxic chambers were analyzed with the hypothesis that the study design impacts occurrence of AMS. Individual symptoms and overall scores of AMS were not different between the three modalities of exposure to a comparable degree of hypoxia, indicating that hypobaria has, if at all, minimal influence on AMS. Studies not focusing versus those focusing on AMS report lower scores and prevalence of AMS at 3,500 m, but not at 4,559 m, while frequent assessment may be associated with more severe AMS. These data suggest that focusing on AMS creates expectations of getting AMS (nocebo effects) and increases its prevalence, while not paying attention reduces negative expectations and thus AMS. On the other hand, interventions promising improvement may cause positive expectations (placebo effect). Information about purpose and dangers of a study, repeated assessments for AMS, previous experiences of AMS, and observation of illness in other study participants are major factors contributing to negative expectations and thus nocebo effects increasing AMS. They should be considered when designing studies and subject information and be reported in detail in publications of studies on AMS.
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Affiliation(s)
- Peter Bärtsch
- Department of Internal Medicine, University Clinic, Heidelberg, Germany
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15
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Staab JE, Muza SR, Fulco CS, Andrew SP, Beidleman BA. Impact of 2 days of staging at 2500-4300 m on sleep quality and quantity following subsequent exposure to 4300 m. Physiol Rep 2021; 9:e15063. [PMID: 34713967 PMCID: PMC8554773 DOI: 10.14814/phy2.15063] [Citation(s) in RCA: 1] [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: 05/10/2021] [Revised: 09/10/2021] [Accepted: 09/12/2021] [Indexed: 12/21/2022] Open
Abstract
The impact of 2 days of staging at 2500-4300 m on sleep quality and quantity following subsequent exposure to 4300 m was determined. Forty-eight unacclimatized men and women were randomly assigned to stage for 2 days at one of four altitudes (2500, 3000, 3500, or 4300 m) prior to assessment on the summit of Pikes Peak (4300 m) for 2 days. Volunteers slept for one night at sea level (SL), two nights at respective staging altitudes, and two nights at Pikes Peak. Each wore a pulse oximeter to measure sleep arterial oxygen saturation (sSpO2 , %) and number of desaturations (DeSHr, events/hr) and a wrist motion detector to estimate sleep awakenings (Awak, awakes/hr) and sleep efficiency (Eff, %). Acute mountain sickness (AMS) was assessed using the Environmental Symptoms Questionnaire and daytime SpO2 was assessed after AMS measurements. The mean of all variables for both staging days (STG) and Pikes Peak days (PP) was calculated. The sSpO2 and daytime SpO2 decreased (p < 0.05) from SL during STG in all groups in a dose-dependent manner. During STG, DeSHr were higher (p < 0.05), Eff was lower (p < 0.05), and AMS symptoms were higher (p < 0.05) in the 3500 and 4300 m groups compared to the 2500 and 3000 m groups while Awak did not differ (p > 0.05) between groups. At PP, the sSpO2 , DeSHr, Awak, and Eff were similar among all groups but the 2500 m group had greater AMS symptoms (p < 0.05) than the other groups. Two days of staging at 2500-4300 m induced a similar degree of sleep acclimatization during subsequent ascent to 4300 m but the 2500 m group was not protected against AMS at 4300 m.
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Affiliation(s)
- Janet E. Staab
- Military Performance DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Stephen R. Muza
- Strategic Scientific Management OfficeU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Charles S. Fulco
- Thermal and Mountain Medicine DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Sean P. Andrew
- Thermal and Mountain Medicine DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
| | - Beth A. Beidleman
- Biophysics and Biomedical Modeling DivisionU.S. Army Research Institute of Environmental MedicineNatickMassachusettsUSA
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16
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Hypoxic Exercise Exacerbates Hypoxemia and Acute Mountain Sickness in Obesity: A Case Analysis. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18179078. [PMID: 34501667 PMCID: PMC8430682 DOI: 10.3390/ijerph18179078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Revised: 08/14/2021] [Accepted: 08/23/2021] [Indexed: 12/21/2022]
Abstract
Acute mountain sickness (AMS) is a common syndrome characterized by headache, dizziness, loss of appetite, weakness, and nausea. As a major public health issue, obesity has increased in high altitude urban residents and intermittent commuters to high altitudes. The present study investigated acute hypoxic exposure and hypoxic exercise on hypoxemia severity and AMS symptoms in a physically active obese man. In this case analysis, peripheral oxygen saturation (SpO2) was used to evaluate hypoxemia, heart rate (HR) and blood pressure (BP) were used to reflect the function of autonomic nervous system (ANS), and Lake Louise scoring (LLS) was used to assess AMS. The results showed that acute hypoxic exposure led to severe hypoxemia (SpO2 = 72%) and tachycardia (HRrest = 97 bpm), and acute hypoxic exercise exacerbated severe hypoxemia (SpO2 = 59%) and ANS dysfunction (HRpeak = 167 bpm, SBP/DBP = 210/97 mmHg). At the end of the 6-h acute hypoxic exposure, the case developed severe AMS (LLS = 10) symptoms of headache, gastrointestinal distress, cyanosis, vomiting, poor appetite, and fatigue. The findings of the case study suggest that high physical activity level appears did not show a reliable protective effect against severe hypoxemia, ANS dysfunction, and severe AMS symptoms in acute hypoxia exposure and hypoxia exercise.
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17
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High-altitude illnesses: Old stories and new insights into the pathophysiology, treatment and prevention. SPORTS MEDICINE AND HEALTH SCIENCE 2021; 3:59-69. [PMID: 35782163 PMCID: PMC9219347 DOI: 10.1016/j.smhs.2021.04.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/11/2021] [Accepted: 04/11/2021] [Indexed: 01/19/2023] Open
Abstract
Areas at high-altitude, annually attract millions of tourists, skiers, trekkers, and climbers. If not adequately prepared and not considering certain ascent rules, a considerable proportion of those people will suffer from acute mountain sickness (AMS) or even from life-threatening high-altitude cerebral (HACE) or/and pulmonary edema (HAPE). Reduced inspired oxygen partial pressure with gain in altitude and consequently reduced oxygen availability is primarily responsible for getting sick in this setting. Appropriate acclimatization by slowly raising the hypoxic stimulus (e.g., slow ascent to high altitude) and/or repeated exposures to altitude or artificial, normobaric hypoxia will largely prevent those illnesses. Understanding physiological mechanisms of acclimatization and pathophysiological mechanisms of high-altitude diseases, knowledge of symptoms and signs, treatment and prevention strategies will largely contribute to the risk reduction and increased safety, success and enjoyment at high altitude. Thus, this review is intended to provide a sound basis for both physicians counseling high-altitude visitors and high-altitude visitors themselves.
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Gaur P, Prasad S, Kumar B, Sharma SK, Vats P. High-altitude hypoxia induced reactive oxygen species generation, signaling, and mitigation approaches. INTERNATIONAL JOURNAL OF BIOMETEOROLOGY 2021; 65:601-615. [PMID: 33156424 DOI: 10.1007/s00484-020-02037-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 10/05/2020] [Accepted: 10/20/2020] [Indexed: 06/11/2023]
Abstract
Homeostasis between pro-oxidants and anti-oxidants is necessary for aerobic life, which if perturbed and shifted towards pro-oxidants results in oxidative stress. It is generally agreed that reactive oxygen species (ROS) production is accelerated with mountainous elevation, which may play a role in spawning serious health crisis. Exposure to increasing terrestrial altitude leads to a reduction in ambient O2 availability in cells producing a series of hypoxic oxidative stress reactions and altering the redox balance in humans. Enormous literature on redox signaling drove research activity towards understanding the role of oxidative stress under normal and challenging conditions like high-altitude hypoxia which grounds for disturbed redox signaling. Excessive ROS production and accumulation of free radicals in cells and tissues can cause various pulmonary, cardiovascular, and metabolic pathophysiological conditions. In order to counteract this oxidative stress and maintain the balance of pro-oxidants and anti-oxidants, an anti-oxidant system exists in the human body, which, however, gets surpassed by elevated ROS levels, but can be strengthened through the use of anti-oxidant supplements. Such cumulative studies of fundamentals on a global concept like oxidative stress and role of anti-oxidants can act as a foundation to further smoothen for researchers to study over health, disease, and other pathophysiological conditions. This review highlights the interconnection between high altitude and oxidative stress and the role of anti-oxidants to protect cells from oxidative damages and to lower the risk of altitude-associated sickness.
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Affiliation(s)
- Priya Gaur
- Endocrinology & Metabolism Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Lucknow Road, Timarpur, Delhi, 110054,, India
| | - Suchita Prasad
- Department of Chemistry, University of Delhi, Delhi, 110007,, India
| | - Bhuvnesh Kumar
- Endocrinology & Metabolism Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Lucknow Road, Timarpur, Delhi, 110054,, India
| | - Sunil K Sharma
- Department of Chemistry, University of Delhi, Delhi, 110007,, India.
| | - Praveen Vats
- Endocrinology & Metabolism Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, Lucknow Road, Timarpur, Delhi, 110054,, India.
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Ewalts M, Dawkins T, Friend AT. Hypoxia research: to control or not to control? That is the question. J Physiol 2021; 599:2141-2142. [PMID: 33590893 DOI: 10.1113/jp281192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Michiel Ewalts
- Bangor School of Sport, Health and Exercise Sciences, Bangor University, Bangor, UK
| | - Tony Dawkins
- Cardiff School of Sport and Health Sciences, Cardiff Metropolitan University, Cardiff, UK
| | - Alexander T Friend
- Bangor School of Sport, Health and Exercise Sciences, Bangor University, Bangor, UK
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20
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Pu X, Lin X, Duan X, Wang J, Shang J, Yun H, Chen Z. Oxidative and Endoplasmic Reticulum Stress Responses to Chronic High-Altitude Exposure During the Development of High-Altitude Pulmonary Hypertension. High Alt Med Biol 2020; 21:378-387. [DOI: 10.1089/ham.2019.0143] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Xiaoyan Pu
- School of Life Science, Qinghai Normal University, Xining, China
- Medical College, Qinghai University, Xining, China
| | - Xue Lin
- Medical College, Qinghai University, Xining, China
| | - Xianglan Duan
- School of Life Science, Qinghai Normal University, Xining, China
| | - Junjie Wang
- School of Life Science, Qinghai Normal University, Xining, China
| | - Jun Shang
- School of Life Science, Qinghai Normal University, Xining, China
| | - Haixia Yun
- School of Life Science, Qinghai Normal University, Xining, China
| | - Zhi Chen
- School of Life Science, Qinghai Normal University, Xining, China
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21
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Dawadi S, Basyal B, Subedi Y. Morbidity Among Athletes Presenting for Medical Care During 3 Iterations of an Ultratrail Race in the Himalayas. Wilderness Environ Med 2020; 31:437-440. [PMID: 33168403 DOI: 10.1016/j.wem.2020.08.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 07/08/2020] [Accepted: 08/06/2020] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Although ultratrail races are increasing in popularity, there is a dearth of data regarding illnesses and medical care at these events. Data about injuries and illnesses for races taking place in the Himalayas, where the nearest medical facility can be hundreds of miles away, are even harder to find. This study aimed to describe the injuries and illnesses befalling the participants of a 7-stage 212 km (132 mi) trail race at high altitude. METHODS Ethical approval was obtained from Nepal Research Health Council. A retrospective study of the record of medical encounters among the 100 participants competing in the Manaslu trail race in Nepal from 2014 to 2016 was performed. Diagnoses were classified into various categories. Informed consent was taken from all participants. RESULTS Acute diarrhea was the most common ailment reported among the participants (18%), followed closely by musculoskeletal problems (17%). Altitude illness made up 6% of care provided. Approximately 35% of the athletes were using acetazolamide as prophylaxis for high altitude illnesses. The 1 case needing evacuation in the 3 iterations was high altitude pulmonary edema. CONCLUSIONS Ultratrail races at high altitude pose a challenge in terms of provision of medical care in a remote setting with limited resources. However, most of the illnesses are minor in nature and easily managed by the race doctor. Knowledge of common illnesses among travelers to the area can help aid in preparation and provision of proper care, especially in remote settings with limited resources.
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Affiliation(s)
- Suvash Dawadi
- CIWEC Hospital and Travel Medicine, Center/Mountain Medicine Society of Nepal, Kathmandu, Nepal.
| | - Bikash Basyal
- Abington Jefferson Health/Mountain Medicine Society of Nepal, Kathmandu, Nepal
| | - Yogesh Subedi
- MedStar Union Memorial Hospital/Mountain Medicine Society of Nepal, Kathmandu, Nepal
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22
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Toussaint CM, Kenefick RW, Petrassi FA, Muza SR, Charkoudian N. Altitude, Acute Mountain Sickness, and Acetazolamide: Recommendations for Rapid Ascent. High Alt Med Biol 2020; 22:5-13. [PMID: 32975448 DOI: 10.1089/ham.2019.0123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Toussaint, Claudia M., Robert W. Kenefick, Frank A. Petrassi, Stephen R. Muza, and Nisha Charkoudian. Altitude, acute mountain sickness, and acetazolamide: recommendations for rapid ascent. High Alt Med Biol. 22:5-13, 2021. Background: Sea level natives ascending rapidly to altitudes above 1,500 m often develop acute mountain sickness (AMS), including nausea, headaches, fatigue, and lightheadedness. Acetazolamide (AZ), a carbonic anhydrase inhibitor, is a commonly used medication for the prevention and treatment of AMS. However, there is continued debate about appropriate dosing, particularly when considering rapid and physically demanding ascents to elevations above 3,500 m by emergency medical and military personnel. Aims: Our goal in the present analysis was to evaluate and synthesize the current literature regarding the use of AZ to determine the most effective dosing for prophylaxis and treatment of AMS for rapid ascents to elevations >3,500 m. These circumstances are specifically relevant to military and emergency medical personnel who often need to ascend rapidly and perform physically demanding tasks upon arrival at altitude. Methods: We conducted a literature search from April 2018 to February 2020 using PubMed, Google Scholar, and Web of Science to identify randomized controlled trials that compared AZ with placebo or other treatment with the primary endpoint of AMS incidence and severity. We included only research articles/studies that focused on evaluation of AZ use during rapid ascent. Results: Four doses of AZ (125, 250, 500, and 750 mg daily) were identified as efficacious in decreasing the incidence and/or severity of AMS during rapid ascents, with evidence of enhanced effectiveness with higher doses. Conclusions: For military, emergency medical, or other activities involving rapid ascent to altitudes >3,500 m, doses 500-750 mg/day within 24 hours of altitude exposure appear to be the most effective for minimizing symptoms of AMS.
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Affiliation(s)
- Claudia M Toussaint
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee, USA.,Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Robert W Kenefick
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Frank A Petrassi
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Stephen R Muza
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts, USA
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23
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Gianfredi V, Albano L, Basnyat B, Ferrara P. Does age have an impact on acute mountain sickness? A systematic review. J Travel Med 2020; 27:5693886. [PMID: 31897482 DOI: 10.1093/jtm/taz104] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 12/10/2019] [Accepted: 12/17/2019] [Indexed: 02/07/2023]
Abstract
Acute mountain sickness (AMS) is the most common form of illness at high altitude; however, it is still unclear whether age is a protective factor or a risk factor for the development of AMS in travellers. In recent decades, the number of travellers aged 60 years or older is increasing. Thus, the care of older travellers is a long-standing issue in travel medicine. This study aims to systematically review the current state of knowledge related to the effect of old age on the risk of AMS. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used, and the following databases were consulted: PubMed/Medline, Embase, Europe PubMed Central (EuropePMC), World Health Organization Library Database (WHOLIS) and Literatura Latino-Americana e do Caribe em Ciências da Saúde (LILACS). The search yielded a total of 532 articles, of which 25 met the inclusion criteria, corresponding to 26 reports. Although the approaches, methods and quality were heterogeneous among the included studies, 12 reported a negative correlation between AMS prevalence and age, 11 detected no relationship and three papers indicated that the age of AMS subjects was significantly higher than controls. Despite these differences, old age does not seem to be a contraindication for travelling at high altitude. Thus, the presented synthesis will be useful for health professionals in travel medicine to better tailor their appropriate care for older adults who travel to destinations at high altitude.
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Affiliation(s)
- Vincenza Gianfredi
- Post-graduate School of Hygiene and Preventive Medicine, Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Luciana Albano
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Buddha Basnyat
- Oxford University Clinical Research Unit, Patan Academy of Health Sciences, Kathmandu, Nepal
| | - Pietro Ferrara
- Research Center on Public Health, University of Milan - Bicocca, Monza, Italy
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24
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Berger MM, Sareban M, Bärtsch P. Acute mountain sickness: Do different time courses point to different pathophysiological mechanisms? J Appl Physiol (1985) 2020; 128:952-959. [DOI: 10.1152/japplphysiol.00305.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Acute mountain sickness (AMS) is a syndrome of nonspecific symptoms (i.e., headache, anorexia, nausea, vomiting, dizziness, and fatigue) that may develop in nonacclimatized individuals after rapid exposure to altitudes ≥2,500 m. In field studies, mean AMS scores usually peak after the first night at a new altitude. Analyses of the individual time courses of AMS in four studies performed at 3,450 m and 4,559 m revealed that three different patterns are hidden in the above-described overall picture. In 41% of those who developed AMS (i.e., AMS-C score >0.70), symptoms peaked on day 1, in 39%, symptoms were most prominent on day 2, and in 20%, symptoms were most prominent on day 3. We suggest to name the different time courses of AMS type I, type II, and type III, respectively. Here, we hypothesize that the variation of time courses of AMS are caused by different pathophysiological mechanisms. This assumption could explain why no consistent correlations between an overall assessment of AMS and single pathophysiological factors have been found in a large number of studies over the past 50 yr. In this paper, we will briefly review the fundamental mechanisms implicated in the pathophysiology of AMS and discuss how they might contribute to the three different AMS time courses.
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Affiliation(s)
- Marc M. Berger
- Department of Anesthesiology, Perioperative and General Critical Care Medicine, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- Department of Anesthesiology and Intensive Care Medicine, University Hospital Essen, Germany
| | - Mahdi Sareban
- University Institute of Sports Medicine, Prevention and Rehabilitation and Research Institute of Molecular Sports Medicine and Rehabilitation, Paracelsus Medical University, Salzburg, Austria
| | - Peter Bärtsch
- Department of Internal Medicine, University of Heidelberg, Heidelberg, Germany
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25
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Ando S, Komiyama T, Sudo M, Higaki Y, Ishida K, Costello JT, Katayama K. The interactive effects of acute exercise and hypoxia on cognitive performance: A narrative review. Scand J Med Sci Sports 2019; 30:384-398. [PMID: 31605635 DOI: 10.1111/sms.13573] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 09/09/2019] [Accepted: 10/04/2019] [Indexed: 12/13/2022]
Abstract
Acute moderate intensity exercise has been shown to improve cognitive performance. In contrast, hypoxia is believed to impair cognitive performance. The detrimental effects of hypoxia on cognitive performance are primarily dependent on the severity and duration of exposure. In this review, we describe how acute exercise under hypoxia alters cognitive performance, and propose that the combined effects of acute exercise and hypoxia on cognitive performance are mainly determined by interaction among exercise intensity and duration, the severity of hypoxia, and duration of exposure to hypoxia. We discuss the physiological mechanism(s) of the interaction and suggest that alterations in neurotransmitter function, cerebral blood flow, and possibly cerebral metabolism are the primary candidates that determine cognitive performance when acute exercise is combined with hypoxia. Furthermore, acclimatization appears to counteract impaired cognitive performance during prolonged exposure to hypoxia although the precise physiological mechanism(s) responsible for this amelioration remain to be elucidated. This review has implications for sporting, occupational, and recreational activities at terrestrial high altitude where cognitive performance is essential. Further studies are required to understand physiological mechanisms that determine cognitive performance when acute exercise is performed in hypoxia.
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Affiliation(s)
- Soichi Ando
- Graduate School of Informatics and Engineering, The University of Electro-Communications, Tokyo, Japan
| | - Takaaki Komiyama
- Center for Education in Liberal Arts and Sciences, Osaka University, Osaka, Japan
| | - Mizuki Sudo
- Meiji Yasuda Life Foundation of Health and Welfare, Tokyo, Japan
| | - Yasuki Higaki
- Faculty of Sports Science, Fukuoka University, Fukuoka, Japan
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan
| | - Joseph T Costello
- Extreme Environments Laboratory, Department of Sport and Exercise Science, University of Portsmouth, Portsmouth, UK
| | - Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan
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26
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Piotrowicz Z, Chalimoniuk M, Płoszczyca K K, Czuba M, Langfort J. Acute normobaric hypoxia does not affect the simultaneous exercise-induced increase in circulating BDNF and GDNF in young healthy men: A feasibility study. PLoS One 2019; 14:e0224207. [PMID: 31644554 PMCID: PMC6808427 DOI: 10.1371/journal.pone.0224207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 10/08/2019] [Indexed: 01/25/2023] Open
Abstract
Physical exercise has a neuromodulatory effect on the central nervous system (CNS) partially by modifying expression of neuropeptides produced and secreted by neurons and glial cells, among which the best examined are brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF). Because both neurotrophins can cross the brain-blood barrier (BBB), their blood levels indirectly reflect their production in the CNS. Moreover, both neuropeptides are involved in modulation of dopaminergic and serotoninergic system function. Because limited information is available on the effects of exercise to volition exhaustion and acute hypoxia on CNS, BDNF and GDNF formation, the aims of the present study were to verify whether 1) acute exercise to exhaustion in addition to neurons also activates glial cells and 2) additional exposure to acute normobaric moderate hypoxia affects their function. In this feasibility study we measured blood concentrations of BDNF, GDNF, and neuropeptides considered as biomarkers of brain damage (bFGF, NGF, S100B, GFAP) in seven sedentary healthy young men who performed a graded exercise test to volitional exhaustion on a cycle ergometer under normoxic (N) and hypoxic conditions: 2,000 m (H2; FiO2 = 16.6%) and 3,000 m altitude (H3; FiO2 = 14.7%). In all conditions serum concentrations of both BDNF and GDNF increased immediately after cessation of exercise (p<0.01). There was no effect of condition or interaction (condition x time of measurement) and exercise on any of the brain damage biomarkers: bFGF, NGF, S100B, GFAP. Moreover, in N (0<0.01) and H3 (p<0.05) exercise caused elevated serum 5-HT concentration. The results suggest that a graded effort to volitional exhaustion in normoxia, as well as hypoxia, simultaneously activates both neurons and astrocytes. Considering that s100B, GFAP, bFGF, and NGF (produced mainly by astrocytes) are markers of brain damage, it can be assumed that a maximum effort in both conditions is safe for the CNS.
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Affiliation(s)
- Zofia Piotrowicz
- Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Małgorzata Chalimoniuk
- Department of Tourism and Health in Biała Podlaska, The Józef Piłsudski University of Physical Education, Warsaw, Poland
| | | | - Miłosz Czuba
- Department of Kinesiology, Institute of Sport, Warsaw, Poland
- Department of Sports Theory, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Józef Langfort
- Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
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27
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Beidleman BA, Fulco CS, Glickman EL, Cymerman A, Kenefick RW, Cadarette BS, Andrew SP, Staab JE, Sils IV, Muza SR. Acute Mountain Sickness is Reduced Following 2 Days of Staging During Subsequent Ascent to 4300 m. High Alt Med Biol 2018; 19:329-338. [PMID: 30517038 DOI: 10.1089/ham.2018.0048] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE To determine whether 2 days of staging at 2500-3500 m, combined with either high or low physical activity, reduces acute mountain sickness (AMS) during subsequent ascent to 4300 m. METHODS Three independent groups of unacclimatized men and women were staged for 2 days at either 2500 m (n = 18), 3000 m (n = 16), or 3500 m (n = 15) before ascending and living for 2 days at 4300 m and compared with a control group that directly ascended to 4300 m (n = 12). All individuals departed to the staging altitudes or 4300 m after spending one night at 2000 m during which they breathed supplemental oxygen to simulate sea level conditions. Half in each group participated in ∼3 hours of daily physical activity while half were sedentary. Women accounted for ∼25% of each group. AMS incidence was assessed using the Environmental Symptoms Questionnaire. AMS was classified as mild (≥0.7 and <1.5), moderate (≥1.5 and <2.6), and severe (≥2.6). RESULTS While staging, the incidence of AMS was lower (p < 0.001) in the 2500 m (0%), 3000 m (13%), and 3500 m (40%) staged groups than the direct ascent control group (83%). After ascent to 4300 m, the incidence of AMS was lower in the 3000 m (43%) and 3500 m (40%) groups than the 2500 m group (67%) and direct ascent control (83%). Neither activity level nor sex influenced the incidence of AMS during further ascent to 4300 m. CONCLUSIONS Two days of staging at either 3000 or 3500 m, with or without physical activity, reduced AMS during subsequent ascent to 4300 m but staging at 3000 m may be recommended because of less incidence of AMS.
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Affiliation(s)
- Beth A Beidleman
- 1 Biophysics and Biomedical Modeling Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Charles S Fulco
- 2 Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | | | - Allen Cymerman
- 2 Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Robert W Kenefick
- 2 Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Bruce S Cadarette
- 2 Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Sean P Andrew
- 2 Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Janet E Staab
- 3 Military Performance Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Ingrid V Sils
- 2 Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Stephen R Muza
- 4 Strategic Scientific Management Office, U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts
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28
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Horiuchi M, Uno T, Endo J, Handa Y, Hasegawa T. Impact of Sleeping Altitude on Symptoms of Acute Mountain Sickness on Mt. Fuji. High Alt Med Biol 2018; 19:193-200. [DOI: 10.1089/ham.2017.0106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Masahiro Horiuchi
- Division of Human Environmental Science, Mt. Fuji Research Institute, Fuji-yoshida, Japan
| | - Tadashi Uno
- Division of Human Environmental Science, Mt. Fuji Research Institute, Fuji-yoshida, Japan
| | - Junko Endo
- Division of Human Environmental Science, Mt. Fuji Research Institute, Fuji-yoshida, Japan
| | - Yoko Handa
- Division of Human Environmental Science, Mt. Fuji Research Institute, Fuji-yoshida, Japan
| | - Tatsuya Hasegawa
- Division of Human Environmental Science, Mt. Fuji Research Institute, Fuji-yoshida, Japan
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29
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Wu Y, Zhang C, Chen Y, Luo YJ. Association between acute mountain sickness (AMS) and age: a meta-analysis. Mil Med Res 2018; 5:14. [PMID: 29747689 PMCID: PMC5946480 DOI: 10.1186/s40779-018-0161-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 04/24/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Acute mountain sickness (AMS) is a potentially lethal condition caused by acute hypoxia after ascending to altitudes higher than 2500 m in a short time. The main symptom of AMS is headache. Numerous risk factors of AMS have been examined, including gender, obesity, ascent rate, age and individual susceptibility. In previous studies, age was considered a predisposing factor for AMS. However, different opinions have been raised in recent years. To clarify the association between AMS and age, we conducted this meta-analysis. METHODS We obtained observational studies that explored risk factors for AMS by searching PubMed, Embase, China National Knowledge Internet (CNKI), the Wanfang database and CQVIP for articles published before March 2017. The studies included were required to provide the mean age and its standard deviation for subjects with and without AMS, the maximum altitude attained and the mode of ascent. The Lake Louse Score (LLS) or the Chinese AMS score (CAS) was used to judge the severity of AMS symptoms and incidence. Studies were pooled for the analysis by using a random effects model in RevMan 5.0. Meta-regression and subgroup analyses were conducted to identify sources of heterogeneity using Stata 14.2 and RevMan 5.0. RESULTS In total, 17 studies were included, and the overall number of subjects with and without AMS was 1810 and 3014, respectively. The age ranged from 10 to 76 years. Analysis of the 17 included studies showed that age was not associated with AMS (mean difference (MD) = 0.10; 95% CI: -0.38-0.58; P = 0.69). CONCLUSION This meta-analysis suggests that there is no association between age and the risk of AMS. Race, age, and ascent mode are common sources of heterogeneity, which may provide an analytical orientation for future heterogeneity analyses.
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Affiliation(s)
- Yu Wu
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China.,Battalion 5 of Cadet Brigade, Army Medical University, Chongqing, 400038, China
| | - Chi Zhang
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China.,Key Laboratory of High Altitude Environmental Medicine of PLA, Army Medical University, Chongqing, 400038, China
| | - Yu Chen
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China.,Key Laboratory of High Altitude Environmental Medicine of PLA, Army Medical University, Chongqing, 400038, China
| | - Yong-Jun Luo
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China. .,Key Laboratory of High Altitude Environmental Medicine of PLA, Army Medical University, Chongqing, 400038, China.
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30
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Muza SR. Wearable physiological sensors and real-time algorithms for detection of acute mountain sickness. J Appl Physiol (1985) 2018; 124:557-563. [DOI: 10.1152/japplphysiol.00367.2017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
This is a minireview of potential wearable physiological sensors and algorithms (process and equations) for detection of acute mountain sickness (AMS). Given the emerging status of this effort, the focus of the review is on the current clinical assessment of AMS, known risk factors (environmental, demographic, and physiological), and current understanding of AMS pathophysiology. Studies that have examined a range of physiological variables to develop AMS prediction and/or detection algorithms are reviewed to provide insight and potential technological roadmaps for future development of real-time physiological sensors and algorithms to detect AMS. Given the lack of signs and nonspecific symptoms associated with AMS, development of wearable physiological sensors and embedded algorithms to predict in the near term or detect established AMS will be challenging. Prior work using [Formula: see text], HR, or HRv has not provided the sensitivity and specificity for useful application to predict or detect AMS. Rather than using spot checks as most prior studies have, wearable systems that continuously measure SpO2 and HR are commercially available. Employing other statistical modeling approaches such as general linear and logistic mixed models or time series analysis to these continuously measured variables is the most promising approach for developing algorithms that are sensitive and specific for physiological prediction or detection of AMS.
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Affiliation(s)
- Stephen R. Muza
- Strategic Science Management Office, US Army Research Institute of Environmental Medicine, Natick, Massachusetts
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31
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Plasma proteomic study of acute mountain sickness susceptible and resistant individuals. Sci Rep 2018; 8:1265. [PMID: 29352170 PMCID: PMC5775437 DOI: 10.1038/s41598-018-19818-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 12/20/2017] [Indexed: 12/20/2022] Open
Abstract
Although extensive studies have focused on the development of acute mountain sickness (AMS), the exact mechanisms of AMS are still obscure. In this study, we used isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis to identify novel AMS−associated biomarkers in human plasma. After 9 hours of hypobaric hypoxia the abundance of proteins related to tricarboxylic acid (TCA) cycle, glycolysis, ribosome, and proteasome were significantly reduced in AMS resistant (AMS−) group, but not in AMS susceptible (AMS+) group. This suggested that AMS− individuals could reduce oxygen consumption via repressing TCA cycle and glycolysis, and reduce energy consumption through decreasing protein degradation and synthesis compared to AMS+ individuals after acute hypoxic exposure. The inflammatory response might be decreased resulting from the repressed TCA cycle. We propose that the ability for oxygen consumption reduction may play an important role in the development of AMS. Our present plasma proteomic study in plateau of the Han Chinese volunteers gives new data to address the development of AMS and potential AMS correlative biomarkers.
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32
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Changes in balance and joint position sense during a 12-day high altitude trek: The British Services Dhaulagiri medical research expedition. PLoS One 2018; 13:e0190919. [PMID: 29342191 PMCID: PMC5771604 DOI: 10.1371/journal.pone.0190919] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 12/23/2017] [Indexed: 11/19/2022] Open
Abstract
Postural control and joint position sense are essential for safely undertaking leisure and professional activities, particularly at high altitude. We tested whether exposure to a 12-day trek with a gradual ascent to high altitude impairs postural control and joint position sense. This was a repeated measures observational study of 12 military service personnel (28±4 years). Postural control (sway velocity measured by a portable force platform) during standing balance, a Sharpened Romberg Test and knee joint position sense were measured, in England (113m elevation) and at 3 research camps (3619m, 4600m and 5140m) on a 12-day high altitude trek in the Dhaulagiri region of Nepal. Pulse oximetry, and Lake Louise scores were also recorded on the morning and evening of each trek day. Data were compared between altitudes and relationships between pulse oximetry, Lake Louise score, and sway velocity were explored. Total sway velocity during standing balance with eyes open (p = 0.003, d = 1.9) and during Sharpened Romberg test with eyes open (p = 0.007, d = 1.6) was significantly greater at altitudes of 3619m and 5140m when compared with sea level. Anterior-posterior sway velocity during standing balance with eyes open was also significantly greater at altitudes of 3619m and 5140m when compared with sea level (p = 0.001, d = 1.9). Knee joint position sense was not altered at higher altitudes. There were no significant correlations between Lake Louise scores, pulse oximetry and postural sway. Despite a gradual ascent profile, exposure to 3619 m was associated with impairments in postural control without impairment in knee joint position sense. Importantly, these impairments did not worsen at higher altitudes of 4600 m or 5140 m. The present findings should be considered during future trekking expeditions when developing training strategies targeted to manage impairments in postural control that occur with increasing altitude.
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Macoun T, Botek M, Krejčí J, McKune AJ. Vagal activity and oxygen saturation response to hypoxia: Effects of aerobic fitness and rating of hypoxia tolerance. ACTA GYMNICA 2017. [DOI: 10.5507/ag.2017.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
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34
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Rossetti GMK, Macdonald JH, Wylie LJ, Little SJ, Newton V, Wood B, Hawkins KA, Beddoe R, Davies HE, Oliver SJ. Dietary nitrate supplementation increases acute mountain sickness severity and sense of effort during hypoxic exercise. J Appl Physiol (1985) 2017; 123:983-992. [DOI: 10.1152/japplphysiol.00293.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 06/28/2017] [Accepted: 07/01/2017] [Indexed: 12/12/2022] Open
Abstract
Dietary nitrate supplementation enhances sea level performance and may ameliorate hypoxemia at high altitude. However, nitrate may exacerbate acute mountain sickness (AMS), specifically headache. This study investigated the effect of nitrate supplementation on AMS symptoms and exercise responses with 6-h hypoxia. Twenty recreationally active men [age, 22 ± 4 yr, maximal oxygen consumption (V̇o2max), 51 ± 6 ml·min−1·kg−1, means ± SD] completed this randomized double-blinded placebo-controlled crossover study. Twelve participants were classified as AMS− on the basis of Environmental Symptoms Questionnaire [Acute Cerebral Mountain Sickness score (AMS-C)] <0.7 in both trials, and five participants were classified as AMS+ on the basis of AMS-C ≥0.7 on placebo. Five days of nitrate supplementation (70-ml beetroot juice containing ~6.4 mmol nitrate daily) increased plasma NO metabolites by 182 µM compared with placebo but did not reduce AMS or improve exercise performance. After 4-h hypoxia [inspired O2 fraction ([Formula: see text]) = 0.124], nitrate increased AMS-C and headache severity (visual analog scale; whole sample ∆10 [1, 20] mm, mean difference [95% confidence interval]; P = 0.03) compared with placebo. In addition, after 5-h hypoxia, nitrate increased sense of effort during submaximal exercise (∆7 [−1, 14]; P = 0.07). In AMS−, nitrate did not alter headache or sense of effort. In contrast, in AMS+, nitrate increased headache severity (∆26 [−3, 56] mm; P = 0.07), sense of effort (∆14 [1, 28]; P = 0.04), oxygen consumption, ventilation, and mean arterial pressure during submaximal exercise. On the next day, in a separate acute hypoxic exercise test ([Formula: see text] = 0.141), nitrate did not improve time to exhaustion at 80% hypoxic V̇o2max. In conclusion, dietary nitrate increases AMS and sense of effort during exercise, particularly in those who experience AMS. Dietary nitrate is therefore not recommended as an AMS prophylactic or ergogenic aid in nonacclimatized individuals at altitude. NEW & NOTEWORTHY This is the first study to identify that the popular dietary nitrate supplement (beetroot) does not reduce acute mountain sickness (AMS) or improve exercise performance during 6-h hypoxia. The consumption of nitrate in those susceptible to AMS exacerbates AMS symptoms (headache) and sense of effort and raises oxygen cost, ventilation, and blood pressure during walking exercise in 6-h hypoxia. These data question the suitability of nitrate supplementation during altitude travel in nonacclimatized people.
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Affiliation(s)
- Gabriella M. K. Rossetti
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Jamie H. Macdonald
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Lee J. Wylie
- Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, St. Luke’s Campus, Exeter, United Kingdom
| | - Samuel J. Little
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Victoria Newton
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Benjamin Wood
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Kieran A. Hawkins
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Rhys Beddoe
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Hannah E. Davies
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
| | - Samuel J. Oliver
- Extremes Research Group, College of Health and Behavioural Sciences, Bangor University, Bangor, United Kingdom; and
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Health of High Altitude Pilgrims: A Neglected Topic. Wilderness Environ Med 2017; 28:275-277. [PMID: 28732756 DOI: 10.1016/j.wem.2017.04.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/21/2017] [Accepted: 04/26/2017] [Indexed: 11/21/2022]
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Sikri G, Bhattachar S, Thapa B. In Response to Risk Determinants of Acute Mountain Sickness by Lawrence and Reid. Wilderness Environ Med 2017; 28:57-58. [DOI: 10.1016/j.wem.2016.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Accepted: 10/12/2016] [Indexed: 10/20/2022]
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Luks AM, Swenson ER, Bärtsch P. Acute high-altitude sickness. Eur Respir Rev 2017; 26:26/143/160096. [PMID: 28143879 PMCID: PMC9488514 DOI: 10.1183/16000617.0096-2016] [Citation(s) in RCA: 224] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 10/23/2016] [Indexed: 12/28/2022] Open
Abstract
At any point 1–5 days following ascent to altitudes ≥2500 m, individuals are at risk of developing one of three forms of acute altitude illness: acute mountain sickness, a syndrome of nonspecific symptoms including headache, lassitude, dizziness and nausea; high-altitude cerebral oedema, a potentially fatal illness characterised by ataxia, decreased consciousness and characteristic changes on magnetic resonance imaging; and high-altitude pulmonary oedema, a noncardiogenic form of pulmonary oedema resulting from excessive hypoxic pulmonary vasoconstriction which can be fatal if not recognised and treated promptly. This review provides detailed information about each of these important clinical entities. After reviewing the clinical features, epidemiology and current understanding of the pathophysiology of each disorder, we describe the current pharmacological and nonpharmacological approaches to the prevention and treatment of these diseases. Lack of acclimatisation is the main risk factor for acute altitude illness; descent is the optimal treatmenthttp://ow.ly/45d2305JyZ0
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Affiliation(s)
- Andrew M Luks
- Dept of Medicine, Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, WA, USA
| | - Erik R Swenson
- Dept of Medicine, Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, WA, USA.,Medical Service, Veterans Affairs Puget Sound Health Care System, Seattle, WA, USA
| | - Peter Bärtsch
- Dept of Internal Medicine, University Clinic Heidelberg, Heidelberg, Germany
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San Martin R, Brito J, Siques P, León-Velarde F. Obesity as a Conditioning Factor for High-Altitude Diseases. Obes Facts 2017; 10:363-372. [PMID: 28810235 PMCID: PMC5644942 DOI: 10.1159/000477461] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 05/10/2017] [Indexed: 12/19/2022] Open
Abstract
Obesity, a worldwide epidemic, has become a major health burden because it is usually accompanied by an increased risk for insulin resistance, diabetes, hypertension, cardiovascular diseases, and even some kinds of cancer. It also results in associated increases in healthcare expenditures and labor and economic consequences. There are also other fields of medicine and biology where obesity or being overweight play a major role, such as high-altitude illnesses (acute mountain sickness, hypoxic pulmonary hypertension, and chronic mountain sickness), where an increasing relationship among these two morbid statuses has been demonstrated. This association could be rooted in the interactions between obesity-related metabolic alterations and critical ventilation impairments due to obesity, which would aggravate hypobaric hypoxia at high altitudes, leading to hypoxemia, which is a trigger for developing high-altitude diseases. This review examines the current literature to support the idea that obesity or overweight could be major conditioning factors at high altitude.
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Affiliation(s)
- Rocío San Martin
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Julio Brito
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
- *Julio Brito, Institute of Health Studies, Universidad Arturo Prat, Avda. Arturo Prat 2120, Iquique, 1110939, Chile,
| | - Patricia Siques
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Fabiola León-Velarde
- Department of Biological and Physiological Sciences. Facultad de Ciencias y Filosofía/ IIA, Universidad Peruana Cayetano Heredia, Lima, Perú
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Abstract
Scenic view at high altitude is a pleasure to the eyes, but it has some shortcoming effects as well. High altitude can be divided into different categories, i.e., high altitude (3000-5000 ft), very high altitude (5000-8000 ft), and extreme altitude (above 8000 ft). Much of the population resides at high altitude, and others go there for tourism. Military personnel are also posted there to defend boundaries. As we ascent to high altitude, partial pressure of oxygen reduces, whereas concentration remains the same; this reduces the availability of oxygen to different body parts. This pathophysiological condition is known as hypobaric hypoxia (HH) which leads to oxidative stress and further causes cognitive dysfunction in some cases. Hypoxia causes neurodegeneration in different brain regions; however, the hippocampus is found to be more prone in comparison to other brain regions. As the hippocampus is affected most, therefore, spatial memory is impaired most during such condition. This chapter will give a brief review of the damaging effect of high altitude on cognition and also throw light on possible herbal interventions at high altitude, which can improve cognitive performance as well as provide protection against the deteriorating effect of hypobaric hypoxia at high altitude.
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Affiliation(s)
- Vishal Jain
- Vallabhbhai Patel Chest Institute, Delhi University, Delhi, 110007, India.
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Horiuchi M, Endo J, Dobashi S, Kiuchi M, Koyama K, Subudhi AW. Effect of progressive normobaric hypoxia on dynamic cerebral autoregulation. Exp Physiol 2016; 101:1276-1284. [DOI: 10.1113/ep085789] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2016] [Accepted: 07/12/2016] [Indexed: 01/05/2023]
Affiliation(s)
- Masahiro Horiuchi
- Division of Human Environmental Science; Mount Fuji Research Institute; Japan
| | - Junko Endo
- Division of Human Environmental Science; Mount Fuji Research Institute; Japan
| | - Shohei Dobashi
- Integrated Graduate School Department of Medicine; Engineering, and Agricultural Sciences; University of Yamanashi; Japan
| | - Masataka Kiuchi
- Integrated Graduate School Department of Medicine; Engineering, and Agricultural Sciences; University of Yamanashi; Japan
| | - Katsuhiro Koyama
- Integrated Graduate School Department of Medicine; Engineering, and Agricultural Sciences; University of Yamanashi; Japan
| | - Andrew W. Subudhi
- Department of Biology; University of Colorado; Colorado Springs CO USA
- Altitude Research Center; University of Colorado Anschutz Medical Campus; Aurora CO USA
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Dobashi S, Horiuchi M, Endo J, Kiuchi M, Koyama K. Cognitive Function and Cerebral Oxygenation During Prolonged Exercise Under Hypoxia in Healthy Young Males. High Alt Med Biol 2016; 17:214-221. [PMID: 27584683 DOI: 10.1089/ham.2016.0036] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Dobashi, Shohei, Masahiro Horiuchi, Junko Endo, Masataka Kiuchi, and Katsuhiro Koyama. Cognitive function and cerebral oxygenation during prolonged exercise under hypoxia in healthy young males. High Alt Med Biol. 17:214-221, 2016.-The present study examined the effect of prolonged hypoxic exercise on cognitive function. Eight healthy male volunteers were required to complete exercise trials (four 30-minute cycling sessions with a 15-minute rest interval) at an intensity corresponding to 50% of their altitude-adjusted peak oxygen uptake under two different conditions: normoxia (room air at 400 m) and hypoxia (fraction of inspired oxygen: 0.141). Cognitive function was evaluated before, during, and 60 minutes after completion of the exercise trial. The color-word Stroop task (CWST) was used to assess cognitive function, with regard to the number of achievements, accuracy rate, and the number of correct responses made within 60 seconds. Cerebral oxygenation was monitored throughout the experimental period using near-infrared spectroscopy. The accuracy rate did not significantly differ between the two trials. A significant reduction in the number of correct responses during simple CWST tasks was detected in the hypoxic condition 60 minutes after exercise (p < 0.05), wherein a significant correlation was identified between reduced task performance on simple CWST and cerebral oxygenation (p < 0.01). These results demonstrate that prolonged exercise under hypoxic conditions induces a reduction in cerebral oxygenation partly associated with impairment of cognitive function.
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Affiliation(s)
- Shohei Dobashi
- 1 Integrated Graduate School Department of Medicine, Engineering, and Agricultural Sciences, University of Yamanashi , Kofu, Japan
| | - Masahiro Horiuchi
- 2 Division of Human Environmental Science, Mt. Fuji Research Institute , Fujiyoshida, Japan
| | - Junko Endo
- 2 Division of Human Environmental Science, Mt. Fuji Research Institute , Fujiyoshida, Japan
| | - Masataka Kiuchi
- 3 Graduate School Department of Education, University of Yamanashi , Kofu, Japan
| | - Katsuhiro Koyama
- 4 Graduate School Department of Interdisciplinary Research, University of Yamanashi , Kofu, Japan
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Mills L, Harper C, Rozwadowski S, Imray C. High Altitude Pulmonary Edema Without Appropriate Action Progresses to Right Ventricular Strain: A Case Study. High Alt Med Biol 2016; 17:228-232. [PMID: 27575244 DOI: 10.1089/ham.2016.0015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mills, Logan, Chris Harper, Sophie Rozwadowski, and Chris Imray. High altitude pulmonary edema without appropriate action progresses to right ventricular strain: A case study. High Alt Med Biol. 17:228-232, 2016.-A 24-year-old male developed high altitude pulmonary edema (HAPE) after three ascents to 4061 m over 3 days, sleeping each night at 2735 m. He complained of exertional dyspnea, dry cough, chest pain, fever, nausea, vertigo, and a severe frontal headache. Inappropriate continuation of ascent despite symptoms led to functional impairment and forced a return to the valley, but dyspnea persisted in addition to new orthopnea. Hospital admission showed hypoxemia, resting tachycardia, and systemic hypertension. ECG revealed right ventricular strain and a chest X-ray revealed right lower zone infiltrates. This case demonstrates that HAPE can develop in previously unaffected individuals given certain precipitating factors, and that in the presence of HAPE, prolonged exposure to altitude with exercise (or exertion) does not confer acclimatization with protective adaptations and that rest and descent are the appropriate actions. The case additionally demonstrates well-characterized right ventricular involvement.
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Affiliation(s)
- Logan Mills
- 1 Medical Teaching Centre, Warwick Medical School , Coventry, United Kingdom
| | - Chris Harper
- 1 Medical Teaching Centre, Warwick Medical School , Coventry, United Kingdom
| | - Sophie Rozwadowski
- 1 Medical Teaching Centre, Warwick Medical School , Coventry, United Kingdom
| | - Chris Imray
- 1 Medical Teaching Centre, Warwick Medical School , Coventry, United Kingdom .,2 Department of Vascular and Endovascular Surgery, University Hospitals Coventry and Warwickshire , Coventry, United Kingdom .,3 Department of Vascular and Endovascular Surgery , Coventry University, Coventry, United Kingdom
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DiPasquale DM, Muza SR, Gunn AM, Li Z, Zhang Q, Harris NS, Strangman GE. Evidence for cerebral edema, cerebral perfusion, and intracranial pressure elevations in acute mountain sickness. Brain Behav 2016; 6:e00437. [PMID: 27099800 PMCID: PMC4831417 DOI: 10.1002/brb3.437] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 12/22/2015] [Accepted: 12/23/2015] [Indexed: 11/09/2022] Open
Abstract
INTRODUCTION We hypothesized that cerebral alterations in edema, perfusion, and/or intracranial pressure (ICP) are related to the development of acute mountain sickness (AMS). METHODS To vary AMS, we manipulated ambient oxygen, barometric pressure, and exercise duration. Thirty-six subjects were tested before, during and after 8 h exposures in (1) normobaric normoxia (NN; 300 m elevation equivalent); (2) normobaric hypoxia (NH; 4400 m equivalent); and (3) hypobaric hypoxia (HH; 4400 m equivalent). After a passive 15 min ascent, each subject participated in either 10 or 60 min of cycling exercise at 50% of heart rate reserve. We measured tissue absorption and scattering via radio-frequency near-infrared spectroscopy (NIRS), optic nerve sheath diameter (ONSD) via ultrasound, and AMS symptoms before, during, and after environmental exposures. RESULTS We observed significant increases in NIRS tissue scattering of 0.35 ± 0.11 cm(-1) (P = 0.001) in subjects with AMS (i.e., AMS+), consistent with mildly increased cerebral edema. We also noted a small, but significant increase in total hemoglobin concentrations with AMS+, 3.2 ± 0.8 μmolL(-1) (P < 0.0005), consistent with increased cerebral perfusion. No effect of exercise duration was found, nor did we detect differences between NH and HH. ONSD assays documented a small but significant increase in ONSD (0.11 ± 0.02 mm; P < 0.0005) with AMS+, suggesting mildly elevated ICP, as well as further increased ONSD with longer exercise duration (P = 0.005). CONCLUSION In AMS+, we found evidence of cerebral edema, elevated cerebral perfusion, and elevated ICP. The observed changes were small but consistent with the reversible nature of AMS.
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Affiliation(s)
- Dana M DiPasquale
- Psychiatry Department Massachusetts General Hospital Harvard Medical School Charlestown Massachusetts
| | - Stephen R Muza
- Environmental Medicine and Military Performance Division U.S. Army Research Institute of Environmental Medicine Natick Massachusetts
| | - Andrea M Gunn
- Psychiatry Department Massachusetts General Hospital Harvard Medical School Charlestown Massachusetts
| | - Zhi Li
- Psychiatry Department Massachusetts General Hospital Harvard Medical School Charlestown Massachusetts
| | - Quan Zhang
- Psychiatry Department Massachusetts General Hospital Harvard Medical School Charlestown Massachusetts; Center for Space Medicine Baylor College of Medicine Houston Texas
| | - N Stuart Harris
- Department of Emergency Medicine Division of Wilderness Medicine Massachusetts General Hospital Harvard Medical School Boston Massachusetts
| | - Gary E Strangman
- Psychiatry Department Massachusetts General Hospital Harvard Medical School Charlestown Massachusetts; Center for Space Medicine Baylor College of Medicine Houston Texas
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Sikri G, Singh K. Optic Nerve Sheath Diameter and Acute Mountain Sickness. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2016; 35:455-456. [PMID: 26795046 DOI: 10.7863/ultra.15.08072] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Affiliation(s)
- Gaurav Sikri
- Department of Physiology, Armed Forces Medical College, Wanowarie, Pune, Maharashtra, India
| | - Krishan Singh
- Department of Physiology, Armed Forces Medical College, Wanowarie, Pune, Maharashtra, India
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Ensemble Input of Group III/IV Muscle Afferents to CNS: A Limiting Factor of Central Motor Drive During Endurance Exercise from Normoxia to Moderate Hypoxia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:325-42. [PMID: 27343106 DOI: 10.1007/978-1-4899-7678-9_22] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We recently hypothesized that across the range of normoxia to severe hypoxia the major determinant of central motor drive (CMD) during endurance exercise switches from a predominantly peripheral origin to a hypoxic-sensitive central component of fatigue. We found that peripheral locomotor muscle fatigue (pLMF) is the prevailing factor limiting central motor drive and therefore exercise performance from normoxia to moderate hypoxia (SaO2 > 75 %). In these levels of arterial hypoxemia, the development of pLMF is confined to a certain limit which varies between humans-pLMF does not develop to this limit in more severe hypoxia (SaO2 < 70 %) and exercise is prematurely terminated presumably to protect the brain from insufficient O2 supply. Based on the observations from normoxia to moderate hypoxia, we outlined a model suggesting that group III/IV muscle afferents impose inhibitory influences on the determination of CMD of working humans during high-intensity endurance exercise with the purpose to regulate and restrict the level of exercise-induced pLMF to an "individual critical threshold." To experimentally test this model, we pharmacologically blocked somatosensory pathways originating in the working limbs during cycling exercise in normoxia. After initial difficulties with a local anesthetic (epidural lidocaine, L3-L4) and associated loss of locomotor muscle strength we switched to an intrathecally applied opioid analgesic (fentanyl, L3-L4). These experiments were the first ever to selectively block locomotor muscle afferents during high-intensity cycling exercise without affecting maximal locomotor muscle strength. In the absence of opioid-mediated neural feedback from the working limbs, CMD was increased and end-exercise pLMF substantially exceeded, for the first time, the individual critical threshold of peripheral fatigue. The outcome of these studies confirm our hypothesis claiming that afferent feedback inhibits CMD and restricts the development of pLMF to an individual critical threshold as observed from normoxia up to moderate hypoxia.
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Van Thienen R, Hespel P. Enhanced muscular oxygen extraction in athletes exaggerates hypoxemia during exercise in hypoxia. J Appl Physiol (1985) 2015; 120:351-61. [PMID: 26607244 DOI: 10.1152/japplphysiol.00210.2015] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 11/22/2015] [Indexed: 01/11/2023] Open
Abstract
High rate of muscular oxygen utilization facilitates the development of hypoxemia during exercise at altitude. Because endurance training stimulates oxygen extraction capacity, we investigated whether endurance athletes are at higher risk to developing hypoxemia and thereby acute mountain sickness symptoms during exercise at simulated high altitude. Elite athletes (ATL; n = 8) and fit controls (CON; n = 7) cycled for 20 min at 100 W (EX100W), as well as performed an incremental maximal oxygen consumption test (EXMAX) in normobaric hypoxia (0.107 inspired O2 fraction) or normoxia (0.209 inspired O2 fraction). Cardiorespiratory responses, arterial Po2 (PaO2), and oxygenation status in m. vastus lateralis [tissue oxygenation index (TOIM)] and frontal cortex (TOIC) by near-infrared spectroscopy, were measured. Muscle O2 uptake rate was estimated from change in oxyhemoglobin concentration during a 10-min arterial occlusion in m. gastrocnemius. Maximal oxygen consumption in normoxia was 70 ± 2 ml·min(-1·)kg(-1) in ATL vs. 43 ± 2 ml·min(-1·)kg(-1) in CON, and in hypoxia decreased more in ATL (-41%) than in CON (-25%, P < 0.05). Both in normoxia at PaO2 of ∼95 Torr, and in hypoxia at PaO2 of ∼35 Torr, muscle O2 uptake was twofold higher in ATL than in CON (0.12 vs. 0.06 ml·min(-1)·100 g(-1); P < 0.05). During EX100W in hypoxia, PaO2 dropped to lower (P < 0.05) values in ATL (27.6 ± 0.7 Torr) than in CON (33.5 ± 1.0 Torr). During EXMAX, but not during EX100W, TOIM was ∼15% lower in ATL than in CON (P < 0.05). TOIC was similar between the groups at any time. This study shows that maintenance of high muscular oxygen extraction rate at very low circulating PaO2 stimulates the development of hypoxemia during submaximal exercise in hypoxia in endurance-trained individuals. This effect may predispose to premature development of acute mountain sickness symptoms during exercise at altitude.
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Affiliation(s)
- Ruud Van Thienen
- Exercise Physiology Research Group, Department of Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Peter Hespel
- Exercise Physiology Research Group, Department of Kinesiology, Katholieke Universiteit Leuven, Leuven, Belgium
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Abstract
Acute high-altitude illness is an encompassing term for the range of pathology that the unacclimatised individual can develop at increased altitude. This includes acute mountain sickness, high-altitude cerebral oedema and high-altitude pulmonary oedema. These conditions represent an increasing clinical problem as more individuals are exposed to the hypobaric hypoxic environment of high altitude for both work and leisure. In this review of acute high-altitude illness, the epidemiology, risk factors and pathophysiology are explored, before their prevention and treatment are discussed. Appropriate ascent rate remains the most effective acute high-altitude illness prevention, with pharmacological prophylaxis indicated in selected individuals. Descent is the definitive treatment for acute high-altitude illness, with the adjuncts of oxygen and specific drug therapies.
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Affiliation(s)
- Tom Smedley
- UCL Centre for Altitude, Space and Extreme Environment Medicine, Portex Unit, Institute of Child Health, London, UK ; Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, University Hospital Southampton NHS Foundation Trust, Southampton, UK
| | - Michael Pw Grocott
- Integrative Physiology and Critical Illness Group, Clinical and Experimental Sciences, Sir Henry Wellcome Laboratories, Faculty of Medicine, University of Southampton, University Hospital Southampton NHS Foundation Trust, Southampton, UK ; Anaesthesia and Critical Care Research Unit, University Hospital Southampton NHS Foundation Trust, Southampton, UK ; NIHR Southampton Respiratory Biomedical Research Unit, Southampton, UK
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Shah NM, Hussain S, Cooke M, O’Hara JP, Mellor A. Wilderness medicine at high altitude: recent developments in the field. Open Access J Sports Med 2015; 6:319-28. [PMID: 26445563 PMCID: PMC4590685 DOI: 10.2147/oajsm.s89856] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Travel to high altitude is increasingly popular. With this comes an increased incidence of high-altitude illness and therefore an increased need to improve our strategies to prevent and accurately diagnose these. In this review, we provide a summary of recent advances of relevance to practitioners who may be advising travelers to altitude. Although the Lake Louise Score is now widely used as a diagnostic tool for acute mountain sickness (AMS), increasing evidence questions the validity of doing so, and of considering AMS as a single condition. Biomarkers, such as brain natriuretic peptide, are likely correlating with pulmonary artery systolic pressure, thus potential markers of the development of altitude illness. Established drug treatments include acetazolamide, nifedipine, and dexamethasone. Drugs with a potential to reduce the risk of developing AMS include nitrate supplements, propagators of nitric oxide, and supplemental iron. The role of exercise in the development of altitude illness remains hotly debated, and it appears that the intensity of exercise is more important than the exercise itself. Finally, despite copious studies demonstrating the value of preacclimatization in reducing the risk of altitude illness and improving performance, an optimal protocol to preacclimatize an individual remains elusive.
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Affiliation(s)
- Neeraj M Shah
- Division of Asthma, Allergy and Lung Biology, King’s College London, UK
| | - Sidra Hussain
- School of Medicine, University College London, London, UK
| | - Mark Cooke
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - John P O’Hara
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
| | - Adrian Mellor
- Research Institute for Sport, Physical Activity and Leisure, Leeds Beckett University, Leeds, UK
- Academic Department of Military Anaesthesia and Critical Care, Royal Centre for Defence Medicine, Birmingham, UK
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Pitman JT, Thapa GB, Stuart Harris N. Field Ultrasound Evaluation of Central Volume Status and Acute Mountain Sickness. Wilderness Environ Med 2015; 26:319-26. [DOI: 10.1016/j.wem.2015.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 02/09/2015] [Accepted: 02/16/2015] [Indexed: 11/26/2022]
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Sikri G, Chawla A. Role of remote ischemic preconditioning against acute mountain sickness during early phase. Physiol Rep 2015; 3:3/8/e12499. [PMID: 26265758 PMCID: PMC4562584 DOI: 10.14814/phy2.12499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Gaurav Sikri
- Department of Physiology; Armed Forces Medical College; Pune India
| | - Anuj Chawla
- Department of Physiology; Armed Forces Medical College; Pune India
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