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Coustet B, Lhuissier FJ, Vincent R, Richalet JP. Electrocardiographic changes during exercise in acute hypoxia and susceptibility to severe high-altitude illnesses. Circulation 2015; 131:786-94. [PMID: 25561515 DOI: 10.1161/circulationaha.114.013144] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND The goals of this study were to compare ECG at moderate exercise in normoxia and hypoxia at the same heart rate, to provide evidence of independent predictors of hypoxia-induced ECG changes, and to evaluate ECG risk factors of severe high-altitude illness. METHODS AND RESULTS A total of 456 subjects performed a 20-minute hypoxia exercise test with continuous recording of ECG and physiological measurements before a sojourn above 4000 m. Hypoxia did not induce any conduction disorder, arrhythmias, or change in QRS axis. The amplitude of the P wave in V1 was lower in hypoxia than in normoxia. The amplitudes of the R, S, and T waves and the Sokolow index decreased in hypoxia. Under hypoxia, the amplitude of the ST segment decreased in II and V6 and increased in V1, the ST slope rose in V5 and V6, and the J point was lower in II, V5, and V6. Multivariate regression of hypoxic/normoxic ratios of electrophysiological parameters and clinical characteristics showed a correlation between the decrease in Sokolow index and T-wave amplitude in V5 with desaturation at exercise. Trained status and low body mass index were associated with a smaller decrease in T-wave amplitude in V5 and V6. Comparison of ECG between subjects suffering or not suffering from severe high-altitude illness failed to show any difference. CONCLUSIONS During a hypoxia exercise test, a dose-dependent hypoxia-induced decrease in the amplitude of the P/QRS/T waves was observed. No standard ECG characteristic predicted the risk of developing severe high-altitude illness. Further studies are required to clarify the cause of these electric changes and their potential predictive role in cardiac events.
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Affiliation(s)
- Baptiste Coustet
- From the Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et Poumon," EA2363 and Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France
| | - François J Lhuissier
- From the Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et Poumon," EA2363 and Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France
| | - Renaud Vincent
- From the Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et Poumon," EA2363 and Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France
| | - Jean-Paul Richalet
- From the Université Paris 13, Sorbonne Paris Cité, Laboratoire "Hypoxie et Poumon," EA2363 and Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France.
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152
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Luks AM. Physiology in Medicine: A physiologic approach to prevention and treatment of acute high-altitude illnesses. J Appl Physiol (1985) 2014; 118:509-19. [PMID: 25539941 DOI: 10.1152/japplphysiol.00955.2014] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
With the growing interest in adventure travel and the increasing ease and affordability of air, rail, and road-based transportation, increasing numbers of individuals are traveling to high altitude. The decline in barometric pressure and ambient oxygen tensions in this environment trigger a series of physiologic responses across organ systems and over a varying time frame that help the individual acclimatize to the low oxygen conditions but occasionally lead to maladaptive responses and one or several forms of acute altitude illness. The goal of this Physiology in Medicine article is to provide information that providers can use when counseling patients who present to primary care or travel medicine clinics seeking advice about how to prevent these problems. After discussing the primary physiologic responses to acute hypoxia from the organ to the molecular level in normal individuals, the review describes the main forms of acute altitude illness--acute mountain sickness, high-altitude cerebral edema, and high-altitude pulmonary edema--and the basic approaches to their prevention and treatment of these problems, with an emphasis throughout on the physiologic basis for the development of these illnesses and their management.
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Affiliation(s)
- Andrew M Luks
- Division of Pulmonary and Critical Care Medicine, University of Washington Seattle, Washington
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153
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Hermand E, Pichon A, Lhuissier FJ, Richalet JP. Periodic breathing in healthy humans at exercise in hypoxia. J Appl Physiol (1985) 2014; 118:115-23. [PMID: 25554800 DOI: 10.1152/japplphysiol.00832.2014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Periodic breathing is frequent in heart failure or ventilatory disorders during sleep, and common during sleep at high altitude, but has been rarely studied in wakefulness and during exercise. A retrospective analysis of ventilation from hypoxia exercise tests was realized in 82 healthy subjects separated into two groups with either high or low ventilatory response to hypoxia at exercise (HVRe). A fast Fourier transform spectral analysis of the breath-by-breath ventilation (V̇e) signal, O2 saturation, and end-tidal PCO2 evidenced a periodic pattern with a period of 11.1 to 12.0 s. The peak power of the V̇e spectrum was higher in the high HVRe group (P < 0.001). A prospective study (25 subjects) was performed to evaluate the influence of cardiorespiratory factors on the amplitude and period of oscillations in various conditions of exercise (20 to 40% maximal aerobic power) and hypoxia (0 to 4,000 m altitude). The period of V̇e was shorter at exercise (vs. rest, P < 0.001) and hypoxia (vs. normoxia, P < 0.001), and inversely related with cardiac output and V̇e (P < 0.001). V̇e peak power was higher at exercise (P < 0.001) and hypoxia (P < 0.001), and was positively related with cardiac output and V̇e (P < 0.001). V̇e peak power in hypoxia was positively related with the ventilatory response to CO2 (HCVR). This novel observation suggests that healthy subjects demonstrate a spontaneous periodic breathing, not clearly observable at rest and in normoxia, but triggered by hypoxic exercise. The periodic pattern is enhanced in subjects with high HVRe and high HCVR, suggesting that oxygen and CO2 play synergistic roles in the modulation of these oscillations.
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Affiliation(s)
- Eric Hermand
- Université Paris 13, Sorbonne Paris Cité, Laboratoire Hypoxie et poumon, Bobigny, France; and
| | - Aurélien Pichon
- Université Paris 13, Sorbonne Paris Cité, Laboratoire Hypoxie et poumon, Bobigny, France; and
| | - François J Lhuissier
- Université Paris 13, Sorbonne Paris Cité, Laboratoire Hypoxie et poumon, Bobigny, France; and Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne, Service de Physiologie, explorations fonctionnelles et médecine du sport, Bobigny, France
| | - Jean-Paul Richalet
- Université Paris 13, Sorbonne Paris Cité, Laboratoire Hypoxie et poumon, Bobigny, France; and Assistance Publique-Hôpitaux de Paris, Hôpital Avicenne, Service de Physiologie, explorations fonctionnelles et médecine du sport, Bobigny, France
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154
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Croughs M, Van Gompel A, Rameckers S, Van den Ende J. Serious altitude illness in travelers who visited a pre-travel clinic. J Travel Med 2014; 21:403-9. [PMID: 25238200 DOI: 10.1111/jtm.12160] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 06/29/2014] [Accepted: 07/15/2014] [Indexed: 02/06/2023]
Abstract
BACKGROUND Few data are available on the incidence and predictors of serious altitude illness in travelers who visit pre-travel clinics. Travel health consultants advise on measures to be taken in case of serious altitude illness but it is not clear if travelers adhere to these recommendations. METHODS Visitors to six travel clinics who planned to travel to an altitude of ≥3,000 m were asked to complete a diary from the first day at 2,000 m until 3 days after reaching the maximum sleeping altitude. Serious altitude illness was defined as having symptoms of serious acute mountain sickness (AMS score ≥ 6) and/or cerebral edema and/or pulmonary edema. RESULTS The incidence of serious altitude illness in the 401 included participants of whom 90% reached ≥4,000 m, was 35%; 23% had symptoms of serious AMS, 25% symptoms of cerebral edema, and 13% symptoms of pulmonary edema. Independent predictors were young age, the occurrence of dark urine, travel in South America or Africa, and lack of acclimatization between 1,000 and 2,500 m. Acetazolamide was brought along by 77% of the responders of whom 41% took at least one dose. Of those with serious altitude illness, 57% had taken at least one dose of acetazolamide, 20% descended below 2,500 m on the same day or the next, and 11% consulted a physician. CONCLUSIONS Serious altitude illness was a very frequent problem in travelers who visited pre-travel clinics. Young age, dark urine, travel in South America or Africa, and lack of acclimatization nights at moderate altitude were independent predictors. Furthermore, we found that seriously ill travelers seldom followed the advice to descend and to visit a physician.
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Affiliation(s)
- Mieke Croughs
- Department of Environment, GGD Hart voor Brabant, 's-Hertogenbosch, The Netherlands; Department of Clinical Sciences, Institute of Tropical Medicine, Antwerp, Belgium
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155
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Bärtsch P. Rebuttal to the pro statement. High Alt Med Biol 2014; 15:322. [PMID: 25251928 DOI: 10.1089/ham.2014.1048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Peter Bärtsch
- University Clinic , Department of Internal Medicine, Division VII Sports Medicine, Heidelberg, Germany
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156
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Richalet JP, Canoui-Poitrine F. Rebuttal to the con statement. High Alt Med Biol 2014; 15:321. [PMID: 25251927 DOI: 10.1089/ham.2014.1092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jean-Paul Richalet
- 1 Université Paris 13 , Sorbonne Paris Cité, EA2363 « Poumon & Hypoxie », U.F.R. SMBH, and AP-HP, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France
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157
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Richalet JP, Canoui-Poitrine F. Pro: Hypoxic Cardiopulmonary Exercise Testing Identifies Subjects at Risk for Severe High Altitude Illnesses. High Alt Med Biol 2014; 15:315-7. [DOI: 10.1089/ham.2014.1032] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jean-Paul Richalet
- Université Paris 13, Sorbonne Paris Cité, EA2363 « Poumon & Hypoxie », U.F.R. SMBH, and AP-HP, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France
| | - Florence Canoui-Poitrine
- Université Paris Est, Faculté de Médecine, EA 4393, Laboratoire d'Investigation Clinique, and AP-HP, Groupe Henri Mondor-Albert Chenevier, Service de Santé Publique, Créteil, France
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158
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Bärtsch P. Con: Hypoxic Cardiopulmonary Exercise Testing Identifies Subjects at Risk for Severe High Altitude Illnesses. High Alt Med Biol 2014; 15:318-20. [DOI: 10.1089/ham.2013.1145] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Peter Bärtsch
- University Clinic, Department of Internal Medicine, Division VII Sports Medicine, Heidelberg, Germany
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159
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de Mol P, de Vries ST, de Koning EJP, Gans ROB, Bilo HJG, Tack CJ. Physical activity at altitude: challenges for people with diabetes: a review. Diabetes Care 2014; 37:2404-13. [PMID: 25061142 DOI: 10.2337/dc13-2302] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND A growing number of subjects with diabetes take part in physical activities at altitude such as skiing, climbing, and trekking. Exercise under conditions of hypobaric hypoxia poses some unique challenges on subjects with diabetes, and the presence of diabetes can complicate safe and successful participation in mountain activities. Among others, altitude can alter glucoregulation. Furthermore, cold temperatures and altitude can complicate accurate reading of glucose monitoring equipment and storage of insulin. These factors potentially lead to dangerous hyperglycemia or hypoglycemia. Over the last years, more information has become available on this subject. PURPOSE To provide an up-to-date overview of the pathophysiological changes during physical activity at altitude and the potential problems related to diabetes, including the use of (continuous) blood glucose monitors and insulin pumps. To propose practical recommendations for preparations and travel to altitude for subjects with diabetes. DATA SOURCES AND SYNTHESIS We researched PubMed, medical textbooks, and related Internet sites, and extracted human studies and data based on relevance for diabetes, exercise, and altitude. LIMITATIONS Given the paucity of controlled trials regarding diabetes and altitude, we composed a narrative review and filled in areas lacking diabetes-specific studies with data obtained from nondiabetic subjects. CONCLUSIONS Subjects with diabetes can take part in activities at high, and even extreme, altitude. However, careful assessment of diabetes-related complications, optimal preparation, and adequate knowledge of glycemic regulation at altitude and altitude-related complications is needed.
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Affiliation(s)
- Pieter de Mol
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Suzanna T de Vries
- Department of Cardiology, Tjongerschans Hospital, Heerenveen, the Netherlands
| | - Eelco J P de Koning
- Department of Endocrinology, Leiden University Medical Centre, Leiden, the NetherlandsDepartment of Nephrology, Leiden University Medical Centre, Leiden, the Netherlands
| | - Reinold O B Gans
- Department of Internal Medicine, University Medical Centre Groningen, Groningen, the Netherlands
| | - Henk J G Bilo
- Department of Internal Medicine, University Medical Centre Groningen, Groningen, the NetherlandsDepartment of Internal Medicine, Isala Clinics, Zwolle, the Netherlands
| | - Cees J Tack
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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160
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Risk prediction score for severe high altitude illness: a cohort study. PLoS One 2014; 9:e100642. [PMID: 25068815 PMCID: PMC4113313 DOI: 10.1371/journal.pone.0100642] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 05/28/2014] [Indexed: 11/19/2022] Open
Abstract
Background Risk prediction of acute mountain sickness, high altitude (HA) pulmonary or cerebral edema is currently based on clinical assessment. Our objective was to develop a risk prediction score of Severe High Altitude Illness (SHAI) combining clinical and physiological factors. Study population was 1017 sea-level subjects who performed a hypoxia exercise test before a stay at HA. The outcome was the occurrence of SHAI during HA exposure. Two scores were built, according to the presence (PRE, n = 537) or absence (ABS, n = 480) of previous experience at HA, using multivariate logistic regression. Calibration was evaluated by Hosmer-Lemeshow chisquare test and discrimination by Area Under ROC Curve (AUC) and Net Reclassification Index (NRI). Results The score was a linear combination of history of SHAI, ventilatory and cardiac response to hypoxia at exercise, speed of ascent, desaturation during hypoxic exercise, history of migraine, geographical location, female sex, age under 46 and regular physical activity. In the PRE/ABS groups, the score ranged from 0 to 12/10, a cut-off of 5/5.5 gave a sensitivity of 87%/87% and a specificity of 82%/73%. Adding physiological variables via the hypoxic exercise test improved the discrimination ability of the models: AUC increased by 7% to 0.91 (95%CI: 0.87–0.93) and 17% to 0.89 (95%CI: 0.85–0.91), NRI was 30% and 54% in the PRE and ABS groups respectively. A score computed with ten clinical, environmental and physiological factors accurately predicted the risk of SHAI in a large cohort of sea-level residents visiting HA regions.
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161
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Song P, Zhang JH, Qin J, Gao XB, Yu J, Tang XG, Tang CF, Huang L. Smoking is associated with the incidence of AMS: a large-sample cohort study. Mil Med Res 2014; 1:16. [PMID: 25722873 PMCID: PMC4340342 DOI: 10.1186/2054-9369-1-16] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2014] [Accepted: 07/17/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In recent years, the number of people visiting high altitudes has increased. After rapidly ascending to a high altitude, some of these individuals, who reside on plains or other areas of low altitude, have suffered from acute mountain sickness (AMS). Smoking interferes with the body's oxygen metabolism, but research about the relationship between smoking and AMS has yielded controversial results. METHODS We collected demographic data, conducted a smoking history and performed physical examinations on 2000 potential study participants, at sea level. Blood pressure (BP) and pulse oxygen saturation (SpO2) were measured for only some of the patients due to time and manpower limitations. We ultimately recruited 520 smokers and 450 nonsmokers according to the inclusion and exclusion criteria of our study. Following acute high-altitude exposure, we examined their Lake Louise Symptom (LLS) scores, BP, HR and SpO2; however, cerebral blood flow (CBF) was measured for only some of the subjects due to limited time, manpower and equipment. RESULTS Both the incidence of AMS and Lake Louise Symptom (LLS) scores were lower in smokers than in nonsmokers. Comparing AMS-related symptoms between nonsmokers and smokers, the incidence and severity of headaches and the incidence of sleep difficulties were lower in smokers than in nonsmokers. The incidences of both cough and mental status change were higher in smokers than in nonsmokers; blood pressure, HR and cerebral blood flow velocity were lower in smokers than in nonsmokers. CONCLUSION Our findings suggest that the incidence of AMS is lower in the smoking group, possibly related to a retardation of cerebral blood flow and a relief of AMS-related symptoms, such as headache.
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Affiliation(s)
- Pan Song
- />Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
| | - Ji-hang Zhang
- />Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
| | - Jun Qin
- />Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
| | - Xu-bin Gao
- />Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
| | - Jie Yu
- />Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
| | - Xu-gang Tang
- />Institute of Internal Medicine-Neurology of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
| | - Cai-fa Tang
- />Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
| | - Lan Huang
- />Institute of Cardiovascular Diseases of PLA, Xinqiao Hospital, Third Military Medical University, Chongqing, 400037 People’s Republic of China
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162
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Vinnikov D, Brimkulov N, Krasotski V, Redding-Jones R, Blanc PD. Risk factors for occupational acute mountain sickness. Occup Med (Lond) 2014; 64:483-9. [DOI: 10.1093/occmed/kqu094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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163
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Abstract
High altitude headache (HAH) has been defined by the International Headache Society as a headache that appears within 24 hours after ascent to 2,500 m or higher [1••]. The headache can appear in isolation or as part of acute mountain sickness (AMS), which has more dramatic symptoms than the headache alone. If symptoms are ignored, more serious conditions such as high altitude cerebral edema (HACE), high altitude pulmonary edema (HAPE), or even death may ensue. While there is no definitive understanding of the underlying pathophysiologic mechanism, it is speculated that HAH occurs from the combination of hypoxemia-induced intracranial vasodilation and subsequent cerebral edema. There are a number of preventive measures that can be adopted prior to ascending, including acclimatization and various medications. A variety of pharmacological interventions are also available to clinicians to treat this extremely widespread condition.
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Affiliation(s)
- J Ivan Lopez
- University of Nevada School of Medicine, Reno, Nevada,
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164
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Subudhi AW, Bourdillon N, Bucher J, Davis C, Elliott JE, Eutermoster M, Evero O, Fan JL, Houten SJV, Julian CG, Kark J, Kark S, Kayser B, Kern JP, Kim SE, Lathan C, Laurie SS, Lovering AT, Paterson R, Polaner DM, Ryan BJ, Spira JL, Tsao JW, Wachsmuth NB, Roach RC. AltitudeOmics: the integrative physiology of human acclimatization to hypobaric hypoxia and its retention upon reascent. PLoS One 2014; 9:e92191. [PMID: 24658407 PMCID: PMC3962396 DOI: 10.1371/journal.pone.0092191] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 02/19/2014] [Indexed: 11/19/2022] Open
Abstract
An understanding of human responses to hypoxia is important for the health of millions of people worldwide who visit, live, or work in the hypoxic environment encountered at high altitudes. In spite of dozens of studies over the last 100 years, the basic mechanisms controlling acclimatization to hypoxia remain largely unknown. The AltitudeOmics project aimed to bridge this gap. Our goals were 1) to describe a phenotype for successful acclimatization and assess its retention and 2) use these findings as a foundation for companion mechanistic studies. Our approach was to characterize acclimatization by measuring changes in arterial oxygenation and hemoglobin concentration [Hb], acute mountain sickness (AMS), cognitive function, and exercise performance in 21 subjects as they acclimatized to 5260 m over 16 days. We then focused on the retention of acclimatization by having subjects reascend to 5260 m after either 7 (n = 14) or 21 (n = 7) days at 1525 m. At 16 days at 5260 m we observed: 1) increases in arterial oxygenation and [Hb] (compared to acute hypoxia: PaO2 rose 9±4 mmHg to 45±4 while PaCO2 dropped a further 6±3 mmHg to 21±3, and [Hb] rose 1.8±0.7 g/dL to 16±2 g/dL; 2) no AMS; 3) improved cognitive function; and 4) improved exercise performance by 8±8% (all changes p<0.01). Upon reascent, we observed retention of arterial oxygenation but not [Hb], protection from AMS, retention of exercise performance, less retention of cognitive function; and noted that some of these effects lasted for 21 days. Taken together, these findings reveal new information about retention of acclimatization, and can be used as a physiological foundation to explore the molecular mechanisms of acclimatization and its retention.
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Affiliation(s)
- Andrew W. Subudhi
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado, United States of America
| | - Nicolas Bourdillon
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Jenna Bucher
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Christopher Davis
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jonathan E. Elliott
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Morgan Eutermoster
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Oghenero Evero
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jui-Lin Fan
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Lemanic Doctoral School of Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Sonja Jameson-Van Houten
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Colleen G. Julian
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jonathan Kark
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Sherri Kark
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Bengt Kayser
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Julia P. Kern
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - See Eun Kim
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Corinna Lathan
- AnthroTronix, Inc., Silver Spring, Maryland, United States of America
| | - Steven S. Laurie
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Andrew T. Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Ryan Paterson
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - David M. Polaner
- Departments of Anesthesiology and Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America
| | - Benjamin J. Ryan
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - James L. Spira
- United States Department of Veterans Affairs, National Center for PTSD, Pacific Islands Health Care System, and Department of Psychiatry, University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii, United States of America
| | - Jack W. Tsao
- Wounded, Ill & Injured Directorate (M9), United States Navy Bureau of Medicine and Surgery, Falls Church, Virginia, United States of America
| | - Nadine B. Wachsmuth
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Robert C. Roach
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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165
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Responses to exercise in normobaric hypoxia: comparison of elite and recreational ski mountaineers. Int J Sports Physiol Perform 2014; 9:978-84. [PMID: 24664934 DOI: 10.1123/ijspp.2013-0524] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
PURPOSE Hypoxia is known to reduce maximal oxygen uptake (VO(2max)) more in trained than in untrained subjects in several lowland sports. Ski mountaineering is practiced mainly at altitude, so elite ski mountaineers spend significantly longer training duration at altitude than their lower-level counterparts. Since acclimatization in hypobaric hypoxia is effective, the authors hypothesized that elite ski mountaineers would exhibit a VO2max decrement in hypoxia similar to that of recreational ski mountaineers. METHODS Eleven elite (E, Swiss national team) and 12 recreational (R) ski mountaineers completed an incremental treadmill test to exhaustion in normobaric hypoxia (H, 3000 m, F(1)O(2) 14.6% ± 0.1%) and in normoxia (N, 485 m, F(1)O(2) 20.9% ± 0.0%). Pulse oxygen saturation in blood (SpO(2)), VO(2max), minute ventilation, and heart rate were recorded. RESULTS At rest, hypoxic ventilatory response was higher (P < .05) in E than in R (1.4 ± 1.9 vs 0.3 ± 0.6 L · min⁻¹ · kg⁻¹). At maximal intensity, SpO(2) was significantly lower (P < .01) in E than in R, both in N (91.1% ± 3.3% vs 94.3% ± 2.3%) and in H (76.4% ± 5.4% vs 82.3% ± 3.5%). In both groups, SpO(2) was lower (P < .01) in H. Between N and H, VO(2max) decreased to a greater extent (P < .05) in E than in R (-18% and -12%, P < .01). In E only, the VO(2max) decrement was significantly correlated with the SpO(2) decrement (r = .74, P < .01) but also with VO(2max) measured in N (r = .64, P < .05). CONCLUSION Despite a probable better acclimatization to altitude, VO(2max) was more reduced in E than in R ski mountaineers, confirming previous results observed in lowlander E athletes.
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MacInnis MJ, Koch S, MacLeod KE, Carter EA, Jain R, Koehle MS, Rupert JL. Acute mountain sickness is not repeatable across two 12-hour normobaric hypoxia exposures. Wilderness Environ Med 2014; 25:143-51. [PMID: 24631230 DOI: 10.1016/j.wem.2013.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 10/11/2013] [Accepted: 11/21/2013] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The purposes of this experiment were to determine the repeatability of acute mountain sickness (AMS), AMS symptoms, and physiological responses across 2 identical hypoxic exposures. METHODS Subjects (n = 25) spent 3 nights at simulated altitude in a normobaric hypoxia chamber: twice at a partial pressure of inspired oxygen (PIO2) of 90mmHg (4000 m equivalent; "hypoxia") and once at a PIO2 of 132 mmHg (1000 m equivalent; "sham") with 14 or more days between exposures. The following variables were measured at hours 0 and 12 of each exposure: AMS severity (ie, Lake Louise score [LLS]), AMS incidence (LLS ≥3), heart rate, oxygen saturation, blood pressure, and the fraction of exhaled nitric oxide. Oxygen saturation and heart rate were also measured while subjects slept. RESULTS The incidence of AMS was not statistically different between the 2 exposures (84% vs 56%, P > .05), but the severity of AMS (ie, LLS) was significantly lower on the second hypoxic exposure (mean [SD], 3.1 [1.8]) relative to the first hypoxic exposure (4.8 [2.3]; P < .001). Headache was the only AMS symptom to have a significantly greater severity on both hypoxic exposures (relative to the sham exposure, P < .05). Physiological variables were moderately to strongly repeatable (intraclass correlation range 0.39 to 0.86) but were not associated with AMS susceptibility (P > .05). CONCLUSIONS The LLS was not repeatable across 2 identical hypoxic exposures. Increased familiarity with the environment (not acclimation) could explain the reduced AMS severity on the second hypoxic exposure. Headache was the most reliable AMS symptom.
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Affiliation(s)
- Martin J MacInnis
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Sarah Koch
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kristin E MacLeod
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric A Carter
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Radha Jain
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael S Koehle
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jim L Rupert
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
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Kriemler S, Bürgi F, Wick C, Wick B, Keller M, Wiget U, Schindler C, Kaufmann BA, Kohler M, Bloch K, Brunner-La Rocca HP. Prevalence of Acute Mountain Sickness at 3500 m Within and Between Families: A Prospective Cohort Study. High Alt Med Biol 2014; 15:28-38. [DOI: 10.1089/ham.2013.1073] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Susi Kriemler
- Institute of Social and Preventive Medicine, University of Zürich, Zurich, Switzerland
| | - Flavia Bürgi
- Institute of Social and Preventive Medicine, University of Zürich, Zurich, Switzerland
| | - Christian Wick
- Institute of Exercise and Health Sciences, University of Basel, Basel, Switzerland
| | - Birgit Wick
- Institute of Exercise and Health Sciences, University of Basel, Basel, Switzerland
| | - Melanie Keller
- Institute of Exercise and Health Sciences, University of Basel, Basel, Switzerland
| | - Urs Wiget
- Swiss Society for Emergency Medicine, Bern, Switzerland
| | - Christian Schindler
- Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland
| | - Beat A. Kaufmann
- Division of Cardiology, University Hospital Basel, Basel, Switzerland
| | - Malcolm Kohler
- Pulmonary Division, University Hospital Zürich, Zurich, Switzerland
| | - Konrad Bloch
- Pulmonary Division, University Hospital Zürich, Zurich, Switzerland
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Cerebral oxygenation during the Richalet hypoxia sensitivity test and cycling time-trial performance in severe hypoxia. Eur J Appl Physiol 2014; 114:1037-48. [DOI: 10.1007/s00421-014-2835-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Accepted: 01/25/2014] [Indexed: 02/03/2023]
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Faulhaber M, Wille M, Gatterer H, Heinrich D, Burtscher M. Resting arterial oxygen saturation and breathing frequency as predictors for acute mountain sickness development: a prospective cohort study. Sleep Breath 2014; 18:669-74. [PMID: 24436093 DOI: 10.1007/s11325-013-0932-2] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Revised: 11/25/2013] [Accepted: 12/18/2013] [Indexed: 11/28/2022]
Abstract
INTRODUCTION The study evaluated the predictive value of arterial oxygen saturation (SaO2) after 30-min hypoxic exposure on subsequent development of acute mountain sickness (AMS) and tested if additional resting cardio-respiratory measurements improve AMS prognosis. METHODS Fifty-five persons were exposed to a simulated altitude of 4,500 m (normobaric hypoxia, FiO2 = 12.5%). Cardio-respiratory parameters, SaO2, blood lactate, and blood pressure were measured after 30 min of exposure. AMS symptoms were recorded after 3, 6, 9, and 12 h (Lake-Louise Score). Three models, based on previously published regression equations for altitude-dependent SaO2 values of AMS-susceptible (SaO2-suscept = 98.34 - 2.72 ∗ alt - 0.35 ∗ alt(2)) and AMS-resistant (SaO2-resist = 96.51 + 0.68 ∗ alt - 0.80 ∗ alt(2)) persons, were applied to predict AMS. Additionally, multivariate logistic regression analyses were conducted to test if additional resting measurements improve AMS prediction. RESULTS The three models correctly predicted AMS development in 62%, 67%, and 69% of the cases. No model showed combined sensitivity and specificity >80%. Sequential logistic regression revealed that the inclusion of tidal volume or breathing frequency in addition to SaO2 improved overall AMS prediction, resulting in 78% and 80% correct AMS prediction, respectively. CONCLUSION Non-invasive measurements of SaO2 after 30-min hypoxic exposure are easy to perform and have the potential to detect AMS-susceptible individuals with a sufficient sensitivity. The additional determination of breathing frequency can improve success in AMS prediction.
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Affiliation(s)
- Martin Faulhaber
- Department of Sport Science, University Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria,
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170
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Zafren K. Prevention of high altitude illness. Travel Med Infect Dis 2014; 12:29-39. [DOI: 10.1016/j.tmaid.2013.12.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 12/05/2013] [Accepted: 12/10/2013] [Indexed: 11/28/2022]
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Nespoulet H, Rupp T, Bachasson D, Tamisier R, Wuyam B, Lévy P, Verges S. Positive expiratory pressure improves oxygenation in healthy subjects exposed to hypoxia. PLoS One 2013; 8:e85219. [PMID: 24376872 PMCID: PMC3871630 DOI: 10.1371/journal.pone.0085219] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 11/25/2013] [Indexed: 11/18/2022] Open
Abstract
Introduction Positive end-expiratory pressure (PEEP) is commonly used in critical care medicine to improve gas exchange. Altitude sickness is associated with exaggerated reduction in arterial oxygenation. We assessed the effect of PEEP and pursed lips breathing (PLB) on arterial and tissue oxygenation under normobaric and hypobaric hypoxic conditions. Methods Sixteen healthy volunteers were exposed to acute normobaric hypoxia (Laboratory study, FiO2=0.12). The protocol consisted in 3-min phases with PEEPs of 0, 5 or 10 cmH2O, PLB or similar ventilation than with PEEP-10, interspaced with 3-min phases of free breathing. Arterial (pulse oximetry) and quadriceps (near-infrared spectroscopy) oxygenation, ventilation, cardiac function, esophageal and gastric pressures and subjects’ subjective perceptions were recorded continuously. In addition, the effect of PEEP on arterial oxygenation was tested at 4,350 m of altitude in 9 volunteers breathing for 20 min with PEEP-10 (Field study). Results During the laboratory study, PEEP-10 increased arterial and quadriceps oxygenation (arterial oxygen saturation +5.6±5.0% and quadriceps oxyhemoglobin +58±73 µmol.cm compared to free breathing; p<0.05). Conversely, PLB did not increase oxygenation. Oxygenation improvement with PEEP-10 was accompanied by an increase in expiratory esophageal and gastric pressures (esophageal pressure swing +5.4±3.2 cmH2O, p<0.05) but no change in minute ventilation, breathing pattern, end-tidal CO2 or cardiac function (all p>0.05) compared to PEEP-0. During the field study, PEEP-10 increased arterial oxygen saturation by +6.7±6.0% after the 3rd minute with PEEP-10 without further significant increase until the 20th minute with PEEP-10. Subjects did not report any significant discomfort with PEEP. Conclusions These data indicate that 10-cmH2O PEEP significantly improves arterial and muscle oxygenation under both normobaric and hypobaric hypoxic conditions in healthy subjects. PEEP-10 could be an attractive non-pharmacological tool to limit blood oxygen desaturation and possibly symptoms at altitude.
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Affiliation(s)
- Hugo Nespoulet
- INSERM U1042, Grenoble, France
- University Grenoble Alpes, Hypoxia-Physiopathology Laboratory (HP2), Grenoble, France
| | - Thomas Rupp
- INSERM U1042, Grenoble, France
- University Grenoble Alpes, Hypoxia-Physiopathology Laboratory (HP2), Grenoble, France
| | - Damien Bachasson
- INSERM U1042, Grenoble, France
- University Grenoble Alpes, Hypoxia-Physiopathology Laboratory (HP2), Grenoble, France
| | - Renaud Tamisier
- INSERM U1042, Grenoble, France
- University Grenoble Alpes, Hypoxia-Physiopathology Laboratory (HP2), Grenoble, France
| | - Bernard Wuyam
- INSERM U1042, Grenoble, France
- University Grenoble Alpes, Hypoxia-Physiopathology Laboratory (HP2), Grenoble, France
| | - Patrick Lévy
- INSERM U1042, Grenoble, France
- University Grenoble Alpes, Hypoxia-Physiopathology Laboratory (HP2), Grenoble, France
| | - Samuel Verges
- INSERM U1042, Grenoble, France
- University Grenoble Alpes, Hypoxia-Physiopathology Laboratory (HP2), Grenoble, France
- * E-mail:
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MacInnis MJ, Lohse KR, Strong JK, Koehle MS. Is previous history a reliable predictor for acute mountain sickness susceptibility? A meta-analysis of diagnostic accuracy. Br J Sports Med 2013; 49:69-75. [DOI: 10.1136/bjsports-2013-092921] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Girard O, Amann M, Aughey R, Billaut F, Bishop DJ, Bourdon P, Buchheit M, Chapman R, D'Hooghe M, Garvican-Lewis LA, Gore CJ, Millet GP, Roach GD, Sargent C, Saunders PU, Schmidt W, Schumacher YO. Position statement--altitude training for improving team-sport players' performance: current knowledge and unresolved issues. Br J Sports Med 2013; 47 Suppl 1:i8-16. [PMID: 24282213 PMCID: PMC3903313 DOI: 10.1136/bjsports-2013-093109] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2013] [Indexed: 01/09/2023]
Abstract
Despite the limited research on the effects of altitude (or hypoxic) training interventions on team-sport performance, players from all around the world engaged in these sports are now using altitude training more than ever before. In March 2013, an Altitude Training and Team Sports conference was held in Doha, Qatar, to establish a forum of research and practical insights into this rapidly growing field. A round-table meeting in which the panellists engaged in focused discussions concluded this conference. This has resulted in the present position statement, designed to highlight some key issues raised during the debates and to integrate the ideas into a shared conceptual framework. The present signposting document has been developed for use by support teams (coaches, performance scientists, physicians, strength and conditioning staff) and other professionals who have an interest in the practical application of altitude training for team sports. After more than four decades of research, there is still no consensus on the optimal strategies to elicit the best results from altitude training in a team-sport population. However, there are some recommended strategies discussed in this position statement to adopt for improving the acclimatisation process when training/competing at altitude and for potentially enhancing sea-level performance. It is our hope that this information will be intriguing, balanced and, more importantly, stimulating to the point that it promotes constructive discussion and serves as a guide for future research aimed at advancing the bourgeoning body of knowledge in the area of altitude training for team sports.
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Affiliation(s)
- Olivier Girard
- Research and Education Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
| | - Markus Amann
- Department of Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Robert Aughey
- Exercise and Active Living, Institute of Sport, Victoria University, Melbourne, Australia
- Western Bulldogs Football Club, Melbourne, Australia
| | | | - David J Bishop
- Exercise and Active Living, Institute of Sport, Victoria University, Melbourne, Australia
| | | | | | - Robert Chapman
- Department of Kinesiology, Indiana University, High Performance Department, USA Track & Field, Indianapolis, Indiana, USA
| | - Michel D'Hooghe
- Fédération Internationale de Football Association (FIFA) Medical Commission and FIFA Medical Assessment and Research Centre (F-MARC), Langerei, 71, 8000 Brugge, Belgium
| | - Laura A Garvican-Lewis
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
- University of Canberra, Canberra, Australia
| | - Christopher J Gore
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
- Exercise Physiology Laboratory, Flinders University, Adelaide, Australia
| | - Grégoire P Millet
- Department of Physiology—Faculty of Biology and Medicine, ISSUL—Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Gregory D Roach
- Appleton Institute for Behavioural Science, Central Queensland University, Adelaide, Australia
| | - Charli Sargent
- Appleton Institute for Behavioural Science, Central Queensland University, Adelaide, Australia
| | - Philo U Saunders
- Department of Physiology, Australian Institute of Sport, Canberra, Australia
- University of Canberra, Canberra, Australia
| | - Walter Schmidt
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Yorck O Schumacher
- Research and Education Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar
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MacInnis MJ, Carter EA, Freeman MG, Pandit BP, Siwakoti A, Subedi A, Timalsina U, Widmer N, Thapa GB, Koehle MS, Rupert JL. A prospective epidemiological study of acute mountain sickness in Nepalese pilgrims ascending to high altitude (4380 m). PLoS One 2013; 8:e75644. [PMID: 24130729 PMCID: PMC3794000 DOI: 10.1371/journal.pone.0075644] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 08/16/2013] [Indexed: 01/14/2023] Open
Abstract
Background Each year, thousands of pilgrims travel to the Janai Purnima festival in Gosainkunda, Nepal (4380 m), ascending rapidly and often without the aid of pharmaceutical prophylaxis. Methods During the 2012 Janai Purnima festival, 538 subjects were recruited in Dhunche (1950 m) before ascending to Gosainkunda. Through interviews, subjects provided demographic information, ratings of AMS symptoms (Lake Louise Scores; LLS), ascent profiles, and strategies for prophylaxis. Results In the 491 subjects (91% follow-up rate) who were assessed upon arrival at Gosainkunda, the incidence of AMS was 34.0%. AMS was more common in females than in males (RR = 1.57; 95% CI = 1.23, 2.00), and the AMS incidence was greater in subjects >35 years compared to subjects ≤35 years (RR = 1.63; 95% CI = 1.36, 1.95). There was a greater incidence of AMS in subjects who chose to use garlic as a prophylactic compared to those who did not (RR = 1.69; 95% CI = 1.26, 2.28). Although the LLS of brothers had a moderate correlation (intraclass correlation = 0.40, p = 0.023), sibling AMS status was a weak predictor of AMS. Conclusions The incidence of AMS upon reaching 4380 m was 34% in a large population of Nepalese pilgrims. Sex, age, and ascent rate were significant factors in the development of AMS, and traditional Nepalese remedies were ineffective in the prevention of AMS.
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Affiliation(s)
- Martin J. MacInnis
- School of Kinesiology, University of British Columbia, Vancouver, Canada
- * E-mail:
| | - Eric A. Carter
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | | | - Bidur Prasad Pandit
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Ashmita Siwakoti
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Ankita Subedi
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Utsav Timalsina
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Nadia Widmer
- Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Ghan Bahadur Thapa
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Michael S. Koehle
- School of Kinesiology, University of British Columbia, Vancouver, Canada
- Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Jim L. Rupert
- School of Kinesiology, University of British Columbia, Vancouver, Canada
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Zhang X, Zhang W, Ma SF, Miasniakova G, Sergueeva A, Ammosova T, Xu M, Nekhai S, Nourai M, Wade MS, Prchal JT, Garcia JGN, Machado RF, Gordeuk VR. Iron deficiency modifies gene expression variation induced by augmented hypoxia sensing. Blood Cells Mol Dis 2013; 52:35-45. [PMID: 23993337 DOI: 10.1016/j.bcmd.2013.07.016] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Accepted: 07/19/2013] [Indexed: 01/20/2023]
Abstract
In congenital Chuvash polycythemia (CP), VHL(R200W) homozygosity leads to elevated hypoxia inducible factor (HIF) levels at normoxia. CP is often treated by phlebotomy resulting in iron deficiency, permitting us to examine the separate and synergistic effects of iron deficiency and HIF signaling on gene expression. We compared peripheral blood mononuclear cell gene expression profiles of eight VHL(R200W) homozygotes with 17 wildtype individuals with normal iron status and found 812 up-regulated and 2120 down-regulated genes at false discovery rate of 0.05. Among differential genes we identified three major gene regulation modules involving induction of innate immune responses, alteration of carbohydrate and lipid metabolism, and down-regulation of cell proliferation, stress-induced apoptosis and T-cell activation. These observations suggest molecular mechanisms for previous observations in CP of lower blood sugar without increased insulin and low oncogenic potential. Studies including 16 additional VHL(R200W) homozygotes with low ferritin indicated that iron deficiency enhanced the induction effect of VHL(R200W) for 50 genes including hemoglobin synthesis loci but suppressed the effect for 107 genes enriched for HIF-2 targets. This pattern is consistent with potentiation of HIF-1α protein stability by iron deficiency but a trend for down-regulation of HIF-2α translation by iron deficiency overriding an increase in HIF-2α protein stability.
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Affiliation(s)
- Xu Zhang
- Comprehensive Sickle Cell Center, Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Wei Zhang
- Department of Pediatrics, University of Illinois at Chicago, Chicago, IL, USA.,Institute of Human Genetics, University of Illinois at Chicago, Chicago, IL, USA
| | - Shwu-Fan Ma
- Section of Pulmonary/Critical Care, Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Galina Miasniakova
- Chuvash Republic Clinical Hospital 2, Cheboksary, Russian Federation, Howard University, Washington, DC
| | - Adelina Sergueeva
- Cheboksary Children's Hospital, Cheboksary, Russian Federation, Howard University, Washington, DC
| | - Tatiana Ammosova
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Min Xu
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Sergei Nekhai
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Mehdi Nourai
- Center for Sickle Cell Disease, Howard University, Washington, DC
| | - Michael S Wade
- Section of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.,Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Josef T Prchal
- Departments of Medicine, Pathology and Genetics, University of Utah and VAH
| | - Joe G N Garcia
- Section of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.,Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Roberto F Machado
- Section of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA.,Institute for Personalized Respiratory Medicine, University of Illinois at Chicago, Chicago, IL, USA
| | - Victor R Gordeuk
- Comprehensive Sickle Cell Center, Section of Hematology/Oncology, Department of Medicine, University of Illinois at Chicago, Chicago, IL, USA
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Kohli P, Sarmiento K, Malhotra A. Update in sleep medicine 2012. Am J Respir Crit Care Med 2013; 187:1056-60. [PMID: 23675714 DOI: 10.1164/rccm.201302-0315up] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Affiliation(s)
- Puja Kohli
- Division of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
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Netzer N, Strohl K, Faulhaber M, Gatterer H, Burtscher M. Hypoxia-related altitude illnesses. J Travel Med 2013; 20:247-55. [PMID: 23809076 DOI: 10.1111/jtm.12017] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Revised: 12/06/2012] [Accepted: 12/07/2012] [Indexed: 01/01/2023]
Abstract
BACKGROUND Millions of tourists and climbers visit high altitudes annually. Many unsuspecting and otherwise healthy individuals may get sick when sojourning to these high regions. Acute mountain sickness represents the most common illness, which is usually benign but can rapidly progress to the more severe and potentially fatal forms of high-altitude cerebral edema and high-altitude pulmonary edema. METHODS Data were identified by searches of Medline (1965 to May 2012) and references from relevant articles and books. Studies, reviews, and books specifically pertaining to the epidemiology, prevention, and treatment of high-altitude illnesses in travelers were selected. RESULTS This review provides information on geographical aspects, physiology/pathophysiology, clinical features, risk factors, and the prevalence of high-altitude illnesses and also state-of-the art recommendations for prevention and treatment of such illnesses. CONCLUSION Given an increasing number of recreational activities at high and extreme altitudes, the general practitioner and specialist are in higher demand for medical recommendations regarding the prevention and treatment of altitude illness. Despite an ongoing scientific discussion and controversies about the pathophysiological causes of altitude illness, treatment and prevention recommendations are clearer with increased experience over the last two decades.
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Affiliation(s)
- Nikolaus Netzer
- Department of Internal Medicine, University of Ulm, Ulm, Germany
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Abstract
A 45-year-old healthy man wishes to climb Mount Kilimanjaro (5895 m) in a 5-day period, starting at 1800 m. The results of a recent exercise stress test were normal; he runs 10 km 4 or 5 times per week and finished a marathon in less than 4 hours last year. He wants to know how he can prevent becoming ill at high altitude and whether training or sleeping under normobaric hypoxic conditions in the weeks before the ascent would be helpful. What would you advise?
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Affiliation(s)
- Peter Bärtsch
- University Clinic, Department of Internal Medicine, Division VII Sports Medicine, Heidelberg, Germany.
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Oxygen therapy in critical illness: precise control of arterial oxygenation and permissive hypoxemia. Crit Care Med 2013; 41:423-32. [PMID: 23263574 DOI: 10.1097/ccm.0b013e31826a44f6] [Citation(s) in RCA: 129] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
OBJECTIVE The management of hypoxemia in critically ill patients is challenging. Whilst the harms of tissue hypoxia are well recognized, the possibility of harm from excess oxygen administration, or other interventions targeted at mitigating hypoxemia, may be inadequately appreciated. The benefits of attempting to fully reverse arterial hypoxemia may be outweighed by the harms associated with high concentrations of supplemental oxygen and invasive mechanical ventilation strategies. We propose two novel related strategies for the management of hypoxemia in critically ill patients. First, we describe precise control of arterial oxygenation involving the specific targeting of arterial partial pressure of oxygen or arterial hemoglobin oxygen saturation to individualized target values, with the avoidance of significant variation from these levels. The aim of precise control of arterial oxygenation is to avoid the harms associated with inadvertent hyperoxia or hypoxia through careful and precise control of arterial oxygen levels. Secondly, we describe permissive hypoxemia: the acceptance of levels of arterial oxygenation lower than is conventionally tolerated in patients. The aim of permissive hypoxemia is to minimize the possible harms caused by restoration of normoxemia while avoiding tissue hypoxia. This review sets out to discuss the strengths and limitations of precise control of arterial oxygenation and permissive hypoxemia as candidate management strategies in hypoxemic critically ill patients. DESIGN We searched PubMed for references to "permissive hypoxemia/hypoxaemia" and "precise control of arterial oxygenation" as well as reference to "profound hypoxemia/hypoxaemia/hypoxia," "severe hypoxemia/hypoxaemia/hypoxia." We searched personal reference libraries in the areas of critical illness and high altitude physiology and medicine. We also identified large clinical studies in patients with critical illness characterized by hypoxemia such as acute respiratory distress syndrome. SUBJECTS Studies were selected that explored the physiology of hypoxemia in healthy volunteers or critically ill patients. SETTING The data were subjectively assessed and combined to generate the narrative. RESULTS Inadequate tissue oxygenation and excessive oxygen administration can be detrimental to outcome but safety thresholds lack definition in critically ill patients. Precise control of arterial oxygenation provides a rational approach to the management of arterial oxygenation that reflects recent clinical developments in other settings. Permissive hypoxemia is a concept that is untested clinically and requires robust investigation prior to consideration of implementation. Both strategies will require accurate monitoring of oxygen administration and arterial oxygenation. Effective, reliable measurement of tissue oxygenation along with the use of selected biomarkers to identify suitable candidates and monitor harm will aid the development of permissive hypoxemia as viable clinical strategy. CONCLUSIONS Implementation of precise control of arterial oxygenation may avoid the harms associated with excessive and inadequate oxygenation. However, at present there is no direct evidence to support the immediate implementation of permissive hypoxemia and a comprehensive evaluation of its value in critically ill patients should be a high research priority.
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Luks AM. Clinician's corner: What do we know about safe ascent rates at high altitude? High Alt Med Biol 2013; 13:147-52. [PMID: 22994513 DOI: 10.1089/ham.2012.1055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Although pharmacologic strategies are available for decreasing the risk of acute altitude illness, the best means of preventing these problems remains undertaking an adequately slow ascent. Guidelines regarding appropriate ascent rates have been published in various forums, and while these guidelines are generally similar to each other in regards to the recommended ascent rates and use of rest days, there is actually little evidence in the literature supporting the particular recommendations. The purpose of this review is to consider these guidelines and the issue of ascent rates in greater detail. Following a discussion of the evidence regarding ascent rates and acclimatization, the review considers several unanswered questions regarding the current guidelines, including the applicability of the guidelines for all altitude travelers, how best to determine the ascent rate, how to implement rest days, and whether pre-acclimatization strategies can be used to facilitate faster than recommended ascents. Given the current state of evidence, there is no reason to alter the current guidelines, as they likely work for the substantial majority of high altitude travelers. It is individuals traveling to high altitude for the first time for whom they remain most important, while those individuals with substantial prior experience at high altitude may opt for faster or slower ascent rates based on their prior experience. Rest days should remain a part of any ascent profile and should be used following any large gains in elevation rather than simply at specified time intervals. Pre-acclimatization strategies may decrease the risk of acute altitude illness but there is insufficient evidence to suggest they can be used to facilitate faster than recommended ascents. Further research may allow changes in practice in the future but for the time being, adherence to the current recommendations is the prudent approach for the majority of high altitude travelers.
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Affiliation(s)
- Andrew M Luks
- Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, Washington 98104, USA.
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Rupp T, Jubeau M, Millet GY, Perrey S, Esteve F, Wuyam B, Levy P, Verges S. The effect of hypoxemia and exercise on acute mountain sickness symptoms. J Appl Physiol (1985) 2012; 114:180-5. [PMID: 23154995 DOI: 10.1152/japplphysiol.00769.2012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Performing exercise during the first hours of hypoxic exposure is thought to exacerbate acute mountain sickness (AMS), but whether this is due to increased hypoxemia or other mechanisms associated with exercise remains unclear. In 12 healthy men, AMS symptoms were assessed during three 11-h experimental sessions: 1) in Hypoxia-exercise, inspiratory O(2) fraction (Fi(O(2))) was 0.12, and subjects performed 4-h cycling at 45% Fi(O(2))-specific maximal power output from the 4th to the 8th hour; 2) in Hypoxia-rest, Fi(O(2)) was continuously adjusted to match the same arterial oxygen saturation as in Hypoxia-exercise, and subjects remained at rest; and 3) in Normoxia-exercise, Fi(O(2)) was 0.21, and subjects cycled as in Hypoxia-exercise at 45% Fi(O(2))-specific maximal power output. AMS scores did not differ significantly between Hypoxia-exercise and Hypoxia-rest, while they were significantly lower in Normoxia-exercise (Lake Louise score: 5.5 ± 2.1, 4.4 ± 2.4, and 2.3 ± 1.5, and cerebral Environmental Symptom Questionnaire: 1.2 ± 0.7, 1.0 ± 1.0, and 0.3 ± 0.4, in Hypoxia-exercise, Hypoxia-rest, and Normoxia-exercise, respectively; P < 0.01). Headache scored by visual analog scale was higher in Hypoxia-exercise and Hypoxia-rest compared with Normoxia-exercise (36 ± 22, 35 ± 25, and 5 ± 6, P < 0.001), while the perception of fatigue was higher in Hypoxia-exercise compared with Hypoxia-rest (60 ± 24, 32 ± 22, and 46 ± 23, in Hypoxia-exercise, Hypoxia-rest, and Normoxia-exercise, respectively; P < 0.01). Despite significant physiological stress during hypoxic exercise and some AMS symptoms induced by normoxic cycling at similar relative workload, exercise does not significantly worsen AMS severity during the first hours of hypoxic exposure at a given arterial oxygen desaturation. Hypoxemia per se appears, therefore, to be the main mechanism underlying AMS, whether or not exercise is performed.
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Effects of a high-carbohydrate versus high-protein meal on acute responses to hypoxia at rest and exercise. Eur J Appl Physiol 2012; 113:691-702. [DOI: 10.1007/s00421-012-2472-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2012] [Accepted: 07/28/2012] [Indexed: 12/21/2022]
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184
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Lhuissier FJ, Canouï-Poitrine F, Richalet JP. Ageing and cardiorespiratory response to hypoxia. J Physiol 2012; 590:5461-74. [PMID: 22907053 DOI: 10.1113/jphysiol.2012.238527] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The risk of severe altitude-induced diseases is related to ventilatory and cardiac responses to hypoxia and is dependent on sex, age and exercise training status. However, it remains unclear how ageing modifies these physiological adaptations to hypoxia. We assessed the physiological responses to hypoxia with ageing through a cross-sectional 20 year study including 4675 subjects (2789 men, 1886 women; 14-85 years old) and a longitudinal study including 30 subjects explored at a mean 10.4 year interval. The influence of sex, training status and menopause was evaluated. The hypoxia-induced desaturation and the ventilatory and cardiac responses to hypoxia at rest and exercise were measured. In men, ventilatory response to hypoxia increased (P < 0.002), while desaturation was less pronounced (P < 0.001) with ageing. Cardiac response to hypoxia was blunted with ageing in both sexes (P < 0.001). Similar results were found in the longitudinal study, with a decrease in cardiac and an increase in ventilatory response to hypoxia with ageing. These adaptive responses were less pronounced or absent in post-menopausal women (P < 0.01). At exercise, desaturation was greater in trained subjects but cardiac and ventilatory responses to hypoxia were preserved by training, especially in elderly people. In conclusion, respiratory response to hypoxia and blood oxygenation improve with ageing in men while cardiac response is blunted with ageing in both sexes. Training aggravates desaturation at exercise in hypoxia, improves the ventilatory response and limits the ageing-induced blunting of cardiac response to hypoxia. Training limits the negative effects of menopause in cardiorespiratory adaptations to hypoxia.
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Affiliation(s)
- François J Lhuissier
- University of Paris 13, Sorbonne Paris Cit´e, EA2363 ‘Réponses cellulaires et fonctionnelles àl'hypoxie', Bobigny, France
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Abstract
A stay at high altitude exposes an individual to various environmental changes (cold, exercise, isolation) but the most stressful for the body is hypoxia. However, the cardiovascular system yields some efficient mechanisms of acclimatization to oxygen lack. Hypoxia activates the adrenergic system and induces a tachycardia that decreases during a prolonged stay at altitude. The desensitization of the adrenergic system leads to a decrease in maximal heart rate and a protection of the myocardium against an energy disequilibrium that could be potentially harmful for the heart. Hypoxia induces a peripheral vasodilation and a pulmonary vasoconstriction, leading to few changes in systemic blood pressure and an increase in pulmonary blood pressure (PHT) that can contribute to a high altitude pulmonary edema. Advice to a cardiac patient who plans to go to high altitude should take into account that all diseases aggravated by increased adrenergic activity or associated with a PHT or a hypoxemia (right-to-left shunt) will be aggravated at high altitude. As altitude increases, a patient with a coronary disease will present an ischemic threshold for a lower power output during an EKG exercise test. The only test allowing predicting the tolerance to high altitude is the hypoxia exercise test realized at 30% of maxVO(2)and at an equivalent altitude of 4,800m.
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Affiliation(s)
- Jean-Paul Richalet
- AP-HP, hôpital Avicenne, service de physiologie, explorations fonctionnelles et médecine du sport, Bobigny cedex, 93009 France.
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Sightings edited by John W. Severinghaus. High Alt Med Biol 2012. [DOI: 10.1089/ham.2012.1312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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