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Rodríguez-Zamora L, Benavente C, Petrer I, Padial P, Timón R, Arguelles J, Feriche B. Hypoxia matters: comparison of external and internal training load markers during an 8-week resistance training program in normoxia, normobaric hypoxia and hypobaric hypoxia. Eur J Appl Physiol 2024; 124:2273-2283. [PMID: 38446192 PMCID: PMC11322269 DOI: 10.1007/s00421-024-05442-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 02/14/2024] [Indexed: 03/07/2024]
Abstract
PURPOSE To compare external and internal training load markers during resistance training (RT) in normoxia (N), intermittent hypobaric hypoxia (HH), and intermittent normobaric hypoxia (NH). METHODS Thirty-three volunteers were assigned an 8-week RT program in either N (690 m, n = 10), HH (2320 m, n = 10), or NH (inspired fraction of oxygen = 15.9%; ~ 2320 m, n = 13). The RT program (3x/week) consisted of six exercises, with three sets of six to 12 repetitions at ~ 70% of one repetition maximum (1RM) with the first session of each week used for analysis. 1RM in back squat and bench press was used to evaluate muscle strength before and after the program. External load was assessed by the volume load relative to body mass (RVL, kg·kg-1). Internal load was assessed by the ratings of perceived exertion (RPE) and heart rate (HR). RESULTS Smaller relative improvements were found for the back squat in the N group (11.5 ± 8.8%) when compared to the NH group (22.2 ± 8.2%, P = 0.01) and the HH group (22 ± 8.1%, P = 0.02). All groups showed similar RVL, HR responses and RPE across the program (P˃0.05). However, reduced HR recovery values, calculated as the difference between the highest HR value (HRpeak) and the resting heart rate after a two min rest, were seen in the N and NH groups across the program (P < 0.05). CONCLUSION It seems that 8 weeks of intermittent RT in hypoxic environments could maximize time-efficiency when aiming to improve strength levels in back squat without evoking higher levels of physiological stress. Performing RT at hypobaric hypoxia may improve the cardiorespiratory response, which in turn could speed recovery.
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Affiliation(s)
- Lara Rodríguez-Zamora
- School of Health and Medical Sciences, Division of Sport Sciences, Örebro University, Örebro, Sweden.
| | - Cristina Benavente
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Irene Petrer
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Paulino Padial
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
| | - Rafa Timón
- Faculty of Sport Sciences, University of Extremadura, Cáceres, Spain
| | - Javier Arguelles
- High Performance Center of Sierra Nevada, Spanish Sport Council, Granada, Spain
| | - Belén Feriche
- Department of Physical Education and Sport, Faculty of Sport Sciences, University of Granada, Granada, Spain
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Liu Z, Yang J, Yang B, Sun M, Ye X, Yu S, Tan H, Hu M, Lv H, Wu B, Gao X, Huang L. Effect of ubiquinol on electrophysiology during high-altitude acclimatization and de-acclimatization: A substudy of the Shigatse CARdiorespiratory fitness (SCARF) randomized clinical trial. Int J Cardiol 2024; 401:131817. [PMID: 38307422 DOI: 10.1016/j.ijcard.2024.131817] [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: 11/09/2023] [Revised: 01/26/2024] [Accepted: 01/28/2024] [Indexed: 02/04/2024]
Abstract
BACKGROUND High-altitude exposure changes the electrical conduction of the heart. However, reports on electrocardiogram (ECG) characteristics and potent prophylactic agents during high-altitude acclimatization and de-acclimatization are inadequate. This study aimed to investigate the effects of ubiquinol on electrophysiology after high-altitude hypoxia and reoxygenation. METHODS The study was a prospective, randomized, double-blind, placebo-controlled trial. Forty-one participants were randomly divided into two groups receiving ubiquinol 200 mg daily or placebo orally 14 days before flying to high altitude (3900 m) until the end of the study. Cardiopulmonary exercise testing was performed at baseline (300 m), on the third day after reaching high altitude, and on the seventh day after returning to baseline. RESULTS Acute high-altitude exposure prolonged resting ventricular repolarization, represented by increased corrected QT interval (455.9 ± 23.4 vs. 427.1 ± 19.1 ms, P < 0.001) and corrected Tpeak-Tend interval (155.5 ± 27.4 vs. 125.3 ± 21.1 ms, P < 0.001), which recovered after returning to low altitude. Ubiquinol supplementation shortened the hypoxia-induced extended Tpeak-Tend interval (-7.7 ms, [95% confidence interval (CI), -13.8 to -1.6], P = 0.014), Tpeak-Tend /QT interval (-0.014 [95% CI, -0.027 to -0.002], P = 0.028), and reserved maximal heart rate (11.9 bpm [95% CI, 3.2 to 20.6], P = 0.013) during exercise at high altitude. Furthermore, the decreased resting amplitude of the ST-segment in the V3 lead was correlated with decreased peak oxygen pulse (R = 0.713, P < 0.001) and maximum oxygen consumption (R = 0.595, P < 0.001). CONCLUSIONS Our results illustrated the electrophysiology changes during high-altitude acclimatization and de-acclimatization. Similarly, ubiquinol supplementation shortened the prolonged Tpeak-Tend interval and reserved maximal heart rate during exercise at high altitude. REGISTRATION URL: www.chictr.org.cn; Unique identifier: ChiCTR2200059900.
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Affiliation(s)
- Zhen Liu
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Jie Yang
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Bingjie Yang
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Mengjia Sun
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Xiaowei Ye
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Shiyong Yu
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Hu Tan
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Mingdong Hu
- Department of Physical Examination, the Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Hailin Lv
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Boji Wu
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Xubin Gao
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China
| | - Lan Huang
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China; Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, PR China.
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Callovini A, Fornasiero A, Savoldelli A, Decet M, Skafidas S, Pellegrini B, Bortolan L, Schena F. Independent, additive and interactive effects of acute normobaric hypoxia and cold on submaximal and maximal endurance exercise. Eur J Appl Physiol 2024; 124:1185-1200. [PMID: 37962573 PMCID: PMC10955012 DOI: 10.1007/s00421-023-05343-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 10/16/2023] [Indexed: 11/15/2023]
Abstract
PURPOSE To evaluate the independent and combined effects of hypoxia (FiO2 = 13.5%) and cold (- 20 °C) on physiological and perceptual responses to endurance exercise. METHODS 14 trained male subjects ( V . O2max: 64 ± 5 mL/kg/min) randomly performed a discontinuous maximal incremental test to exhaustion on a motorized treadmill under four environmental conditions: Normothermic-Normoxia (N), Normothermic-Hypoxia (H), Cold-Normoxia (C) and Cold-Hypoxia (CH). Performance and physiological and perceptual responses throughout exercise were evaluated. RESULTS Maximal WorkLoad (WL) and WL at lactate threshold (LT) were reduced in C (- 2.3% and - 3.5%) and H (- 18.0% and - 21.7%) compared to N, with no interactive (p = 0.25 and 0.81) but additive effect in CH (- 21.5% and - 24.6%). Similarly, HRmax and Vemax were reduced in C (- 3.2% and - 14.6%) and H (- 5.0% and - 7%), showing additive effects in CH (- 7.7% and - 16.6%). At LT, additive effect of C (- 2.8%) and H (- 3.8%) on HR reduction in CH (- 5.7%) was maintained, whereas an interactive effect (p = 0.007) of the two stressors combined was noted on Ve (C: - 3.1%, H: + 5.5%, CH: - 10.9%). [La] curve shifted on the left in CH, displaying an interaction effect between the 2 stressors on this parameter. Finally, RPE at LT was exclusively reduced by hypoxia (p < 0.001), whereas TSmax is synergistically reduced by cold and hypoxia (interaction p = 0.047). CONCLUSION If compared to single stress exposure, exercise performance and physiological and perceptual variables undergo additive or synergistic effects when cold and hypoxia are combined. These results provide new insight into human physiological responses to extreme environments.
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Affiliation(s)
- A Callovini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy.
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - A Fornasiero
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - A Savoldelli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy
| | - M Decet
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - S Skafidas
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
| | - B Pellegrini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - L Bortolan
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - F Schena
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Guo Y, Liu X, Zhang Q, Shi Z, Zhang M, Chen J. Can acute high-altitude sickness be predicted in advance? REVIEWS ON ENVIRONMENTAL HEALTH 2024; 39:27-36. [PMID: 36165715 DOI: 10.1515/reveh-2022-0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
In high-altitude environments, the oxygen and air density are decreased, and the temperature and humidity are low. When individuals enter high-altitude areas, they are prone to suffering from acute mountain sickness (AMS) because they cannot tolerate hypoxia. Headache, fatigue, dizziness, and gastrointestinal reactions are the main symptoms of AMS. When these symptoms cannot be effectively alleviated, they can progress to life-threatening high-altitude pulmonary edema or high-altitude cerebral edema. If the risk of AMS can be effectively assessed before people enter high-altitude areas, then the high-risk population can be promptly discouraged from entering the area, or drug intervention can be established in advance to prevent AMS occurrence and avoid serious outcomes. This article reviews recent studies related to the early-warning biological indicators of AMS to provide a new perspective on the prevention of AMS.
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Affiliation(s)
- Yan Guo
- Medical College of Soochow University, Suzhou, Jiangsu Province, China
- Department of Pathology, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
| | - Xiao Liu
- Department of Basic Medical Sciences, The 960th Hospital of PLA, Jinan, Shandong Province, China
| | - Qiang Zhang
- Department of Neurosurgery, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
| | - Zhongshan Shi
- Department of Intensive Care Medicine, Ge er mu People's Hospital, Ge er mu, Qinghai Province, China
| | - Menglan Zhang
- Department of Pathology, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
| | - Jie Chen
- Department of Pathology, Qinghai Provincial People's Hospital, Xining, Qinghai Province, China
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Richalet JP, Hermand E, Lhuissier FJ. Cardiovascular physiology and pathophysiology at high altitude. Nat Rev Cardiol 2024; 21:75-88. [PMID: 37783743 DOI: 10.1038/s41569-023-00924-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/16/2023] [Indexed: 10/04/2023]
Abstract
Oxygen is vital for cellular metabolism; therefore, the hypoxic conditions encountered at high altitude affect all physiological functions. Acute hypoxia activates the adrenergic system and induces tachycardia, whereas hypoxic pulmonary vasoconstriction increases pulmonary artery pressure. After a few days of exposure to low oxygen concentrations, the autonomic nervous system adapts and tachycardia decreases, thereby protecting the myocardium against high energy consumption. Permanent exposure to high altitude induces erythropoiesis, which if excessive can be deleterious and lead to chronic mountain sickness, often associated with pulmonary hypertension and heart failure. Genetic factors might account for the variable prevalence of chronic mountain sickness, depending on the population and geographical region. Cardiovascular adaptations to hypoxia provide a remarkable model of the regulation of oxygen availability at the cellular and systemic levels. Rapid exposure to high altitude can have adverse effects in patients with cardiovascular diseases. However, intermittent, moderate hypoxia might be useful in the management of some cardiovascular disorders, such as coronary heart disease and heart failure. The aim of this Review is to help physicians to understand the cardiovascular responses to hypoxia and to outline some recommendations that they can give to patients with cardiovascular disease who wish to travel to high-altitude destinations.
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Affiliation(s)
- Jean-Paul Richalet
- Hypoxie et Poumon, Université Sorbonne Paris Nord, INSERM U1272, Paris, France.
| | - Eric Hermand
- Unité de Recherche Pluridisciplinaire Sport Santé Société, ULR 7369-URePSSS, Université Littoral Côte d'Opale, Université Artois, Université Lille, CHU Lille, Dunkirk, France
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Bourdillon N, Subudhi AW, Fan JL, Evero O, Elliott JE, Lovering AT, Roach RC, Kayser B. AltitudeOmics: effects of 16 days acclimatization to hypobaric hypoxia on muscle oxygen extraction during incremental exercise. J Appl Physiol (1985) 2023; 135:823-832. [PMID: 37589059 PMCID: PMC10642515 DOI: 10.1152/japplphysiol.00100.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Revised: 07/11/2023] [Accepted: 08/03/2023] [Indexed: 08/18/2023] Open
Abstract
Acute altitude exposure lowers arterial oxygen content ([Formula: see text]) and cardiac output ([Formula: see text]) at peak exercise, whereas O2 extraction from blood to working muscles remains similar. Acclimatization normalizes [Formula: see text] but not peak [Formula: see text] nor peak oxygen consumption (V̇o2peak). To what extent acclimatization impacts muscle O2 extraction remains unresolved. Twenty-one sea-level residents performed an incremental cycling exercise to exhaustion near sea level (SL), in acute (ALT1) and chronic (ALT16) hypoxia (5,260 m). Arterial blood gases, gas exchange at the mouth and oxy- (O2Hb) and deoxyhemoglobin (HHb) of the vastus lateralis were recorded to assess arterial O2 content ([Formula: see text]), [Formula: see text], and V̇o2. The HHb-V̇o2 slope was taken as a surrogate for muscle O2 extraction. During moderate-intensity exercise, HHb-V̇o2 slope increased to a comparable extent at ALT1 (2.13 ± 0.94) and ALT16 (2.03 ± 0.88) compared with SL (1.27 ± 0.12), indicating increased O2 extraction. However, the HHb/[Formula: see text] ratio increased from SL to ALT1 and then tended to go back to SL values at ALT16. During high-intensity exercise, HHb-V̇o2 slope reached a break point beyond which it decreased at SL and ALT1, but not at ALT16. Increased muscle O2 extraction during submaximal exercise was associated with decreased [Formula: see text] in acute hypoxia. The significantly greater muscle O2 extraction during maximal exercise in chronic hypoxia is suggestive of an O2 reserve.NEW & NOTEWORTHY During incremental exercise muscle deoxyhemoglobin (HHb) and oxygen consumption (V̇o2) both increase linearly, and the slope of their relationship is an indirect index of local muscle O2 extraction. The latter was assessed at sea level, in acute and during chronic exposure to 5,260 m. The demonstrated presence of a muscle O2 extraction reserve during chronic exposure is coherent with previous studies indicating both limited muscle oxidative capacity and decrease in motor drive.
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Affiliation(s)
- Nicolas Bourdillon
- Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
| | - Andrew W Subudhi
- Hybl Sports Medicine and Performance Center, Department of Human Physiology and Nutrition, University of Colorado, Colorado Springs, Colorado, United States
| | - Jui-Lin Fan
- Department of Physiology, Faculty of Medical & Health Sciences, Manaaki Manawa-The Centre for Heart Research, University of Auckland, Auckland, New Zealand
| | - Oghenero Evero
- Altitude Research Center, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Jonathan E Elliott
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Andrew T Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States
| | - Robert C Roach
- Altitude Research Center, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States
| | - Bengt Kayser
- Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
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Yang J, Ye X, Liu Z, Sun M, Yu S, Lv H, Wu B, Zhang C, Gu W, He J, Wang X, Huang L. Effect of ubiquinol on cardiorespiratory fitness during high-altitude acclimatization and de-acclimatization in healthy adults: the Shigatse CARdiorespiratory fitness study design. Front Cardiovasc Med 2023; 10:1129144. [PMID: 37560117 PMCID: PMC10407655 DOI: 10.3389/fcvm.2023.1129144] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 07/10/2023] [Indexed: 08/11/2023] Open
Abstract
Cardiorespiratory function influences exercise capacity and is an important determinant of high-altitude adaptation. Some studies have investigated the characteristics of changes in cardiorespiratory fitness during high-altitude acclimatization. However, studies on changes in cardiorespiratory fitness during high-altitude de-acclimatization are still lacking and have not yet been elucidated. Furthermore, few drugs have been studied to improve cardiorespiratory function during both processes. The Shigatse CARdiorespiratory Fitness (SCARF) study is a single-center, randomized, double-blind, placebo-control clinical trial to explore the effects of ubiquinol on cardiorespiratory fitness during high-altitude acclimatization and de-acclimatization in healthy adults. Participants will be randomly assigned 1:1 to ubiquinol 200 mg daily or a placebo for 14 days before departure until the end of data collection after return in 7 days. Cardiorespiratory fitness is the primary outcome, while acute mountain sickness and high-altitude de-acclimatization symptoms are secondary endpoints. In addition, laboratory measurements, including routine blood tests and serological measurements, will be performed. To the best of our knowledge, the SCARF study will be the first to reveal the changes in the cardiorespiratory fitness characteristics during high-altitude acclimatization and de-acclimatization. Furthermore, the results of this study will contribute to exploring whether ubiquinol supplementation could be beneficial for endurance exercise capacity at different altitudes and help improve adaptation to acute hypoxia and de-acclimatization. Clinical Trial Registration: This study has been registered in the Chinese Clinical Trial Register (www.chictr.org.cn) as ChiCTR2200059900 and ChiCTR2200066328.
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Affiliation(s)
- Jie Yang
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xiaowei Ye
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhen Liu
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Mengjia Sun
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Shiyong Yu
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Hailin Lv
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Boji Wu
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Chen Zhang
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Wenzhu Gu
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jingyu He
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xuhong Wang
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lan Huang
- Institute of Cardiovascular Diseases of PLA, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
- Department of Cardiology, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
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Ye X, Sun M, Yu S, Yang J, Liu Z, Lv H, Wu B, He J, Wang X, Huang L. Smartwatch-Based Maximum Oxygen Consumption Measurement for Predicting Acute Mountain Sickness: Diagnostic Accuracy Evaluation Study. JMIR Mhealth Uhealth 2023; 11:e43340. [PMID: 37410528 PMCID: PMC10360014 DOI: 10.2196/43340] [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: 10/09/2022] [Revised: 12/11/2022] [Accepted: 06/09/2023] [Indexed: 07/07/2023] Open
Abstract
BACKGROUND Cardiorespiratory fitness plays an important role in coping with hypoxic stress at high altitudes. However, the association of cardiorespiratory fitness with the development of acute mountain sickness (AMS) has not yet been evaluated. Wearable technology devices provide a feasible assessment of cardiorespiratory fitness, which is quantifiable as maximum oxygen consumption (VO2max) and may contribute to AMS prediction. OBJECTIVE We aimed to determine the validity of VO2max estimated by the smartwatch test (SWT), which can be self-administered, in order to overcome the limitations of clinical VO2max measurements. We also aimed to evaluate the performance of a VO2max-SWT-based model in predicting susceptibility to AMS. METHODS Both SWT and cardiopulmonary exercise test (CPET) were performed for VO2max measurements in 46 healthy participants at low altitude (300 m) and in 41 of them at high altitude (3900 m). The characteristics of the red blood cells and hemoglobin levels in all the participants were analyzed by routine blood examination before the exercise tests. The Bland-Altman method was used for bias and precision assessment. Multivariate logistic regression was performed to analyze the correlation between AMS and the candidate variables. A receiver operating characteristic curve was used to evaluate the efficacy of VO2max in predicting AMS. RESULTS VO2max decreased after acute high altitude exposure, as measured by CPET (25.20 [SD 6.46] vs 30.17 [SD 5.01] at low altitude; P<.001) and SWT (26.17 [SD 6.71] vs 31.28 [SD 5.17] at low altitude; P<.001). Both at low and high altitudes, VO2max was slightly overestimated by SWT but had considerable accuracy as the mean absolute percentage error (<7%) and mean absolute error (<2 mL·kg-1·min-1), with a relatively small bias compared with VO2max-CPET. Twenty of the 46 participants developed AMS at 3900 m, and their VO2max was significantly lower than that of those without AMS (CPET: 27.80 [SD 4.55] vs 32.00 [SD 4.64], respectively; P=.004; SWT: 28.00 [IQR 25.25-32.00] vs 32.00 [IQR 30.00-37.00], respectively; P=.001). VO2max-CPET, VO2max-SWT, and red blood cell distribution width-coefficient of variation (RDW-CV) were found to be independent predictors of AMS. To increase the prediction accuracy, we used combination models. The combination of VO2max-SWT and RDW-CV showed the largest area under the curve for all parameters and models, which increased the area under the curve from 0.785 for VO2max-SWT alone to 0.839. CONCLUSIONS Our study demonstrates that the smartwatch device can be a feasible approach for estimating VO2max. In both low and high altitudes, VO2max-SWT showed a systematic bias toward a calibration point, slightly overestimating the proper VO2max when investigated in healthy participants. The SWT-based VO2max at low altitude is an effective indicator of AMS and helps to better identify susceptible individuals following acute high-altitude exposure, particularly by combining the RDW-CV at low altitude. TRIAL REGISTRATION Chinese Clinical Trial Registry ChiCTR2200059900; https://www.chictr.org.cn/showproj.html?proj=170253.
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Affiliation(s)
- Xiaowei Ye
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Mengjia Sun
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Shiyong Yu
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jie Yang
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Zhen Liu
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Hailin Lv
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Boji Wu
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Jingyu He
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Xuhong Wang
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
| | - Lan Huang
- Institute of Cardiovascular Diseases of People's Liberation Army, The Second Affiliated Hospital, Army Medical University (Third Military Medical University), Chongqing, China
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9
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Seiler T, Nakas CT, Brill AK, Hefti U, Hilty MP, Perret-Hoigné E, Sailer J, Kabitz HJ, Merz TM, Pichler Hefti J. Do cardiopulmonary exercise tests predict summit success and acute mountain sickness? A prospective observational field study at extreme altitude. Br J Sports Med 2023:bjsports-2022-106211. [PMID: 36898769 DOI: 10.1136/bjsports-2022-106211] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/22/2023] [Indexed: 03/12/2023]
Abstract
OBJECTIVE During a high-altitude expedition, the association of cardiopulmonary exercise testing (CPET) parameters with the risk of developing acute mountain sickness (AMS) and the chance of reaching the summit were investigated. METHODS Thirty-nine subjects underwent maximal CPET at lowlands and during ascent to Mount Himlung Himal (7126 m) at 4844 m, before and after 12 days of acclimatisation, and at 6022 m. Daily records of Lake-Louise-Score (LLS) determined AMS. Participants were categorised as AMS+ if moderate to severe AMS occurred. RESULTS Maximal oxygen uptake (V̇O2max) decreased by 40.5%±13.7% at 6022 m and improved after acclimatisation (all p<0.001). Ventilation at maximal exercise (VEmax) was reduced at 6022 m, but higher VEmax was related to summit success (p=0.031). In the 23 AMS+ subjects (mean LLS 7.4±2.4), a pronounced exercise-induced oxygen desaturation (ΔSpO2exercise) was found after arrival at 4844 m (p=0.005). ΔSpO2exercise >-14.0% identified 74% of participants correctly with a sensitivity of 70% and specificity of 81% for predicting moderate to severe AMS. All 15 summiteers showed higher V̇O2max (p<0.001), and a higher risk of AMS in non-summiteers was suggested but did not reach statistical significance (OR: 3.64 (95% CI: 0.78 to 17.58), p=0.057). V̇O2max ≥49.0 mL/min/kg at lowlands and ≥35.0 mL/min/kg at 4844 m predicted summit success with a sensitivity of 46.7% and 53.3%, and specificity of 83.3% and 91.3%, respectively. CONCLUSION Summiteers were able to sustain higher VEmax throughout the expedition. Baseline V̇O2max below 49.0 mL/min/kg was associated with a high chance of 83.3% for summit failure, when climbing without supplemental oxygen. A pronounced drop of SpO2exercise at 4844 m may identify climbers at higher risk of AMS.
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Affiliation(s)
- Thomas Seiler
- Department of Pulmonary Medicine, Inselspital,Bern University Hospital, University of Bern, Bern, Switzerland
| | - Christos T Nakas
- Institute of Clinical Chemistry, Inselspital University Hospital, University of Bern, Bern, Switzerland.,Laboratory of Biometry, University of Thessaly, Volos, Greece
| | - Anne-Kathrin Brill
- Department of Pulmonary Medicine, Inselspital,Bern University Hospital, University of Bern, Bern, Switzerland
| | - Urs Hefti
- Swiss Sportclinic, Bern, Switzerland
| | - Matthias Peter Hilty
- Department of Intensive Care Medicine, University Hospital Zurich, Zurich, Switzerland
| | - Eveline Perret-Hoigné
- Department of Pediatrics, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Jannis Sailer
- Swiss Sportclinic, Bern, Switzerland.,Orthopedics and Traumatology, Hospital Nidwalden, Stans, Switzerland
| | - Hans-Joachim Kabitz
- Department of Internal Medicine II Pneumology Cardiology Intensive Care Medicine, Klinikum Konstanz, Konstanz, Germany
| | - Tobias M Merz
- Cardiovascular Intensive Care Unit, Auckland City Hospital, Auckland, New Zealand.,Department of Intensive Care Medicine, Inselspital, Bern University Hospital, University of Bern, University of Bern, Bern, Switzerland
| | - Jacqueline Pichler Hefti
- Department of Pulmonary Medicine, Inselspital,Bern University Hospital, University of Bern, Bern, Switzerland .,Swiss Sportclinic, Bern, Switzerland
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10
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Richalet J, Hermand E. Modeling the oxygen transport to the myocardium at maximal exercise at high altitude. Physiol Rep 2022; 10:e15262. [PMID: 35439356 PMCID: PMC9017981 DOI: 10.14814/phy2.15262] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/22/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023] Open
Abstract
Exposure to high altitude induces a decrease in oxygen pressure and saturation in the arterial blood, which is aggravated by exercise. Heart rate (HR) at maximal exercise decreases when altitude increases in prolonged exposure to hypoxia. We developed a simple model of myocardial oxygenation in order to demonstrate that the observed blunting of maximal HR at high altitude is necessary for the maintenance of a normal myocardial oxygenation. Using data from the available scientific literature, we estimated the myocardial venous oxygen pressure and saturation at maximal exercise in two conditions: (1) with actual values of maximal HR (decreasing with altitude); (2) with sea-level values of maximal heart rate, whatever the altitude (no change in HR). We demonstrated that, in the absence of autoregulation of maximal HR, myocardial tissue oxygenation would be incompatible with life above 6200 m-7600 m, depending on the hypothesis concerning a possible increase in coronary reserve (increase in coronary blood flow at exercise). The decrease in maximal HR at high altitude could be explained by several biological mechanisms involving the autonomic nervous system and its receptors on myocytes. These experimental and clinical observations support the hypothesis that there exists an integrated system at the cellular level, which protects the myocardium from a hazardous disequilibrium between O2 supply and O2 consumption at high altitude.
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Affiliation(s)
- Jean‐Paul Richalet
- UMR INSERM U1272 Hypoxie & PoumonUniversité Sorbonne Paris NordBobignyFrance
| | - Eric Hermand
- Université Littoral Côte d’OpaleUniversité ArtoisUniversité Lille, CHU LilleULR 7369 ‐ URePSSS‐Unité de Recherche Pluridisciplinaire Sport Santé SociétéDunkerqueFrance
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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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Exogenous Ketone Supplements in Athletic Contexts: Past, Present, and Future. Sports Med 2022; 52:25-67. [PMID: 36214993 PMCID: PMC9734240 DOI: 10.1007/s40279-022-01756-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2022] [Indexed: 12/15/2022]
Abstract
The ketone bodies acetoacetate (AcAc) and β-hydroxybutyrate (βHB) have pleiotropic effects in multiple organs including brain, heart, and skeletal muscle by serving as an alternative substrate for energy provision, and by modulating inflammation, oxidative stress, catabolic processes, and gene expression. Of particular relevance to athletes are the metabolic actions of ketone bodies to alter substrate utilisation through attenuating glucose utilisation in peripheral tissues, anti-lipolytic effects on adipose tissue, and attenuation of proteolysis in skeletal muscle. There has been long-standing interest in the development of ingestible forms of ketone bodies that has recently resulted in the commercial availability of exogenous ketone supplements (EKS). These supplements in the form of ketone salts and ketone esters, in addition to ketogenic compounds such as 1,3-butanediol and medium chain triglycerides, facilitate an acute transient increase in circulating AcAc and βHB concentrations, which has been termed 'acute nutritional ketosis' or 'intermittent exogenous ketosis'. Some studies have suggested beneficial effects of EKS to endurance performance, recovery, and overreaching, although many studies have failed to observe benefits of acute nutritional ketosis on performance or recovery. The present review explores the rationale and historical development of EKS, the mechanistic basis for their proposed effects, both positive and negative, and evidence to date for their effects on exercise performance and recovery outcomes before concluding with a discussion of methodological considerations and future directions in this field.
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13
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Płoszczyca K, Czuba M, Chalimoniuk M, Gajda R, Baranowski M. Red Blood Cell 2,3-Diphosphoglycerate Decreases in Response to a 30 km Time Trial Under Hypoxia in Cyclists. Front Physiol 2021; 12:670977. [PMID: 34211402 PMCID: PMC8239298 DOI: 10.3389/fphys.2021.670977] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 05/11/2021] [Indexed: 11/14/2022] Open
Abstract
Red blood cell 2,3-diphosphoglycerate (2,3-DPG) is one of the factors of rightward-shifted oxygen dissociation curves and decrease of Hb-O2 affinity. The reduction of Hb-O2 affinity is beneficial to O2 unloading at the tissue level. In the current literature, there are no studies about the changes in 2,3-DPG level following acute exercise in moderate hypoxia in athletes. For this reason, the aim of this study was to analyze the effect of prolonged intense exercise under normoxic and hypoxic conditions on 2,3-DPG level in cyclists. Fourteen male trained cyclists performed a simulation of a 30 km time trial (TT) in normoxia and normobaric hypoxia (FiO2 = 16.5%, ~2,000 m). During the TT, the following variables were measured: power, blood oxygen saturation (SpO2), and heart rate (HR). Before and immediately after exercise, the blood level of 2,3-DPG and acid–base equilibrium were determined. The results showed that the mean SpO2 during TT in hypoxia was 8% lower than in normoxia. The reduction of SpO2 in hypoxia resulted in a decrease of average power by 9.6% (p < 0.001) and an increase in the 30 km TT completion time by 3.8% (p < 0.01) compared to normoxia. The exercise in hypoxia caused a significant (p < 0.001) decrease in 2,3-DPG level by 17.6%. After exercise in normoxia, a downward trend of 2,3-DPG level was also observed, but this effect was not statistically significant. The analysis also revealed that changes of acid–base balance were significantly larger (p < 0.05) after exercise in hypoxia than in normoxia. In conclusion, intense exercise in hypoxic conditions leads to a decrease in 2,3-DPG concentration, primarily due to exercise-induced acidosis.
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Affiliation(s)
- Kamila Płoszczyca
- Department of Kinesiology, Institute of Sport - National Research Institute, Warsaw, Poland
| | - Miłosz Czuba
- Department of Kinesiology, Institute of Sport - National Research Institute, Warsaw, Poland
| | - Małgorzata Chalimoniuk
- Department of Physical Education and Health in Biala Podlaska, Józef Piłsudski University of Physical Education in Warsaw, Biala Podlaska, Poland
| | - Robert Gajda
- Center for Sports Cardiology, Gajda-Med Medical Center in Pułtusk, Pułtusk, Poland
| | - Marcin Baranowski
- Department of Physiology, Medical University of Bialystok, Bialystok, Poland
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14
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Modelling the relationships between arterial oxygen saturation, exercise intensity and the level of aerobic performance in acute hypoxia. Eur J Appl Physiol 2021; 121:1993-2003. [PMID: 33782716 DOI: 10.1007/s00421-021-04667-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 03/16/2021] [Indexed: 10/21/2022]
Abstract
PURPOSE The aim of this study was to establish a model to estimate the level of arterial oxygen saturation (SpO2) and help determine the appropriate hypoxic dose in humans exercising in acute hypoxia. METHODS SpO2 values were collected in seven untrained (UTS) and seven endurance-trained male subjects (ETS) who performed six cycle incremental and maximal tests at sea level and at simulated altitudes of 1000, 1500, 2500, 3500 and 4500 m. Oxygen uptake was continuously measured and maximal oxygen uptake ([Formula: see text]) was determined in each subject and at each altitude. Intensity was expressed as percentage of [Formula: see text]. RESULTS There were strong non-linear relationships between altitude and SpO2 at low, moderate and high intensity both in ETS and UTS (r = 0.97, p < 0.001). SpO2 was significantly correlated to exercise intensity at sea level and at all simulated altitudes in ETS but only from 2500 m in UTS. There were inverse correlations between SpO2 and sea-level [Formula: see text] at all altitudes, which were stronger from 2500 m and with the increase in exercise intensity. The three-variable model we established predicts (p < 0.001) the SpO2 level of individuals exercising in acute hypoxia based on their sea-level [Formula: see text], the intensity of exercise and the altitude level. CONCLUSION The model demonstrates that the drop of SpO2 during exercise in acute hypoxia is larger with the increase in both sea-level [Formula: see text] and exercise intensity. The model also highlights that the pivotal altitude from which the fall in SpO2 is exacerbated is between 2000 and 2500 m, depending on both sea-level [Formula: see text] and exercise intensity.
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15
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A Focused Review on the Maximal Exercise Responses in Hypo- and Normobaric Hypoxia: Divergent Oxygen Uptake and Ventilation Responses. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2020; 17:ijerph17145239. [PMID: 32698542 PMCID: PMC7400084 DOI: 10.3390/ijerph17145239] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/14/2020] [Accepted: 07/15/2020] [Indexed: 12/26/2022]
Abstract
The literature suggests that acute hypobaric (HH) and normobaric (NH) hypoxia exposure elicits different physiological responses. Only limited information is available on whether maximal cardiorespiratory exercise test outcomes, performed on either the treadmill or the cycle ergometer, are affected differently by NH and HH. A focused literature review was performed to identify relevant studies reporting cardiorespiratory responses in well-trained male athletes (individuals with a maximal oxygen uptake, VO2max > 50 mL/min/kg at sea level) to cycling or treadmill running in simulated acute HH or NH. Twenty-one studies were selected. The exercise tests in these studies were performed in HH (n = 90) or NH (n = 151) conditions, on a bicycle ergometer (n = 178) or on a treadmill (n = 63). Altitudes (simulated and terrestrial) varied between 2182 and 5400 m. Analyses (based on weighted group means) revealed that the decline in VO2max per 1000 m gain in altitude was more pronounced in acute NH vs. HH (-7.0 ± 1.4% vs. -5.6 ± 0.9%). Maximal minute ventilation (VEmax) increased in acute HH but decreased in NH with increasing simulated altitude (+1.9 ± 0.9% vs. -1.4 ± 1.8% per 1000 m gain in altitude). Treadmill running in HH caused larger decreases in arterial oxygen saturation and heart rate than ergometer cycling in acute HH, which was not the case in NH. These results indicate distinct differences between maximal cardiorespiratory responses to cycling and treadmill running in acute NH or HH. Such differences should be considered when interpreting exercise test results and/or monitoring athletic training.
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16
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Sumi D, Hayashi N, Yatsutani H, Goto K. Exogenous glucose oxidation during endurance exercise in hypoxia. Physiol Rep 2020; 8:e14457. [PMID: 32652803 PMCID: PMC7354086 DOI: 10.14814/phy2.14457] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 04/27/2020] [Accepted: 04/30/2020] [Indexed: 12/22/2022] Open
Abstract
Purpose Endurance exercise in hypoxia promotes carbohydrate (CHO) metabolism. However, detailed CHO metabolism remains unclear. The purpose of this study was to evaluate the effects of endurance exercise in moderate hypoxia on exogenous glucose oxidation at the same energy expenditure or relative exercise intensity. Methods Nine active healthy males completed three trials on different days, consisting of 30 min of running at each exercise intensity: (a) exercise at 65% of normoxic maximal oxygen uptake in normoxia [NOR, fraction of inspired oxygen (FiO2) = 20.9%, 10.6 ± 0.3 km/h], (b) exercise at the same relative exercise intensity with NOR in hypoxia (HYPR, FiO2 = 14.5%, 9.4 ± 0.3 km/h), and (c) exercise at the same absolute exercise intensity with NOR in hypoxia (HYPA, FiO2 = 14.5%, 10.6 ± 0.3 km/h). The subjects consumed 113C‐labeled glucose immediately before exercise, and expired gas samples were collected during exercise to determine 13C‐excretion (calculated by 13CO2/12CO2). Results The exercise‐induced increase in blood lactate was significantly augmented in the HYPA than in the NOR and HYPR (p = .001). HYPA involved a significantly higher respiratory exchange ratio (RER) during exercise compared with the other two trials (p < .0001). In contrast, exogenous glucose oxidation (13C‐excretion) during exercise was significantly lower in the HYPA than in the NOR (p = .03). No significant differences were observed in blood lactate elevation, RER, or exogenous glucose oxidation between NOR and HYPR. Conclusion Endurance exercise in moderate hypoxia caused a greater exercise‐induced blood lactate elevation and RER compared with the running exercise at same absolute exercise intensity in normoxia. However, exogenous glucose oxidation (13C‐excretion) during exercise was attenuated compared with the same exercise in normoxia.
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Affiliation(s)
- Daichi Sumi
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.,Research Fellow of Japan Society for the Promotion of Science, Chiyodaku, Japan
| | - Nanako Hayashi
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Haruka Yatsutani
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kazushige Goto
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan.,Faculty of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
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17
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Mourot L, Millet GP. Is Maximal Heart Rate Decrease Similar Between Normobaric Versus Hypobaric Hypoxia in Trained and Untrained Subjects? High Alt Med Biol 2018; 20:94-98. [PMID: 30489174 DOI: 10.1089/ham.2018.0104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We compared the decrease in maximal heart rate (HRmax) from normoxia to normobaric (NH) and hypobaric (HH) hypoxia, respectively, in trained and untrained subjects (n = 187). HRmax data in normoxia and NH (n = 55) or HH (n = 26) were collected from 81 publications. No study directly compared HRmax in NH and HH. Concomitant arterial oxygen saturation (SaO2) and HRmax data were found in 60 studies. Overall, the results showed that the higher the desaturation, the greater the decrease in HRmax. Since desaturation appeared to be slightly higher during HH versus NH and was higher in trained than in untrained subjects, the decrease in HRmax tended (p = 0.07) to be higher in trained subjects in HH than in NH (e.g., -12.7 bpm vs. -8.6 bpm at 4000 m), whereas in untrained subjects the difference was negligible (-9.9 bpm vs. -8.3 bpm). To conclude, when compared with normoxia, the decrease in HRmax was slightly higher in HH than in NH in trained subjects. However, this result has to be confirmed and from a practical point of view, one may question the significance of this difference as well as the relevance of using different HR values for prescribing training intensity during exercise performed in NH or in HH.
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Affiliation(s)
- Laurent Mourot
- 1 EA 3920 Prognostic Markers and Regulatory Factors of Cardiovascular Diseases and Exercise Performance, Health, Innovation Platform, University of Franche-Comté, Besançon, France.,2 Tomsk Polytechnic University, Tomsk, Russia
| | - Grégoire P Millet
- 3 Faculty of Biology and Medicine, ISSUL, Institute of Sport Sciences, University of Lausanne, Switzerland
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18
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Sumi D, Kojima C, Kasai N, Goto K. The effects of endurance exercise in hypoxia on acid-base balance and potassium kinetics: a randomized crossover design in male endurance athletes. SPORTS MEDICINE - OPEN 2018; 4:45. [PMID: 30317397 PMCID: PMC6186263 DOI: 10.1186/s40798-018-0160-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Accepted: 10/04/2018] [Indexed: 11/25/2022]
Abstract
Background Exercise-induced disturbance of acid-base balance and accumulation of extracellular potassium (K+) are suggested to elicit fatigue. Exercise under hypoxic conditions may augment exercise-induced alterations of these two factors compared with exercise under normoxia. In the present study, we investigated acid-base balance and potassium kinetics in response to exercise under moderate hypoxic conditions in endurance athletes. Methods Nine trained middle-to-long distance athletes [maximal oxygen uptake (VO2max) 57.2 ± 1.0 mL/kg/min] completed two different trials on different days, consisting of exercise in moderate hypoxia [fraction of inspired oxygen (FiO2) = 14.5%, H trial] and exercise in normoxia (FiO2 = 20.9%, N trial). They performed interval endurance exercise (8 × 4 min pedaling at 80% of VO2max alternated with 2-min intervals of active rest at 40% of VO2max) under hypoxic or normoxic conditions. Venous blood samples were obtained to determine blood lactate, pH, bicarbonate ion, and K+ concentrations before exercise, during exercise, and after exercise. Results The blood lactate concentrations increased significantly with exercise in both trials. Exercise-induced blood lactate elevations were significantly greater in the N trial than in the H trial at all time points (P = 0.012). Bicarbonate ion concentrations (P = 0.001) and blood pH (P = 0.019) during exercise and post-exercise periods were significantly lower in the N trial than in the H trial. A significantly greater exercise-induced elevation in blood K+ concentration was produced in the N trial than in the H trial during exercise and immediately after exercise (P = 0.03). Conclusions High-intensity interval exercise on a cycle ergometer under moderate hypoxic conditions did not elicit a decrease in blood pH or elevation in K+ levels compared with an equivalent level of exercise under normoxic conditions.
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Affiliation(s)
- Daichi Sumi
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Chihiro Kojima
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Nobukazu Kasai
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan
| | - Kazushige Goto
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Shiga, Japan. .,Faculty of Sports and Health Science, Ritsumeikan University, 1-1-1, Nojihigashi, Kusatsu, Shiga, 525-8577, Japan.
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19
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Gonzalez NC, Kuwahira I. Systemic Oxygen Transport with Rest, Exercise, and Hypoxia: A Comparison of Humans, Rats, and Mice. Compr Physiol 2018; 8:1537-1573. [PMID: 30215861 DOI: 10.1002/cphy.c170051] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this article is to compare and contrast the known characteristics of the systemic O2 transport of humans, rats, and mice at rest and during exercise in normoxia and hypoxia. This analysis should help understand when rodent O2 transport findings can-and cannot-be applied to human responses to similar conditions. The O2 -transport system was analyzed as composed of four linked conductances: ventilation, alveolo-capillary diffusion, circulatory convection, and tissue capillary-cell diffusion. While the mechanisms of O2 transport are similar in the three species, the quantitative differences are naturally large. There are abundant data on total O2 consumption and on ventilatory and pulmonary diffusive conductances under resting conditions in the three species; however, there is much less available information on pulmonary gas exchange, circulatory O2 convection, and tissue O2 diffusion in mice. The scarcity of data largely derives from the difficulty of obtaining blood samples in these small animals and highlights the need for additional research in this area. In spite of the large quantitative differences in absolute and mass-specific O2 flux, available evidence indicates that resting alveolar and arterial and venous blood PO2 values under normoxia are similar in the three species. Additionally, at least in rats, alveolar and arterial blood PO2 under hypoxia and exercise remain closer to the resting values than those observed in humans. This is achieved by a greater ventilatory response, coupled with a closer value of arterial to alveolar PO2 , suggesting a greater efficacy of gas exchange in the rats. © 2018 American Physiological Society. Compr Physiol 8:1537-1573, 2018.
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Affiliation(s)
- Norberto C Gonzalez
- Department of Molecular and Integrative Physiology, University of Kansas Medical Center, Kansas City, Kansas, USA
| | - Ichiro Kuwahira
- Department of Pulmonary Medicine, Tokai University School of Medicine, Tokai University Tokyo Hospital, Tokyo, Japan
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Sumi D, Kojima C, Goto K. Impact of Endurance Exercise in Hypoxia on Muscle Damage, Inflammatory and Performance Responses. J Strength Cond Res 2018; 32:1053-1062. [PMID: 28368957 DOI: 10.1519/jsc.0000000000001911] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Sumi, D, Kojima, C, and Goto, K. Impact of endurance exercise in hypoxia on muscle damage, inflammatory and performance responses. J Strength Cond Res 32(4): 1053-1062, 2018-This study evaluated muscle damage and inflammatory and performance responses after high-intensity endurance exercise in moderate hypoxia among endurance athletes. Nine trained endurance athletes completed 2 different trials on different days: exercise under moderate hypoxia (H trial, FiO2 = 14.5%) and normoxia (N trial, FiO2 = 20.9%). They performed interval exercises (10 × 3-minute running at 95% of V[Combining Dot Above]O2max with 60-second of active rest at 60% of V[Combining Dot Above]O2max) followed by 30-minute of continuous running at 85% of V[Combining Dot Above]O2max under either hypoxic or normoxic conditions. Venous blood samples were collected 4 times: before exercise, 0, 60, and 120-minute after exercise. The time to exhaustion (TTE) during running at 90% of V[Combining Dot Above]O2max was also determined to evaluate endurance capacity 120-minute after the training session. The H trial induced a significantly greater exercise-induced elevation in the blood lactate concentration than did the N trial (p = 0.02), whereas the elevation in the exercise-induced myoglobin concentration (muscle damage marker) was significantly greater in the N trial than in the H trial (p = 0.005). There was no significant difference in plasma interleukin-6 (inflammatory marker) concentration between the H and N trials. The TTE was shorter in the N trial (613 ± 65 seconds) than in the H trial (783 ± 107 seconds, p = 0.02). In conclusion, among endurance athletes, endurance exercise under moderate hypoxic conditions did not facilitate an exercise-induced muscle damage response or cause a further reduction in the endurance capacity compared with equivalent exercise under normoxic conditions.
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Affiliation(s)
- Daichi Sumi
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Chihiro Kojima
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Japan
| | - Kazushige Goto
- Graduate School of Sports and Health Science, Ritsumeikan University, Kusatsu, Japan.,Faculty of Sports and Health Science, Ritsumeikan University, Kusatsu, Japan
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21
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Fornasiero A, Savoldelli A, Skafidas S, Stella F, Bortolan L, Boccia G, Zignoli A, Schena F, Mourot L, Pellegrini B. Delayed parasympathetic reactivation and sympathetic withdrawal following maximal cardiopulmonary exercise testing (CPET) in hypoxia. Eur J Appl Physiol 2018; 118:2189-2201. [PMID: 30051338 DOI: 10.1007/s00421-018-3945-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 07/13/2018] [Indexed: 12/14/2022]
Abstract
PURPOSE This study investigated the effects of acute hypoxic exposure on post-exercise cardiac autonomic modulation following maximal cardiopulmonary exercise testing (CPET). METHODS Thirteen healthy men performed CPET and recovery in normoxia (N) and normobaric hypoxia (H) (FiO2 = 13.4%, ≈ 3500 m). Post-exercise cardiac autonomic modulation was assessed during recovery (300 s) through the analysis of fast-phase and slow-phase heart rate recovery (HRR) and heart rate variability (HRV) indices. RESULTS Both short-term, T30 (mean difference (MD) 60.0 s, 95% CI 18.2-101.8, p = 0.009, ES 1.01), and long-term, HRRt (MD 21.7 s, 95% CI 4.1-39.3, p = 0.020, ES 0.64), time constants of HRR were higher in H. Fast-phase (30 and 60 s) and slow-phase (300 s) HRR indices were reduced in H either when expressed in bpm or in percentage of HRpeak (p < 0.05). Chronotropic reserve recovery was lower in H than in N at 30 s (MD - 3.77%, 95% CI - 7.06 to - 0.49, p = 0.028, ES - 0.80) and at 60 s (MD - 7.23%, 95% CI - 11.45 to - 3.01, p = 0.003, ES - 0.81), but not at 300 s (p = 0.436). Concurrently, Ln-RMSSD was reduced in H at 60 and 90 s (p < 0.01) but not at other time points during recovery (p > 0.05). CONCLUSIONS Affected fast-phase, slow-phase HRR and HRV indices suggested delayed parasympathetic reactivation and sympathetic withdrawal after maximal exercise in hypoxia. However, a similar cardiac autonomic recovery was re-established within 5 min after exercise cessation. These findings have several implications in cardiac autonomic recovery interpretation and in HR assessment in response to high-intensity hypoxic exercise.
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Affiliation(s)
- Alessandro Fornasiero
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy. .,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - Aldo Savoldelli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Spyros Skafidas
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Federico Stella
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Lorenzo Bortolan
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Gennaro Boccia
- NeuroMuscularFunction Research Group, Department of Medical Sciences, School of Exercise and Sport Sciences, University of Turin, Turin, Italy
| | - Andrea Zignoli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy
| | - Federico Schena
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - Laurent Mourot
- Laboratory of Prognostic Markers and Regulatory Factors of Cardiovascular Diseases and Exercise Performance, Health, Innovation Platform (EA 3920), University of Bourgogne Franche-Comté, Besançon, France.,Tomsk Polytechnic University, Tomsk, Russia
| | - Barbara Pellegrini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, via Matteo del Ben, 5/b, 38068, Rovereto, Italy.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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22
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Mourot L. Limitation of Maximal Heart Rate in Hypoxia: Mechanisms and Clinical Importance. Front Physiol 2018; 9:972. [PMID: 30083108 PMCID: PMC6064954 DOI: 10.3389/fphys.2018.00972] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/02/2018] [Indexed: 12/17/2022] Open
Abstract
The use of exercise intervention in hypoxia has grown in popularity amongst patients, with encouraging results compared to similar intervention in normoxia. The prescription of exercise for patients largely rely on heart rate recordings (percentage of maximal heart rate (HRmax) or heart rate reserve). It is known that HRmax decreases with high altitude and the duration of the stay (acclimatization). At an altitude typically chosen for training (2,000-3,500 m) conflicting results have been found. Whether or not this decrease exists or not is of importance since the results of previous studies assessing hypoxic training based on HR may be biased due to improper intensity. By pooling the results of 86 studies, this literature review emphasizes that HRmax decreases progressively with increasing hypoxia. The dose–response is roughly linear and starts at a low altitude, but with large inter-study variabilities. Sex or age does not seem to be a major contributor in the HRmax decline with altitude. Rather, it seems that the greater the reduction in arterial oxygen saturation, the greater the reduction in HRmax, due to an over activity of the parasympathetic nervous system. Only a few studies reported HRmax at sea/low level and altitude with patients. Altogether, due to very different experimental design, it is difficult to draw firm conclusions in these different clinical categories of people. Hence, forthcoming studies in specific groups of patients are required to properly evaluate (1) the HRmax change during acute hypoxia and the contributing factors, and (2) the physiological and clinical effects of exercise training in hypoxia with adequate prescription of exercise training intensity if based on heart rate.
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Affiliation(s)
- Laurent Mourot
- EA 3920 Prognostic Markers and Regulatory Factors of Cardiovascular Diseases and Exercise Performance, Health, Innovation Platform, University of Franche-Comté, Besançon, France.,Tomsk Polytechnic University, Tomsk, Russia
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23
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Fornasiero A, Savoldelli A, Boccia G, Zignoli A, Bortolan L, Schena F, Pellegrini B. Physiological factors associated with ski-mountaineering vertical race performance. SPORT SCIENCES FOR HEALTH 2017. [DOI: 10.1007/s11332-017-0407-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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24
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Messier FM, Le Moyec L, Santi C, Gaston AF, Triba MN, Roca E, Durand F. The impact of moderate altitude on exercise metabolism in recreational sportsmen: a nuclear magnetic resonance metabolomic approach. Appl Physiol Nutr Metab 2017; 42:1135-1141. [PMID: 28666093 DOI: 10.1139/apnm-2016-0717] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Although it is known that altitude impairs performance in endurance sports, there is no consensus on the involvement of energy substrates in this process. The objective of the present study was to determine whether the metabolomic pathways used during endurance exercise differ according to whether the effort is performed at sea level or at moderate altitude (at the same exercise intensity, using proton nuclear magnetic resonance, 1H NMR). Twenty subjects performed two 60-min endurance exercise tests at sea level and at 2150 m at identical relative intensity on a cycle ergometer. Blood plasma was obtained from venous blood samples drawn before and after exercise. 1H NMR spectral analysis was then performed on the plasma samples. A multivariate statistical technique was applied to the NMR data. The respective relative intensities of the sea level and altitude endurance tests were essentially the same when expressed as a percentage of the maximal oxygen uptake measured during the corresponding incremental maximal exercise test. Lipid use was similar at sea level and at altitude. In the plasma, levels of glucose, glutamine, alanine, and branched-chain amino acids had decreased after exercise at altitude but not after exercise at sea level. The decrease in plasma glucose and free amino acid levels observed after exercise at altitude indicated that increased involvement of the protein pathway was necessary but not sufficient for the maintenance of glycaemia. Metabolomics is a powerful means of gaining insight into the metabolic changes induced by exercise at altitude.
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Affiliation(s)
- Florian M Messier
- a Laboratoire Européen Performance Santé Altitude EA4604 - Université de Perpignan Via Domitia, Département STAPS, 7 Avenue Pierre de Coubertin, Font-Romeu, France
| | - Laurence Le Moyec
- b Unité de Biologie Intégrative et Adaptation à l'Exercice, EA 7362, Université d'Evry Val D'Essonne, Evry, France
| | - Carole Santi
- a Laboratoire Européen Performance Santé Altitude EA4604 - Université de Perpignan Via Domitia, Département STAPS, 7 Avenue Pierre de Coubertin, Font-Romeu, France
| | - Anne-Fleur Gaston
- a Laboratoire Européen Performance Santé Altitude EA4604 - Université de Perpignan Via Domitia, Département STAPS, 7 Avenue Pierre de Coubertin, Font-Romeu, France
| | - Mohamed N Triba
- c Chimie Structures Propriétés de Biomatériaux et d'Agents Thérapeutiques, CNRS UMR 7244, Université Paris 13 Sorbonne Paris Cité, Bobigny, France
| | - Emma Roca
- a Laboratoire Européen Performance Santé Altitude EA4604 - Université de Perpignan Via Domitia, Département STAPS, 7 Avenue Pierre de Coubertin, Font-Romeu, France.,d Facultat de Medicina, Universitat de Girona, C/Emili Grahit 77, Girona, Spain
| | - Fabienne Durand
- a Laboratoire Européen Performance Santé Altitude EA4604 - Université de Perpignan Via Domitia, Département STAPS, 7 Avenue Pierre de Coubertin, Font-Romeu, France
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25
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MEDEX2015: Greater Sea-Level Fitness Is Associated with Lower Sense of Effort During Himalayan Trekking Without Worse Acute Mountain Sickness. High Alt Med Biol 2017; 18:152-162. [DOI: 10.1089/ham.2016.0088] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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26
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Black MI, Potter CR, Corbett J, Clark CCT, Draper SB. Maximal Oxygen Uptake Is Achieved in Hypoxia but Not Normoxia during an Exhaustive Severe Intensity Run. Front Physiol 2017; 8:96. [PMID: 28270770 PMCID: PMC5319197 DOI: 10.3389/fphys.2017.00096] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 02/06/2017] [Indexed: 01/01/2023] Open
Abstract
Highly aerobically trained individuals are unable to achieve maximal oxygen uptake (V˙O2max) during exhaustive running lasting ~2 min, instead V˙O2 plateaus below V˙O2max after ~1 min. Hypoxia offers the opportunity to study the (V˙O2) response to an exhaustive run relative to a hypoxia induced reduction in V˙O2max. The aim of this study was to explore whether there is a difference in the percentage of V˙O2max achieved (during a 2 min exhaustive run) in normoxia and hypoxia. Fourteen competitive middle distance runners (normoxic V˙O2max 67.0 ± 5.2 ml.kg−1.min−1) completed exhaustive treadmill ramp tests and constant work rate (CWR) tests in normoxia and hypoxia (FiO2 0.13). The V˙O2 data from the CWR tests were modeled using a single exponential function. End exercise normoxic CWR V˙O2 was less than normoxic V˙O2max (86 ± 6% ramp, P < 0.001). During the hypoxic CWR test, hypoxic V˙O2max was achieved (102 ± 8% ramp, P = 0.490). The phase II time constant was greater in hypoxia (12.7 ± 2.8 s) relative to normoxia (10.4 ± 2.6 s) (P = 0.029). The results demonstrate that highly aerobically trained individuals cannot achieve V˙O2max during exhaustive severe intensity treadmill running in normoxia, but can achieve the lower V˙O2max in hypoxia despite a slightly slower V˙O2 response.
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Affiliation(s)
- Matthew I Black
- School of Sport, Exercise and Health Sciences, Loughborough University Loughborough, UK
| | | | - Jo Corbett
- Department of Sport and Exercise Science, University of Portsmouth Portsmouth, UK
| | - Cain C T Clark
- HE Sport, University Centre, Hartpury College Gloucestershire, UK
| | - Stephen B Draper
- HE Sport, University Centre, Hartpury College Gloucestershire, UK
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Exercise-Induced Hypoxaemia Developed at Sea-Level Influences Responses to Exercise at Moderate Altitude. PLoS One 2016; 11:e0161819. [PMID: 27583364 PMCID: PMC5008680 DOI: 10.1371/journal.pone.0161819] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 08/12/2016] [Indexed: 11/20/2022] Open
Abstract
Purpose The aim of this study was to investigate the impact of exercise-induced hypoxaemia (EIH) developed at sea-level on exercise responses at moderate acute altitude. Methods Twenty three subjects divided in three groups of individuals: highly trained with EIH (n = 7); highly trained without EIH (n = 8) and untrained participants (n = 8) performed two maximal incremental tests at sea-level and at 2,150 m. Haemoglobin O2 saturation (SpO2), heart rate, oxygen uptake (VO2) and several ventilatory parameters were measured continuously during the tests. Results EIH athletes had a drop in SpO2 from 99 ± 0.8% to 91 ± 1.2% from rest to maximal exercise at sea-level, while the other groups did not exhibit a similar decrease. EIH athletes had a greater decrease in VO2max at altitude compared to non-EIH and untrained groups (-22 ± 7.9%, -16 ± 5.3% and -13 ± 9.4%, respectively). At altitude, non-EIH athletes had a similar drop in SpO2 as EIH athletes (13 ± 0.8%) but greater than untrained participants (6 ± 1.0%). EIH athletes showed greater decrease in maximal heart rate than non-EIH athletes at altitude (8 ± 3.3 bpm and 5 ± 2.9 bpm, respectively). Conclusion EIH athletes demonstrated specific cardiorespiratory response to exercise at moderate altitude compared to non-EIH athletes with a higher decrease in VO2max certainly due to the lower ventilator and HRmax responses. Thus EIH phenomenon developed at sea-level negatively impact performance and cardiorespiratory responses at acute moderate altitude despite no potentiated O2 desaturation.
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BROCHERIE FRANCK, MILLET GRÉGOIREP, MORIN JEANBENOIT, GIRARD OLIVIER. Mechanical Alterations to Repeated Treadmill Sprints in Normobaric Hypoxia. Med Sci Sports Exerc 2016; 48:1570-9. [DOI: 10.1249/mss.0000000000000937] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Hittinger EA, Maher JL, Nash MS, Perry AC, Signorile JF, Kressler J, Jacobs KA. Ischemic preconditioning does not improve peak exercise capacity at sea level or simulated high altitude in trained male cyclists. Appl Physiol Nutr Metab 2016; 40:65-71. [PMID: 25474566 DOI: 10.1139/apnm-2014-0080] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ischemic preconditioning (IPC) may improve blood flow and oxygen delivery to tissues, including skeletal muscle, and has the potential to improve intense aerobic exercise performance, especially that which results in arterial hypoxemia. The aim of the study was to determine the effects of IPC of the legs on peak exercise capacity (W(peak)), submaximal and peak cardiovascular hemodynamics, and peripheral capillary oxygen saturation (SpO2) in trained males at sea level (SL) and simulated high altitude (HA; 13.3% FIO2, ∼ 3650 m). Fifteen highly trained male cyclists and triathletes completed 2 W(peak) tests (SL and HA) and 4 experimental exercise trials (10 min at 55% altitude-specific W(peak) then increasing by 30 W every 2 min until exhaustion) with and without IPC. HA resulted in significant arterial hypoxemia during exercise compared with SL (73% ± 6% vs. 93% ± 4% SpO2, p < 0.001) that was associated with 21% lower W(peak) values. IPC did not significantly improve W(peak) at SL or HA. Additionally, IPC failed to improve cardiovascular hemodynamics or SpO2 during submaximal exercise or at W(peak). In conclusion, IPC performed 45 min prior to exercise does not improve W(peak) or systemic oxygen delivery during submaximal or peak exercise at SL or HA. Future studies must examine the influence of IPC on local factors, such as working limb blood flow, oxygen delivery, and arteriovenous oxygen difference as well as whether the effectiveness of IPC is altered by the volume of muscle made ischemic, the timing prior to exercise, and high altitude acclimatization.
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Affiliation(s)
- Elizabeth A Hittinger
- a Department of Kinesiology and Sport Sciences, University of Miami, Coral Gables, FL 33146, USA
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30
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Fan JL, Kayser B. Fatigue and Exhaustion in Hypoxia: The Role of Cerebral Oxygenation. High Alt Med Biol 2016; 17:72-84. [DOI: 10.1089/ham.2016.0034] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Affiliation(s)
- Jui-Lin Fan
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
- Department of Surgery & Anaesthesia, University of Otago, Wellington, New Zealand
| | - Bengt Kayser
- Institute of Sports Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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Rodway GW, Lovelace AJ, Lanspa MJ, McIntosh SE, Bell J, Briggs B, Weaver LK, Yanowitz F, Grissom CK. Sildenafil and Exercise Capacity in the Elderly at Moderate Altitude. Wilderness Environ Med 2016; 27:307-15. [PMID: 27116921 DOI: 10.1016/j.wem.2016.01.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 12/15/2015] [Accepted: 01/20/2016] [Indexed: 11/17/2022]
Abstract
OBJECTIVE Hypobaric hypoxia decreases exercise capacity and causes hypoxic pulmonary vasoconstriction and pulmonary hypertension. The phosphodiesterase-5 inhibitor sildenafil is a pulmonary vasodilator that may improve exercise capacity at altitude. We aimed to determine whether sildenafil improves exercise capacity, measured as maximal oxygen consumption (peak V̇o2), at moderate altitude in adults 60 years or older. METHODS The design was a randomized, double-blind, placebo-controlled, crossover study. After baseline cardiopulmonary exercise testing at 1400 m, 12 healthy participants (4 women) aged 60 years or older, who reside permanently at approximately 1400 m and are regularly active in self-propelled mountain recreation above 2000 m, performed maximal cardiopulmonary cycle exercise tests in a hypobaric chamber at a simulated altitude of 2750 m after ingesting sildenafil and after ingesting a placebo. RESULTS After placebo, mean peak V̇o2 was significantly lower at 2750 m than 1400 m: 37.0 mL · kg(-1) · min(-1) (95% CI, 32.7 to 41.3) vs 39.1 mL · kg(-1) · min(-1) (95% CI, 33.5 to 44.7; P = .020). After placebo, there was no difference in heart rate (HR) or maximal workload at either altitude (z = 0.182; P = .668, respectively). There was no difference between sildenafil and placebo at 2750 m in peak V̇o2 (P = .668), O2 pulse (P = .476), cardiac index (P = .143), stroke volume index (z = 0.108), HR (z = 0.919), or maximal workload (P = .773). Transthoracic echocardiography immediately after peak exercise at 2750 m showed tricuspid annular plane systolic velocity was significantly higher after sildenafil than after placebo (P = .019), but showed no difference in tricuspid annular plane systolic excursion (P = .720). CONCLUSIONS Sildenafil (50 mg) did not improve exercise capacity in adults 60 years or older at moderate altitude in our study. This might be explained by a "dosing effect" or insufficiently high altitude.
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Affiliation(s)
- George W Rodway
- University of Utah School of Nursing, Salt Lake City, UT (Dr Rodway).
| | - Anne J Lovelace
- Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)
| | - Michael J Lanspa
- Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)
| | | | - James Bell
- Intermountain Medical Center (Mr Bell and Dr Weaver), Murray, UT; Hyperbaric Medicine (Mr Bell), LDS Hospital, Salt Lake City, UT
| | - Ben Briggs
- Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)
| | - Lindell K Weaver
- Intermountain Medical Center (Mr Bell and Dr Weaver), Murray, UT; Department of Pulmonary and Critical Care (Dr Weaver); School of Medicine (Drs Weaver and Yanowitz), University of Utah, Salt Lake City, UT
| | - Frank Yanowitz
- and ECG Services and Cardiac Rehabilitation (Dr Yanowitz); School of Medicine (Drs Weaver and Yanowitz), University of Utah, Salt Lake City, UT
| | - Colin K Grissom
- Department of Pulmonary and Critical Care (Ms Lovelace, Drs Lanspa and Grissom, and Mr Briggs)
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Gaston AF, Roca E, Doucende G, Hapkova I, Subirats E, Durand F. Réponses physiologiques à l’exercice en altitude modérée : intérêt de la mesure de la SpO2. Sci Sports 2016. [DOI: 10.1016/j.scispo.2015.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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33
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Drain J, Billing D, Neesham-Smith D, Aisbett B. Predicting physiological capacity of human load carriage - a review. APPLIED ERGONOMICS 2016; 52:85-94. [PMID: 26360198 DOI: 10.1016/j.apergo.2015.07.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2013] [Revised: 06/07/2015] [Accepted: 07/07/2015] [Indexed: 06/05/2023]
Abstract
This review article aims to evaluate a proposed maximum acceptable work duration model for load carriage tasks. It is contended that this concept has particular relevance to physically demanding occupations such as military and firefighting. Personnel in these occupations are often required to perform very physically demanding tasks, over varying time periods, often involving load carriage. Previous research has investigated concepts related to physiological workload limits in occupational settings (e.g. industrial). Evidence suggests however, that existing (unloaded) workload guidelines are not appropriate for load carriage tasks. The utility of this model warrants further work to enable prediction of load carriage durations across a range of functional workloads for physically demanding occupations. If the maximum duration for which personnel can physiologically sustain a load carriage task could be accurately predicted, commanders and supervisors could better plan for and manage tasks to ensure operational imperatives were met whilst minimising health risks for their workers.
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Affiliation(s)
- Jace Drain
- Land Division, Defence Science and Technology Organisation, 506 Lorimer Street, Fishermans Bend, 3207, Australia.
| | - Daniel Billing
- Land Division, Defence Science and Technology Organisation, 506 Lorimer Street, Fishermans Bend, 3207, Australia
| | - Daniel Neesham-Smith
- Centre for Exercise and Sports Science, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, 3125, Australia
| | - Brad Aisbett
- Centre for Exercise and Sports Science, School of Exercise and Nutrition Sciences, Deakin University, 221 Burwood Highway, Burwood, 3125, Australia
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MONTERO DAVID, DIAZ-CAÑESTRO CANDELA, LUNDBY CARSTEN. Endurance Training and V˙O2max. Med Sci Sports Exerc 2015; 47:2024-33. [DOI: 10.1249/mss.0000000000000640] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Puthon L, Bouzat P, Rupp T, Robach P, Favre-Juvin A, Verges S. Physiological characteristics of elite high-altitude climbers. Scand J Med Sci Sports 2015; 26:1052-9. [DOI: 10.1111/sms.12547] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2015] [Indexed: 11/27/2022]
Affiliation(s)
- L. Puthon
- HP2 Laboratory; Faculté de Médecine; Grenoble Alpes University; Batiment Jean Roget; Grenoble France
- U1042; Faculté de Médecine; INSERM; Batiment Jean Roget; Grenoble France
- Pôle Anesthésie Réanimation; CHU de Grenoble; Grenoble France
| | - P. Bouzat
- Pôle Anesthésie Réanimation; CHU de Grenoble; Grenoble France
- Grenoble Institute of Neurosciences; INSERM U836; Grenoble France
| | - T. Rupp
- Laboratoire de Physiologie de l'Exercice; Université Savoie Mont Blanc; Chambéry France
| | - P. Robach
- HP2 Laboratory; Faculté de Médecine; Grenoble Alpes University; Batiment Jean Roget; Grenoble France
- U1042; Faculté de Médecine; INSERM; Batiment Jean Roget; Grenoble France
- Medical Department; Ecole Nationale des Sports de Montagne; site de l'Ecole Nationale de Ski et d'Alpinisme; Chamonix France
| | - A. Favre-Juvin
- HP2 Laboratory; Faculté de Médecine; Grenoble Alpes University; Batiment Jean Roget; Grenoble France
- U1042; Faculté de Médecine; INSERM; Batiment Jean Roget; Grenoble France
| | - S. Verges
- HP2 Laboratory; Faculté de Médecine; Grenoble Alpes University; Batiment Jean Roget; Grenoble France
- U1042; Faculté de Médecine; INSERM; Batiment Jean Roget; Grenoble France
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Montero D. Arterial dilator function in athletes: present and future perspectives. Front Physiol 2015; 6:163. [PMID: 26042052 PMCID: PMC4436563 DOI: 10.3389/fphys.2015.00163] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/06/2015] [Indexed: 01/23/2023] Open
Affiliation(s)
- David Montero
- Zurich Center for Integrative Human Physiology, Institute of Physiology, University of Zurich Zurich, Switzerland
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Richalet JP, Lhuissier FJ. Aging, Tolerance to High Altitude, and Cardiorespiratory Response to Hypoxia. High Alt Med Biol 2015; 16:117-24. [DOI: 10.1089/ham.2015.0030] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Jean-Paul Richalet
- Université Paris 13, Sorbonne Paris Cité, “Hypoxie et Poumon,” Bobigny, France
- AP-HP, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France
| | - François J. Lhuissier
- Université Paris 13, Sorbonne Paris Cité, “Hypoxie et Poumon,” Bobigny, France
- AP-HP, Hôpital Avicenne, Service de Physiologie, Explorations Fonctionnelles et Médecine du Sport, Bobigny, France
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Montero D, Díaz-Cañestro C. Maximal cardiac output in athletes: influence of age. Eur J Prev Cardiol 2015; 22:1588-600. [PMID: 25595549 DOI: 10.1177/2047487314566759] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Accepted: 12/12/2014] [Indexed: 11/17/2022]
Abstract
BACKGROUND The decline in maximal oxygen consumption (VO2max) with age seems to be exacerbated in endurance-trained athletes (EA) relative to untrained healthy subjects. Whether maximal cardiac output (Qmax) parallels this group-specific decline with age remains uncertain. Therefore, we sought to systematically review the literature and determine whether Qmax is similarly enhanced in EA across all ages relative to age-matched untrained counterparts. DESIGN AND METHODS We conducted a systematic search of MEDLINE, Cochrane and Web of Science from their inceptions until June 2014 for articles evaluating Qmax in athletes. A meta-analysis was performed to determine the standardized mean difference (SMD) in Qmax between EA and age-matched untrained healthy subjects. Included studies had to (i) comprise EA and control groups matched for body size or (ii) present Qmax values normalized for body size. Subgroup and meta-regression analyses were used to study the influence of age and potential moderating factors. RESULTS Eighteen studies were selected after systematic review, comprising 268 EA and 232 age-matched untrained subjects. Nine studies involved young EA (mean age ≤40 years) while nine studies involved master EA (mean age >55 years). After data pooling, young and master EA groups showed higher Qmax compared with control groups (SMD = 1.49 and SMD = 1.68, respectively; both p < 0.0001). The SMD in Qmax between EA and control groups was similar in studies in young EA compared with studies in master EA (p = 0.61). Moreover, the SMD in VO2max between EA and control groups did not differ in studies in young EA compared with studies in master EA (p = 0.37). In meta-regression analyses, the difference in percentage of body fat between EA and control groups was inversely associated with the SMD in Qmax (B = - 0.17, p = 0.01) and the SMD in VO2max (B = -0.20, p = 0.01). Mean age was not associated with the SMD in Qmax (B = -0.001, P = 0.90) nor with the SMD in VO2max (B = 0.01, P = 0.58). CONCLUSIONS Based on current published studies, the enhanced Qmax observed in EA compared with untrained healthy subjects matched for body size is not affected by age but may be related, at least in part, to the improved body composition of EA.
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Affiliation(s)
- David Montero
- Department of Internal Medicine, Maastricht University Medical Centre (MUMC), the Netherlands Cardiovascular Research Institute Maastricht (CARIM), the Netherlands
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MacNutt MJ, Peters CM, Chan C, Moore J, Shum S, Sheel AW. Day-to-day variability in cardiorespiratory responses to hypoxic cycle exercise. Appl Physiol Nutr Metab 2014; 40:155-61. [PMID: 25603431 DOI: 10.1139/apnm-2014-0297] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Repeatedly performing exercise in hypoxia could elicit an independent training response and become an unintended co-intervention. The primary purposes of this study were to determine if hypoxic exercise responses changed across repeated testing and to assess the day-to-day variability of commonly used measures of cardiorespiratory and metabolic responses to hypoxic exercise. Healthy young males (aged 23 ± 2 years) with a maximal O2 consumption of 50.7 ± 4.7 mL·kg(-1)·min(-1) performed 5 trials (H1 to H5) over a 2-week period in hypoxia (fraction of inspired oxygen = 0.13). Participants completed 3-min stages at 20%, 40%, 60%, and 10% of individual peak power. With increasing cycle exercise intensity there were increases in minute ventilation, O2 consumption, CO2 production, respiratory exchange ratio, heart rate (HR), blood lactate concentration, and ratings of perceived exertion for legs and respiratory system along with a reduction in oxyhaemoglobin saturation (%SpO2) (all p < 0.001). There were no systematic changes from H1 to H5 (p > 0.05). Most measures were highly repeatable across testing sessions with the coefficient of variation (CV) averaging ≤10% of the mean value in all variables except O2 consumption (17%), CO2 production (11%) and blood lactate concentration (17%). For HR and %SpO2 the CV was <5%. The exercise protocol did not elicit a training response when repeated 5 times during a 2-week period and the variability of exercise responses was low. We conclude that this protocol allows detection of small changes in cardiorespiratory responses to hypoxic exercise that might occur during exposure to hypoxia.
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Ferretti G. Maximal oxygen consumption in healthy humans: theories and facts. Eur J Appl Physiol 2014; 114:2007-36. [PMID: 24986693 DOI: 10.1007/s00421-014-2911-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Accepted: 05/12/2014] [Indexed: 12/17/2022]
Abstract
This article reviews the concept of maximal oxygen consumption ([Formula: see text]) from the perspective of multifactorial models of [Formula: see text] limitation. First, I discuss procedural aspects of [Formula: see text] measurement: the implications of ramp protocols are analysed within the theoretical work of Morton. Then I analyse the descriptive physiology of [Formula: see text], evidencing the path that led to the view of monofactorial cardiovascular or muscular [Formula: see text] limitation. Multifactorial models, generated by the theoretical work of di Prampero and Wagner around the oxygen conductance equation, represented a radical change of perspective. These models are presented in detail and criticized with respect to the ensuing experimental work. A synthesis between them is proposed, demonstrating how much these models coincide and converge on the same conclusions. Finally, I discuss the cases of hypoxia and bed rest, the former as an example of the pervasive effects of the shape of the oxygen equilibrium curve, the latter as a neat example of adaptive changes concerning the entire respiratory system. The conclusion is that the concept of cardiovascular [Formula: see text] limitation is reinforced by multifactorial models, since cardiovascular oxygen transport provides most of the [Formula: see text] limitation, at least in normoxia. However, the same models show that the role of peripheral resistances is significant and cannot be neglected. The role of peripheral factors is greater the smaller is the active muscle mass. In hypoxia, the intervention of lung resistances as limiting factors restricts the role played by cardiovascular and peripheral factors.
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Affiliation(s)
- Guido Ferretti
- Département des Neurosciences Fondamentales, Université de Genève, 1 Rue Michel Servet, 1211, Geneva 4, Switzerland,
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Schiffer TA, Ekblom B, Lundberg JO, Weitzberg E, Larsen FJ. Dynamic regulation of metabolic efficiency explains tolerance to acute hypoxia in humans. FASEB J 2014; 28:4303-11. [DOI: 10.1096/fj.14-251710] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Tomas A. Schiffer
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Björn Ekblom
- Åstrand Laboratory of Work PhysiologySwedish School of Sports and Health SciencesStockholmSweden
| | - Jon O. Lundberg
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Eddie Weitzberg
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
| | - Filip J. Larsen
- Department of Physiology and PharmacologyKarolinska InstitutetStockholmSweden
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Kayser B. Pro: All dwellers at high altitude are persons of impaired physical and mental powers. High Alt Med Biol 2014; 14:205-7. [PMID: 24067175 DOI: 10.1089/ham.2013.1045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Bengt Kayser
- Institute of Sports Sciences of the University of Lausanne , Lausanne, Switzerland
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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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Lara B, Salinero JJ, Del Coso J. Altitude is Positively Correlated to Race Time during the Marathon. High Alt Med Biol 2014; 15:64-9. [DOI: 10.1089/ham.2013.1060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Beatriz Lara
- Exercise Physiology Laboratory, Camilo José Cela University, Madrid, Spain
| | - Juan José Salinero
- Exercise Physiology Laboratory, Camilo José Cela University, Madrid, Spain
| | - Juan Del Coso
- Exercise Physiology Laboratory, Camilo José Cela University, Madrid, Spain
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Desplanches D, Amami M, Dupré-Aucouturier S, Valdivieso P, Schmutz S, Mueller M, Hoppeler H, Kreis R, Flück M. Hypoxia refines plasticity of mitochondrial respiration to repeated muscle work. Eur J Appl Physiol 2013; 114:405-17. [PMID: 24327174 PMCID: PMC3895187 DOI: 10.1007/s00421-013-2783-8] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2013] [Accepted: 11/25/2013] [Indexed: 11/29/2022]
Abstract
Purpose We explored whether altered expression of factors tuning mitochondrial metabolism contributes to muscular adaptations with endurance training in the condition of lowered ambient oxygen concentration (hypoxia) and whether these adaptations relate to oxygen transfer as reflected by subsarcolemmal mitochondria and oxygen metabolism in muscle. Methods Male volunteers completed 30 bicycle exercise sessions in normoxia or normobaric hypoxia (4,000 m above sea level) at 65 % of the respective peak aerobic power output. Myoglobin content, basal oxygen consumption, and re-oxygenation rates upon reperfusion after 8 min of arterial occlusion were measured in vastus muscles by magnetic resonance spectroscopy. Biopsies from vastus lateralis muscle, collected pre and post a single exercise bout, and training, were assessed for levels of transcripts and proteins being associated with mitochondrial metabolism. Results Hypoxia specifically lowered the training-induced expression of markers of respiratory complex II and IV (i.e. SDHA and isoform 1 of COX-4; COX4I1) and preserved fibre cross-sectional area. Concomitantly, trends (p < 0.10) were found for a hypoxia-specific reduction in the basal oxygen consumption rate, and improvements in oxygen repletion, and aerobic performance in hypoxia. Repeated exercise in hypoxia promoted the biogenesis of subsarcolemmal mitochondria and this was co-related to expression of isoform 2 of COX-4 with higher oxygen affinity after single exercise, de-oxygenation time and myoglobin content (r ≥ 0.75). Conversely, expression in COX4I1 with training correlated negatively with changes of subsarcolemmal mitochondria (r < −0.82). Conclusion Hypoxia-modulated adjustments of aerobic performance with repeated muscle work are reflected by expressional adaptations within the respiratory chain and modified muscle oxygen metabolism.
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Affiliation(s)
- Dominique Desplanches
- Centre de Génétique et de Physiologie Moléculaire et Cellulaire, CNRS UMR 5534, Université Lyon 1, Villeurbanne, France
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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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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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Marocolo M, Barbosa Neto O, Vianna JM, Lauria ADA, Orsatti FL, Mota GRD. Análise da correlação entre o protocolo Polar Fitness Test® para predição de VO2máx e ergoespirometria. REV BRAS MED ESPORTE 2012. [DOI: 10.1590/s1517-86922012000300012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
INTRODUÇÃO: A importância da mensuração do consumo máximo de oxigênio (<img border=0 id="_x0000_i1026" src="/img/revistas/rbme/v18n3/v.jpg" align=absmiddle>O2máx)é justificada por sua aceitação internacional como o melhor parâmetro fisiológico para avaliar a capacidade funcional do sistema cardiorrespiratório tanto em atletas como em não atletas que treinam fisicamente com objetivo de obter melhor saúde. OBJETIVO: Verificar a concordância entre os protocolos Polar Fitness Test® para a estimativa do <img border=0 id="_x0000_i1027" src="/img/revistas/rbme/v18n3/v.jpg" align=absmiddle>O2máx e o teste de esforço máximo com medida direta de gases. MÉTODOS: Dezessete homens ativos (22,5 ± dois anos) participaram. Em repouso, aplicou-se o protocolo Polar Fitness Test® e, em seguida, a coleta direta de gases sob o esforço máximo, em esteira, seguindo o protocolo de Bruce. RESULTADOS: Houve diferença significativa entre os valores médios dos métodos para estimativa do <img border=0 id="_x0000_i1028" src="/img/revistas/rbme/v18n3/v.jpg" align=absmiddle>O2máx. O protocolo Polar Fitness Test® subestimou o <img border=0 id="_x0000_i1029" src="/img/revistas/rbme/v18n3/v.jpg" align=absmiddle>O2máx, em média 15% (IC95%: 24; -53%) comparado com a medida direta de gases. Os valores obtidos pelo Polar Fitness Test® não tiveram boa correlação com a medida direta em ergoespirômetro (r = 0,1). CONCLUSÃO: O protocolo Polar Fitness Test® não é válido para a estimativa do <img border=0 id="_x0000_i1030" src="/img/revistas/rbme/v18n3/v.jpg" align=absmiddle>O2máx em homens jovens ativos fisicamente.
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Lhuissier FJ, Brumm M, Ramier D, Richalet JP. Ventilatory and cardiac responses to hypoxia at submaximal exercise are independent of altitude and exercise intensity. J Appl Physiol (1985) 2011; 112:566-70. [PMID: 22194322 DOI: 10.1152/japplphysiol.00906.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The hypoxic exercise test combining a 4,800-m simulated altitude and a cycloergometer exercise at 30% of normoxic maximal aerobic power (MAP) is used to evaluate the individual chemosensitivity to hypoxia in submaximal exercise conditions. This test allows the calculation of three main parameters: the decrease in arterial oxygen saturation induced by hypoxia at exercise (ΔSa(e)) and the ventilatory (HVR(e)) and cardiac (HCR(e)) responses to hypoxia at exercise. The aim of this study was to determine the influence of altitude and exercise intensity on the values of ΔSa(e), HVR(e), and HCR(e). Nine subjects performed hypoxic tests at three simulated altitudes (3,000 m, 4,000 m, and 4,800 m) and three exercise intensities (20%, 30%, and 40% MAP). ΔSa(e) increased with altitude and was higher for 40% MAP than for 20% or 30% (P < 0.05). For a constant heart rate, the loss in power output induced by hypoxia, relative to ΔSa(e), was independent of altitude (4,000-4,800 m) and of exercise intensity. HVR(e) and HCR(e) were independent of altitude (3,000-4,800 m) and exercise intensity (20%-40% MAP). Moreover, the intraindividual variability of responses to hypoxia was lower during moderate exercise than at rest (P < 0.05 to P < 0.001). Therefore, we suggest that HVR(e) and HCR(e) are invariant parameters that can be considered as intrinsic physiological characteristics of chemosensitivity to hypoxia.
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Affiliation(s)
- François J Lhuissier
- Université Paris 13, EA 2363 Réponses cellulaires et fonctionnelles à l'hypoxie, France.
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Burtscher M, Mairer K, Wille M, Gatterer H, Ruedl G, Faulhaber M, Sumann G. Short-term exposure to hypoxia for work and leisure activities in health and disease: which level of hypoxia is safe? Sleep Breath 2011; 16:435-42. [PMID: 21499843 DOI: 10.1007/s11325-011-0521-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2010] [Revised: 03/16/2011] [Accepted: 04/05/2011] [Indexed: 12/11/2022]
Abstract
INTRODUCTION Exposures to natural and simulated altitudes entail reduced oxygen availability and thus hypoxia. Depending on the level of hypoxia, the duration of exposure, the individual susceptibility, and preexisting diseases, health problems of variable severity may arise. Although millions of people are regularly or occasionally performing mountain sport activities, are transported by airplanes, and are more and more frequently exposed to short-term hypoxia in athletic training facilities or at their workplace, e.g., with fire control systems, there is no clear consensus on the level of hypoxia which is generally well tolerated by human beings when acutely exposed for short durations (hours to several days). CONCLUSIONS Available data from peer-reviewed literature report adaptive responses even to altitudes below 2,000 m or corresponding normobaric hypoxia (F(i)O(2) > 16.4%), but they also suggest that most of exposed subjects without severe preexisting diseases can tolerate altitudes up to 3,000 m (F(i)O(2) > 14.5%) well. However, physical activity and unusual environmental conditions may increase the risk to get sick. Large interindividual variations of responses to hypoxia have to be expected, especially in persons with preexisting diseases. Thus, the assessment of those responses by hypoxic challenge testing may be helpful whenever possible.
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Affiliation(s)
- Martin Burtscher
- Department of Sport Science, Medical Section, University of Innsbruck, Fürstenweg 185, 6020, Innsbruck, Austria.
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