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Cinca-Morros S, Álvarez-Herms J. The Importance of Maintaining and Improving a Healthy Gut Microbiota in Athletes as a Preventive Strategy to Improve Heat Tolerance and Acclimatization. Microorganisms 2024; 12:1160. [PMID: 38930542 PMCID: PMC11205789 DOI: 10.3390/microorganisms12061160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 06/04/2024] [Accepted: 06/05/2024] [Indexed: 06/28/2024] Open
Abstract
Exposure to passive heat (acclimation) and exercise under hot conditions (acclimatization), known as heat acclimation (HA), are methods that athletes include in their routines to promote faster recovery and enhance physiological adaptations and performance under hot conditions. Despite the potential positive effects of HA on health and physical performance in the heat, these stimuli can negatively affect gut health, impairing its functionality and contributing to gut dysbiosis. Blood redistribution to active muscles and peripheral vascularization exist during exercise and HA stimulus, promoting intestinal ischemia. Gastrointestinal ischemia can impair intestinal permeability and aggravate systemic endotoxemia in athletes during exercise. Systemic endotoxemia elevates the immune system as an inflammatory responses in athletes, impairing their adaptive capacity to exercise and their HA tolerance. Better gut microbiota health could benefit exercise performance and heat tolerance in athletes. This article suggests that: (1) the intestinal modifications induced by heat stress (HS), leading to dysbiosis and altered intestinal permeability in athletes, can decrease health, and (2) a previously acquired microbial dysbiosis and/or leaky gut condition in the athlete can negatively exacerbate the systemic effects of HA. Maintaining or improving the healthy gut microbiota in athletes can positively regulate the intestinal permeability, reduce endotoxemic levels, and control the systemic inflammatory response. In conclusion, strategies based on positive daily habits (nutrition, probiotics, hydration, chronoregulation, etc.) and preventing microbial dysbiosis can minimize the potentially undesired effects of applying HA, favoring thermotolerance and performance enhancement in athletes.
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Affiliation(s)
- Sergi Cinca-Morros
- Microfluidics Cluster UPV/EHU, Analytical Microsystems & Materials for Lab-on-a-Chip (AMMa-LOAC) Group, Analytical Chemistry Department, University of the Basque Country UPV/EHU, 01006 Vitoria-Gasteiz, Spain
- Microfluidics Cluster UPV/EHU, BIOMICs Microfluidics Group, Lascaray Research Center, University of the Basque Country UPV/EHU, 01006 Vitoria-Gasteiz, Spain
| | - Jesús Álvarez-Herms
- Physiology and Molecular Laboratory (Phymolab), 40170 Collado Hermoso, Spain;
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Yi L, Wu J, Yan B, Wang Y, Zou M, Zhang Y, Li F, Qiu J, Girard O. Effects of three weeks base training at moderate simulated altitude with or without hypoxic residence on exercise capacity and physiological adaptations in well-trained male runners. PeerJ 2024; 12:e17166. [PMID: 38563004 PMCID: PMC10984165 DOI: 10.7717/peerj.17166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 03/06/2024] [Indexed: 04/04/2024] Open
Abstract
Objectives To test the hypothesis that 'live high-base train high-interval train low' (HiHiLo) altitude training, compared to 'live low-train high' (LoHi), yields greater benefits on performance and physiological adaptations. Methods Sixteen young male middle-distance runners (age, 17.0 ± 1.5 y; body mass, 58.8 ± 4.9 kg; body height, 176.3 ± 4.3 cm; training years, 3-5 y; training distance per week, 30-60 km.wk-1) with a peak oxygen uptake averaging ~65 ml.min-1.kg-1 trained in a normobaric hypoxia chamber (simulated altitude of ~2,500 m, monitored by heart rate ~170 bpm; thrice weekly) for 3 weeks. During this period, the HiHiLo group (n = 8) stayed in normobaric hypoxia (at ~2,800 m; 10 h.day-1), while the LoHi group (n = 8) resided near sea level. Before and immediately after the intervention, peak oxygen uptake and exercise-induced arterial hypoxemia responses (incremental cycle test) as well as running performance and time-domain heart rate variability (5-km time trial) were assessed. Hematological variables were monitored at baseline and on days 1, 7, 14 and 21 during the intervention. Results Peak oxygen uptake and running performance did not differ before and after the intervention in either group (all P > 0.05). Exercise-induced arterial hypoxemia responses, measured both at submaximal (240 W) and maximal loads during the incremental test, and log-transformed root mean square of successive R-R intervals during the 4-min post-run recovery period, did not change (all P > 0.05). Hematocrit, mean reticulocyte absolute count and reticulocyte percentage increased above baseline levels on day 21 of the intervention (all P < 0.001), irrespective of group. Conclusions Well-trained runners undertaking base training at moderate simulated altitude for 3 weeks, with or without hypoxic residence, showed no performance improvement, also with unchanged time-domain heart rate variability and exercise-induced arterial hypoxemia responses.
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Affiliation(s)
- Longyan Yi
- China Institute of Sport and Health Sciences, Beijing Sport University, Beijing, China
| | - Jian Wu
- School of Kinesiology and Health, Capital University of Physical Education and Sports, Beijing, China
| | - Bing Yan
- China Institute of Sport and Health Sciences, Beijing Sport University, Beijing, China
| | - Yang Wang
- China Institute of Sport and Health Sciences, Beijing Sport University, Beijing, China
| | - Menghui Zou
- China Athletics School, Beijing Sport University, Beijing, China
| | - Yimin Zhang
- China Institute of Sport and Health Sciences, Beijing Sport University, Beijing, China
- Key Laboratory of Exercise and Physical Fitness (Beijing Sport University), Ministry of Education, Beijing, China
| | - Feifei Li
- Centre for Health and Exercise Science Research, Department of Sport, Physical Education and Health, Hong Kong Baptist University, Beijing, China
| | - Junqiang Qiu
- Department of Exercise Biochemistry, Exercise Science School, Beijing Sport University, Beijing, China
| | - Olivier Girard
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia.
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Feng X, Zhao L, Chen Y, Wang Z, Lu H, Wang C. Optimal type and dose of hypoxic training for improving maximal aerobic capacity in athletes: a systematic review and Bayesian model-based network meta-analysis. Front Physiol 2023; 14:1223037. [PMID: 37745240 PMCID: PMC10513096 DOI: 10.3389/fphys.2023.1223037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Objective: This study aimed to compare and rank the effect of hypoxic practices on maximum oxygen consumption (VO2max) in athletes and determine the hypoxic dose-response correlation using network meta-analysis. Methods: The Web of Science, PubMed, EMBASE, and EBSCO databases were systematically search for randomized controlled trials on the effect of hypoxc interventions on the VO2max of athletes published from inception until 21 February 2023. Studies that used live-high train-high (LHTH), live-high train-low (LHTL), live-high, train-high/low (HHL), intermittent hypoxic training (IHT), and intermittent hypoxic exposure (IHE) interventions were primarily included. LHTL was further defined according to the type of hypoxic environment (natural and simulated) and the altitude of the training site (low altitude and sea level). A meta-analysis was conducted to determine the standardized mean difference between the effects of various hypoxic interventions on VO2max and dose-response correlation. Furthermore, the hypoxic dosage of the different interventions were coordinated using the "kilometer hour" model. Results: From 2,072 originally identified titles, 59 studies were finally included in this study. After data pooling, LHTL, LHTH, and IHT outperformed normoxic training in improving the VO2max of athletes. According to the P-scores, LHTL combined with low altitude training was the most effective intervention for improving VO2max (natural: 0.92 and simulated: 0.86) and was better than LHTL combined with sea level training (0.56). A reasonable hypoxic dose range for LHTH (470-1,130 kmh) and HL (500-1,415 kmh) was reported with an inverted U-shaped curve relationship. Conclusion: Different types of hypoxic training compared with normoxic training serve as significant approaches for improving aerobic capacity in athletes. Regardless of the type of hypoxic training and the residential condition, LHTL with low altitude training was the most effective intervention. The characteristics of the dose-effect correlation of LHTH and LHTL may be associated with the negative effects of chronic hypoxia.
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Affiliation(s)
- Xinmiao Feng
- Sports Coaching College, Beijing Sports University, Beijing, China
| | - Linlin Zhao
- Sports Coaching College, Beijing Sports University, Beijing, China
| | | | - Zihao Wang
- Capital Institute of Physical Education and Sports, Beijing, Beijing, China
| | - Hongyuan Lu
- Sports Coaching College, Beijing Sports University, Beijing, China
| | - Chuangang Wang
- Sports Coaching College, Beijing Sports University, Beijing, China
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Nordsborg NB, Bonne TC, Breenfeldt Andersen A, Sørensen H, Bejder J. Glucocorticoids Accelerate Erythropoiesis in Healthy Humans-Should the Use in Sports Be Reevaluated? Med Sci Sports Exerc 2023; 55:1334-1341. [PMID: 36878016 DOI: 10.1249/mss.0000000000003156] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
Abstract
PURPOSE The World Anti-Doping Agency prohibits glucocorticoid administration in competition but not in periods out of competition. Glucocorticoid usage is controversial as it may improve performance, albeit debated. A hitherto undescribed but performance-relevant effect of glucocorticoids in healthy humans is accelerated erythropoiesis. We investigated whether a glucocorticoid injection accelerates erythropoiesis, increases total hemoglobin mass, and improves exercise performance. METHODS In a counterbalanced, randomized, double-blinded, placebo-controlled crossover design (3 months washout), 10 well-trained males (peak oxygen uptake, 60 ± 3 mL O 2 ·min -1 ·kg -1 ) were injected with 40 mg triamcinolone acetonide (glucocorticoid group) or saline (placebo group) in the gluteal muscles. Venous blood samples collected before and 7-10 h, 1, 3, 7, 14, and 21 d after treatment were analyzed for hemoglobin concentration and reticulocyte percentage. Hemoglobin mass and mean power output in a 450-kcal time trial were measured before as well as 1 and 3 wk after treatment. RESULTS A higher reticulocyte percentage was evident 3 d (19% ± 30%, P < 0.05) and 7 d (48% ± 38%, P < 0.001) after glucocorticoid administration, compared with placebo, whereas hemoglobin concentration was similar between groups. Additionally, hemoglobin mass was higher ( P < 0.05) 7 d (glucocorticoid, 886 ± 104 g; placebo, 872 ± 103 g) and 21 d (glucocorticoid, 879 ± 111 g; placebo, 866 ± 103 g) after glucocorticoid administration compared with placebo. Mean power output was similar between groups 7 d (glucocorticoid, 278 ± 64 W; placebo, 275 ± 62 W) and 21 d (glucocorticoid, 274 ± 62 W; placebo, 275 ± 60 W) after treatment. CONCLUSIONS Intramuscular injection of 40 mg triamcinolone acetonide accelerates erythropoiesis and increases hemoglobin mass but does not improve aerobic exercise performance in the present study. The results are important for sport physicians administering glucocorticoids and prompt a reconsideration of glucocorticoid usage in sport.
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Affiliation(s)
| | - Thomas Christian Bonne
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, DENMARK
| | | | - Henrik Sørensen
- Department of Anesthesiology, Centre for Cancer and Organ Diseases, Rigshospitalet, University of Copenhagen, Copenhagen, DENMARK
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, DENMARK
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Girard O, Levine BD, Chapman RF, Wilber R. "Living High-Training Low" for Olympic Medal Performance: What Have We Learned 25 Years After Implementation? Int J Sports Physiol Perform 2023; 18:563-572. [PMID: 37116895 DOI: 10.1123/ijspp.2022-0501] [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] [Received: 12/31/2022] [Revised: 02/16/2023] [Accepted: 03/28/2023] [Indexed: 04/30/2023]
Abstract
BACKGROUND Altitude training is often regarded as an indispensable tool for the success of elite endurance athletes. Historically, altitude training emerged as a key strategy to prepare for the 1968 Olympics, held at 2300 m in Mexico City, and was limited to the "Live High-Train High" method for endurance athletes aiming for performance gains through improved oxygen transport. This "classical" intervention was modified in 1997 by the "Live High-Train Low" (LHTL) model wherein athletes supplemented acclimatization to chronic hypoxia with high-intensity training at low altitude. PURPOSE This review discusses important considerations for successful implementation of LHTL camps in elite athletes based on experiences, both published and unpublished, of the authors. APPROACH The originality of our approach is to discuss 10 key "lessons learned," since the seminal work by Levine and Stray-Gundersen was published in 1997, and focusing on (1) optimal dose, (2) individual responses, (3) iron status, (4) training-load monitoring, (5) wellness and well-being monitoring, (6) timing of the intervention, (7) use of natural versus simulated hypoxia, (8) robustness of adaptative mechanisms versus performance benefits, (9) application for a broad range of athletes, and (10) combination of methods. Successful LHTL strategies implemented by Team USA athletes for podium performance at Olympic Games and/or World Championships are presented. CONCLUSIONS The evolution of the LHTL model represents an essential framework for sport science, in which field-driven questions about performance led to critical scientific investigation and subsequent practical implementation of a unique approach to altitude training.
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Affiliation(s)
- Olivier Girard
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, WA,Australia
| | - Benjamin D Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, TX,USA
- University of Texas Southwestern Medical Center, Dallas, TX,USA
| | - Robert F Chapman
- Human Performance Laboratory, Department of Kinesiology, Indiana University Bloomington, Bloomington, IN,USA
| | - Randall Wilber
- United States Olympic Committee, Colorado Springs, CO,USA
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Training in Hypoxia at Alternating High Altitudes Is a Factor Favoring the Increase in Sports Performance. Healthcare (Basel) 2022; 10:healthcare10112296. [PMID: 36421619 PMCID: PMC9691031 DOI: 10.3390/healthcare10112296] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 11/12/2022] [Accepted: 11/14/2022] [Indexed: 11/19/2022] Open
Abstract
Training above 1800 m causes increases in hemoglobin, erythropoietin and VO2max values in the bodies of athletes. The purpose of this study is to prove that living at an altitude of 1850 m and training at 2200 m (LHTH+) is more effective than living and training at 2000 m (LHTH). Ten endurance athletes (age 21.2 ± 1.5 years, body mass 55.8 ± 4.3 kg, height 169 ± 6 cm, performance 3000 m 8:35 ± 0:30 min) performed three training sessions of 30 days, in three different situations: [1] living and training at 2000 m altitude (LHTH), [2] living at 1850 m and training at 2200 m (LHTH+), and [3] living and training at 300 m (LLTL). The differences in erythropoietin (EPO), hemoglobin (Hb) concentration, and VO2max values were compared before and at the end of each training session. Data analysis indicated that LHTH training caused an increase in EPO values (by 1.0 ± 0.8 mU/mL, p = 0.002 < 0.05.); Hb (by 1.1 ± 0.3 g/dL, p < 0.001); VO2max (by 0.9 ± 0.23 mL/kg/min, p < 0.001). LHTH+ training caused an increase in EPO values (by 1.9 ± 0.5 mU/ML, p < 0.001); Hb (by 1.4 ± 0.5 g/dL, p < 0.001); VO2max (by 1.7 ± 0.3 mL/kg/min, p < 0.001). At the LLTL training, EPO values do not have a significant increase (p = 0.678 > 0.050; 1 ± 0.1 mU/mL, 0.1 ± 0.9%.), Hb (0.1 ± 0.0 g/dL, 0.3 ± 0.3%), VO2max (0.1 ± 0.1, 0.2 ± 0.2%, p = 0.013 < 0.05). Living and training at altitudes of 2000 m (LHTH) and living at 1850 m training at 2200 m (LHTH+) resulted in significant improvements in EPO, Hb, and VO2max that exceeded the changes in these parameters, following traditional training at 300 m (LLTL). LHTH+ training has significantly greater changes than LHTH training, favorable to increasing sports performance. The results of this study can serve as guidelines for athletic trainers in their future work, in the complete structure of multi-year planning and programming, and thus improve the process of development and performance training.
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Arrebola-Moreno AL, Casuso RA, Bejder J, Bonne TC, Breenfeldt Andersen A, Aragón-Vela J, Nordsborg NB, Huertas JR. Does Hypoxia and Stress Erythropoiesis Compromise Cardiac Function in Healthy Adults? A Randomized Trial. SPORTS MEDICINE - OPEN 2022; 8:137. [PMID: 36334130 PMCID: PMC9637068 DOI: 10.1186/s40798-022-00531-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Accepted: 10/20/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVES To investigate whether recombinant human erythropoietin (rHuEPO) injections during an altitude training camp impact heart function. METHODS Thirty (12 women) moderately trained subjects stayed at 2320 m altitude for 4 weeks while training. Subjects were randomized to placebo (isotonic saline) or rHuEPO (20 IU/kg body weight) i.v. injections. Transthoracic echocardiography imaging was acquired 3 days after arrival to altitude and prior to the first placebo or rHuEPO injection as well as one day after the last rHuEPO injection three weeks later. RESULTS rHuEPO did not alter cardiovascular morphology parameters, systolic or diastolic function. In the placebo group, altitude exposure improved left ventricle (LV) systolic function due to an increased twist angle but rHuEPO had no additional effects. Pulmonary arterial systolic pressure was unaffected in either group. Notably, rHuEPO hampered LV untwist rate without affecting LV early filling. CONCLUSION rHuEPO provided during mild altitude exposure does not cause any major effects on heart function. The observed alteration in LV untwist induced by rHuEPO is unlikely to have a meaningful clinical effect. Trial Registration Registered on www. CLINICALTRIALS gov (NCT04227665).
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Affiliation(s)
| | - Rafael A. Casuso
- grid.4489.10000000121678994Department of Physiology, Institute of Nutrition and Food Technology, University of Granada, Granada, Spain ,grid.449008.10000 0004 1795 4150Department of Health Sciences, Universidad Loyola Andalucía, Sevilla, Spain
| | - Jacob Bejder
- grid.5254.60000 0001 0674 042XDepartment of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Thomas Christian Bonne
- grid.5254.60000 0001 0674 042XDepartment of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Andreas Breenfeldt Andersen
- grid.5254.60000 0001 0674 042XDepartment of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jerónimo Aragón-Vela
- grid.4489.10000000121678994Department of Physiology, Institute of Nutrition and Food Technology, University of Granada, Granada, Spain
| | - Nikolai B. Nordsborg
- grid.5254.60000 0001 0674 042XDepartment of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jesús R. Huertas
- grid.4489.10000000121678994Department of Physiology, Institute of Nutrition and Food Technology, University of Granada, Granada, Spain
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Breenfeldt Andersen A, Bonne TC, Bejder J, Jung G, Ganz T, Nemeth E, Olsen NV, Huertas JR, Nordsborg NB. Effects of altitude and recombinant human erythropoietin on iron metabolism: a randomized controlled trial. Am J Physiol Regul Integr Comp Physiol 2021; 321:R152-R161. [PMID: 34160288 DOI: 10.1152/ajpregu.00070.2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Current markers of iron deficiency (ID), such as ferritin and hemoglobin, have shortcomings, and hepcidin and erythroferrone (ERFE) could be of clinical relevance in relation to early assessment of ID. Here, we evaluate whether exposure to altitude-induced hypoxia (2,320 m) alone, or in combination with recombinant human erythropoietin (rHuEPO) treatment, affects hepcidin and ERFE levels before alterations in routine ID biomarkers and stress erythropoiesis manifest. Two interventions were completed, each comprising a 4-wk baseline, a 4-wk intervention at either sea level or altitude, and a 4-wk follow-up. Participants (n = 39) were randomly assigned to 20 IU·kg body wt-1 rHuEPO or placebo injections every second day for 3 wk during the two intervention periods. Venous blood was collected weekly. Altitude increased ERFE (P ≤ 0.001) with no changes in hepcidin or routine iron biomarkers, making ERFE of clinical relevance as an early marker of moderate hypoxia. rHuEPO treatment at sea level induced a similar pattern of changes in ERFE (P < 0.05) and hepcidin levels (P < 0.05), demonstrating the impact of accelerated erythropoiesis and not of other hypoxia-induced mechanisms. Compared with altitude alone, concurrent rHuEPO treatment and altitude exposure induced additive changes in hepcidin (P < 0.05) and ERFE (P ≤ 0.001) parallel with increases in hematocrit (P < 0.001), demonstrating a relevant range of both hepcidin and ERFE. A poor but significant correlation between hepcidin and ERFE was found (R2 = 0.13, P < 0.001). The findings demonstrate that hepcidin and ERFE are more rapid biomarkers of changes in iron demands than routine iron markers. Finally, ERFE and hepcidin may be sensitive markers in an antidoping context.
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Affiliation(s)
| | - Thomas C Bonne
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Grace Jung
- Department of Medicine and Pathology, Center for Iron Disorders, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Tomas Ganz
- Department of Medicine and Pathology, Center for Iron Disorders, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Elizabeta Nemeth
- Department of Medicine and Pathology, Center for Iron Disorders, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California
| | - Niels Vidiendal Olsen
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jesús Rodríguez Huertas
- Department of Physiology, Faculty of Sport Sciences, Institute of Nutrition and Food Technology, Biomedical Research Centre, University of Granada, Armilla, Spain
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Jeppesen JS, Breenfeldt Andersen A, Bonne TC, Thomassen M, Sørensen H, Nordsborg NB, Olsen NV, Huertas JR, Bejder J. Immature reticulocytes are sensitive and specific to low-dose erythropoietin treatment at sea level and altitude. Drug Test Anal 2021; 13:1331-1340. [PMID: 33739618 DOI: 10.1002/dta.3031] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/16/2021] [Accepted: 03/16/2021] [Indexed: 11/07/2022]
Abstract
We investigated whether immature reticulocyte fraction (IRF) and immature reticulocytes to red blood cells ratio (IR/RBC) are sensitive biomarkers for low-dose recombinant human erythropoietin (rhEpo) treatment at sea level (SL) and moderate altitude (AL) and whether multi (FACS) or single (Sysmex-XN) fluorescence flow cytometry is superior for IRF and IR/RBC determination. Thirty-nine participants completed two interventions, each containing a 4-week baseline, a 4-week SL or AL (2,230 m) exposure, and a 4-week follow-up. During exposure, rhEpo (20 IU kg-1 ) or placebo (PLA) was injected at SL (SLrhEpo , n = 25, SLPLA n = 9) and AL (ALrhEpo , n = 12, ALPLA n = 27) every second day for 3 weeks. Venous blood was collected weekly. Sysmex measurements revealed that IRF and IR/RBC were up to ~70% (P < 0.01) and ~190% (P < 0.001) higher in SLrhEpo than SLPLA during treatment and up to ~45% (P < 0.001) and ~55% (P < 0.01) lower post-treatment, respectively. Compared with ALPLA , IRF and IR/RBC were up to ~20% (P < 0.05) and ~45% (P < 0.001) lower post-treatment in SLrhEpo , respectively. In ALrhEpo , IRF and IR/RBC were up to ~40% (P < 0.05) and ~110% (P < 0.001) higher during treatment and up to ~25% (P < 0.05) and ~40% (P < 0.05) lower post-treatment, respectively, compared with ALPLA . Calculated thresholds provided ~90% sensitivity for both biomarkers at SL and 33% (IRF) and 66% (IR/RBC) at AL. Specificity was >99%. Single-fluorescence flow cytometry coefficient of variation was >twofold higher at baseline (P < 0.001) and provided larger or similar changes compared to multi-fluorescence, albeit with smaller precision. In conclusion, IRF and IR/RBC were sensitive and specific biomarkers for low-dose rhEpo misuse at SL and AL.
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Affiliation(s)
- Jan Sommer Jeppesen
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | | | - Thomas Christian Bonne
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Martin Thomassen
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Helle Sørensen
- Data Science Lab, Department of Mathematical Sciences, University of Copenhagen, Copenhagen, Denmark
| | | | - Niels Vidiendal Olsen
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jesús Rodríguez Huertas
- Department of Physiology, Faculty of Sport Sciences, Institute of Nutrition and Food Technology, Biomedical Research Centre, University of Granada, Armilla, Spain
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
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10
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Breenfeldt Andersen A, Bejder J, Bonne T, Olsen NV, Nordsborg N. Repeated Wingate sprints is a feasible high-quality training strategy in moderate hypoxia. PLoS One 2020; 15:e0242439. [PMID: 33186393 PMCID: PMC7665825 DOI: 10.1371/journal.pone.0242439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Accepted: 11/02/2020] [Indexed: 12/21/2022] Open
Abstract
Sprint-interval training (SIT) is efficient at improving maximal aerobic capacity and anaerobic fitness at sea-level and may be a feasible training strategy at altitude. Here, it was evaluated if SIT intensity can be maintained in mild to moderate hypoxia. It was hypothesized that 6 x 30 s Wingate sprint performance with 2 min active rest between sprints can be performed in hypoxic conditions corresponding to ~3,000 m of altitude without reducing mean power output (MPO). In a single-blinded, randomized crossover design, ten highly-trained male endurance athletes with a maximal oxygen uptake ([Formula: see text]O2max) of 68 ± 5 mL O2 × min-1 × kg-1 completed 6 x 30 s all-out Wingate cycling sprints separated by two-minute active recovery on four separate days in a hypobaric chamber. The ambient pressure within the chamber on each experimental day was 772 mmHg (~0 m), 679 mmHg (~915 m), 585 mmHg (~ 2,150 m), and 522 mmHg (~3,050 m), respectively. MPO was not different at sea-level and up to ~2,150 m (~1% and ~3% non-significant decrements at ~915 and ~2,150 m, respectively), whereas MPO was ~5% lower (P<0.05) at ~3,050 m. Temporal differences between altitudes was not different for peak power output (PPO), despite a main effect of altitude. In conclusion, repeated Wingate exercise can be completed by highly-trained athletes at altitudes up to ~2,150 m without compromising MPO or PPO. In contrast, MPO was compromised in hypobaric hypoxia corresponding to ~3,050 m. Thus, SIT may be an efficient strategy for athletes sojourning to moderate altitude and aiming to maintain training quality.
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Affiliation(s)
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Thomas Bonne
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Niels Vidiendal Olsen
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
- Department of Neuroanesteshia, The Neuroscience Center, Copenhagen University Hospital (Rigshospitalet), Copenhagen, Denmark
| | - Nikolai Nordsborg
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
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Bejder J, Breenfeldt Andersen A, Bonne TC, Linkis J, Olsen NV, Huertas JR, Nordsborg NB. Hematological adaptations and detection of recombinant human erythropoietin combined with chronic hypoxia. Drug Test Anal 2020; 13:360-368. [PMID: 32955164 DOI: 10.1002/dta.2931] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/31/2020] [Accepted: 09/09/2020] [Indexed: 01/26/2023]
Abstract
This study evaluated whether recombinant human erythropoietin (rhEpo) treatment combined with chronic hypoxia provided an additive erythropoietic response and whether the athlete biological passport (ABP) sensitivity improved with hypoxia. Two interventions were completed, each containing 4 weeks baseline, 4 weeks exposure at sea level or 2,320 m of altitude, and 4 weeks follow-up. Participants were randomly assigned to 20 IU·kg bw-1 rhEpo or placebo injections every second day for 3 weeks during the exposure period at sea level (rhEpo n = 25, placebo n = 9) or at altitude (rhEpo n = 12, placebo n = 27). Venous blood was analyzed weekly. Combining rhEpo and hypoxia induced larger changes compared with rhEpo or hypoxia alone for [Hb] (p < 0.001 and p > 0.05, respectively), reticulocyte percentage (p < 0.001), and OFF-hr score (p < 0.01 and p < 0.001, respectively). The most pronounced effect was observed for reticulocyte percentage with up to ~35% (p < 0.001) and ~45% (p < 0.001) higher levels compared with rhEpo or hypoxia only, respectively. The ABP sensitivity for the combined treatment was 54 and 35 percentage points higher for [Hb] (p < 0.05) and reticulocyte percentage (p < 0.05), respectively, but similar for OFF-hr score, compared with rhEpo at sea level. Across any time point, [Hb] and OFF-hr score combined identified 14 unique true-positive participants (56%) at sea level and 12 unique true-positive participants (100%) at altitude. However, a concurrent reduction in specificity existed at altitude. In conclusion, rhEpo treatment combined with hypoxic exposure provided an additive erythropoietic response compared with rhEpo or hypoxic exposure alone. Correspondingly, ABP was more sensitive to rhEpo at altitude than at sea level, but a compromised specificity existed with hypoxic exposure.
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Affiliation(s)
- Jacob Bejder
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | | | - Thomas Christian Bonne
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Jesper Linkis
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Niels Vidiendal Olsen
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Jesús Rodríguez Huertas
- Department of Physiology, Faculty of Sport Sciences, Institute of Nutrition and Food Technology, Biomedical Research Centre, University of Granada, Granada, Spain
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12
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Álvarez-Herms J, Julià-Sánchez S, Corbi F, Odriozola-Martínez A, Burtscher M. Putative Role of Respiratory Muscle Training to Improve Endurance Performance in Hypoxia: A Review. Front Physiol 2019; 9:1970. [PMID: 30697170 PMCID: PMC6341067 DOI: 10.3389/fphys.2018.01970] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 12/31/2018] [Indexed: 12/22/2022] Open
Abstract
Respiratory/inspiratory muscle training (RMT/IMT) has been proposed to improve the endurance performance of athletes in normoxia. In recent years, due to the increased use of hypoxic training method among athletes, the RMT applicability has also been tested as a method to minimize adverse effects since hyperventilation may cause respiratory muscle fatigue during prolonged exercise in hypoxia. We performed a review in order to determine factors potentially affecting the change in endurance performance in hypoxia after RMT in healthy subjects. A comprehensive search was done in the electronic databases MEDLINE and Google Scholar including keywords: “RMT/IMT,” and/or “endurance performance,” and/or “altitude” and/or “hypoxia.” Seven appropriate studies were found until April 2018. Analysis of the studies showed that two RMT methods were used in the protocols: respiratory muscle endurance (RME) (isocapnic hyperpnea: commonly 10–30′, 3–5 d/week) in three of the seven studies, and respiratory muscle strength (RMS) (Powerbreathe device: commonly 2 × 30 reps at 50% MIP (maximal inspiratory pressure), 5–7 d/week) in the remaining four studies. The duration of the protocols ranged from 4 to 8 weeks, and it was found in synthesis that during exercise in hypoxia, RMT promoted (1) reduced respiratory muscle fatigue, (2) delayed respiratory muscle metaboreflex activation, (3) better maintenance of SaO2 and blood flow to locomotor muscles. In general, no increases of maximal oxygen uptake (VO2max) were described. Ventilatory function improvements (maximal inspiratory pressure) achieved by using RMT fostered the capacity to adapt to hypoxia and minimized the impact of respiratory stress during the acclimatization stage in comparison with placebo/sham. In conclusion, RMT was found to elicit general positive effects mainly on respiratory efficiency and breathing patterns, lower dyspneic perceptions and improved physical performance in conditions of hypoxia. Thus, this method is recommended to be used as a pre-exposure tool for strengthening respiratory muscles and minimizing the adverse effects caused by hypoxia related hyperventilation. Future studies will assess these effects in elite athletes.
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Affiliation(s)
- Jesús Álvarez-Herms
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Sonia Julià-Sánchez
- Department of Cell Biology, Physiology and Immunology, Faculty of Biology, University of Barcelona, Barcelona, Spain
| | - Francisco Corbi
- National Institute of Physical Education of Catalonia (INEFC) - Lleida Centre, University of Lleida, Lleida, Spain
| | - Adrian Odriozola-Martínez
- Department of Genetics, Anthropology and Physiology, University of the Basque Country (UPV), Campus de Bizkaia, Bilbao, Spain
| | - Martin Burtscher
- Department of Sport Science, University Innsbruck, Innsbruck, Austria
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13
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Girard O, Brocherie F, Millet GP. Effects of Altitude/Hypoxia on Single- and Multiple-Sprint Performance: A Comprehensive Review. Sports Med 2018; 47:1931-1949. [PMID: 28451905 DOI: 10.1007/s40279-017-0733-z] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Many sport competitions, typically involving the completion of single- (e.g. track-and-field or track cycling events) and multiple-sprint exercises (e.g. team and racquet sports, cycling races), are staged at terrestrial altitudes ranging from 1000 to 2500 m. Our aim was to comprehensively review the current knowledge on the responses to either acute or chronic altitude exposure relevant to single and multiple sprints. Performance of a single sprint is generally not negatively affected by acute exposure to simulated altitude (i.e. normobaric hypoxia) because an enhanced anaerobic energy release compensates for the reduced aerobic adenosine triphosphate production. Conversely, the reduction in air density in terrestrial altitude (i.e. hypobaric hypoxia) leads to an improved sprinting performance when aerodynamic drag is a limiting factor. With the repetition of maximal efforts, however, repeated-sprint ability is more altered (i.e. with earlier and larger performance decrements) at high altitudes (>3000-3600 m or inspired fraction of oxygen <14.4-13.3%) compared with either normoxia or low-to-moderate altitudes (<3000 m or inspired fraction of oxygen >14.4%). Traditionally, altitude training camps involve chronic exposure to low-to-moderate terrestrial altitudes (<3000 m or inspired fraction of oxygen >14.4%) for inducing haematological adaptations. However, beneficial effects on sprint performance after such altitude interventions are still debated. Recently, innovative 'live low-train high' methods, in isolation or in combination with hypoxic residence, have emerged with the belief that up-regulated non-haematological peripheral adaptations may further improve performance of multiple sprints compared with similar normoxic interventions.
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Affiliation(s)
- Olivier Girard
- Aspetar Orthopaedic and Sports Medicine Hospital, Athlete Health and Performance Research Centre, Doha, Qatar.
- ISSUL, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland.
| | - Franck Brocherie
- Laboratory Sport, Expertise and Performance (EA 7370), Research Department, French Institute of Sport (INSEP), Paris, France
- ISSUL, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
| | - Grégoire P Millet
- ISSUL, Institute of Sport Sciences, University of Lausanne, Lausanne, Switzerland
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Turner G, Fudge BW, Pringle JSM, Maxwell NS, Richardson AJ. Altitude training in endurance running: perceptions of elite athletes and support staff. J Sports Sci 2018; 37:163-172. [PMID: 29932816 DOI: 10.1080/02640414.2018.1488383] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
This study sought to establish perceptions of elite endurance athletes on the role and worth of altitude training. Elite British endurance runners were surveyed to identify the altitude and hypoxic training methods utilised, along with reasons for use, and any situational, cultural and behaviour factors influencing these. Prior to the 2012 Olympics Games, 39 athletes and 20 support staff (coaches/practitioners) completed an internet-based survey to establish differences between current practices and the accepted "best-practice". Almost all of the athletes (98%) and support staff (95%) surveyed had utilised altitude and hypoxic training, or had advised it to athletes. 75% of athletes believed altitude and hypoxia to be a "very important" factor in their training regime, with 50% of support staff believing the same. Athletes and support staff were in agreement of the methods of altitude training utilised (i.e. 'hypoxic dose' and strategy), with camps lasting 3-4 weeks at 1,500-2,500 m being the most popular. Athletes and support staff are utilising altitude and hypoxic training methods in a manner agreeing with research-based suggestions. The survey identified a number of specific challenges and priorities, which could provide scope to optimise future altitude training methods for endurance performance in these elite groups.
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Affiliation(s)
- Gareth Turner
- a Centre for Sport and Exercise Science and Medicine (SESAME) , University of Brighton , Eastbourne , UK.,c EIS Performance Centre , Loughborough University , Loughborough , UK
| | - Barry W Fudge
- b National Performance Centre , Loughborough University , Loughborough , UK
| | - Jamie S M Pringle
- c EIS Performance Centre , Loughborough University , Loughborough , UK
| | - Neil S Maxwell
- a Centre for Sport and Exercise Science and Medicine (SESAME) , University of Brighton , Eastbourne , UK
| | - Alan J Richardson
- a Centre for Sport and Exercise Science and Medicine (SESAME) , University of Brighton , Eastbourne , UK
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15
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Bejder J, Nordsborg NB. Specificity of “Live High-Train Low” Altitude Training on Exercise Performance. Exerc Sport Sci Rev 2018; 46:129-136. [DOI: 10.1249/jes.0000000000000144] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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16
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Botek M, Krejčí J, McKune A. Sex Differences in Autonomic Cardiac Control and Oxygen Saturation Response to Short-Term Normobaric Hypoxia and Following Recovery: Effect of Aerobic Fitness. Front Endocrinol (Lausanne) 2018; 9:697. [PMID: 30532736 PMCID: PMC6265316 DOI: 10.3389/fendo.2018.00697] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2018] [Accepted: 11/05/2018] [Indexed: 01/06/2023] Open
Abstract
Introduction: The main aims of this study were to investigate autonomic nervous system (ANS) and arterial oxygen saturation (SpO2) responses to simulated altitude in males and females, and to determine the association between maximal oxygen uptake (VO2max) and these responses. Materials and Methods: Heart rate variability (HRV) and SpO2 were monitored in a resting supine position during Preliminary (6 min normoxia), Hypoxia (10 min, fraction of inspired oxygen (FiO2) of 9.6%, simulated altitude ~6,200 m) and Recovery (6 min normoxia) phases in 28 males (age 23.7 ± 1.7 years, normoxic VO2max 59.0 ± 7.8 ml.kg-1.min-1, body mass index (BMI) 24.2 ± 2.1 kg.m-2) and 30 females (age 23.8 ± 1.8 years, VO2max 45.1 ± 8.7 ml.kg-1.min-1, BMI 21.8 ± 3.0 kg.m-2). Spectral analysis of HRV quantified the ANS activity by means of low frequency (LF, 0.05-0.15 Hz) and high frequency (HF, 0.15-0.50 Hz) power, transformed by natural logarithm (Ln). Time domain analysis incorporated the square root of the mean of the squares of the successive differences (rMSSD). Results: There were no significant differences in SpO2 level during hypoxia between the males (71.9 ± 7.5%) and females (70.8 ± 7.1%). Vagally-related HRV variables (Ln HF and Ln rMSSD) exhibited no significant differences between sexes across each phase. However, while the sexes demonstrated similar Ln LF/HF values during the Preliminary phase, the males (0.5 ± 1.3) had a relatively higher (p = 0.001) sympathetic activity compared to females (-0.6 ± 1.4) during the Hypoxia phase. Oxygen desaturation during resting hypoxia was significantly correlated with VO2max in males (r = -0.45, p = 0.017) but not in females (r = 0.01, p = 0.952) and difference between regression lines were significant (p = 0.024). Conclusions: Despite similar oxygen desaturation levels, males exhibited a relatively higher sympathetic responses to hypoxia exposure compared with females. In addition, the SpO2 response to resting hypoxia exposure was related to maximal aerobic capacity in males but not females.
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Affiliation(s)
- Michal Botek
- Department of Natural Sciences in Kinanthropology, Faculty of Physical Culture, Palacký University Olomouc, Olomouc, Czechia
| | - Jakub Krejčí
- Department of Natural Sciences in Kinanthropology, Faculty of Physical Culture, Palacký University Olomouc, Olomouc, Czechia
- *Correspondence: Jakub Krejčí
| | - Andrew McKune
- Discipline of Sport and Exercise Science, School of Rehabilitation and Exercise Sciences, Research Institute for Sport and Exercise Science, University of Canberra, Canberra, ACT, Australia
- Discipline of Biokinetics, Exercise and Leisure Sciences, School of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
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Wonnabussapawich P, Hamlin MJ, Lizamore CA, Manimmanakorn N, Leelayuwat N, Tunkamnerdthai O, Thuwakum W, Manimmanakorn A. Living and Training at 825 m for 8 Weeks Supplemented With Intermittent Hypoxic Training at 3,000 m Improves Blood Parameters and Running Performance. J Strength Cond Res 2017; 31:3287-3294. [DOI: 10.1519/jsc.0000000000002227] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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18
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Álvarez-Herms J, Julià-Sánchez S, Gatterer H, Blank C, Corbi F, Pagès T, Burtscher M, Viscor G. Anaerobic training in hypoxia: A new approach to stimulate the rating of effort perception. Physiol Behav 2016; 163:37-42. [PMID: 27126970 DOI: 10.1016/j.physbeh.2016.04.035] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2015] [Revised: 01/20/2016] [Accepted: 04/18/2016] [Indexed: 01/20/2023]
Abstract
This study compared subjective effort perception with objective physiological measures during high-intensive intermittent exercise performed in normoxia, moderate hypoxia (FiO2: 16.5%) and severe hypoxia (FiO2: 13.5%). Sixteen physically active subjects performed an equal training session on three different days. Training consisted of 6 "all-out" series of continuous jumps lasting for 15s each. Average power output during the jumps was similar in all three conditions (~3200W). Greater hypoxemia was observed in hypoxia as compared to normoxia. Likewise, a significantly higher value in perceived effort was observed after hypoxia training as compared to normoxia training (p<0.05). Whereas blood lactate concentrations immediately after training were not different between normoxia and hypoxia, creatine kinase increased in moderate (p=0.02) and severe (p<0.01) hypoxia compared to normoxia 24h after the training. Perceived fatigue was also significantly elevated 24h after hypoxic exercise only. Heart rate variability pre and 24h after exercise showed a tendency to sympathetic predominance in severe hypoxia as compared to moderate hypoxia and normoxia. In conclusion, a single session of anaerobic exercise can be executed at the same intensity in moderate/severe hypoxia as in normoxia. This type of hypoxic training may be considered as a method potentially to improve the ability tolerating discomfort and consequently also exercise performance.
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Affiliation(s)
- J Álvarez-Herms
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Diagonal Sud, Facultat de Biologia, Avinguda Diagonal, 643, 08028 Barcelona, Spain.
| | - S Julià-Sánchez
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Diagonal Sud, Facultat de Biologia, Avinguda Diagonal, 643, 08028 Barcelona, Spain.
| | - H Gatterer
- Department of Sport Science, Medical Section, University of Innsbruck, Fürstenweg 185, Innsbruck, Austria.
| | - C Blank
- Department for Medical Sciences and Health Systems Management, Institute for Sports Medicine, Alpine Medicine & Health Tourism, UMIT, Eduard-Wallnöfer-Zentrum 1, 6060 Hall in Tirol, Austria.
| | - F Corbi
- National Institute of Physical Education of Catalonia, Faculty of Lleida, University of Lleida, Complex de la Caparrella, s/n, 25192, Spain.
| | - T Pagès
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Diagonal Sud, Facultat de Biologia, Avinguda Diagonal, 643, 08028 Barcelona, Spain.
| | - M Burtscher
- Department of Sport Science, Medical Section, University of Innsbruck, Fürstenweg 185, Innsbruck, Austria.
| | - G Viscor
- Department of Physiology and Immunology, Faculty of Biology, University of Barcelona, Diagonal Sud, Facultat de Biologia, Avinguda Diagonal, 643, 08028 Barcelona, Spain.
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19
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Álvarez-Herms J, Julià-Sánchez S, Corbi F, Pagès T, Viscor G. A program of circuit resistance training under hypobaric hypoxia conditions improves the anaerobic performance of athletes. Sci Sports 2016. [DOI: 10.1016/j.scispo.2015.08.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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