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Endo Y, Zhu C, Giunta E, Guo C, Koh DJ, Sinha I. The Role of Hypoxia and Hypoxia Signaling in Skeletal Muscle Physiology. Adv Biol (Weinh) 2024; 8:e2200300. [PMID: 37817370 DOI: 10.1002/adbi.202200300] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 04/06/2023] [Indexed: 10/12/2023]
Abstract
Hypoxia and hypoxia signaling play an integral role in regulating skeletal muscle physiology. Environmental hypoxia and tissue hypoxia in muscles cue for their appropriate physiological response and adaptation, and cause an array of cellular and metabolic changes. In addition, muscle stem cells (satellite cells), exist in a hypoxic state, and this intrinsic hypoxic state correlates with their quiescence and stemness. The mechanisms of hypoxia-mediated regulation of satellite cells and myogenesis are yet to be characterized, and their seemingly contradicting effects reported leave their exact roles somewhat perplexing. This review summarizes the recent findings on the effect of hypoxia and hypoxia signaling on the key aspects of muscle physiology, namely, stem cell maintenance and myogenesis with a particular attention given to distinguish the intrinsic versus local hypoxia in an attempt to better understand their respective regulatory roles and how their relationship affects the overall response. This review further describes their mechanistic links and their possible implications on the relevant pathologies and therapeutics.
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Affiliation(s)
- Yori Endo
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard University, Boston, MA, 02115, USA
| | - Christina Zhu
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard University, Boston, MA, 02115, USA
- Texas Tech University Health Sciences Center School of Medicine, Lubbock, TX, 79430, USA
| | - Elena Giunta
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard University, Boston, MA, 02115, USA
- Ludwig-Maximilians-Universität München, Geschwister-Scholl-Platz 1, 80539, München, Germany
| | - Cynthia Guo
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard University, Boston, MA, 02115, USA
- Warren Alpert Medical School, Brown University, Providence, RI, 02903, USA
| | - Daniel J Koh
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard University, Boston, MA, 02115, USA
| | - Indranil Sinha
- Division of Plastic and Reconstructive Surgery, Department of Surgery, Brigham and Women's Hospital, Harvard University, Boston, MA, 02115, USA
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Mukai K, Ohmura H, Takahashi Y, Ebisuda Y, Yoneda K, Miyata H. Physiological and skeletal muscle responses to high-intensity interval exercise in Thoroughbred horses. Front Vet Sci 2023; 10:1241266. [PMID: 38026631 PMCID: PMC10679931 DOI: 10.3389/fvets.2023.1241266] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Accepted: 10/19/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction The purpose of this study was to determine whether acute high-intensity interval exercise or sprint interval exercise induces greater physiological and skeletal muscle responses compared to moderate-intensity continuous exercise in horses. Methods In a randomized crossover design, eight trained Thoroughbred horses performed three treadmill exercise protocols consisting of moderate-intensity continuous exercise (6 min at 70% VO2max; MICT), high-intensity interval exercise (6 × 30 s at 100% VO2max; HIIT), and sprint interval exercise (6 × 15 s at 120% VO2max; SIT). Arterial blood samples were collected to measure blood gas variables and plasma lactate concentration. Biopsy samples were obtained from the gluteus medius muscle before, immediately after, 4 h, and 24 h after exercise for biochemical analysis, western blotting and real-time RT-PCR. Effects of time and exercise protocol were analyzed using mixed models (p < 0.05). Results Heart rate and plasma lactate concentration at the end of exercise were higher in HIIT and SIT than those in MICT (heart rate, HIIT vs. MICT, p = 0.0005; SIT vs. MICT, p = 0.0015; lactate, HIIT vs. MICT, p = 0.0014; SIT vs. MICT, p = 0.0003). Arterial O2 saturation and arterial pH in HIIT and SIT were lower compared with MICT (SaO2, HIIT vs. MICT, p = 0.0035; SIT vs. MICT, p = 0.0265; pH, HIIT vs. MICT, p = 0.0011; SIT vs. MICT, p = 0.0023). Muscle glycogen content decreased significantly in HIIT (p = 0.0004) and SIT (p = 0.0016) immediately after exercise, but not in MICT (p = 0.19). Phosphorylation of AMP-activated protein kinase (AMPK) in HIIT showed a significant increase immediately after exercise (p = 0.014), but the increase was not significant in MICT (p = 0.13) and SIT (p = 0.39). At 4 h after exercise, peroxisome proliferator-activated receptor γ co-activator-1α mRNA increased in HIIT (p = 0.0027) and SIT (p = 0.0019) and vascular endothelial growth factor mRNA increased in SIT (p = 0.0002). Discussion Despite an equal run distance, HIIT and SIT cause more severe arterial hypoxemia and lactic acidosis compared with MICT. In addition, HIIT activates the AMPK signaling cascade, and HIIT and SIT elevate mitochondrial biogenesis and angiogenesis, whereas MICT did not induce any significant changes to these signaling pathways.
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Affiliation(s)
- Kazutaka Mukai
- Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan
| | - Hajime Ohmura
- Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan
| | - Yuji Takahashi
- Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan
| | - Yusaku Ebisuda
- Sports Science Division, Equine Research Institute, Japan Racing Association, Shimotsuke, Japan
| | - Koki Yoneda
- Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Hirofumi Miyata
- Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
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Johnson MG, Adam E, Watt A, Page AE. Effects of High-Speed Training on Messenger RNA Expression in Two-Year-Old Thoroughbred Racehorses. J Equine Vet Sci 2023; 128:104892. [PMID: 37433342 DOI: 10.1016/j.jevs.2023.104892] [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: 05/03/2023] [Revised: 07/06/2023] [Accepted: 07/06/2023] [Indexed: 07/13/2023]
Abstract
Accumulating high-speed exercise has been identified as a significant risk factor for catastrophic injuries in racing Thoroughbreds. Injuries, regardless of severity, are a main cause of withdrawal from the racing industry, raising animal welfare concerns and resulting in significant economic losses. While most of the current literature focuses on injuries incurred during racing rather than training, the present study aims to help fill this gap. As such, peripheral blood was collected weekly, prior to exercise or administration of medication, from eighteen, two-year-old Thoroughbreds throughout their first season of race training. Messenger RNA (mRNA) was isolated and used to analyze the expression of 34 genes via RT-qPCR. Statistical analysis of the noninjured horses (n = 6) showed that 13 genes were significantly correlated with increasing average weekly high-speed furlong performance. Additionally, there was a negative correlation for CXCL1, IGFBP3, and MPO with both cumulative high-speed furlongs and week of training for all horses. Comparison of both groups showed opposing correlations between the anti-inflammatory index (IL1RN, IL-10, and PTGS1) and average weekly high-speed furlong performance. Furthermore, evaluation of training effects on mRNA expression during the weeks surrounding injury, showed differences between groups in IL-13 and MMP9 at -3 and -2 weeks prior to injury. While some previously reported relationships between exercise adaptation and mRNA expression were not noted in this study, this may have been due to the small sample size. Several novel correlations, however, were identified and warrant further investigation as markers of exercise adaptation or potential risk for injury.
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Affiliation(s)
- Mackenzie G Johnson
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY
| | - Emma Adam
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY
| | | | - Allen E Page
- Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY.
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Muramoto Y, Nakashima D, Amano T, Harita T, Sugai K, Daigo K, Iwasawa Y, Ichihara G, Okawara H, Sawada T, Kinoda A, Yamada Y, Kimura T, Sato K, Katsumata Y. Estimation of maximal lactate steady state using the sweat lactate sensor. Sci Rep 2023; 13:10366. [PMID: 37365235 DOI: 10.1038/s41598-023-36983-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 06/13/2023] [Indexed: 06/28/2023] Open
Abstract
A simple, non-invasive algorithm for maximal lactate steady state (MLSS) assessment has not been developed. We examined whether MLSS can be estimated from the sweat lactate threshold (sLT) using a novel sweat lactate sensor for healthy adults, with consideration of their exercise habits. Fifteen adults representing diverse fitness levels were recruited. Participants with/without exercise habits were defined as trained/untrained, respectively. Constant-load testing for 30 min at 110%, 115%, 120%, and 125% of sLT intensity was performed to determine MLSS. The tissue oxygenation index (TOI) of the thigh was also monitored. MLSS was not fully estimated from sLT, with 110%, 115%, 120%, and 125% of sLT in one, four, three, and seven participants, respectively. The MLSS based on sLT was higher in the trained group as compared to the untrained group. A total of 80% of trained participants had an MLSS of 120% or higher, while 75% of untrained participants had an MLSS of 115% or lower based on sLT. Furthermore, compared to untrained participants, trained participants continued constant-load exercise even if their TOI decreased below the resting baseline (P < 0.01). MLSS was successfully estimated using sLT, with 120% or more in trained participants and 115% or less in untrained participants. This suggests that trained individuals can continue exercising despite decreases in oxygen saturation in lower extremity skeletal muscles.
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Affiliation(s)
- Yuki Muramoto
- Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Daisuke Nakashima
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | | | | | - Kazuhisa Sugai
- School of Veterinary Nursing and Technology, Faculty of Veterinary Science, Nippon Veterinary and Life Science University, Tokyo, Japan
| | - Kyohei Daigo
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Yuji Iwasawa
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Genki Ichihara
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan
| | - Hiroki Okawara
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Tomonori Sawada
- Department of Orthopaedic Surgery, Keio University School of Medicine, Tokyo, Japan
| | - Akira Kinoda
- Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Yuichi Yamada
- Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Takeshi Kimura
- Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Kazuki Sato
- Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan
| | - Yoshinori Katsumata
- Institute for Integrated Sports Medicine, Keio University School of Medicine, Tokyo, Japan.
- Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
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Kong Z, Lei OK, Sun S, Li L, Shi Q, Zhang H, Nie J. Hypoxic repeated sprint interval training improves cardiorespiratory fitness in sedentary young women. J Exerc Sci Fit 2022; 20:100-107. [PMID: 35154334 PMCID: PMC8819388 DOI: 10.1016/j.jesf.2022.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 01/19/2022] [Accepted: 01/22/2022] [Indexed: 12/12/2022] Open
Affiliation(s)
- Zhaowei Kong
- Faculty of Education, University of Macau, Macao, China
| | - On Kei Lei
- Faculty of Education, University of Macau, Macao, China
| | - Shengyan Sun
- Institute of Physical Education, Huzhou University, Huzhou, Zhejiang Province, China
| | - Lei Li
- School of Physical Education, Ludong University, Shandong Province, China
| | - Qingde Shi
- School of Health Sciences and Sports, Macao Polytechnic Institute, Macao, China
| | - Haifeng Zhang
- College of Physical Education, Hebei Normal University, Shijiazhuang, Hebei Province, China
| | - Jinlei Nie
- School of Health Sciences and Sports, Macao Polytechnic Institute, Macao, China
- Corresponding author. School of Health Sciences and Sports, Macao Polytechnic Institute, Rua de Luís Gonzaga Gomes, Macao, China.
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Alduraywish AA. Cardiorespiratory and metabolic fitness indicators in novice volleyball trainees: effect of 1-week antioxidant supplementation with N-acetyl-cysteine/zinc/vitamin C. J Int Med Res 2021; 49:3000605211067125. [PMID: 34939440 PMCID: PMC8725015 DOI: 10.1177/03000605211067125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2021] [Accepted: 11/29/2021] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES This study aimed to determine the effect of 7-day dietary supplementation of N-acetylcysteine (NAC)/zinc/vitamin C on the time-to-exhaustion (TTE), the cardiorespiratory fitness (CRF) index, and metabolic indicators. METHODS This study enrolled volleyball student trainees (n = 18 men) who took NAC/zinc/vitamin C (750 mg/5 mg/100 mg) for 7 days at Jouf University, Saudi Arabia. The CRF index and TTE were determined. Serum concentrations of metabolic regulators (insulin, betatrophin, and hepatocyte growth factor), biomarkers of cellular damage/hypoxia, and indicators of lipid and glycemic control were measured. RESULTS Supplementation improved the TTE and CRF index, and lowered cytochrome c, C-reactive protein, hypoxia-inducible factor-1α (HIF-1α), total cholesterol, insulin, and glycated hemoglobin values. Before and after supplementation, the CRF index was negatively correlated with body mass index and positively correlated with the TTE. Before supplementation, the CRF index was positively correlated with betatrophin concentrations, and hepatocyte growth factor concentrations were positively correlated with betatrophin concentrations and negatively correlated with the homeostasis model assessment of insulin resistance index. After supplementation, the CRF index was negatively correlated with HIF-1α concentrations and metabolites. Additionally, the TTE was negatively correlated with HIF-1α, cytochrome c, and triacylglycerol concentrations. CONCLUSION Supplementation of NAC/zinc/vitamin C improves metabolic and CRF performance.
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Lemieux P, Birot O. Altitude, Exercise, and Skeletal Muscle Angio-Adaptive Responses to Hypoxia: A Complex Story. Front Physiol 2021; 12:735557. [PMID: 34552509 PMCID: PMC8450406 DOI: 10.3389/fphys.2021.735557] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Accepted: 08/16/2021] [Indexed: 12/18/2022] Open
Abstract
Hypoxia, defined as a reduced oxygen availability, can be observed in many tissues in response to various physiological and pathological conditions. As a hallmark of the altitude environment, ambient hypoxia results from a drop in the oxygen pressure in the atmosphere with elevation. A hypoxic stress can also occur at the cellular level when the oxygen supply through the local microcirculation cannot match the cells’ metabolic needs. This has been suggested in contracting skeletal myofibers during physical exercise. Regardless of its origin, ambient or exercise-induced, muscle hypoxia triggers complex angio-adaptive responses in the skeletal muscle tissue. These can result in the expression of a plethora of angio-adaptive molecules, ultimately leading to the growth, stabilization, or regression of muscle capillaries. This remarkable plasticity of the capillary network is referred to as angio-adaptation. It can alter the capillary-to-myofiber interface, which represent an important determinant of skeletal muscle function. These angio-adaptive molecules can also be released in the circulation as myokines to act on distant tissues. This review addresses the respective and combined potency of ambient hypoxia and exercise to generate a cellular hypoxic stress in skeletal muscle. The major skeletal muscle angio-adaptive responses to hypoxia so far described in this context will be discussed, including existing controversies in the field. Finally, this review will highlight the molecular complexity of the skeletal muscle angio-adaptive response to hypoxia and identify current gaps of knowledges in this field of exercise and environmental physiology.
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Affiliation(s)
- Pierre Lemieux
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Olivier Birot
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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de Meeûs d’Argenteuil C, Boshuizen B, Oosterlinck M, van de Winkel D, De Spiegelaere W, de Bruijn CM, Goethals K, Vanderperren K, Delesalle CJG. Flexibility of equine bioenergetics and muscle plasticity in response to different types of training: An integrative approach, questioning existing paradigms. PLoS One 2021; 16:e0249922. [PMID: 33848308 PMCID: PMC8043414 DOI: 10.1371/journal.pone.0249922] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 03/26/2021] [Indexed: 12/16/2022] Open
Abstract
Equine bioenergetics have predominantly been studied focusing on glycogen and fatty acids. Combining omics with conventional techniques allows for an integrative approach to broadly explore and identify important biomolecules. Friesian horses were aquatrained (n = 5) or dry treadmill trained (n = 7) (8 weeks) and monitored for: evolution of muscle diameter in response to aquatraining and dry treadmill training, fiber type composition and fiber cross-sectional area of the M. pectoralis, M. vastus lateralis and M. semitendinosus and untargeted metabolomics of the M. pectoralis and M. vastus lateralis in response to dry treadmill training. Aquatraining was superior to dry treadmill training to increase muscle diameter in the hindquarters, with maximum effect after 4 weeks. After dry treadmill training, the M. pectoralis showed increased muscle diameter, more type I fibers, decreased fiber mean cross sectional area, and an upregulated oxidative metabolic profile: increased β-oxidation (key metabolites: decreased long chain fatty acids and increased long chain acylcarnitines), TCA activity (intermediates including succinyl-carnitine and 2-methylcitrate), amino acid metabolism (glutamine, aromatic amino acids, serine, urea cycle metabolites such as proline, arginine and ornithine) and xenobiotic metabolism (especially p-cresol glucuronide). The M. vastus lateralis expanded its fast twitch profile, with decreased muscle diameter, type I fibers and an upregulation of glycolytic and pentose phosphate pathway activity, and increased branched-chain and aromatic amino acid metabolism (cis-urocanate, carnosine, homocarnosine, tyrosine, tryptophan, p-cresol-glucuronide, serine, methionine, cysteine, proline and ornithine). Trained Friesians showed increased collagen and elastin turn-over. Results show that branched-chain amino acids, aromatic amino acids and microbiome-derived xenobiotics need further study in horses. They feed the TCA cycle at steps further downstream from acetyl CoA and most likely, they are oxidized in type IIA fibers, the predominant fiber type of the horse. These study results underline the importance of reviewing existing paradigms on equine bioenergetics.
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Affiliation(s)
- Constance de Meeûs d’Argenteuil
- Department of Virology, Parasitology and Immunology, Research Group of Comparative Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Berit Boshuizen
- Department of Virology, Parasitology and Immunology, Research Group of Comparative Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
- Wolvega Equine Hospital, Oldeholtpade, The Netherlands
| | - Maarten Oosterlinck
- Department of Surgery and Anaesthesiology of Domestic Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | | | - Ward De Spiegelaere
- Department of Morphology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | | | - Klara Goethals
- Department of Nutrition, Genetics and Ethology, Research Group Biometrics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Katrien Vanderperren
- Department of Veterinary Medical Imaging and Small Animal Orthopaedics, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Cathérine John Ghislaine Delesalle
- Department of Virology, Parasitology and Immunology, Research Group of Comparative Physiology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
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van Doorslaer de Ten Ryen S, Francaux M, Deldicque L. Regulation of satellite cells by exercise in hypoxic conditions: a narrative review. Eur J Appl Physiol 2021; 121:1531-1542. [PMID: 33745023 DOI: 10.1007/s00421-021-04641-4] [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: 11/10/2020] [Accepted: 02/10/2021] [Indexed: 12/16/2022]
Abstract
PURPOSE To investigate in vivo the adaptations of satellite cell induced by exercise performed in acute or chronic hypoxic conditions and their contribution to muscle remodeling and hypertrophy. METHODS Search terms related to exercise, hypoxia and satellite cells were entered on Embase, PubMed and Scopus. Studies were selected for their relevance in terms of regulation of satellite cells by in vivo exercise and muscle contraction in hypoxic conditions. RESULTS Satellite cell activation and proliferation seem to be enabled after acute hypoxic exercise via regulations induced by myogenic regulatory factors. Several studies reported also a role of the inflammatory pathway nuclear factor-kappa B and angiogenic factors such as vascular endothelial growth factor, both known to upregulate myogenesis. By stimulating angiogenesis, repeated exercise performed in acute hypoxia might contribute to satellite cell activation. Contrary to such exercise conditions, chronic exposure to hypoxia downregulates myogenesis despite the maintenance of physical activity. This impaired myogenesis might be induced by excessive oxidative stress and proteolysis. CONCLUSION In vivo studies suggest that, in comparison to exercise or hypoxia alone, exercise performed in a hypoxic environment, may improve or impair muscle remodeling induced by contractile activity depending upon the duration of hypoxia. Satellite cells seem to be major actors in these dichotomous adaptations. Further research on the role of angiogenesis, types of contraction and autophagy is needed for a better understanding of their respective role in hypoxic exercise-induced modulations of satellite cell activity in human.
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Affiliation(s)
- Sophie van Doorslaer de Ten Ryen
- Institute of Neuroscience, Université Catholique de Louvain, Place Pierre de Coubertin, 1 L08.10.01, 1348, Louvain-la-Neuve, Belgium
| | - Marc Francaux
- Institute of Neuroscience, Université Catholique de Louvain, Place Pierre de Coubertin, 1 L08.10.01, 1348, Louvain-la-Neuve, Belgium
| | - Louise Deldicque
- Institute of Neuroscience, Université Catholique de Louvain, Place Pierre de Coubertin, 1 L08.10.01, 1348, Louvain-la-Neuve, Belgium.
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Ohmura H, Mukai K, Matsui A, Takahashi T, Jones JH. Cardiopulmonary function during supramaximal exercise in hypoxia, normoxia and hyperoxia in Thoroughbred horses. J Equine Sci 2020; 31:67-73. [PMID: 33376442 PMCID: PMC7750644 DOI: 10.1294/jes.31.67] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Accepted: 09/16/2020] [Indexed: 11/01/2022] Open
Abstract
Supramaximal exercise while inspiring different O2 gases may induce different responses in cardiopulmonary function at the same relative and/or absolute exercise intensity. The purpose of this study was to compare the effects of supramaximal exercise in hypoxia, normoxia and hyperoxia on cardiopulmonary function in Thoroughbred horses. Using a crossover design, five well-trained horses were made to run up a 6% grade on a treadmill at supramaximal speeds sustainable for approximately 110 sec (approximately 115% V̇O2max) while breathing normoxic gas (NO, 21% O2) or hypoxic gas (LO, 15.3% O2) in random order. Horses also ran at the same speed, incline and run time as in NO while breathing hyperoxic gas (HONO, 28.8% O2) and as in LO while breathing normoxic gas (NOLO). Runs were on different days, and cardiopulmonary variables were analyzed with repeated-measures ANOVA and the Holm-Šidák method for pairwise comparisons. Supramaximal speeds differed significantly between NO and LO (14.0 ± 0.5 [SD] m/sec vs. 12.6 ± 0.5 m/sec), but run times to exhaustion did not (112 ± 17 sec vs. 103 ± 14 sec). The V̇O2max in NO was higher than that in LO (165 ± 11 vs. 120 ± 15 ml (min× kg)), as was the arterial oxygen tension (66 ± 5 vs. 45 ± 2 Torr). Oxygen consumption was increased in HONO and NOLO compared with the values in NO and LO, respectively. Supramaximal exercise in hypoxia induces more severe hypoxemia and decreases V̇O2max compared with normoxia at the same relative intensity. Conversely, supramaximal exercise in hyperoxia alleviates hypoxemia and increases V̇O2 compared with normoxia at the same absolute intensity.
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Affiliation(s)
- Hajime Ohmura
- Sports Science Division, Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - Kazutaka Mukai
- Sports Science Division, Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - Akira Matsui
- Sports Science Division, Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - Toshiyuki Takahashi
- Sports Science Division, Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - James H Jones
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, CA 95616, U.S.A
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Heriansyah T, Chomsy IN, Kumboyono K, Pratiwi PA, Wihastuti TA. Expression of Hypoxia-Inducible Factor-1α (HIF1A) and Lp-PLA2 in Low, Intermediate, and High Cardiovascular Disease Risk Population. Vasc Health Risk Manag 2020; 16:507-513. [PMID: 33299319 PMCID: PMC7720284 DOI: 10.2147/vhrm.s283367] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 11/19/2020] [Indexed: 11/23/2022] Open
Abstract
BACKGROUND The pathomechanism of CVD is a complex and multifactorial process. The primary mechanism of CVD is atherosclerosis. Inflammation in atherogenesis raises the risk of hypoxia, which will activate hypoxia-inducible factor-1α (HIF1A). Also, together with lipoprotein-associated phospholipase A2 (Lp-PLA2), an inflammatory mediator for atherogenesis. PURPOSE This study aims to measure the hypoxia-inducible factor-1α (HIF1A) expression and its correlation to Lp-PLA2 expression at low-risk, intermediate, and high-risk CVD populations. PATIENTS AND METHODS The study used a correlational analysis method with a total sampling technique in 160 individuals in the risk population. The atherosclerosis risk group was analyzed using the Framingham Risk Score and categorized into low, intermediate, and high-risk groups. Venous blood samples taken from respondents were measured using the ELISA method with Lp-PLA2 and HIF-1α as parameters. Data were analyzed using normality test, homogeneity test, one-way ANOVA, post hoc-Tukey HSD, and Pearson correlation. RESULTS The concentration of HIF1A had a very strong correlation with Lp-PLA2 expression, both in the low-risk group (r = 0.512), intermediate (r = 0.512), and high (r = 0.715) (P <0.05). However, the concentrations of Lp-PLA2 did not match the FRS. CONCLUSION HIF1A expression increased with increasing risk, while Lp-PLA2 expression decreased with increasing risk of atherosclerosis based on the FRS category. There is a significant correlation between HIF1A expression and Lp-PLA2 expression based on FRS.
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Affiliation(s)
- Teuku Heriansyah
- Department of Cardiology and Vascular Medicine, Syiah Kuala University, Banda Aceh23111, Indonesia
| | - Indah Nur Chomsy
- Master Program in Biomedical Science, Faculty of Medicine, Brawijaya University, Malang65145, Indonesia
| | - Kumboyono Kumboyono
- Nursing Department, Faculty of Medicine, University of Brawijaya, Malang65145, Indonesia
| | | | - Titin Andri Wihastuti
- Department of Biomedicine, Faculty of Medicine, Brawijaya University, Malang65145, Indonesia
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Denham J, McCluskey M, Denham MM, Sellami M, Davie AJ. Epigenetic control of exercise adaptations in the equine athlete: Current evidence and future directions. Equine Vet J 2020; 53:431-450. [PMID: 32671871 DOI: 10.1111/evj.13320] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 06/04/2020] [Accepted: 06/25/2020] [Indexed: 12/11/2022]
Abstract
Horses (Equus ferus caballus) have evolved over the past 300 years in response to man-made selection for particular athletic traits. Some of the selected traits were selected based on the size and horses' muscular power (eg Clydesdales), whereas other breeds were bred for peak running performance (eg Thoroughbred and Arabian). Although the physiological changes and some of the cellular adaptations responsible for athletic potential of horses have been identified, the molecular mechanisms are only just beginning to be comprehensively investigated. The purpose of this review was to outline and discuss the current understanding of the molecular mechanisms underpinning the athletic performance and cardiorespiratory fitness in athletic breeds of horses. A brief review of the biology of epigenetics is provided, including discussion on DNA methylation, histone modifications and small RNAs, followed by a summary and critical review of the current work on the exercise-induced epigenetic and transcriptional changes in horses. Important unanswered questions and currently unexplored areas that deserve attention are highlighted. Finally, a rationale for the analysis of epigenetic modifications in the context with exercise-related traits and ailments associated with athletic breeds of horses is outlined in order to help guide future research.
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Affiliation(s)
- Joshua Denham
- RMIT University, School of Health and Biomedical Sciences, Melbourne, VIC, Australia
| | | | | | - Maha Sellami
- Qatar University, College of Arts and Sciences (CAS), Sport Science Program (SSP), Doha, Qatar
| | - Allan J Davie
- Australian Equine Racing and Research Centre (AERR), Ballina, NSW, Australia
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Li J, Li Y, Atakan MM, Kuang J, Hu Y, Bishop DJ, Yan X. The Molecular Adaptive Responses of Skeletal Muscle to High-Intensity Exercise/Training and Hypoxia. Antioxidants (Basel) 2020; 9:E656. [PMID: 32722013 PMCID: PMC7464156 DOI: 10.3390/antiox9080656] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/19/2020] [Accepted: 07/21/2020] [Indexed: 12/31/2022] Open
Abstract
High-intensity exercise/training, especially interval exercise/training, has gained popularity in recent years. Hypoxic training was introduced to elite athletes half a century ago and has recently been adopted by the general public. In the current review, we have summarised the molecular adaptive responses of skeletal muscle to high-intensity exercise/training, focusing on mitochondrial biogenesis, angiogenesis, and muscle fibre composition. The literature suggests that (peroxisome proliferator-activated receptor gamma coactivator 1-alpha) PGC-1α, vascular endothelial growth factor (VEGF), and hypoxia-inducible factor 1-alpha (HIF1-α) might be the main mediators of skeletal muscle adaptations to high-intensity exercises in hypoxia. Exercise is known to be anti-inflammatory, while the effects of hypoxia on inflammatory signalling are more complex. The anti-inflammatory effects of a single session of exercise might result from the release of anti-inflammatory myokines and other cytokines, as well as the downregulation of Toll-like receptor signalling, while training-induced anti-inflammatory effects may be due to reductions in abdominal and visceral fat (which are main sources of pro-inflammatory cytokines). Hypoxia can lead to inflammation, and inflammation can result in tissue hypoxia. However, the hypoxic factor HIF1-α is essential for preventing excessive inflammation. Disease-induced hypoxia is related to an upregulation of inflammatory signalling, but the effects of exercise-induced hypoxia on inflammation are less conclusive. The effects of high-intensity exercise under hypoxia on skeletal muscle molecular adaptations and inflammatory signalling have not been fully explored and are worth investigating in future studies. Understanding these effects will lead to a more comprehensive scientific basis for maximising the benefits of high-intensity exercise.
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Affiliation(s)
- Jia Li
- College of Physical Education, Southwest University, Chongqing 400715, China;
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
| | - Yanchun Li
- China Institute of Sport and Health Science, Beijing Sport University, Beijing 100192, China; (Y.L.); (Y.H.)
| | - Muhammed M. Atakan
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
- Division of Nutrition and Metabolism in Exercise, Faculty of Sport Sciences, Hacettepe University, 06800 Ankara, Turkey
| | - Jujiao Kuang
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
| | - Yang Hu
- China Institute of Sport and Health Science, Beijing Sport University, Beijing 100192, China; (Y.L.); (Y.H.)
| | - David J. Bishop
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
| | - Xu Yan
- Institute for Health and Sport (iHeS), Victoria University, P.O. Box 14428, Melbourne 8001, Australia; (M.M.A.); (J.K.); (D.J.B.)
- Sarcopenia Research Program, Australia Institute for Musculoskeletal Sciences (AIMSS), Melbourne 3021, Australia
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Wang W, Mukai K, Takahashi K, Ohmura H, Takahashi T, Hatta H, Kitaoka Y. Short-term hypoxic training increases monocarboxylate transporter 4 and phosphofructokinase activity in Thoroughbreds. Physiol Rep 2020; 8:e14473. [PMID: 32512646 PMCID: PMC7279979 DOI: 10.14814/phy2.14473] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/03/2020] [Accepted: 05/09/2020] [Indexed: 12/18/2022] Open
Abstract
The aim of this study was to investigate effects of short-term hypoxic training on lactate metabolism in the gluteus medius muscle of Thoroughbreds. Using crossover design (3 months washout), eight Thoroughbred horses were trained for 2 weeks in normoxia (FI O2 = 21%) and hypoxia (FI O2 = 18%) each. They ran at 95% maximal oxygen consumption (V̇O2max ) on a treadmill inclined at 6% for 2 min (3 days/week) measured under normoxia. Before and after each training period, all horses were subjected to an incremental exercise test (IET) under normoxia. Following the 2-week trainings, V̇O2max in IET increased significantly under both oxygen conditions. The exercise duration in IET increased significantly only after hypoxic training. The monocarboxylate transporter (MCT) 1 protein levels remained unchanged after training under both oxygen conditions, whereas MCT4 protein levels increased significantly after training in hypoxia but not after training in normoxia. Phosphofructokinase activity increased significantly only after hypoxic training, whereas cytochrome c oxidase activity increased significantly only after normoxic training. Our results suggest that hypoxic training efficiently enhances glycolytic capacity and levels of the lactate transporter protein MCT4, which facilitates lactate efflux from the skeletal muscle.
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Affiliation(s)
- Wenxin Wang
- Department of Human SciencesKanagawa UniversityKanagawaJapan
| | - Kazutaka Mukai
- Equine Research InstituteJapan Racing AssociationTochigiJapan
| | - Kenya Takahashi
- Department of Sports SciencesThe University of TokyoTokyoJapan
| | - Hajime Ohmura
- Equine Research InstituteJapan Racing AssociationTochigiJapan
| | | | - Hideo Hatta
- Department of Sports SciencesThe University of TokyoTokyoJapan
| | - Yu Kitaoka
- Department of Human SciencesKanagawa UniversityKanagawaJapan
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Comparison of the Effectiveness of High-Intensity Interval Training in Hypoxia and Normoxia in Healthy Male Volunteers: A Pilot Study. BIOMED RESEARCH INTERNATIONAL 2019; 2019:7315714. [PMID: 31662994 PMCID: PMC6778879 DOI: 10.1155/2019/7315714] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/02/2019] [Revised: 08/07/2019] [Accepted: 09/05/2019] [Indexed: 01/05/2023]
Abstract
Aims The study investigated the effect of high-intensity interval training in hypoxia and normoxia on serum concentrations of proangiogenic factors, nitric oxide, and inflammatory responses in healthy male volunteers. Methods Twelve physically active male subjects completed a high-intensity interval training (HIIT) in normoxia (NorTr) and in normobaric hypoxia (HypTr) (FiO2 = 15.2%). The effects of HIIT in hypoxia and normoxia on maximal oxygen uptake, hypoxia-inducible factor-1-alpha, vascular endothelial growth factor, nitric oxide, and cytokines were analyzed. Results HIIT in hypoxia significantly increases maximal oxygen uptake (p=0.01) levels compared to pretraining levels. Serum hypoxia-inducible factor-1 (p=0.01) and nitric oxide levels (p=0.05), vascular endothelial growth factor (p=0.04), and transforming growth factor-β (p=0.01) levels were increased in response to exercise test after hypoxic training. There was no effect of training conditions for serum baseline angiogenic factors and cytokines (p > 0.05) with higher HIF-1α and NO levels after hypoxic training compared to normoxic training (F = 9.1; p < 0.01 and F = 5.7; p < 0.05, respectively). Conclusions High-intensity interval training in hypoxia seems to induce beneficial adaptations to exercise mediated via a significant increase in the serum concentrations of proangiogenic factors and serum nitric oxide levels compared to the same training regimen in normoxia.
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Wang R, Guo S, Tian H, Huang Y, Yang Q, Zhao K, Kuo CH, Hong S, Chen P, Liu T. Hypoxic Training in Obese Mice Improves Metabolic Disorder. Front Endocrinol (Lausanne) 2019; 10:527. [PMID: 31440207 PMCID: PMC6694298 DOI: 10.3389/fendo.2019.00527] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/17/2019] [Indexed: 12/29/2022] Open
Abstract
Hypoxic training has been reported to lower obesity morbidity without clear underlying mechanisms. This study investigates the effect of hypoxic training on metabolic changes, particularly, on liver metabolism of high fat diet (HFD)-induced obese mice. We compared the hypoxic training group with normoxic sedentary, normoxic training, and hypoxic sedentary groups. Body weight, fat mass, glucose tolerance and liver physiology were determined after 4 weeks intervention. In both normoxic training and hypoxic training groups, body weight was lower than the normoxic sedentary group, with less fat mass. Insulin sensitivity was improved after hypoxic training. Moreover, liver metabolomics revealed insights into the protective effect of hypoxic training on HFD-induced fatty liver. Taken together, these findings provide a molecular metabolic mechanism for hypoxic training.
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Affiliation(s)
- Ru Wang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
- *Correspondence: Ru Wang
| | - Shanshan Guo
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Haili Tian
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Yiru Huang
- State Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
| | - Qin Yang
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Kewei Zhao
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
| | - Chia-Hua Kuo
- Laboratory of Exercise Biochemistry, University of Taipei, Taipei, Taiwan
| | - Shangyu Hong
- State Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
| | - Peijie Chen
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
- Peijie Chen
| | - Tiemin Liu
- School of Kinesiology, Shanghai University of Sport, Shanghai, China
- State Key Laboratory of Genetic Engineering, Department of Endocrinology and Metabolism, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
- Tiemin Liu
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Nagahisa H, Miyata H. Influence of hypoxic stimulation on angiogenesis and satellite cells in mouse skeletal muscle. PLoS One 2018; 13:e0207040. [PMID: 30408093 PMCID: PMC6224099 DOI: 10.1371/journal.pone.0207040] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/23/2018] [Indexed: 01/22/2023] Open
Abstract
We clarified in our previous study that hypoxic training promotes angiogenesis in skeletal muscle, but the mechanism of angiogenesis in skeletal muscle remains unknown. In this study, we investigated the influence of differences in hypoxia exposure on angiogenesis in skeletal muscles at differing ages and metabolic characteristics at which the production of reactive oxygen species and nitric oxide may differ. Ten-week-old (young) and 20-month-old (old) mice were separated into control (N), continuous hypoxia (H), and intermittent hypoxia (IH) groups. The H group was exposed to 16% O2 hypoxia for 5 days and the IH group was exposed to 16% O2 hypoxia at one-hour intervals during the light period for 5 days. After completion of hypoxia exposure, the soleus and gastrocnemius muscles were immediately excised, and mRNA expression of angiogenesis- and satellite cell-related genes was investigated using real-time RT-PCR. In addition, muscle fiber type composition, muscle fiber area, number of satellite cells, and capillary density were measured immunohistochemically. In the young soleus muscle, the muscle fiber area was decreased in the H group, and mRNA expression of satellite cell activation-related MyoD, MHCe, and BDNF was significantly increased. On the other hand, in the old soleus muscle, nNOS and VEGF-A mRNA expression, and the capillary density were significantly increased in the H group. In the superficial portion of the gastrocnemius, mRNA expression of FGF2, an angiogenic factor secreted by satellite cells, was significantly increased in the young IH group. In addition, a positive correlation between VEGF-A mRNA expression and nNOS mRNA expression in the soleus muscle and eNOS mRNA expression in the superficial portion of the gastrocnemius was noted. These data demonstrated that age, hypoxia exposure method and muscle metabolic characteristics are related, which results in significant differences in angiogenesis.
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Affiliation(s)
- Hiroshi Nagahisa
- Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
| | - Hirofumi Miyata
- Biological Sciences, Graduate School of Sciences and Technology for Innovation, Yamaguchi University, Yamaguchi, Japan
- * E-mail:
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Davie AJ, Wen L, Cust ARE, Beavers R, Fyfe T, Zhou S. The effects of moderate intensity training in a hypoxic environment on transcriptional responses in Thoroughbred horses. Biol Open 2017; 6:1035-1040. [PMID: 28583927 PMCID: PMC5550905 DOI: 10.1242/bio.020388] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
This study investigated the effects of six weeks of normobaric hypoxic training on transcriptional expression of the genes associated with mitochondrial and glycolytic activities in Thoroughbred horses. Eight horses were divided into two groups of four. They completed an identical incremental, moderate intensity training program, except that one group trained in a hypoxic chamber with 15% oxygen for 30 min on alternate days except Sundays (HT), while the other group trained in normal air (NC). Prior to and post training, heart rate and blood lactate were measured during an incremental treadmill test. Muscle biopsy samples were taken prior to and 24 h post the training period for qPCR analysis of mRNA changes in VEGF, PPARγ, HIF-1α, PGC-1α, COX4, AK3, LDH, PFK, PKm and SOD-2. No significant differences between the HT and NC were detected by independent-samples t-test with Bonferroni correction for multiple comparisons (P>0.05) in relative changes of mRNA abundance. There were no significant differences between groups for heart rate and blood lactate during the treadmill test. The outcomes indicated that this hypoxia training program did not cause a significant variation in basal level expression of the selected mRNAs in Thoroughbreds as compared with normoxic training.
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Affiliation(s)
- Allan J Davie
- Southern Cross University, School of Health and Human Sciences, Lismore, NSW 2480, Australia
| | - Li Wen
- Tianjin University of Sports, Tianjin Key Laboratory of Exercise Physiology and Sports Medicine, Tianjin 300381, China
| | | | - Rosalind Beavers
- Southern Cross University, School of Health and Human Sciences, Lismore, NSW 2480, Australia
| | - Tom Fyfe
- Pulford Air and Gas, Sydney, NSW 2141, Australia
| | - Shi Zhou
- Southern Cross University, School of Health and Human Sciences, Lismore, NSW 2480, Australia
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Ohmura H, Mukai K, Takahashi Y, Takahashi T, Jones JH. Hypoxic training increases maximal oxygen consumption in Thoroughbred horses well-trained in normoxia. J Equine Sci 2017; 28:41-45. [PMID: 28721122 PMCID: PMC5506448 DOI: 10.1294/jes.28.41] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Accepted: 03/16/2017] [Indexed: 11/06/2022] Open
Abstract
Hypoxic training is effective for improving athletic performance in humans. It increases maximal oxygen consumption (V̇O2max) more than normoxic training in untrained horses. However, the effects of hypoxic training on
well-trained horses are unclear. We measured the effects of hypoxic training on V̇O2max of 5 well-trained horses in which V̇O2max had not increased over 3 consecutive weeks of supramaximal treadmill training
in normoxia which was performed twice a week. The horses trained with hypoxia (15% inspired O2) twice a week. Cardiorespiratory valuables were analyzed with analysis of variance between before and after 3 weeks of
hypoxic training. Mass-specific V̇O2max increased after 3 weeks of hypoxic training (178 ± 10 vs. 194 ± 12.3 ml O2 (STPD)/(kg × min), P<0.05) even though all-out training in normoxia had not increased
V̇O2max. Absolute V̇O2max also increased after hypoxic training (86.6 ± 6.2 vs. 93.6 ± 6.6 l O2 (STPD)/min, P<0.05). Total running distance after hypoxic training increased 12% compared to
that before hypoxic training; however, the difference was not significant. There were no significant differences between pre- and post-hypoxic training for end-run plasma lactate concentrations or packed cell volumes. Hypoxic
training may increase V̇O2max even though it is not increased by normoxic training in well-trained horses, at least for the durations of time evaluated in this study. Training while breathing hypoxic gas may have the
potential to enhance normoxic performance of Thoroughbred horses.
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Affiliation(s)
- Hajime Ohmura
- Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - Kazutaka Mukai
- Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - Yuji Takahashi
- Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - Toshiyuki Takahashi
- Equine Research Institute, Japan Racing Association, Tochigi 329-0412, Japan
| | - James H Jones
- School of Veterinary Medicine, University of California, Davis, CA 95616, U.S.A
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