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Callovini A, Fornasiero A, Savoldelli A, Decet M, Skafidas S, Pellegrini B, Bortolan L, Schena F. Independent, additive and interactive effects of acute normobaric hypoxia and cold on submaximal and maximal endurance exercise. Eur J Appl Physiol 2024; 124:1185-1200. [PMID: 37962573 PMCID: PMC10955012 DOI: 10.1007/s00421-023-05343-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Accepted: 10/16/2023] [Indexed: 11/15/2023]
Abstract
PURPOSE To evaluate the independent and combined effects of hypoxia (FiO2 = 13.5%) and cold (- 20 °C) on physiological and perceptual responses to endurance exercise. METHODS 14 trained male subjects ( V . O2max: 64 ± 5 mL/kg/min) randomly performed a discontinuous maximal incremental test to exhaustion on a motorized treadmill under four environmental conditions: Normothermic-Normoxia (N), Normothermic-Hypoxia (H), Cold-Normoxia (C) and Cold-Hypoxia (CH). Performance and physiological and perceptual responses throughout exercise were evaluated. RESULTS Maximal WorkLoad (WL) and WL at lactate threshold (LT) were reduced in C (- 2.3% and - 3.5%) and H (- 18.0% and - 21.7%) compared to N, with no interactive (p = 0.25 and 0.81) but additive effect in CH (- 21.5% and - 24.6%). Similarly, HRmax and Vemax were reduced in C (- 3.2% and - 14.6%) and H (- 5.0% and - 7%), showing additive effects in CH (- 7.7% and - 16.6%). At LT, additive effect of C (- 2.8%) and H (- 3.8%) on HR reduction in CH (- 5.7%) was maintained, whereas an interactive effect (p = 0.007) of the two stressors combined was noted on Ve (C: - 3.1%, H: + 5.5%, CH: - 10.9%). [La] curve shifted on the left in CH, displaying an interaction effect between the 2 stressors on this parameter. Finally, RPE at LT was exclusively reduced by hypoxia (p < 0.001), whereas TSmax is synergistically reduced by cold and hypoxia (interaction p = 0.047). CONCLUSION If compared to single stress exposure, exercise performance and physiological and perceptual variables undergo additive or synergistic effects when cold and hypoxia are combined. These results provide new insight into human physiological responses to extreme environments.
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Affiliation(s)
- A Callovini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy.
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
| | - A Fornasiero
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - A Savoldelli
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Cellular, Computational and Integrative Biology, University of Trento, Trento, Italy
| | - M Decet
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
| | - S Skafidas
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
| | - B Pellegrini
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - L Bortolan
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Engineering for Innovation Medicine, University of Verona, Verona, Italy
| | - F Schena
- CeRiSM, Sport Mountain and Health Research Centre, University of Verona, Rovereto, Italy
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy
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Schwendinger F, Looser V, Gerber M, Schmidt-Trucksäss A. Autonomic dysfunction and exercise intolerance in post-COVID-19 - An as yet underestimated organ system? Int J Clin Health Psychol 2024; 24:100429. [PMID: 38348143 PMCID: PMC10859561 DOI: 10.1016/j.ijchp.2023.100429] [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: 09/26/2023] [Accepted: 12/11/2023] [Indexed: 02/15/2024] Open
Abstract
Individuals recovering from COVID-19 often present with persistent symptoms, particularly exercise intolerance and low cardiorespiratory fitness. Put simply, the Wasserman gear system describes the interdependence of heart, lungs, and musculature as determinants of cardiorespiratory fitness. Based on this system, recent findings indicate a contribution of peripheral, cardiovascular, and lung diffusion limitations to persistent symptoms of exercise intolerance and low cardiorespiratory fitness. The autonomic nervous system as an organ system involved in the pathophysiology of exercise intolerance and low cardiorespiratory fitness, has received only little attention as of yet. Hence, our article discusses contribution of the autonomic nervous system through four potential pathways, namely alterations in (1) cerebral hemodynamics, (2) afferent and efferent signaling, (3) central hypersensitivity, and (4) appraisal and engagement in physical activity. These pathways are summarized in a psycho-pathophysiological model. Consequently, this article encourages a shift in perspective by examining the state of the pulmonary and cardiovascular system, the periphery, and auxiliary, the autonomic nervous system as potential underlying mechanisms for exercise intolerance and low cardiorespiratory fitness in patients with post-COVID-19.
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Affiliation(s)
- F. Schwendinger
- Division of Sports and Exercise Medicine, Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, 4052 Basel, Switzerland
| | - V.N. Looser
- Division of Sports Science, Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, 4052 Basel, Switzerland
| | - M. Gerber
- Division of Sports Science, Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, 4052 Basel, Switzerland
| | - A. Schmidt-Trucksäss
- Division of Sports and Exercise Medicine, Department of Sport, Exercise and Health, University of Basel, Grosse Allee 6, 4052 Basel, Switzerland
- Department of Clinical Research, University Hospital Basel, University of Basel, Schanzenstrasse 55, 4056 Basel, Switzerland
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Farra SD, Jacobs I. Arterial desaturation rate does not influence self-selected knee extension force but alters ventilatory response to progressive hypoxia: A pilot study. Physiol Rep 2024; 12:e15892. [PMID: 38172088 PMCID: PMC10764295 DOI: 10.14814/phy2.15892] [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: 11/15/2023] [Revised: 12/04/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024] Open
Abstract
The absolute magnitude and rate of arterial desaturation each independently impair whole-body aerobic exercise. This study examined potential mechanisms underlying the rate-dependent relationship. Utilizing an exercise protocol involving unilateral, intermittent, isometric knee extensions (UIIKE), we provided sufficient reperfusion time between contractions to reduce the accumulation of intramuscular metabolic by-products that typically stimulate muscle afferents. The objective was to create a milieu conducive to accentuating any influence of arterial desaturation rate on muscular fatigue. Eight participants completed four UIIKE sessions, performing one 3 s contraction every 30s at a perceived intensity of 50% MVC for 25 min. Participants voluntarily adjusted their force generation to maintain perceptual effort at 50% MVC without feedback. Reductions in inspired oxygen fraction (FI O2 ) decreased arterial saturation from >98% to 70% with varying rates in three trials: FAST (5.3 ± 1.3 min), MED (11.8 ± 2.7 min), and SLOW (19.9 ± 3.7 min). FI O2 remained at 0.21 during the control trial. Force generation and muscle activation remained at baseline levels throughout UIIKE trials, unaffected by the magnitude or rate of desaturation. Minute ventilation increased with hypoxia (p < 0.05), and faster desaturation rates magnified this response. These findings demonstrate that arterial desaturation magnitude and rate independently affect ventilation, but do not influence fatigue development during UIIKE.
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Affiliation(s)
- Saro D. Farra
- Faculty of Kinesiology & Physical EducationUniversity of TorontoTorontoOntarioCanada
| | - Ira Jacobs
- Faculty of Kinesiology & Physical EducationUniversity of TorontoTorontoOntarioCanada
- Tanenbaum Institute for Science in Sport, University of TorontoTorontoOntarioCanada
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Faulhaber M, Schneider S, Rausch LK, Dünnwald T, Menz V, Gatterer H, Kennedy MD, Schobersberger W. Repeated Short-Term Bouts of Hyperoxia Improve Aerobic Performance in Acute Hypoxia. J Strength Cond Res 2023; 37:2016-2022. [PMID: 37729514 DOI: 10.1519/jsc.0000000000004502] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
ABSTRACT Faulhaber, M, Schneider, S, Rausch, LK, Dünnwald, T, Menz, V, Gatterer, H, Kennedy, MD, and Schobersberger, W. Repeated short-term bouts of hyperoxia improve aerobic performance in acute hypoxia. J Strength Cond Res 37(10): 2016-2022, 2023-This study aimed to test the effects of repeated short-term bouts of hyperoxia on maximal 5-minute cycling performance under acute hypoxic conditions (3,200 m). Seventeen healthy and recreationally trained individuals (7 women and 10 men) participated in this randomized placebo-controlled cross-over trial. The procedures included a maximal cycle ergometer test and 3 maximal 5-minute cycling time trials (TTs). TT1 took place in normoxia and served for habituation and reference. TT2 and TT3 were conducted in normobaric hypoxia (15.0% inspiratory fraction of oxygen). During TT2 and TT3, the subjects were breathing through a face mask during five 15-second periods. The face mask was connected through a nonrebreathing T valve to a 300-L bag filled with 100% oxygen (intermittent hyperoxia) or ambient hypoxic air (placebo). The main outcome was the mean power output during the TT. Statistical significance level was set at p < 0.05. The mean power output was higher in the intermittent hyperoxia compared with the placebo condition (255.5 ± 49.6 W vs. 247.4 ± 48.2 W, p = 0.001). Blood lactate concentration and ratings of perceived exertion were significantly lower by about 9.7 and 7.3%, respectively, in the intermittent hyperoxia compared with the placebo condition, whereas heart rate values were unchanged. IH application increased arterial oxygen saturation (82.9 ± 2.6% to 92.4 ± 3.3%, p < 0.001). Repeated 15-second bouts of hyperoxia, applied during high-intensity exercise in hypoxia, are sufficient to increase power output. Future studies should focus on potential dose-response effects and the involved mechanisms.
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Affiliation(s)
- Martin Faulhaber
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
- Austrian Society of Alpine and High-Altitude Medicine, Mieming, Austria
| | - Sina Schneider
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
| | - Linda K Rausch
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
| | - Tobias Dünnwald
- Institute for Sport Medicine, Alpine Medicine and Health Tourism (ISAG), Private University for Health Sciences, Medical Informatics and Technology (UMIT Tirol), Tirol, Austria
| | - Verena Menz
- Department of Sport Science, Universität Innsbruck, Innsbruck, Austria
| | - Hannes Gatterer
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Michael D Kennedy
- Faculty of Kinesiology, Sport and Recreation, College of Health Sciences, University of Alberta, Edmonton, Alberta, Canada; and
| | - Wolfgang Schobersberger
- Institute for Sport Medicine, Alpine Medicine and Health Tourism (ISAG), Private University for Health Sciences, Medical Informatics and Technology (UMIT Tirol), Tirol, Austria
- Institute for Sport Medicine, Alpine Medicine anad Health Tourism (ISAG), Tirol Kliniken GmbH, Innsbruck, Austria
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Huang CT, Ruan SY, Lai F, Chien JY, Yu CJ. Prognostic Value of Pace Variability, a Novel 6MWT-Derived Feature, in Patients with Chronic Obstructive Pulmonary Disease. Int J Chron Obstruct Pulmon Dis 2023; 18:1555-1564. [PMID: 37497382 PMCID: PMC10368117 DOI: 10.2147/copd.s407708] [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: 03/28/2023] [Accepted: 07/03/2023] [Indexed: 07/28/2023] Open
Abstract
Purpose The 6-minute walk test (6MWT) is often used to evaluate chronic obstructive pulmonary disease (COPD) patients' functional capacity, with 6-minute walk distance (6MWD) and related measures being linked to mortality and hospitalizations. This study investigates the prognostic value of pace variability, a significant indicator in sports medicine, during the 6MWT for COPD patients. Patients and Methods We retrospectively screened consecutive COPD patients who had been prospectively enrolled in a pay-for-performance program from January 2019 to May 2020 to determine their eligibility. Patient characteristics, including demographics, exacerbation history, and 6MWT data, were analyzed to investigate their potential associations with prognosis. The primary outcome was a composite of adverse events, including overall mortality or hospitalizations due to exacerbations during a 1-year follow-up period. To analyze the 6MWT data, we divided it into three 2-minute epochs and calculated the average walk speed for each epoch. We defined pace variability as the difference between the maximum and minimum average speed in a single 2-minute epoch, divided by the average speed for the entire 6-minute walk test. Results A total of 163 patients with COPD were included in the study, and 19 of them (12%) experienced the composite adverse outcome. Multivariable logistic regression analyses revealed that two predictors were independently associated with the composite outcome: % predicted 6MWD <72 (adjusted odds ratio [aOR] 7.080; 95% confidence interval [CI] 1.481-33.847) and pace variability ≥0.39 (aOR 9.444; 95% CI 2.689-33.170). Patients with either of these adverse prognostic features had significantly worse composite outcome-free survival, with both log-rank P values less than 0.005. Notably, COPD patients with both adverse features experienced an especially poor outcome after 1 year. Conclusion Patients with COPD who exhibited greater pace variability during the 6MWT had a significantly higher risk of overall mortality and COPD-related hospitalizations, indicating a worse prognosis.
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Affiliation(s)
- Chun-Ta Huang
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Sheng-Yuan Ruan
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Feipei Lai
- Graduate Institute of Biomedical Electronics and Bioinformatics, National Taiwan University, Taipei, Taiwan
- Department of Computer Science & Information Engineering, National Taiwan University, Taipei, Taiwan
- Department of Electrical Engineering, National Taiwan University, Taipei, Taiwan
| | - Jung-Yien Chien
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Chong-Jen Yu
- Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan
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Świątkiewicz M, Gaździński S, Madeyski M, Kossowski B, Langfort J, Bogorodzki P, Zawadzka-Bartczak E, Sklinda K, Walecki J, Grieb P. Increased brain 1H-MRS glutamate and lactate signals following maximal aerobic capacity exercise in young healthy males: an exploratory study. Biol Sport 2023; 40:665-673. [PMID: 37398967 PMCID: PMC10286605 DOI: 10.5114/biolsport.2023.118335] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 05/05/2022] [Accepted: 07/14/2022] [Indexed: 08/11/2023] Open
Abstract
Physical exercise involves increased neuronal activity of many brain structures, but 1H-MRS investigations on the effects of human brain glutamate (Glu) concentrations on acute exercise have been sparse. Previous studies consistently found increases in brain lactate (Lac) concentrations following graded exercise up to 85% of the predicted maximal heart rate. However, the reported effects on brain concentrations of glutamine and glutamate were not consistent. This study aimed to determine the effect of acute intense graded maximal exercise on 1H-MRS signals related to concentrations of Glu, glutamate+glutamine (Glx), and Lac. Young adult males were randomly divided into two groups and subjected to 1H-MRS when resting (NE) or shortly after cessation of the intense graded exercise intended to pass the anaerobic threshold (E). 1H-MRS spectra were acquired from the large voxel encompassing the occipito-parietal cortex only once. Estimates of Glu, Glx, and Lac concentrations were calculated in institutional units by normalizing to a spectroscopic signal originating from creatine-containing compounds (Cr). Concentrations of Glu, Glx, and Lac were respectively 11%, 12.6%, and 48.5% higher in E than in NE (p < 0.001). The increased brain Lac signal in the exercising group indicated that in our experiment, vigorous exercise resulted in passing the anaerobic threshold and lactate apparently entered the brain. Concomitantly glutamate-related resonance signals from the vicinity of the occipito-parietal cortex were significantly increased; physiological mechanisms underlying these phenomena require further study. Future studies should evaluate whether the normalization rate of these concentrations is a marker of general physical fitness.
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Affiliation(s)
- Maciej Świątkiewicz
- Department of Experimental Pharmacology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
| | - Stefan Gaździński
- Military Institute of Aviation Medicine, Warsaw, Poland
- Interinstitute Laboratory of New Diagnostic Applications of MRI (CNSLab), Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 02-109 Warsaw, Poland
| | | | - Bartosz Kossowski
- Laboratory of Brain Imaging, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
- Interinstitute Laboratory of New Diagnostic Applications of MRI (CNSLab), Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 02-109 Warsaw, Poland
| | - Józef Langfort
- Institute of Sport Sciences, The Jerzy Kukuczka Academy of Physical Education, Katowice, Poland
| | - Piotr Bogorodzki
- Faculty of Electronics, Warsaw University of Technology Warsaw, Poland
- Small Animal Magnetic Resonance Imaging Laboratory, Mossakowski Medical Research Centre, Polish Academy of Sciences, 02-106 Warsaw, Poland
- Interinstitute Laboratory of New Diagnostic Applications of MRI (CNSLab), Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, 02-109 Warsaw, Poland
| | | | | | - Jerzy Walecki
- Military Institute of Aviation Medicine, Warsaw, Poland
| | - Paweł Grieb
- Department of Experimental Pharmacology, Mossakowski Medical Research Institute, Polish Academy of Sciences, Warsaw, Poland
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Zhang Q, Haselden WD, Charpak S, Drew PJ. Could respiration-driven blood oxygen changes modulate neural activity? Pflugers Arch 2023; 475:37-48. [PMID: 35761104 PMCID: PMC9794637 DOI: 10.1007/s00424-022-02721-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 05/26/2022] [Accepted: 06/16/2022] [Indexed: 01/31/2023]
Abstract
Oxygen is critical for neural metabolism, but under most physiological conditions, oxygen levels in the brain are far more than are required. Oxygen levels can be dynamically increased by increases in respiration rate that are tied to the arousal state of the brain and cognition, and not necessarily linked to exertion by the body. Why these changes in respiration occur when oxygen is already adequate has been a long-standing puzzle. In humans, performance on cognitive tasks can be affected by very high or very low oxygen levels, but whether the physiological changes in blood oxygenation produced by respiration have an appreciable effect is an open question. Oxygen has direct effects on potassium channels, increases the degradation rate of nitric oxide, and is rate limiting for the synthesis of some neuromodulators. We discuss whether oxygenation changes due to respiration contribute to neural dynamics associated with attention and arousal.
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Affiliation(s)
- Qingguang Zhang
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA
| | - William D Haselden
- Medical Scientist Training Program, College of Medicine, The Pennsylvania State University, Hershey, PA, 17033, USA
| | - Serge Charpak
- Institut de La Vision, INSERM, CNRS, Sorbonne Université, Paris, France
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Patrick J Drew
- Center for Neural Engineering, Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, 16802, USA.
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, 16802, USA.
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Arriel RA, Souza HLR, Sasaki JE, Marocolo M. Current Perspectives of Cross-Country Mountain Biking: Physiological and Mechanical Aspects, Evolution of Bikes, Accidents and Injuries. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:12552. [PMID: 36231848 PMCID: PMC9565958 DOI: 10.3390/ijerph191912552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/21/2022] [Revised: 09/23/2022] [Accepted: 09/29/2022] [Indexed: 06/16/2023]
Abstract
Mountain biking (MTB) is a cycling modality performed on a variety of unpaved terrain. Although the cross-country Olympic race is the most popular cross-country (XC) format, other XC events have gained increased attention. XC-MTB has repeatedly modified its rules and race format. Moreover, bikes have been modified throughout the years in order to improve riding performance. Therefore, the aim of this review was to present the most relevant studies and discuss the main results on the XC-MTB. Limited evidence on the topic suggests that the XC-MTB events present a variation in exercise intensity, demanding cardiovascular fitness and high power output. Nonetheless, these responses and demands seem to change according to each event. The characteristics of the cyclists differ according to the performance level, suggesting that these parameters may be important to achieve superior performance in XC-MTB. Moreover, factors such as pacing and ability to perform technical sections of the circuit might influence general performance. Bicycles equipped with front and rear suspension (i.e., full suspension) and 29″ wheels have been shown to be effective on the XC circuit. Lastly, strategies such as protective equipment, bike fit, resistance training and accident prevention measures can reduce the severity and the number of injuries.
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Affiliation(s)
- Rhaí André Arriel
- Department of Physiology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora 36036-330, Brazil
| | - Hiago L. R. Souza
- Department of Physiology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora 36036-330, Brazil
| | - Jeffer Eidi Sasaki
- Laboratory UFTM, Federal University of Triangulo Mineiro, Uberaba 38061-500, Brazil
| | - Moacir Marocolo
- Department of Physiology, Institute of Biological Sciences, Federal University of Juiz de Fora, Juiz de Fora 36036-330, Brazil
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但 晴, 白 婧, 蔡 钟, 林 琨, 李 泱. [Changes of myocardial calcium currents in rats with myocardial injury induced by running exercise during acute hypoxia]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2022; 42:1359-1366. [PMID: 36210709 PMCID: PMC9550543 DOI: 10.12122/j.issn.1673-4254.2022.09.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Indexed: 11/24/2022]
Abstract
OBJECTIVE To investigate the changes in myocardial calcium currents in rats subjected to forced running exercise during acute hypoxia and their association with myocardial injury. METHODS Forty SD rats were randomized into quiescent group and running group either in normal oxygen (NQ and NR groups, respectively) or in acute hypoxia (HQ and HR groups, respectively). Hypoxia was induced by keeping the rats in a hypobaric oxygen chamber (PaO2=61.6kpa) for 4 h a day; the rats in the two running groups were forced to run on running wheels for 4 h each day. Rat ventricular myocytes was isolated by enzymatic digestion for recording action potentials and currents using patch clamp technique, and confocal Ca2+ imaging was used to monitor intracellular Ca2+ levels. The expressions of Cav1.2 channel and the cardiac ryanodine receptor (RyR2) were determined using Western blotting. RESULTS Compared with those in NQ group, the rats in HR group showed significantly decreased SOD activity (P < 0.01), increased h-FABP, hs-CRP and IMA levels (P < 0.05 or 0.01), obvious myocardial pathology, and prolonged APD50 and APD90 (P < 0.05). Of the different stress conditions, forced running in acute hypoxia resulted in the most prominent increase of the densities of ICa, L currents, causing also a significant left shift of the steady state activation curve and a significant right shift of the steady state inactivation curve. Compared with those in NQ group, the rats in NR, HQ and HR groups all exhibited higher rates of spontaneous calcium wave events in the cardiac myocytes, increased frequency of calcium sparks with lowered amplitude, enhanced calcium release amplitude in the ventricular myocytes, and delayed calcium ion reabsorption; in particular, these changes were the most conspicuous in HR group (P < 0.05 or 0.01). There was also a significant increase in the protein levels of Cav1.2 channel and RyR2 receptor in HR group (P < 0.05 or 0.01). CONCLUSIONS The mechanism of myocardial injury in rats subjected to forced running in acute hypoxia may involve the increase of oxidative stress and calcium current and intracellular calcium overload.
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Affiliation(s)
- 晴 但
- 解放军总医院第一医学中心心血管内科,北京 100039Department of Cardiology, Fist Medical Center, Chinese PLA General Hospital, Beijing 100000, China
| | - 婧 白
- 郑州大学第一附属医院心血管内科,河南 郑州 450052Department of Cardiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou 450000, China
| | - 钟奇 蔡
- 中国人民解放军南部战区总医院干部病房,广东 广州 510014Cadre's Ward, General Hospital of Southern Theater Command of PLA, Guangzhou 510000, China
| | - 琨 林
- 解放军总医院第一医学中心心血管内科,北京 100039Department of Cardiology, Fist Medical Center, Chinese PLA General Hospital, Beijing 100000, China
| | - 泱 李
- 解放军总医院第六医学中心心血管 病医学部,北京 100048Department of Cardiology, Sixth Medical Center, Chinese PLA General Hospital, Beijing 100048, China
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Davidson I, Parker ZJ. Falls in people post-Guillain-Barré syndrome in the United Kingdom: A national cross-sectional survey of community based adults. HEALTH & SOCIAL CARE IN THE COMMUNITY 2022; 30:e2590-e2603. [PMID: 35015326 PMCID: PMC9546005 DOI: 10.1111/hsc.13703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 12/08/2021] [Accepted: 12/17/2021] [Indexed: 06/14/2023]
Abstract
Guillain-Barré syndrome (GBS) has several enduring effects that can lead to further harm and/or lower quality of life. These effects include falling and body pain, neither of which have been fully explored. This study aims to examine the risk factors associated with falling and potential causes of body pain in a post-GBS population. A cross-sectional survey of 216 participants was conducted using an electronic questionnaire that included. Self-report measures for: overall health, balance, anxiety and depression levels, body pain and demographics related to GBS experience and falls. A large proportion of individuals post-GBS experience ongoing problems beyond those expected with ageing. Comparative tests indicated that people reporting falls in the previous 12 months had: poorer levels of mobility, poorer F-scores, higher levels of body pain, poorer balance, poorer anxiety and depression scores and higher levels of fatigue. Gender did not appear to contribute to falls. Injuries following falls were associated with a lack of physiotherapy postdischarge and time since GBS. In a regression analysis of the identified and expected key variables, age and body pain statistically predicted falls. In over a quarter of cases reported here, respondents did not receive community physiotherapy following hospital discharge. In the midst and aftermath of COVID-19, provision of rehabilitation needs to be recalibrated, not just for COVID patients, but the wider community with ongoing needs. Issues around well-being and quality of life in the post-GBS community also need further consideration.
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Affiliation(s)
- Ian Davidson
- Department of Health ProfessionalsManchester Metropolitan UniversityManchesterUK
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Jaberzadeh S, Zoghi M. Transcranial Direct Current Stimulation Enhances Exercise Performance: A Mini Review of the Underlying Mechanisms. FRONTIERS IN NEUROERGONOMICS 2022; 3:841911. [PMID: 38235480 PMCID: PMC10790841 DOI: 10.3389/fnrgo.2022.841911] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 03/18/2022] [Indexed: 01/19/2024]
Abstract
Exercise performance (EP) is affected by a combination of factors including physical, physiological, and psychological factors. This includes factors such as peripheral, central, and mental fatigue, external peripheral factors such as pain and temperature, and psychological factors such as motivation and self-confidence. During the last century, numerous studies from different fields of research were carried out to improve EP by modifying these factors. During the last two decades, the focus of research has been mainly moved toward the brain as a dynamic ever-changing organ and the ways changes in this organ may lead to improvements in physical performance. Development of centrally-acting performance modifiers such as level of motivation or sleep deprivation and the emergence of novel non-invasive brain stimulation (NIBS) techniques such as transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) are the key motives behind this move. This article includes three sections. Section Introduction provides an overview of the mechanisms behind the reduction of EP. The main focus of the Effects of tDCS on EP section is to provide a brief description of the effects of tDCS on maximal and submaximal types of exercise and finally, the section Mechanisms Behind the Effects of tDCS on EP provides description of the mechanisms behind the effects of tDCS on EP.
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Affiliation(s)
- Shapour Jaberzadeh
- Non-invasive Brain Stimulation and Neuroplasticity Laboratory, Department of Physiotherapy, School of Primary and Allied Health Care, Faculty of Medicine, Nursing and Health Science, Monash University, Melbourne, VIC, Australia
| | - Maryam Zoghi
- Discipline of Physiotherapy, School of Health, Federation University Australia, Churchill, VIC, Australia
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12
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Lavin KM, Coen PM, Baptista LC, Bell MB, Drummer D, Harper SA, Lixandrão ME, McAdam JS, O’Bryan SM, Ramos S, Roberts LM, Vega RB, Goodpaster BH, Bamman MM, Buford TW. State of Knowledge on Molecular Adaptations to Exercise in Humans: Historical Perspectives and Future Directions. Compr Physiol 2022; 12:3193-3279. [PMID: 35578962 PMCID: PMC9186317 DOI: 10.1002/cphy.c200033] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
For centuries, regular exercise has been acknowledged as a potent stimulus to promote, maintain, and restore healthy functioning of nearly every physiological system of the human body. With advancing understanding of the complexity of human physiology, continually evolving methodological possibilities, and an increasingly dire public health situation, the study of exercise as a preventative or therapeutic treatment has never been more interdisciplinary, or more impactful. During the early stages of the NIH Common Fund Molecular Transducers of Physical Activity Consortium (MoTrPAC) Initiative, the field is well-positioned to build substantially upon the existing understanding of the mechanisms underlying benefits associated with exercise. Thus, we present a comprehensive body of the knowledge detailing the current literature basis surrounding the molecular adaptations to exercise in humans to provide a view of the state of the field at this critical juncture, as well as a resource for scientists bringing external expertise to the field of exercise physiology. In reviewing current literature related to molecular and cellular processes underlying exercise-induced benefits and adaptations, we also draw attention to existing knowledge gaps warranting continued research effort. © 2021 American Physiological Society. Compr Physiol 12:3193-3279, 2022.
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Affiliation(s)
- Kaleen M. Lavin
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Center for Human Health, Resilience, and Performance, Institute for Human and Machine Cognition, Pensacola, Florida, USA
| | - Paul M. Coen
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Liliana C. Baptista
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Margaret B. Bell
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Devin Drummer
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Sara A. Harper
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Manoel E. Lixandrão
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Jeremy S. McAdam
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Samia M. O’Bryan
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Sofhia Ramos
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Lisa M. Roberts
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Rick B. Vega
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Bret H. Goodpaster
- Translational Research Institute for Metabolism and Diabetes, Advent Health, Orlando, Florida, USA
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida, USA
| | - Marcas M. Bamman
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Cell, Developmental, and Integrative Biology, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Center for Human Health, Resilience, and Performance, Institute for Human and Machine Cognition, Pensacola, Florida, USA
| | - Thomas W. Buford
- Center for Exercise Medicine, The University of Alabama at Birmingham, Birmingham, Alabama, USA
- Department of Medicine, Division of Gerontology, Geriatrics and Palliative Care, The University of Alabama at Birmingham, Birmingham, Alabama, USA
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13
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The Problem of Effort Distribution in Heavy Glycolytic Trials with Special Reference to the 400 m Dash in Track and Field. BIOLOGY 2022; 11:biology11020216. [PMID: 35205083 PMCID: PMC8869504 DOI: 10.3390/biology11020216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/25/2022] [Accepted: 01/27/2022] [Indexed: 11/17/2022]
Abstract
Simple Summary Short, intensive, but above lactate threshold physical trials or competitions which last <1 min but are close to this time limit, are on the border between glycolytic and aerobic efforts. The distribution of effort is critical in these tasks to achieve the best possible results. However, it is still unclear which of the general rules, descending from the theory, should be adopted by athletes (or any other subject facing a similar task). The 400 m dash competition of track and field has been taken in this systematic review as a paradigm for surveying the determinant factors which influence the pacing strategy and the end of effort. From the literature it emerges that there are several approaches, grounded in the philosophical basis of effort, which determine effort distribution. The problem is still open and a clear direction has not yet emerged from the available studies on the topic. Abstract Background. Biological factors are ultimately responsible for the cessation of effort in short, maximal glycolytic efforts. However, how these factors are sensed by the brain and act in a loop or feedforward way to regulate the distribution of effort is still unclear. Methods: A systematic review of existing literature on short term glycolytic exercise has been performed on publicly available databases (Google Scholar and Pudmed). Results: The problem of effort termination in fast maximal glycolytic activities after 100 years of research is still open. It is not clear if a central governor of effort exists, if the limitations are in the energy transport and utilization system, or in the psycho-social factors. Conclusions. The solution probably resides in a mixture of factors, but how the different components interact is still a mystery for science due to the philosophical grounding of the experimental approaches.
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14
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Marillier M, Gruet M, Bernard AC, Verges S, Neder JA. The Exercising Brain: An Overlooked Factor Limiting the Tolerance to Physical Exertion in Major Cardiorespiratory Diseases? Front Hum Neurosci 2022; 15:789053. [PMID: 35126072 PMCID: PMC8813863 DOI: 10.3389/fnhum.2021.789053] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 12/28/2021] [Indexed: 12/18/2022] Open
Abstract
“Exercise starts and ends in the brain”: this was the title of a review article authored by Dr. Bengt Kayser back in 2003. In this piece of work, the author highlights that pioneer studies have primarily focused on the cardiorespiratory-muscle axis to set the human limits to whole-body exercise tolerance. In some circumstances, however, exercise cessation may not be solely attributable to these players: the central nervous system is thought to hold a relevant role as the ultimate site of exercise termination. In fact, there has been a growing interest relative to the “brain” response to exercise in chronic cardiorespiratory diseases, and its potential implication in limiting the tolerance to physical exertion in patients. To reach these overarching goals, non-invasive techniques, such as near-infrared spectroscopy and transcranial magnetic stimulation, have been successfully applied to get insights into the underlying mechanisms of exercise limitation in clinical populations. This review provides an up-to-date outline of the rationale for the “brain” as the organ limiting the tolerance to physical exertion in patients with cardiorespiratory diseases. We first outline some key methodological aspects of neuromuscular function and cerebral hemodynamics assessment in response to different exercise paradigms. We then review the most prominent studies, which explored the influence of major cardiorespiratory diseases on these outcomes. After a balanced summary of existing evidence, we finalize by detailing the rationale for investigating the “brain” contribution to exercise limitation in hitherto unexplored cardiorespiratory diseases, an endeavor that might lead to innovative lines of applied physiological research.
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Affiliation(s)
- Mathieu Marillier
- Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
- HP2 Laboratory, INSERM U1300, Grenoble Alpes University, Grenoble, France
| | - Mathieu Gruet
- IAPS Laboratory, University of Toulon, Toulon, France
| | - Anne-Catherine Bernard
- Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
- HP2 Laboratory, INSERM U1300, Grenoble Alpes University, Grenoble, France
| | - Samuel Verges
- HP2 Laboratory, INSERM U1300, Grenoble Alpes University, Grenoble, France
| | - J Alberto Neder
- Laboratory of Clinical Exercise Physiology, Queen's University and Kingston General Hospital, Kingston, ON, Canada
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15
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Melo LT, Rodrigues A, Cabral EE, Tanaka T, Goligher EC, Brochard L, Reid WD. Prefrontal cortex activation during incremental inspiratory loading in healthy participants. Respir Physiol Neurobiol 2021; 296:103827. [PMID: 34808586 DOI: 10.1016/j.resp.2021.103827] [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: 06/06/2021] [Revised: 10/01/2021] [Accepted: 11/11/2021] [Indexed: 11/28/2022]
Abstract
We aimed to investigate whether changes in prefrontal cortex (PFC) oxyhemoglobin (O2Hb) and deoxyhemoglobin (HHb) associates with inspiratory muscle effort during inspiratory threshold loading (ITL) in healthy participants. Participants performed an incremental ITL. Breathing pattern, partial pressure of end-tidal CO2 (PETCO2), mouth pressure and O2Hb and HHb over the right dorsolateral PFC, sternocleidomastoid (SCM), and diaphragm/intercostals (Dia/IC) were monitored. Fourteen healthy participants (8 men; 29 ± 5 years) completed testing. Dyspnea was higher post- than pre-ITL (5 ± 1 vs. 0 ± 1, respectively; P<0.05). PFC O2Hb increased (P < 0.001) and HHb decreased (P = 0.001) at low loads but remained stable with increasing ITL intensities. PFC total hemoglobin increased at task failure compared to rest. SCM HHb increased throughout increasing intensities. SCM and Dia/IC total hemoglobin increased in the at task failure compared to rest. PETCO2 did not change (P = 0.528). PFC is activated early during the ITL but does not show central fatigue at task failure despite greater dyspnea and an imbalance of SCM oxygen demand and delivery.
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Affiliation(s)
- Luana T Melo
- Department of Physical Therapy, University of Toronto, Ontario, Canada; Keenan Centre for Biomedical Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada
| | - Antenor Rodrigues
- Department of Physical Therapy, University of Toronto, Ontario, Canada; Keenan Centre for Biomedical Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada.
| | - Elis Emmanuelle Cabral
- Department of Physical Therapy, University of Toronto, Ontario, Canada; Performance Lab, Pneumocardiovascular and Respiratory Muscles (PneumoCardioVascular Lab/HUOL), Department of Physical Therapy, Federal University of Rio Grande do Norte (UFRN), Rio Grande do Norte, Brazil
| | - Takako Tanaka
- Department of Physical Therapy, University of Toronto, Ontario, Canada; Department of Cardiopulmonary Rehabilitation Science, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | - Ewan C Goligher
- Division of Respirology, Department of Medicine, University Health Network, Toronto, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada; Department of Physiology, University of Toronto, Toronto, Canada
| | - Laurent Brochard
- Keenan Centre for Biomedical Research, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada; Department of Medicine, University of Toronto, Toronto, Canada
| | - W Darlene Reid
- Department of Physical Therapy, University of Toronto, Ontario, Canada; Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, Canada; KITE, Toronto Rehabilitation Institute, University Health Network, Toronto, Canada
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16
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Ghorbani M, Clark CCT. Brain function during central fatigue induced by intermittent high-intensity cycling. Neurol Sci 2021; 42:3655-3661. [PMID: 33439390 DOI: 10.1007/s10072-020-04965-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Accepted: 12/04/2020] [Indexed: 11/24/2022]
Abstract
BACKGROUND The central governor model putatively explains the mechanism of endurance exercise-induced central fatigue, however high-intensity exercise-induced central fatigue strategies have not been investigated yet. This study aimed to examine how central fatigue affects neural response alterations, as measured by electroencephalographic (EEG) recordings, in intermittent high-intensity cycling. METHODS Neural responses were assessed by measuring the alteration of brainwaves based on spectral energy band estimates during an intermittent, high-intensity, 60-min exercise bout on a cycle ergometer. The cycle ergometer incline was changed every 10 min in an intermittent pattern (10-20-5-20-5-10°). EEG was used to analyze altering brain function. Heart rate (HR), blood lactate (BL), and rating of perceived exertion (RPE) were measured after the participants completed each change in incline. RESULTS The results showed that HR, BL, and RPE increased at an incline of 20° in comparison to a 5° incline. The spectral power of EEG was significantly increased (P ˂ 0.01) in the alpha and beta frequency ranges with a change in inclines between 5 and 20°. The spectral power of the EEG was significantly increased (P ˂ 0.01) over the whole frequency range from rest (theta + 251%, alpha + 165%, beta + 145%). CONCLUSION Higher, relative intensities (10 and 20°) increased brain function, regardless of fatigue occurrence. HIIT (high-intensity interval training) led to an alteration in the neural response. Further work investigating the usefulness of HIIT to improve brain function is warranted.
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Affiliation(s)
- Mehrangiz Ghorbani
- Department of Physical Education and Sport Sciences, Islamic Azad University Bijar Branch, Bijar, Iran.
| | - Cain C T Clark
- Centre for Sport, Exercise and Life Sciences, Coventry University, Coventry, CV1 5FB, UK
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17
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Möller F, Jacobi E, Hoffmann U, Muth T, Schipke JD. Oxygen-enriched Air Decreases Ventilation during High-intensity Fin-swimming Underwater. Int J Sports Med 2021; 43:230-236. [PMID: 34399427 PMCID: PMC8885326 DOI: 10.1055/a-1554-5093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Oxygen-enriched air is commonly used in the sport of SCUBA-diving and might affect ventilation and heart rate, but little work exists for applied diving settings. We hypothesized that ventilation is decreased especially during strenuous underwater fin-swimming when using oxygen-enriched air as breathing gas. Ten physically-fit divers (age: 25±4; 5 females; 67±113 open-water dives) performed incremental underwater fin-swimming until exhaustion at 4 m water depth with either normal air or oxygen-enriched air (40% O
2
) in a double-blind, randomized within-subject design. Heart rate and ventilation were measured throughout the dive and maximum whole blood lactate samples were determined post-exercise. ANOVAs showed a significant effect for the factor breathing gas (F(1, 9)=7.52; P=0.023; η
2p
=0.455), with a lower ventilation for oxygen-enriched air during fin-swimming velocities of 0.6 m·s
−1
(P=0.032) and 0.8 m·s
−1
(P=0.037). Heart rate, lactate, and time to exhaustion showed no significant differences. These findings indicate decreased ventilation by an elevated oxygen fraction in the breathing gas when fin-swimming in shallow-water submersion with high velocity (>0.5 m·s
−1
). Applications are within involuntary underwater exercise or rescue scenarios for all dives with limited gas supply.
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Affiliation(s)
- Fabian Möller
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Elena Jacobi
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Uwe Hoffmann
- Department of Exercise Physiology, German Sport University Cologne, Cologne, Germany
| | - Thomas Muth
- Occupational, Social, Environmental Medicine, Heinrich-Heine-Universitat Dusseldorf, Dusseldorf, Germany
| | - Jochen D Schipke
- Research Group Experimenal Surgery, University Hospital Düsseldorf, Dusseldorf, Germany
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18
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Müller J, Lichtblau M, Saxer S, Calendo LR, Carta AF, Schneider SR, Berlier C, Furian M, Bloch KE, Schwarz EI, Ulrich S. Effect of Breathing Oxygen-Enriched Air on Exercise Performance in Patients With Pulmonary Hypertension Due to Heart Failure With Preserved Ejection Fraction: A Randomized, Placebo-Controlled, Crossover Trial. Front Med (Lausanne) 2021; 8:692029. [PMID: 34395475 PMCID: PMC8357069 DOI: 10.3389/fmed.2021.692029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/24/2021] [Indexed: 11/13/2022] Open
Abstract
Objective: To evaluate the effects of breathing oxygen-enriched air (oxygen) on exercise performance in patients with pulmonary hypertension due to heart failure with preserved ejection fraction (PH-HFpEF). Methods: Ten patients with PH-HFpEF (five women, age 60 ± 9 y, mPAP 37 ± 14 mmHg, PAWP 18 ± 2 mmHg, PVR 3 ± 3 WU, resting SpO2 98 ± 2%) performed two-cycle incremental exercise tests (IET) and two constant-work-rate exercise test (CWRET) at 75% maximal work-rate (Wmax), each with ambient air (FiO2 0.21) and oxygen (FiO2 0.5) in a randomized, single-blinded, cross-over design. The main outcomes were the change in Wmax (IET) and cycling time (CWRET) with oxygen vs. air. Blood gases at rest and end-exercise, dyspnea by Borg CR10 score at end-exercise; continuous SpO2, minute ventilation (V'E), carbon dioxide output (V'CO2), and cerebral and quadricep muscle tissue oxygenation (CTO and QMTO) were measured. Results: With oxygen vs. air, Wmax (IET) increased from 94 ± 36 to 99 ± 36 W, mean difference (95% CI) 5.4 (0.9–9.8) W, p = 0.025, and cycling time (CWRET) from 532 ± 203 to 680 ± 76 s, +148 (31.8–264) s, p = 0.018. At end-exercise with oxygen, Borg dyspnea score and V'E/V'CO2 were lower, whereas PaO2 and end-tidal PaCO2 were higher. Other parameters were unchanged. Conclusion: Patients with PH-HFpEF not revealing resting hypoxemia significantly improved their exercise performance while breathing oxygen-enriched air along with less subjective dyspnea sensation, a better blood oxygenation, and an enhanced ventilatory efficiency. Future studies should investigate whether prolonged training with supplemental oxygen would increase the training effect and, potentially, daily activity for PH-HFpEF patients. Clinical Trial Registration: [clinicaltrials.gov], identifier [NCT04157660].
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Affiliation(s)
- Julian Müller
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Mona Lichtblau
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Stéphanie Saxer
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Luigi-Riccardo Calendo
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Arcangelo F Carta
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Simon R Schneider
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Charlotte Berlier
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Michael Furian
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Konrad E Bloch
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland.,Centre for Integrative Human Physiology, University of Zürich, Zürich, Switzerland
| | - Esther I Schwarz
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland
| | - Silvia Ulrich
- Pulmonary Clinic, University Hospital Zürich, Zürich, Switzerland.,Faculty of Medicine, University of Zürich, Zürich, Switzerland.,Centre for Integrative Human Physiology, University of Zürich, Zürich, Switzerland
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Boutou AK, Dipla K, Zafeiridis A, Markopoulou A, Papadopoulos S, Kritikou S, Panagiotidou E, Stanopoulos I, Pitsiou G. A randomized placebo-control trial of the acute effects of oxygen supplementation on exercise hemodynamics, autonomic modulation, and brain oxygenation in patients with pulmonary hypertension. Respir Physiol Neurobiol 2021; 290:103677. [PMID: 33957299 DOI: 10.1016/j.resp.2021.103677] [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: 12/25/2020] [Revised: 04/05/2021] [Accepted: 04/30/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND The integrative physiological effects of O2 treatment on patients with pulmonary hypertension (PH) during exercise, have not been fully investigated. We simultaneously evaluated, for the first time, the effect of oxygen supplementation on hemodynamic responses, autonomic modulation, tissue oxygenation, and exercise performance in patients with pulmonary arterial hypertension (PAH)/Chronic Thromboembolic PH(CTEPH). MATERIAL-METHODS In this randomized, cross-over, placebo-controlled trial, stable outpatients with PAH/CTEPH underwent maximal cardiopulmonary exercise testing, followed by two submaximal trials, during which they received supplementary oxygen (O2) or medical-air. Continuous, non-invasive hemodynamics were monitored via photophlythesmography. Cerebral and quadriceps muscle oxygenation were recorded via near-infrared spectroscopy. Autonomic function was assessed by heart rate variability; root mean square of successive differences (RMSSD) and standard-deviation-Poincare-plot (SD1) were used as indices of parasympathetic output. Baroreceptor sensitivity (BRS) was assessed throughout the protocols. RESULTS Nine patients (51.4 ± 9.4 years) were included. With O2-supplementation patients exercised for longer (p = 0.01), maintained higher cerebral oxygenated hemoglobin (O2Hb;p = 0.02) levels, exhibited an amelioration in cortical deoxygenation (HHb;p = 0.02), and had higher average cardiac output (CO) during exercise (p < 0.05), compared to medical air; with no differences in muscle oxygenation. With O2-supplementation patients exhibited higher BRS and sample-entropy throughout the protocol (p < 0.05) vs. medical air, and improved the blunted RMSSD, SD1 responses during exercise (p = 0.024). CONCLUSION We show that O2 administration improves BRS and autonomic function during submaximal exercise in PAH/CTEPH, without significantly affecting muscle oxygenation. The improved autonomic function, along with enhancements in cardiovascular function and cerebral oxygenation, probably contributes to increased exercise tolerance with O2-supplementation in PH patients.
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Affiliation(s)
- Afroditi K Boutou
- Department of Respiratory Medicine, "G. Papanikolaou Hospital", Thessaloniki, Greece.
| | - Konstantina Dipla
- Exercise Physiology & Biochemistry Laboratory, Dept. of Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Andreas Zafeiridis
- Exercise Physiology & Biochemistry Laboratory, Dept. of Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | | | - Stavros Papadopoulos
- Exercise Physiology & Biochemistry Laboratory, Dept. of Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Stella Kritikou
- Exercise Physiology & Biochemistry Laboratory, Dept. of Sport Sciences at Serres, Aristotle University of Thessaloniki, Greece
| | - Evangelia Panagiotidou
- Respiratory Failure Department, "G. Papanikolaou" Hospital, Aristotle University of Thessaloniki, Greece
| | - Ioannis Stanopoulos
- Respiratory Failure Department, "G. Papanikolaou" Hospital, Aristotle University of Thessaloniki, Greece
| | - Georgia Pitsiou
- Respiratory Failure Department, "G. Papanikolaou" Hospital, Aristotle University of Thessaloniki, Greece
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20
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Pryor JL, Johnson EC, Yoder HA, Looney DP. Keeping Pace: A Practitioner-Focused Review of Pacing Strategies in Running. Strength Cond J 2020. [DOI: 10.1519/ssc.0000000000000505] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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21
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Levine A, Buono MJ. Rating of perceived exertion increases synergistically during prolonged exercise in a combined heat and hypoxic environment. J Therm Biol 2019; 84:99-102. [PMID: 31466796 DOI: 10.1016/j.jtherbio.2019.06.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 05/31/2019] [Accepted: 06/03/2019] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to determine the cardiovascular, thermoregulatory, and perceived exertion responses during 2 h of moderate intensity exercise in a combined high heat (38 °C, 40% relative humidity) and hypoxic (15% O2) environment. Ten healthy volunteers completed 2 h of treadmill walking at 40% of maximal oxygen uptake in four different conditions, each separated by approximately 1 week: (1) control, 23 °C/20.9% O2, (2) heat, 38 °C/20.9% O2, (3) hypoxia, 23 °C/15% O2, and (4) combined heat/hypoxia, 38 °C/15% O2. Compared to the responses seen in each condition alone, heart rate (HR) and core temperature (Tcore) showed an additive increase in the combined heat and hypoxic environment after 2 h of moderate intensity exercise. The most important new finding was that the mean rating of perceived exertion (RPE) increased synergistically 3.3 units when exercising in the combined high heat and hypoxic environment, compared to 1.9 units in the heat condition alone. The results suggest that RPE is a conscious perception of effort that plays a regulatory function to ensure that the work rate remains at an intensity that can be safely sustained, rather than simply a marker of exercise intensity. Such results also support previous anecdotal reports that exercise on hot days at altitude seem unusually difficult.
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Affiliation(s)
- Ashley Levine
- School of Exercise and Nutritional Sciences, San Diego State University San Diego, CA, 92182, United States
| | - Michael J Buono
- Biology Department, San Diego State University, San Diego, CA, 92182, United States; School of Exercise and Nutritional Sciences, San Diego State University San Diego, CA, 92182, United States.
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Gronwald T, Hoos O, Hottenrott K. Effects of Acute Normobaric Hypoxia on Non-linear Dynamics of Cardiac Autonomic Activity During Constant Workload Cycling Exercise. Front Physiol 2019; 10:999. [PMID: 31427992 PMCID: PMC6688521 DOI: 10.3389/fphys.2019.00999] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 07/18/2019] [Indexed: 12/12/2022] Open
Abstract
Aim Measurements of Non-linear dynamics of heart rate variability (HRV) provide new possibilities to monitor cardiac autonomic activity during exercise under different environmental conditions. Using detrended fluctuation analysis (DFA) technique to assess correlation properties of heart rate (HR) dynamics, the present study examines the influence of normobaric hypoxic conditions (HC) in comparison to normoxic conditions (NC) during a constant workload exercise. Materials and Methods Nine well trained cyclists performed a continuous workload exercise on a cycle ergometer with an intensity corresponding to the individual anaerobic threshold until voluntary exhaustion under both NC and HC (15% O2). The individual exercise duration was normalized to 10% sections (10-100%). During exercise HR and RR-intervals were continuously-recorded. Besides HRV time-domain measurements (meanRR, SDNN), fractal correlation properties using short-term scaling exponent alpha1 of DFA were calculated. Additionally, blood lactate (La), oxygen saturation of the blood (SpO2), and rating of perceived exertion (RPE) were recorded in regular time intervals. Results We observed significant changes under NC and HC for all parameters from the beginning to the end of the exercise (10% vs. 100%) except for SpO2 and SDNN during NC: increases for HR, La, and RPE in both conditions; decreases for SpO2 and SDNN during HC, meanRR and DFA-alpha1 during both conditions. Under HC HR (40-70%), La (10-90%), and RPE (50-90%) were significantly-higher, SpO2 (10-100%), meanRR (40-70%), and DFA-alpha1 (20-60%) were significantly-lower than under NC. Conclusion Under both conditions, prolonged exercise until voluntary exhaustion provokes a lower total variability combined with a reduction in the amplitude and correlation properties of RR fluctuations which may be attributed to increased organismic demands. Additionally, HC provoked higher demands and loss of correlation properties at an earlier stage during the exercise regime, implying an accelerated alteration of cardiac autonomic regulation.
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Affiliation(s)
- Thomas Gronwald
- Department of Performance, Neuroscience, Therapy and Health, MSH Medical School Hamburg, Hamburg, Germany
| | - Olaf Hoos
- Center for Sports and Physical Education, Julius Maximilians University of Würzburg, Würzburg, Germany
| | - Kuno Hottenrott
- Institute of Sports Science, Martin Luther University of Halle-Wittenberg, Halle, Germany
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Porter MS, Fenton J, Reed KE. The effects of hyperoxia on repeated sprint cycling performance & muscle fatigue. J Sci Med Sport 2019; 22:1344-1348. [PMID: 31337587 DOI: 10.1016/j.jsams.2019.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Revised: 05/29/2019] [Accepted: 07/05/2019] [Indexed: 11/19/2022]
Abstract
OBJECTIVES Hyperoxia (>21% oxygen) can evoke performance improvements in aerobic and anaerobic exercise. The aims of the current study were to determine the effects of breathing hyperoxic gas (fraction of inspired oxygen [FiO2] 1.00) on repeated cycle performance, and to assess the nature and extent of fatigue after intermittent sprinting. DESIGN & METHODS Testing (n=14 males) comprised two visits to the laboratory. Each session involved 10×15s repeated cycle sprints breathing FiO2 1.00 (hyperoxia) or FiO2 0.21 (normoxia). Muscle fatigue was measured pre and post sprints using Maximal Voluntary Contraction (MVC), voluntary activation (VA) and potentiated doublet twitch (PTF). Blood lactate (BLa) was taken between sprints. Paired samples t-tests were used to examine difference between conditions in power output (peak and mean Watts) and BLa. Two-way ANOVA was used to examine fatigue variables pre and post sprints according to condition. RESULTS Mean power output was 4% greater in hyperoxia (p<0.01), with no difference in peak power (p>0.05). There was a significant increase in BLa in hyperoxia compared with normoxia (p<0.01) in sprints 4 and 8, as well as meaningful difference in sprints 4-10. There was no significant difference in fatigue factors (MVC, VA and PTF) (p>0.05) in response to the cycling, although a large drop in PTF occurred in both conditions. CONCLUSION Hyperoxia can elicit improvements in mean cycling power, with no significant change in post exercise muscle fatigue. Hyperoxia as a training aid may provide performance enhancing effects during repeated sprint cycling by reducing concurrent muscle fatigue, primarily via peripheral factors.
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Affiliation(s)
- Michael S Porter
- School of Sport, Rehabilitation & Exercise Sciences, University of Essex, United Kingdom
| | - Jordan Fenton
- School of Sport, Rehabilitation & Exercise Sciences, University of Essex, United Kingdom
| | - Katharine E Reed
- School of Sport, Rehabilitation & Exercise Sciences, University of Essex, United Kingdom.
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Martínez-Aguilar GM, Gutiérrez D. Using cortico-muscular and cortico-cardiac coherence to study the role of the brain in the development of muscular fatigue. Biomed Signal Process Control 2019. [DOI: 10.1016/j.bspc.2018.10.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Fryer S, Stone K, Dickson T, Wilhelmsen A, Cowen D, Faulkner J, Lambrick D, Stoner L. The effects of 4 weeks normobaric hypoxia training on microvascular responses in the forearm flexor. J Sports Sci 2018; 37:1235-1241. [PMID: 30558476 DOI: 10.1080/02640414.2018.1554177] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Intermittent exposure to hypoxia can lead to improved endurance performance. Currently, it is unclear whether peripheral adaptions play a role in improving oxygen delivery and utilization following both training and detraining. This study aimed to characterize skeletal muscle blood flow (mBF), oxygen consumption (mV̇O2), and perfusion adaptations to i) 4-weeks handgrip training in hypoxic and normoxic conditions, and ii) following 4-weeks detraining. Using a randomised crossover design, 9 males completed 30-min handgrip training four times a week in hypoxic (14% FiO2 ~ 3250m altitude) and normoxic conditions. mBF, mV̇O2 and perfusion were assessed pre, post 4-weeks training, and following 4-weeks detraining. Hierarchical linear modelling found that mV̇O2 increased at a significantly faster rate (58%) with hypoxic training (0.09 mlO2·min-1 · 100g-1 per week); perfusion increased at a significantly (69%) faster rate with hypoxic training (3.72 μM per week). mBF did not significantly change for the normoxic condition, but there was a significant increase of 0.38 ml· min-1 · 100ml-1 per week (95% CI: 0.35, 0.40) for the hypoxic condition. During 4-weeks detraining, mV̇O2 and perfusion significantly declined at similar rates for both conditions, whereas mBF decreased significantly faster following hypoxic training. Four weeks hypoxic training increases the delivery and utilisation of oxygen in the periphery.
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Affiliation(s)
- S Fryer
- a School of Sport and Exercise , University of Gloucestershire , Gloucester , UK
| | - K Stone
- a School of Sport and Exercise , University of Gloucestershire , Gloucester , UK
| | - T Dickson
- a School of Sport and Exercise , University of Gloucestershire , Gloucester , UK
| | - A Wilhelmsen
- b School of Life Sciences, Metabolic and Molecular Physiology Research Group , University of Nottingham , UK
| | - D Cowen
- a School of Sport and Exercise , University of Gloucestershire , Gloucester , UK
| | - J Faulkner
- c Faculty of Business, Law and Sport , University of Winchester , Winchester , UK
| | - D Lambrick
- d Faculty of Health Sciences , University of Southampton , Southampton , UK
| | - L Stoner
- e Department of Sport and Exercise , University of North Carolina , Chapel Hill , NC , USA
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26
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Saligan LN. Collaborative Framework to Advance Symptom Science: An Intramural Perspective. J Nurs Scholarsh 2018; 51:17-25. [PMID: 30375716 DOI: 10.1111/jnu.12445] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/18/2018] [Indexed: 12/12/2022]
Abstract
PURPOSE To describe the collaborative framework used by National Institute of Nursing Research (NINR) investigators to advance symptom science and to provide a research exemplar. MODEL The National Institutes of Health (NIH) Symptom Science Model (SSM) was developed to guide symptom science researchers to understand the molecular underpinnings of symptoms using innovative "omics" approaches. The process begins with a review of the literature to understand the state of the science of the symptoms of interest and is followed by cross-sectional, case-controlled, or longitudinal studies to identify potential biological correlates of these symptoms. The final steps include validation of these potential symptom biomarkers using multidisciplinary, collaborative, preclinical experiments, and proof-of-concept clinical trials. RESEARCH EXEMPLAR Using the NIH SSM as a guide, the identification of biologic correlates of symptoms using omics and bioinformatic strategies depends on determining the distinct phenotype of the symptoms of interest. The identified biologic correlates of these symptoms are then validated for their functional relevance using in vitro and ex vivo experiments, or through proof-of-concept clinical trials. NINR investigators observed that activation of specific receptors in neural networks can trigger inflammation-related fatigue development and predispose patients to develop chronicity of symptoms. Specifically targeting these neural receptors can reduce symptom intensity. CONCLUSIONS Through using the NIH SSM as a guide, NINR investigators quickly generate data and discoveries that significantly advance symptom science by simultaneously collaborating with multiple experts and core laboratories to identify more correlates and validate their functional relevance in order to further understand the biological underpinnings of the symptoms of interest. CLINICAL RELEVANCE The collaborative framework used by NINR investigators as guided by the NIH SSM identifies functionally relevant clinical markers that can explain the biological underpinnings of symptoms and can be targeted to optimize symptom management.
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Affiliation(s)
- Leorey N Saligan
- Psi Beta, Nurse Scientist, National Institute of Nursing Research, Division of Intramural Research, National Institutes of Health, Bethesda, MD, USA
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Abstract
Knowledge about possible brain mechanisms involved in the regulation of exercise intensity has vastly grown over the last decade. The current review attempts to condense this knowledge currently published with a focus on brain imaging studies. A number of psychological manipulations known to influence exercise intensity are discussed with respect to their possibly underlying brain structures. Although far from forming a complete picture, current knowledge allows to speculate on various possible influences and their corresponding neural bases. Especially, the roles of the insular cortex, anterior cingulate cortex, basal ganglia and prefrontal cortex structures are discussed. Interoceptive signals processed in the insular cortex can influence motor activity likely via anterior cingulate cortex with themselves being influenced by higher order prefrontal cortical regions (e.g., when mediating expectancy effects). Such higher order prefrontal regions can also modulate motivation and thus motor activity by influencing valuation processes in the midbrain and other structures.
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Affiliation(s)
- Kai Lutz
- Vascular Neurology and Neurorehabilitation, University of Zürich, Zürich, Switzerland; Cereneo center for interdisciplinary research (cefir), Vitznau, Switzerland; Cereneo center for neurology and rehabilitation, Vitznau, Switzerland.
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28
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Mourot L. Limitation of Maximal Heart Rate in Hypoxia: Mechanisms and Clinical Importance. Front Physiol 2018; 9:972. [PMID: 30083108 PMCID: PMC6064954 DOI: 10.3389/fphys.2018.00972] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 07/02/2018] [Indexed: 12/17/2022] Open
Abstract
The use of exercise intervention in hypoxia has grown in popularity amongst patients, with encouraging results compared to similar intervention in normoxia. The prescription of exercise for patients largely rely on heart rate recordings (percentage of maximal heart rate (HRmax) or heart rate reserve). It is known that HRmax decreases with high altitude and the duration of the stay (acclimatization). At an altitude typically chosen for training (2,000-3,500 m) conflicting results have been found. Whether or not this decrease exists or not is of importance since the results of previous studies assessing hypoxic training based on HR may be biased due to improper intensity. By pooling the results of 86 studies, this literature review emphasizes that HRmax decreases progressively with increasing hypoxia. The dose–response is roughly linear and starts at a low altitude, but with large inter-study variabilities. Sex or age does not seem to be a major contributor in the HRmax decline with altitude. Rather, it seems that the greater the reduction in arterial oxygen saturation, the greater the reduction in HRmax, due to an over activity of the parasympathetic nervous system. Only a few studies reported HRmax at sea/low level and altitude with patients. Altogether, due to very different experimental design, it is difficult to draw firm conclusions in these different clinical categories of people. Hence, forthcoming studies in specific groups of patients are required to properly evaluate (1) the HRmax change during acute hypoxia and the contributing factors, and (2) the physiological and clinical effects of exercise training in hypoxia with adequate prescription of exercise training intensity if based on heart rate.
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Affiliation(s)
- Laurent Mourot
- EA 3920 Prognostic Markers and Regulatory Factors of Cardiovascular Diseases and Exercise Performance, Health, Innovation Platform, University of Franche-Comté, Besançon, France.,Tomsk Polytechnic University, Tomsk, Russia
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29
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Abstract
Hyperoxia results from the inhalation of mixtures of gas containing higher partial pressures of oxygen (O2) than normal air at sea level. Exercise in hyperoxia affects the cardiorespiratory, neural and hormonal systems, as well as energy metabolism in humans. In contrast to short-term exposure to hypoxia (i.e. a reduced partial pressure of oxygen), acute hyperoxia may enhance endurance and sprint interval performance by accelerating recovery processes. This narrative literature review, covering 89 studies published between 1975 and 2016, identifies the acute ergogenic effects and health concerns associated with hyperoxia during exercise; however, long-term adaptation to hyperoxia and exercise remain inconclusive. The complexity of the biological responses to hyperoxia, as well as the variations in (1) experimental designs (e.g. exercise intensity and modality, level of oxygen, number of participants), (2) muscles involved (arms and legs) and (3) training status of the participants may account for the discrepancies.
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30
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Fernández Menéndez A, Saudan G, Sperisen L, Hans D, Saubade M, Millet GP, Malatesta D. Effects of Short-Term Normobaric Hypoxic Walking Training on Energetics and Mechanics of Gait in Adults with Obesity. Obesity (Silver Spring) 2018; 26:819-827. [PMID: 29575698 DOI: 10.1002/oby.22131] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 12/07/2017] [Accepted: 01/11/2018] [Indexed: 02/05/2023]
Abstract
OBJECTIVE The aim of this study was to compare the effects of short-term hypoxic versus normoxic training at preferred walking speed (PWS) on energetics, mechanics, efficiency, and metabolic risk markers in individuals with obesity. METHODS Twenty-three subjects with obesity performed nine 1-hour sessions at PWS under hypoxia (3,000 m, n = 12; BMI: 34.0 ± 0.8 kg/m2 ) or normoxia (360 m, n = 11; BMI: 32.9 ± 0.8 kg/m2 ). Participants performed six 5-minute walking trials at different speeds (PWS, 0.56, 0.83, 1.11, 1.39, and 1.67 m/s). The net energy cost, external mechanical work, and rated perceived exertion (RPE) were measured at these speeds. Body composition and blood samples were collected. RESULTS PWS tended to be slower under hypoxia than normoxia (-6.7%; P = 0.092) during the training, and this difference reached significance the third week (-8.9%; P = 0.05). After training, PWS significantly increased (+ 8.2%; P ≤ 0.001), while RPE decreased (P = 0.005). Ankle range of motion (P = 0.03) and vertical displacement of the center of mass (P = 0.02) significantly increased in both groups. CONCLUSIONS A walking training program under hypoxia at slower PWS than in normoxia elicited similar responses in metabolic risk factors, energetics, and mechanics of walking in individuals with obesity. Both programs increased PWS, decreased RPE, and induced gait-pattern adaptations, which protected against orthopedic injury in these individuals.
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Affiliation(s)
- Aitor Fernández Menéndez
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Gilles Saudan
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Ludovic Sperisen
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Didier Hans
- Center for Bone Diseases, Lausanne University Hospital, Lausanne, Switzerland
| | - Mathieu Saubade
- Sports Medicine Unit, Swiss Olympic Medical Center, Lausanne University Hospital, Lausanne, Switzerland
| | - Grégoire P Millet
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Davide Malatesta
- Institute of Sport Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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31
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Noakes TD. Response to: Lessons from Popper for science, paradigm shifts, scientific revolutions and exercise physiology. BMJ Open Sport Exerc Med 2018; 4:e000277. [PMID: 29388623 PMCID: PMC5783026 DOI: 10.1136/bmjsem-2017-000277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/19/2017] [Indexed: 11/04/2022] Open
Affiliation(s)
- Timothy David Noakes
- Department of Human Biology, University of Cape Town, Cape Town, Western Cape, South Africa
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32
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Affiliation(s)
- D. A. Cardinale
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
- Elite Performance Centre, Bosön - Swedish Sports Confederation, Lidingö, Sweden
| | - B. Ekblom
- Åstrand Laboratory, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
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33
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Hollins L. The NICE 10 minute physical restraint rule: A discussion of the relative risks. J Psychiatr Ment Health Nurs 2017; 24:719-726. [PMID: 28766829 DOI: 10.1111/jpm.12414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/26/2017] [Indexed: 11/26/2022]
Affiliation(s)
- L Hollins
- Risk Assessor/Researcher, Epping, Essex, UK
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34
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Venhorst A, Micklewright D, Noakes TD. Towards a three-dimensional framework of centrally regulated and goal-directed exercise behaviour: a narrative review. Br J Sports Med 2017; 52:957-966. [PMID: 28835409 DOI: 10.1136/bjsports-2016-096907] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Revised: 06/19/2017] [Accepted: 07/21/2017] [Indexed: 01/10/2023]
Abstract
The Central Governor Model (CGM) ignited a paradigm shift from concepts of catastrophic failure towards central regulation of exercise performance. However, the CGM has focused on the central integration of afferent feedback in homeostatic control. Accordingly, it neglected the important role of volitional self-regulatory control and the integration of affective components inherently attached to all physiological cues. Another limitation is the large reliance on the Gestalt phenomenon of perceived exertion. Thus, progress towards a comprehensive multidimensional model of perceived fatigability and exercise regulation is needed. Drawing on Gate Control Theory of pain, we propose a three-dimensional framework of centrally regulated and goal-directed exercise behaviour, which differentiates between sensory, affective and cognitive processes shaping the perceptual milieu during exercise. We propose that: (A) perceived mental strain and perceived physical strain are primary determinants of pacing behaviour reflecting sensory-discriminatory processes necessary to align planned behaviour with current physiological state, (B) core affect plays a primary and mediatory role in exercise and performance regulation, and its underlying two dimensions hedonicity and arousal reflect affective-motivational processes triggering approach and avoidance behaviour, and (C) the mindset-shift associated with an action crisis plays a primary role in volitional self-regulatory control reflecting cognitive-evaluative processes between further goal-pursuit and goal-disengagement. The proposed framework has the potential to enrich theory development in centrally regulated and goal-directed exercise behaviour by emphasising the multidimensional dynamic processes underpinning perceived fatigability and provides a practical outline for investigating the complex interplay between the psychophysiological determinants of pacing and performance during prolonged endurance exercise.
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Affiliation(s)
- Andreas Venhorst
- Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, South Africa
| | - Dominic Micklewright
- School of Sport, Rehabilitation and Exercise Sciences, University of Essex, Colchester, UK
| | - Timothy D Noakes
- Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, South Africa
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35
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Robergs RA. Lessons from Popper for science, paradigm shifts, scientific revolutions and exercise physiology. BMJ Open Sport Exerc Med 2017; 3:e000226. [PMID: 29021907 PMCID: PMC5633729 DOI: 10.1136/bmjsem-2017-000226] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2017] [Indexed: 11/26/2022] Open
Abstract
A connection has been made to the possible role of the central governor model (CGM) to be a paradigm shift within the exercise sciences. Unfortunately, very little evidence was presented to support this notion, and a narrow view of scientific philosophy was used to reflect on the role of the CGM in understanding exercise physiology and the pursuit of a more ideal scientific method. When contrasting the scientific philosophies of Kuhn to Popper, and applying the tenant of falsification to the research and commentary on the CGM, it is probable that the scholarship pertaining to the CGM adheres more to pseudoscience than science. To improve the scientific contributions of research on the CGM, fellow scientists need to adopt a more critical platform where questions are raised and research designs are employed in efforts to refute the theory. The inability to falsify a theory is the most meaningful way to prove that it is likely to be correct. To support this development, the CGM needs to be more carefully worded to form a theory that clearly reveals key features that can be researched and potentially falsified. In addition, the wording of the CGM needs to allow scientists to make predictions that can then be tested in controlled experimental research studies. Until this happens for the CGM and all other pertinent paradigms within exercise physiology, the discipline will never rise out of the abyss of normal science to extraordinary science involving paradigm shifts and scientific revolutions.
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Affiliation(s)
- Robert Andrew Robergs
- School of Exercise and Nutrition Sciences, Queensland University of Technology, Kelvin Grove, Queensland, Australia
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36
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Ulrich S, Schneider SR, Bloch KE. Effect of hypoxia and hyperoxia on exercise performance in healthy individuals and in patients with pulmonary hypertension: a systematic review. J Appl Physiol (1985) 2017; 123:1657-1670. [PMID: 28775065 DOI: 10.1152/japplphysiol.00186.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Exercise performance is determined by oxygen supply to working muscles and vital organs. In healthy individuals, exercise performance is limited in the hypoxic environment at altitude, when oxygen delivery is diminished due to the reduced alveolar and arterial oxygen partial pressures. In patients with pulmonary hypertension (PH), exercise performance is already reduced near sea level due to impairments of the pulmonary circulation and gas exchange, and, presumably, these limitations are more pronounced at altitude. In studies performed near sea level in healthy subjects, as well as in patients with PH, maximal performance during progressive ramp exercise and endurance of submaximal constant-load exercise were substantially enhanced by breathing oxygen-enriched air. Both in healthy individuals and in PH patients, these improvements were mediated by a better arterial, muscular, and cerebral oxygenation, along with a reduced sympathetic excitation, as suggested by the reduced heart rate and alveolar ventilation at submaximal isoloads, and an improved pulmonary gas exchange efficiency, especially in patients with PH. In summary, in healthy individuals and in patients with PH, alterations in the inspiratory Po2 by exposure to hypobaric hypoxia or normobaric hyperoxia reduce or enhance exercise performance, respectively, by modifying oxygen delivery to the muscles and the brain, by effects on cardiovascular and respiratory control, and by alterations in pulmonary gas exchange. The understanding of these physiological mechanisms helps in counselling individuals planning altitude or air travel and prescribing oxygen therapy to patients with PH.
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Affiliation(s)
- Silvia Ulrich
- Pulmonary Division and Center for Human Integrative Physiology, University of Zurich , Zurich , Switzerland
| | - Simon R Schneider
- Pulmonary Division and Center for Human Integrative Physiology, University of Zurich , Zurich , Switzerland
| | - Konrad E Bloch
- Pulmonary Division and Center for Human Integrative Physiology, University of Zurich , Zurich , Switzerland
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Skorski S, Abbiss CR. The Manipulation of Pace within Endurance Sport. Front Physiol 2017; 8:102. [PMID: 28289392 PMCID: PMC5326767 DOI: 10.3389/fphys.2017.00102] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2016] [Accepted: 02/07/2017] [Indexed: 01/14/2023] Open
Abstract
In any athletic event, the ability to appropriately distribute energy is essential to prevent premature fatigue prior to the completion of the event. In sport science literature this is termed "pacing." Within the past decade, research aiming to better understand the underlying mechanisms influencing the selection of an athlete's pacing during exercise has dramatically increased. It is suggested that pacing is a combination of anticipation, knowledge of the end-point, prior experience and sensory feedback. In order to better understand the role each of these factors have in the regulation of pace, studies have often manipulated various conditions known to influence performance such as the feedback provided to participants, the starting strategy or environmental conditions. As with all research there are several factors that should be considered in the interpretation of results from these studies. Thus, this review aims at discussing the pacing literature examining the manipulation of: (i) energy expenditure and pacing strategies, (ii) kinematics or biomechanics, (iii) exercise environment, and (iv) fatigue development.
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Affiliation(s)
- Sabrina Skorski
- Institute of Sports and Preventive Medicine, Saarland University Saarbrücken, Germany
| | - Chris R Abbiss
- Centre for Exercise and Sports Science Research, School of Exercise and Health Sciences, Edith Cowan University Joondalup, WA, Australia
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Davies MJ, Clark B, Welvaert M, Skorski S, Garvican-Lewis LA, Saunders P, Thompson KG. Effect of Environmental and Feedback Interventions on Pacing Profiles in Cycling: A Meta-Analysis. Front Physiol 2016; 7:591. [PMID: 27994554 PMCID: PMC5136559 DOI: 10.3389/fphys.2016.00591] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/14/2016] [Indexed: 11/15/2022] Open
Abstract
In search of their optimal performance athletes will alter their pacing strategy according to intrinsic and extrinsic physiological, psychological and environmental factors. However, the effect of some of these variables on pacing and exercise performance remains somewhat unclear. Therefore, the aim of this meta-analysis was to provide an overview as to how manipulation of different extrinsic factors affects pacing strategy and exercise performance. Only self-paced exercise studies that provided control and intervention group(s), reported trial variance for power output, disclosed the type of feedback received or withheld, and where time-trial power output data could be segmented into start, middle and end sections; were included in the meta-analysis. Studies with similar themes were grouped together to determine the mean difference (MD) with 95% confidence intervals (CIs) between control and intervention trials for: hypoxia, hyperoxia, heat-stress, pre-cooling, and various forms of feedback. A total of 26 studies with cycling as the exercise modality were included in the meta-analysis. Of these, four studies manipulated oxygen availability, eleven manipulated heat-stress, four implemented pre-cooling interventions and seven studies manipulated various forms of feedback. Mean power output (MPO) was significantly reduced in the middle and end sections (p < 0.05), but not the start section of hypoxia and heat-stress trials compared to the control trials. In contrast, there was no significant change in trial or section MPO for hyperoxic or pre-cooling conditions compared to the control condition (p > 0.05). Negative feedback improved overall trial MPO and MPO in the middle section of trials (p < 0.05), while informed feedback improved overall trial MPO (p < 0.05). However, positive, neutral and no feedback had no significant effect on overall trial or section MPO (p > 0.05). The available data suggests exercise regulation in hypoxia and heat-stress is delayed in the start section of trials, before significant reductions in MPO occur in the middle and end of the trial. Additionally, negative feedback involving performance deception may afford an upward shift in MPO in the middle section of the trial improving overall performance. Finally, performance improvements can be retained when participants are informed of the deception.
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Affiliation(s)
- Michael J Davies
- University of Canberra Research Institute for Sport and ExerciseBruce, ACT, Australia; Department of Physiology, Australian Institute of SportBruce, ACT, Australia
| | - Bradley Clark
- University of Canberra Research Institute for Sport and Exercise Bruce, ACT, Australia
| | - Marijke Welvaert
- University of Canberra Research Institute for Sport and ExerciseBruce, ACT, Australia; Department of Physiology, Australian Institute of SportBruce, ACT, Australia
| | - Sabrina Skorski
- University of Canberra Research Institute for Sport and ExerciseBruce, ACT, Australia; Institute of Sports and Preventive Medicine, Saarland UniversitySaarbrücken, Germany
| | - Laura A Garvican-Lewis
- University of Canberra Research Institute for Sport and ExerciseBruce, ACT, Australia; Department of Physiology, Australian Institute of SportBruce, ACT, Australia; Mary Mackillop Institute for Health Research, Australian Catholic UniversityMelbourne, VIC, Australia
| | - Philo Saunders
- Department of Physiology, Australian Institute of Sport Bruce, ACT, Australia
| | - Kevin G Thompson
- University of Canberra Research Institute for Sport and Exercise Bruce, ACT, Australia
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Colakoglu M, Ozkaya O, Balci GA, Yapicioglu B. Re-Evaluation of Old Findings on Stroke Volume Responses to Exercise and Recovery by Nitrous-Oxide Rebreathin. J Hum Kinet 2016; 53:73-79. [PMID: 28149412 PMCID: PMC5260577 DOI: 10.1515/hukin-2016-0011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
It is important to verify the old findings of Cumming (1972) and Goldberg and Shephard (1980) who showed that stroke volume (SV) may be higher during recovery rather than during exercise, in order to organize the number of intervals throughout training sessions. The purpose of this study was to re-evaluate individual SV responses to various upright cycling exercises using the nitrous-oxide rebreathing method. Nine moderate to well-trained male athletes volunteered to take part in the study (maximal O2 uptake (VO2max): 60.2 ± 7 mL⋅min-1⋅kg-1). Workloads ranging from 40-100% of VO2max were applied to determine individual peak SV (SVpeak) response. Results showed that SV responses were higher during exercise compared to recovery in all exercise loads from 40-100% of VO2max. Mean SV responses to individual SVpeak loads were also higher during exercise compared to recovery (122.9 ± 2.5 versus 105.3 ± 5.93 mL). The highest SV responses to 10 min exercises of 40-70% of VO2max were obtained in the 5th or 7.5th min of each stage (p≤0.05). Meanwhile, during 5 min exercises between 80-100% of VO2max, peak SV responses were observed in the 3rd min of loading (p≤0.05). In conclusion, individual SVpeak levels encountered over wide exercise intensity ranges showed that SVpeak development may also be correlated to exercise intensity corresponding to individual SVpeak loads.
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Affiliation(s)
- Muzaffer Colakoglu
- Ege University, School of Physical Education and Sports, Coaching Education Department, Izmir, Turkey
| | - Ozgur Ozkaya
- Ege University, School of Physical Education and Sports, Coaching Education Department, Izmir, Turkey
| | - Gorkem Aybars Balci
- Ege University, School of Physical Education and Sports, Coaching Education Department, Izmir, Turkey
| | - Bulent Yapicioglu
- Ege University, School of Physical Education and Sports, Coaching Education Department, Izmir, Turkey
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Role of Ratings of Perceived Exertion during Self-Paced Exercise: What are We Actually Measuring? Sports Med 2016; 45:1235-1243. [PMID: 26054383 DOI: 10.1007/s40279-015-0344-5] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Ratings of perceived exertion (RPE) and effort are considered extremely important in the regulation of intensity during self-paced physical activity. While effort and exertion are slightly different constructs, these terms are often used interchangeably within the literature. The development of perceptions of both effort and exertion is a complicated process involving numerous neural processes occurring in various regions within the brain. It is widely accepted that perceptions of effort are highly dependent on efferent copies of central drive which are sent from motor to sensory regions of the brain. Additionally, it has been suggested that perceptions of effort and exertion are integrated based on the balance between corollary discharge and actual afferent feedback; however, the involvement of peripheral afferent sensory feedback in the development of such perceptions has been debated. As such, this review examines the possible difference between effort and exertion, and the implications of such differences in understanding the role of such perceptions in the regulation of pace during exercise.
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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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Zinner C, Holmberg HC, Sperlich B. Topical application of cream containing nonivamide and nicoboxil does not enhance the performance of experienced cyclists during a 4-km time-trial. Eur J Appl Physiol 2016; 116:969-74. [DOI: 10.1007/s00421-016-3357-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 03/10/2016] [Indexed: 10/22/2022]
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Ensemble Input of Group III/IV Muscle Afferents to CNS: A Limiting Factor of Central Motor Drive During Endurance Exercise from Normoxia to Moderate Hypoxia. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:325-42. [PMID: 27343106 DOI: 10.1007/978-1-4899-7678-9_22] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We recently hypothesized that across the range of normoxia to severe hypoxia the major determinant of central motor drive (CMD) during endurance exercise switches from a predominantly peripheral origin to a hypoxic-sensitive central component of fatigue. We found that peripheral locomotor muscle fatigue (pLMF) is the prevailing factor limiting central motor drive and therefore exercise performance from normoxia to moderate hypoxia (SaO2 > 75 %). In these levels of arterial hypoxemia, the development of pLMF is confined to a certain limit which varies between humans-pLMF does not develop to this limit in more severe hypoxia (SaO2 < 70 %) and exercise is prematurely terminated presumably to protect the brain from insufficient O2 supply. Based on the observations from normoxia to moderate hypoxia, we outlined a model suggesting that group III/IV muscle afferents impose inhibitory influences on the determination of CMD of working humans during high-intensity endurance exercise with the purpose to regulate and restrict the level of exercise-induced pLMF to an "individual critical threshold." To experimentally test this model, we pharmacologically blocked somatosensory pathways originating in the working limbs during cycling exercise in normoxia. After initial difficulties with a local anesthetic (epidural lidocaine, L3-L4) and associated loss of locomotor muscle strength we switched to an intrathecally applied opioid analgesic (fentanyl, L3-L4). These experiments were the first ever to selectively block locomotor muscle afferents during high-intensity cycling exercise without affecting maximal locomotor muscle strength. In the absence of opioid-mediated neural feedback from the working limbs, CMD was increased and end-exercise pLMF substantially exceeded, for the first time, the individual critical threshold of peripheral fatigue. The outcome of these studies confirm our hypothesis claiming that afferent feedback inhibits CMD and restricts the development of pLMF to an individual critical threshold as observed from normoxia up to moderate hypoxia.
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Wehrlin JP, Marti B, Hallén J. Hemoglobin Mass and Aerobic Performance at Moderate Altitude in Elite Athletes. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 903:357-74. [PMID: 27343108 DOI: 10.1007/978-1-4899-7678-9_24] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
Fore more than a decade, the live high-train low (LHTL) approach, developed by Levine and Stray-Gundersen, has been widely used by elite endurance athletes. Originally, it was pointed out, that by living at moderate altitude, athletes should benefit from an increased red cell volume (RCV) and hemoglobin mass (Hbmass), while the training at low altitudes should prevent the disadvantage of reduced training intensity at moderate altitude. VO2max is reduced linearly by about 6-8 % per 1000 m increasing altitude in elite athletes from sea level to 3000 m, with corresponding higher relative training intensities for the same absolute work load. With 2 weeks of acclimatization, this initial deficit can be reduced by about one half. It has been debated during the last years whether sea-level training or exposure to moderate altitude increases RCV and Hbmass in elite endurance athletes. Studies which directly measured Hbmass with the optimized CO-rebreathing technique demonstrated that Hbmass in endurance athletes is not influenced by sea-level training. We documented that Hbmass is not increased after 3 years of training in national team cross-country skiers. When athletes are exposed to moderate altitude, new studies support the argument that it is possible to increase Hbmass temporarily by 5-6 %, provided that athletes spend >400 h at altitudes above 2300-2500 m. However, this effect size is smaller than the reported 10-14 % higher Hbmass values of endurance athletes living permanently at 2600 m. It remains to be investigated whether endurance athletes reach these values with a series of LHTL camps.
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Affiliation(s)
- Jon Peter Wehrlin
- Swiss Federal Institute of Sport, Magglingen, Switzerland. .,Norwegian School of Sport Sciences, Oslo, Norway.
| | - Bernard Marti
- Swiss Federal Institute of Sport, Magglingen, Switzerland
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45
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Prefrontal and motor cortex EEG responses and their relationship to ventilatory thresholds during exhaustive incremental exercise. Eur J Appl Physiol 2015; 115:1939-48. [DOI: 10.1007/s00421-015-3177-x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 04/19/2015] [Indexed: 10/23/2022]
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Woodside JDS, Gutowski M, Fall L, James PE, McEneny J, Young IS, Ogoh S, Bailey DM. Systemic oxidative-nitrosative-inflammatory stress during acute exercise in hypoxia; implications for microvascular oxygenation and aerobic capacity. Exp Physiol 2014; 99:1648-62. [DOI: 10.1113/expphysiol.2014.081265] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- John D. S. Woodside
- Vascular Physiology Unit; Institute of Cardiovascular Science; University College London; London UK
| | - Mariusz Gutowski
- Institute of Biochemistry and Cell Biology; Shanghai Institute for Biological Sciences; Chinese Academy of Sciences; Shanghai China
| | - Lewis Fall
- Neurovascular Research Laboratory; Faculty of Life Sciences and Education; University of South Wales; Pontypridd UK
| | - Philip E. James
- Wales Heart Research Institute; Cardiff University School of Medicine; Heath Park Cardiff Pontypridd UK
| | - Jane McEneny
- Centre for Public Health; Nutrition and Metabolism Group; Queen's University Belfast; Belfast UK
| | - Ian S. Young
- Centre for Public Health; Nutrition and Metabolism Group; Queen's University Belfast; Belfast UK
| | - Shigehiko Ogoh
- Department of Biomedical Engineering; Toyo University; Kawagoe-Shi Saitama Japan
| | - Damian M. Bailey
- Neurovascular Research Laboratory; Faculty of Life Sciences and Education; University of South Wales; Pontypridd UK
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Effects of exercise and vasodilators on cerebral tissue oxygenation in pulmonary hypertension. Lung 2014; 193:113-20. [PMID: 25413133 DOI: 10.1007/s00408-014-9667-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 11/09/2014] [Indexed: 12/31/2022]
Abstract
BACKGROUND Arterial and thromboembolic pulmonary hypertension (PH) lead to arterial hypoxaemia. OBJECTIVE To investigate whether cerebral tissue oxygenation (CTO) in patients with PH is reduced and whether this is associated with reduced exercise tolerance. METHODS 16 patients with PH (mean pulmonary arterial pressure ≥25 mmHg, 14 arterial, 2 chronic thromboembolic) and 15 controls underwent right heart catheterisation with monitoring of CTO at rest, during maximal bicycle exercise and during inhalation of oxygen and NO. The 6 min walk distance (6MWD) was measured. RESULTS Median CTO in PH-patients at rest was 62 % (quartiles 53; 71), during exercise 60 % (53; 65); corresponding values in controls were 65 % (73; 73) (P = NS) and 68 % (66; 70) (p = .013 vs. PH). Inhalation of NO and oxygen improved CTO in PH. In multivariate regression analysis CTO at maximal exercise predicted the work load achieved when controlled for age, pulmonary vascular resistance and mixed venous oxygen saturation (R (2) = .419, p < .000); in addition, the 6MWD was predicted by CTO (adjusted R (2) = .511, p < .000). CONCLUSION In PH-patients but not in controls CTO decreased during exercise. Since CTO was an independent predictor of the work load achieved and the 6MWD cerebral hypoxia may contribute to exercise limitation in PH. Clinicaltrials.gov: NCT01463514.
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Ivamoto RK, Nakamoto FP, Vancini RL, Benedito-Silva AA, de Lira CAB, Andrade MDS. The influence of acute hypoxic exposure on isokinetic muscle force production. SPRINGERPLUS 2014; 3:604. [PMID: 25392777 PMCID: PMC4203786 DOI: 10.1186/2193-1801-3-604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 10/06/2014] [Indexed: 11/10/2022]
Abstract
To investigated whether an acute hypoxic stimulus affects muscle strength development assessed by isokinetic dynamometry during maximal knee extension. A total of 15 healthy young men participated in this study (61.9 ± 6.1 kg; 1.72 ± 0.08 m; 20.9 ± 2.6 years). We evaluated knee extension and flexion isokinetic dynamometer performance in normoxic and hypoxic conditions. The analyzed parameters, for concentric contraction, were peak torque and total work measured at 1.05 and 5.23 rad/s; and fatigue index measured at 5.23 rad/s. During isokinetic testing, heart rate and oxygen saturation (SpO2) were monitored. Hypoxic conditions (3,600 m) were simulated, via a mixing chamber, with the dilution being constantly controlled by a PO2 probe. Test reproducibility results (test-retest) for all isokinetic knee parameters were classified as moderate to almost perfect (ICC = 0.694 to 0.932). SpO2 was 88.4 ± 3.4% in the hypoxic condition and 97.1 ± 0.7% in the normoxic condition (p = 0.000, effect size = 0.87). Heart rate was not significantly different between normoxic and hypoxic conditions at the end of the test. There were no significant differences in isokinetic variables evaluated for the extensor and flexor muscles at concentric contraction between the normoxic and hypoxic conditions. Our findings indicate that reduced arterial oxygenation per se has no effect on the muscular isokinetic strength of the knee extensors.
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Affiliation(s)
- Rafael Kenji Ivamoto
- Departamento de Fisiologia, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu, 862, 5º andar, Ed. Ciências Biomédicas, CEP 04023-062 São Paulo, SP Brazil
| | - Fernanda Patti Nakamoto
- Departamento de Fisiologia, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu, 862, 5º andar, Ed. Ciências Biomédicas, CEP 04023-062 São Paulo, SP Brazil
| | - Rodrigo Luiz Vancini
- Centro de Educação Física e Desportos (CEFD), Universidade Federal do Espírito Santo (UFES), Vitória, ES Brazil
| | | | - Claudio Andre Barbosa de Lira
- Setor de Fisiologia Humana e do Exercício, Faculdade de Educação Física e Dança (FEFD), Universidade Federal de Goiás (UFG), Goiânia, GO Brazil
| | - Marília Dos Santos Andrade
- Departamento de Fisiologia, Universidade Federal de São Paulo (UNIFESP), Rua Botucatu, 862, 5º andar, Ed. Ciências Biomédicas, CEP 04023-062 São Paulo, SP Brazil
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Colakoglu M, Ozkaya O, Balci GA, Yapicioglu B. Shorter intervals at peak SV vs.V̇O2max may yield high SV with less physiological stress. Eur J Sport Sci 2014; 15:623-30. [PMID: 25307847 DOI: 10.1080/17461391.2014.966762] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The purpose of this study was to evaluate whether greater and sustainable stroke volume (SV) responses may be obtained by exercise intensities corresponding to peak SV (SVpeak) vs. maximal O2 consumption (VO2max), and short vs. long intervals (SI vs. LI). Nine moderate- to well-trained male athletes competing at regional level specialists of cyclist, track and field volunteered to take part in the study (VO2max: 59.7 ± 7.4 mL·min(-1)·kg(-1)). Following familiarisation sessions, VO2max was determined, and then SVpeak was evaluated using exercise intensities at 40%-100% of VO2max by nitrous-oxide rebreathing (N2ORB) method. Then each separate participant exercised wattages corresponding to individual VO2max and SVpeak during both SI (SIVO2max and SI(SVpeak)) and LI (LIVO2max and LI(SVpeak)) workouts on a cycle ergometer. Main results showed that both SIVO2max and SI(SVpeak) yielded greater SV responses than LIVO2max and LI(SVpeak) (p ≤ 0.05). Mean SV responses were greater in LI(SVpeak) than in LIVO2max (p ≤ 0.05), but there was no statistical difference between SI(SVpeak) and SIVO2max. However, there was significantly less physiological stress based on VO2, respiratory exchange ratio, heart rate and rate of perceived exhaustion in SVpeak than in [Formula: see text] intensities (p ≤ 0.05). Moreover, SV responses at exercise phases increased in the early stages and remain stable until the end of SIVO2max and SI(SVpeak) workouts (p > 0.05), while they were gradually decreasing in LIVO2max and LI(SVpeak) sessions (p ≤ 0.05). In conclusion, if the aim of a training session is to improve SVpeak with less physiological stress, SI(SVpeak) seems a better alternative than other modalities tested in the present study.
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Affiliation(s)
- Muzaffer Colakoglu
- a School of Physical Education and Sports, Coaching Education Department , Ege University , Izmir , Turkey
| | - Ozgur Ozkaya
- a School of Physical Education and Sports, Coaching Education Department , Ege University , Izmir , Turkey
| | - Gorkem Aybars Balci
- a School of Physical Education and Sports, Coaching Education Department , Ege University , Izmir , Turkey
| | - Bulent Yapicioglu
- a School of Physical Education and Sports, Coaching Education Department , Ege University , Izmir , Turkey
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50
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Scott BR, Slattery KM, Dascombe BJ. Intermittent hypoxic resistance training: does it provide added benefit? Front Physiol 2014; 5:397. [PMID: 25352810 PMCID: PMC4195285 DOI: 10.3389/fphys.2014.00397] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 09/24/2014] [Indexed: 01/27/2023] Open
Affiliation(s)
- Brendan R Scott
- Applied Sports Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of Newcastle Ourimbah, NSW, Australia
| | - Katie M Slattery
- Applied Sports Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of Newcastle Ourimbah, NSW, Australia ; New South Wales Institute of Sport Sydney, NSW, Australia
| | - Ben J Dascombe
- Applied Sports Science and Exercise Testing Laboratory, Faculty of Science and Information Technology, University of Newcastle Ourimbah, NSW, Australia
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