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Hardy TA, Chadwick MR, Ferguson C, Cross TJ, Taylor BJ. Differential effects of exercise intensity and tolerable duration on exercise-induced diaphragm and expiratory muscle fatigue. J Appl Physiol (1985) 2024; 136:1591-1603. [PMID: 38695354 DOI: 10.1152/japplphysiol.00007.2024] [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: 01/04/2024] [Revised: 04/26/2024] [Accepted: 04/26/2024] [Indexed: 06/16/2024] Open
Abstract
We investigated the effect of exercise intensity and tolerable duration on the development of exercise-induced diaphragm and expiratory muscle fatigue. Ten healthy adults (25 ± 5 yr; 2 females) cycled to intolerance on three separate occasions: 1) 5% below critical power ( 0.05). In conclusion, the magnitude of exercise-induced diaphragm fatigue was greater after longer-duration severe exercise than after shorter-duration severe and heavy exercise. By contrast, the magnitude of exercise-induced expiratory muscle fatigue was unaffected by exercise intensity and tolerable duration.NEW & NOTEWORTHY Exercise-induced respiratory muscle fatigue contributes to limiting exercise tolerance. Accordingly, better understanding the exercise conditions under which respiratory muscle fatigue occurs is warranted. Although heavy-intensity as well as short- and long-duration severe-intensity exercise performed to intolerance elicit diaphragm and expiratory muscle fatigue, we find, for the first time, that the relationship between exercise intensity, exercise duration, and the magnitude of exercise-induced fatigue is different for the diaphragm compared with the expiratory muscles.
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Affiliation(s)
- Tim A Hardy
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- Faculty of Medicine & Health, Leeds Institute of Rheumatic & Musculoskeletal Medicine, University of Leeds, Leeds, United Kingdom
| | - Matt R Chadwick
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
| | - Carrie Ferguson
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California, United States
| | - Troy J Cross
- School of Health Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Bryan J Taylor
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, United Kingdom
- Cardiovascular Diseases, Department of Cardiovascular Medicine, Mayo Clinic Florida, Jacksonville, Florida, United States
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2
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Peters CM, Dempsey JA, Hopkins SR, Sheel AW. Is the Lung Built for Exercise? Advances and Unresolved Questions. Med Sci Sports Exerc 2023; 55:2143-2159. [PMID: 37443459 PMCID: PMC11186580 DOI: 10.1249/mss.0000000000003255] [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] [Indexed: 07/15/2023]
Abstract
ABSTRACT Nearly 40 yr ago, Professor Dempsey delivered the 1985 ACSM Joseph B. Wolffe Memorial Lecture titled: "Is the lung built for exercise?" Since then, much experimental work has been directed at enhancing our understanding of the functional capacity of the respiratory system by applying complex methodologies to the study of exercise. This review summarizes a symposium entitled: "Revisiting 'Is the lung built for exercise?'" presented at the 2022 American College of Sports Medicine annual meeting, highlighting the progress made in the last three-plus decades and acknowledging new research questions that have arisen. We have chosen to subdivide our topic into four areas of active study: (i) the adaptability of lung structure to exercise training, (ii) the utilization of airway imaging to better understand how airway anatomy relates to exercising lung mechanics, (iii) measurement techniques of pulmonary gas exchange and their importance, and (iv) the interactions of the respiratory and cardiovascular system during exercise. Each of the four sections highlights gaps in our knowledge of the exercising lung. Addressing these areas that would benefit from further study will help us comprehend the intricacies of the lung that allow it to meet and adapt to the acute and chronic demands of exercise in health, aging, and disease.
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Affiliation(s)
| | - Jerome A Dempsey
- Population Health Science, John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison, Madison, WI
| | - Susan R Hopkins
- Department of Radiology, University of California San Diego, La Jolla, CA
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MacAskill W, Hoffman B, Johnson MA, Sharpe GR, Rands J, Wotherspoon SE, Gevorkov Y, Kolbe‐Alexander TL, Mills DE. The effects of age on dyspnea and respiratory mechanical and neural responses to exercise in healthy men. Physiol Rep 2023; 11:e15794. [PMID: 37604647 PMCID: PMC10442526 DOI: 10.14814/phy2.15794] [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: 06/24/2023] [Revised: 08/02/2023] [Accepted: 08/02/2023] [Indexed: 08/23/2023] Open
Abstract
The respiratory muscle pressure generation and inspiratory and expiratory neuromuscular recruitment patterns in younger and older men were compared during exercise, alongside descriptors of dyspnea. Healthy younger (n = 8, 28 ± 5 years) and older (n = 8, 68 ± 4 years) men completed a maximal incremental cycling test. Esophageal, gastric (Pga ) and transdiaphragmatic pressures, and electromyography (EMG) of the crural diaphragm were measured using a micro-transducer and EMG catheter. EMG of the parasternal intercostals, sternocleidomastoids, and rectus abdominis were measured using skin surface electrodes. After the exercise test, participants completed a questionnaire to evaluate descriptors of dyspnea. Pga at end-expiration, Pga expiratory tidal swings, and the gastric pressure-time product (PTPga ) at absolute and relative minute ventilation were higher (p < 0.05) for older compared to younger men. There were no differences in EMG responses between older and younger men. Younger men were more likely to report shallow breathing (p = 0.005) than older men. Our findings showed younger and older men had similar respiratory neuromuscular activation patterns and reported different dyspnea descriptors, and that older men had greater expiratory muscle pressure generation during exercise. Greater expiratory muscle pressures in older men may be due to compensatory mechanisms designed to offset increasing airway resistance due to aging. These results may have implications for exercise-induced expiratory muscle fatigue in older men.
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Affiliation(s)
- William MacAskill
- School of Health and Medical SciencesUniversity of Southern QueenslandIpswichQueenslandAustralia
- Respiratory and Exercise Physiology Research Group, School of Health and WellbeingUniversity of Southern QueenslandIpswichQueenslandAustralia
- Centre for Health ResearchInstitute for Resilient Regions, University of Southern QueenslandIpswichQueenslandAustralia
- Rural Clinical SchoolGriffith UniversityToowoombaQueenslandAustralia
| | - Ben Hoffman
- School of Health and Medical SciencesUniversity of Southern QueenslandIpswichQueenslandAustralia
- Centre for Health ResearchInstitute for Resilient Regions, University of Southern QueenslandIpswichQueenslandAustralia
| | - Michael A. Johnson
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and TechnologyNottingham Trent UniversityNottinghamshireUK
| | - Graham R. Sharpe
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and TechnologyNottingham Trent UniversityNottinghamshireUK
| | - Joshua Rands
- School of Health and Medical SciencesUniversity of Southern QueenslandIpswichQueenslandAustralia
- Respiratory and Exercise Physiology Research Group, School of Health and WellbeingUniversity of Southern QueenslandIpswichQueenslandAustralia
| | | | - Yaroslav Gevorkov
- Institute of Vision Systems, Hamburg University of TechnologyHamburgGermany
| | - Tracy L. Kolbe‐Alexander
- School of Health and Medical SciencesUniversity of Southern QueenslandIpswichQueenslandAustralia
- Centre for Health ResearchInstitute for Resilient Regions, University of Southern QueenslandIpswichQueenslandAustralia
- UCT Research Centre for Health through Physical Activity, Lifestyle and Sport (HPALS), Division of Research Unit for Exercise Science and Sports Medicine, Faculty of Health SciencesUniversity of Cape TownCape TownSouth Africa
| | - Dean E. Mills
- School of Health and Medical SciencesUniversity of Southern QueenslandIpswichQueenslandAustralia
- Respiratory and Exercise Physiology Research Group, School of Health and WellbeingUniversity of Southern QueenslandIpswichQueenslandAustralia
- Centre for Health ResearchInstitute for Resilient Regions, University of Southern QueenslandIpswichQueenslandAustralia
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4
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Illidi CR, Romer LM, Johnson MA, Williams NC, Rossiter HB, Casaburi R, Tiller NB. Distinguishing science from pseudoscience in commercial respiratory interventions: an evidence-based guide for health and exercise professionals. Eur J Appl Physiol 2023; 123:1599-1625. [PMID: 36917254 PMCID: PMC10013266 DOI: 10.1007/s00421-023-05166-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 02/19/2023] [Indexed: 03/16/2023]
Abstract
Respiratory function has become a global health priority. Not only is chronic respiratory disease a leading cause of worldwide morbidity and mortality, but the COVID-19 pandemic has heightened attention on respiratory health and the means of enhancing it. Subsequently, and inevitably, the respiratory system has become a target of the multi-trillion-dollar health and wellness industry. Numerous commercial, respiratory-related interventions are now coupled to therapeutic and/or ergogenic claims that vary in their plausibility: from the reasonable to the absurd. Moreover, legitimate and illegitimate claims are often conflated in a wellness space that lacks regulation. The abundance of interventions, the range of potential therapeutic targets in the respiratory system, and the wealth of research that varies in quality, all confound the ability for health and exercise professionals to make informed risk-to-benefit assessments with their patients and clients. This review focuses on numerous commercial interventions that purport to improve respiratory health, including nasal dilators, nasal breathing, and systematized breathing interventions (such as pursed-lips breathing), respiratory muscle training, canned oxygen, nutritional supplements, and inhaled L-menthol. For each intervention we describe the premise, examine the plausibility, and systematically contrast commercial claims against the published literature. The overarching aim is to assist health and exercise professionals to distinguish science from pseudoscience and make pragmatic and safe risk-to-benefit decisions.
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Affiliation(s)
- Camilla R Illidi
- Clinical Exercise and Respiratory Physiology Laboratory, Department of Kinesiology and Physical Education, Faculty of Education, McGill University, Montréal, QC, Canada
| | - Lee M Romer
- Division of Sport, Health and Exercise Sciences, College of Health, Medicine and Life Sciences, Brunel University London, Uxbridge, UK
| | - Michael A Johnson
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, Nottinghamshire, UK
| | - Neil C Williams
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, Nottinghamshire, UK
| | - Harry B Rossiter
- Institute of Respiratory Medicine and Exercise Physiology, Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, 1124 W. Carson Street, CDCRC Building, Torrance, CA, 90502, USA
| | - Richard Casaburi
- Institute of Respiratory Medicine and Exercise Physiology, Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, 1124 W. Carson Street, CDCRC Building, Torrance, CA, 90502, USA
| | - Nicholas B Tiller
- Institute of Respiratory Medicine and Exercise Physiology, Division of Respiratory and Critical Care Physiology and Medicine, The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, 1124 W. Carson Street, CDCRC Building, Torrance, CA, 90502, USA.
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5
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Ryan BJ, Seeley AD, Pitsas DM, Mayer TA, Caldwell AR, Ceaser TG, Luippold AJ, Charkoudian N, Salgado RM. Influence of graded hypercapnia on endurance exercise performance in healthy humans. Am J Physiol Regul Integr Comp Physiol 2022; 323:R638-R647. [PMID: 36094451 PMCID: PMC9602925 DOI: 10.1152/ajpregu.00132.2022] [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: 06/20/2022] [Revised: 08/22/2022] [Accepted: 09/06/2022] [Indexed: 11/22/2022]
Abstract
Military and/or emergency services personnel may be required to perform high-intensity physical activity during exposure to elevated inspired carbon dioxide (CO2). Although many of the physiological consequences of hypercapnia are well characterized, the effects of graded increases in inspired CO2 on self-paced endurance performance have not been determined. The aim of this study was to compare the effects of 0%, 2%, and 4% inspired CO2 on 2-mile run performance, as well as physiological and perceptual responses during time trial exercise. Twelve physically active volunteers (peak oxygen uptake = 49 ± 5 mL·kg-1·min-1; 3 women) performed three experimental trials in a randomized, single-blind, crossover manner, breathing 21% oxygen with either 0%, 2%, or 4% CO2. During each trial, participants completed 10 min of walking at ∼40% peak oxygen uptake followed by a self-paced 2-mile treadmill time trial. One participant was unable to complete the 4% CO2 trial due to lightheadedness during the run. Compared with the 0% CO2 trial, run performance was 5 ± 3% and 7 ± 3% slower in the 2% and 4% CO2 trials, respectively (both P < 0.001). Run performance was significantly slower with 4% versus 2% CO2 (P = 0.046). The dose-dependent performance impairments were accompanied by stepwise increases in mean ventilation, despite significant reductions in running speed. Dyspnea and headache were significantly elevated during the 4% CO2 trial compared with both the 0% and 2% trials. Overall, our findings show that graded increases in inspired CO2 impair endurance performance in a stepwise manner in healthy humans.
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Affiliation(s)
- Benjamin J Ryan
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Afton D Seeley
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Dina M Pitsas
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Thomas A Mayer
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Aaron R Caldwell
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee
| | - Tyrone G Ceaser
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Adam J Luippold
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Nisha Charkoudian
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Roy M Salgado
- Thermal and Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
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6
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Travers G, Kippelen P, Trangmar SJ, González-Alonso J. Physiological Function during Exercise and Environmental Stress in Humans-An Integrative View of Body Systems and Homeostasis. Cells 2022; 11:383. [PMID: 35159193 PMCID: PMC8833916 DOI: 10.3390/cells11030383] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/26/2022] Open
Abstract
Claude Bernard's milieu intérieur (internal environment) and the associated concept of homeostasis are fundamental to the understanding of the physiological responses to exercise and environmental stress. Maintenance of cellular homeostasis is thought to happen during exercise through the precise matching of cellular energetic demand and supply, and the production and clearance of metabolic by-products. The mind-boggling number of molecular and cellular pathways and the host of tissues and organ systems involved in the processes sustaining locomotion, however, necessitate an integrative examination of the body's physiological systems. This integrative approach can be used to identify whether function and cellular homeostasis are maintained or compromised during exercise. In this review, we discuss the responses of the human brain, the lungs, the heart, and the skeletal muscles to the varying physiological demands of exercise and environmental stress. Multiple alterations in physiological function and differential homeostatic adjustments occur when people undertake strenuous exercise with and without thermal stress. These adjustments can include: hyperthermia; hyperventilation; cardiovascular strain with restrictions in brain, muscle, skin and visceral organs blood flow; greater reliance on muscle glycogen and cellular metabolism; alterations in neural activity; and, in some conditions, compromised muscle metabolism and aerobic capacity. Oxygen supply to the human brain is also blunted during intense exercise, but global cerebral metabolism and central neural drive are preserved or enhanced. In contrast to the strain seen during severe exercise and environmental stress, a steady state is maintained when humans exercise at intensities and in environmental conditions that require a small fraction of the functional capacity. The impact of exercise and environmental stress upon whole-body functions and homeostasis therefore depends on the functional needs and differs across organ systems.
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Affiliation(s)
- Gavin Travers
- The European Astronaut Centre, The European Space Agency, Linder Höhe, 51147 Cologne, Germany;
| | - Pascale Kippelen
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge UB8 3PH, UK;
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Steven J. Trangmar
- School of Life and Health Sciences, University of Roehampton, London SW15 4JD, UK;
| | - José González-Alonso
- Centre for Human Performance, Exercise and Rehabilitation, Brunel University London, Uxbridge UB8 3PH, UK;
- Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
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7
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MacAskill W, Hoffman B, Johnson MA, Sharpe GR, Mills DE. Pressure measurement characteristics of a micro-transducer and balloon catheters. Physiol Rep 2021; 9:e14831. [PMID: 33938126 PMCID: PMC8090844 DOI: 10.14814/phy2.14831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Accepted: 03/14/2021] [Indexed: 11/24/2022] Open
Abstract
Respiratory pressure responses to cervical magnetic stimulation are important measurements in monitoring the mechanical function of the respiratory muscles. Pressures can be measured using balloon catheters or a catheter containing integrated micro‐transducers. However, no research has provided a comprehensive analysis of their pressure measurement characteristics. Accordingly, the aim of this study was to provide a comparative analysis of these characteristics in two separate experiments: (1) in vitro with a reference pressure transducer following a controlled pressurization; and (2) in vivo following cervical magnetic stimulations. In vitro the micro‐transducer catheter recorded pressure amplitudes and areas which were in closer agreement to the reference pressure transducer than the balloon catheter. In vivo there was a main effect for stimulation power and catheter for esophageal (Pes), gastric (Pga), and transdiaphragmatic (Pdi) pressure amplitudes (p < 0.001) with the micro‐transducer catheter recording larger pressure amplitudes. There was a main effect of stimulation power (p < 0.001) and no main effect of catheter for esophageal (p = 0.481), gastric (p = 0.923), and transdiaphragmatic (p = 0.964) pressure areas. At 100% stimulator power agreement between catheters for Pdi amplitude (bias =6.9 cmH2O and LOA −0.61 to 14.27 cmH2O) and pressure areas (bias = −0.05 cmH2O·s and LOA −1.22 to 1.11 cmH2O·s) were assessed. At 100% stimulator power, and compared to the balloon catheters, the micro‐transducer catheter displayed a shorter 10–90% rise time, contraction time, latency, and half‐relaxation time, alongside greater maximal rates of change in pressure for esophageal, gastric, and transdiaphragmatic pressure amplitudes (p < 0.05). These results suggest that caution is warranted if comparing pressure amplitude results utilizing different catheter systems, or if micro‐transducers are used in clinical settings while applying balloon catheter‐derived normative values. However, pressure areas could be used as an alternative point of comparison between catheter systems.
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Affiliation(s)
- William MacAskill
- Respiratory and Exercise Physiology Research Group, School of Health and Wellbeing, University of Southern Queensland, Ipswich, Australia.,Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, Australia
| | - Ben Hoffman
- Respiratory and Exercise Physiology Research Group, School of Health and Wellbeing, University of Southern Queensland, Ipswich, Australia.,Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, Australia.,School of Human Movement and Nutrition Sciences, The University of Queensland, Brisbane, Australia
| | - Michael A Johnson
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Graham R Sharpe
- Exercise and Health Research Group, Sport, Health and Performance Enhancement (SHAPE) Research Centre, School of Science and Technology, Nottingham Trent University, Nottingham, United Kingdom
| | - Dean E Mills
- Respiratory and Exercise Physiology Research Group, School of Health and Wellbeing, University of Southern Queensland, Ipswich, Australia.,Centre for Health Research, Institute for Resilient Regions, University of Southern Queensland, Ipswich, Australia
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8
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Dominelli PB, Wiggins CC, Roy TK, Secomb TW, Curry TB, Joyner MJ. The Oxygen Cascade During Exercise in Health and Disease. Mayo Clin Proc 2021; 96:1017-1032. [PMID: 33714599 PMCID: PMC8026750 DOI: 10.1016/j.mayocp.2020.06.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 06/08/2020] [Accepted: 06/29/2020] [Indexed: 12/28/2022]
Abstract
The oxygen transport cascade describes the physiological steps that bring atmospheric oxygen into the body where it is delivered and consumed by metabolically active tissue. As such, the oxygen cascade is fundamental to our understanding of exercise in health and disease. Our narrative review will highlight each step of the oxygen transport cascade from inspiration of atmospheric oxygen down to mitochondrial consumption in both healthy active males and females along with clinical conditions. We will focus on how different steps interact along with principles of homeostasis, physiological redundancies, and adaptation. In particular, we highlight some of the parallels between elite athletes and clinical conditions in terms of the oxygen cascade.
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Affiliation(s)
| | - Chad C Wiggins
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN
| | - Tuhin K Roy
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN
| | - Timothy W Secomb
- Departments of Physiology and Mathematics, University of Arizona, Tucson
| | - Timothy B Curry
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN
| | - Michael J Joyner
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN.
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9
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Hardy TA, Paula-Ribeiro M, Silva BM, Lyall GK, Birch KM, Ferguson C, Taylor BJ. The cardiovascular consequences of fatiguing expiratory muscle work in otherwise resting healthy humans. J Appl Physiol (1985) 2021; 130:421-434. [PMID: 33356985 DOI: 10.1152/japplphysiol.00116.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In 11 healthy adults (25 ± 4 yr; 2 female, 9 male subjects), we investigated the effect of expiratory resistive loaded breathing [65% maximal expiratory mouth pressure (MEP), 15 breaths·min-1, duty cycle 0.5; ERLPm] on mean arterial pressure (MAP), leg vascular resistance (LVR), and leg blood flow ([Formula: see text]). On a separate day, a subset of five male subjects performed ERL targeting 65% of maximal expiratory gastric pressure (ERLPga). ERL-induced expiratory muscle fatigue was confirmed by a 17 ± 5% reduction in MEP (P < 0.05) and a 16 ± 12% reduction in the gastric twitch pressure response to magnetic nerve stimulation (P = 0.09) from before to after ERLPm and ERLPga, respectively. From rest to task failure in ERLPm and ERLPga, MAP increased (ERLPm = 31 ± 10 mmHg, ERLPga = 18 ± 9 mmHg, both P < 0.05), but group mean LVR and [Formula: see text] were unchanged (ERLPm: LVR = 0.78 ± 0.21 vs. 0.97 ± 0.36 mmHg·mL-1·min, [Formula: see text] = 133 ± 34 vs. 152 ± 74 mL·min-1; ERLPga: LVR = 0.70 ± 0.21 vs. 0.84 ± 0.33 mmHg·mL-1·min, [Formula: see text] = 160 ± 48 vs. 179 ± 110 mL·min-1) (all P ≥ 0.05). Interestingly, [Formula: see text] during ERLPga oscillated within each breath, increasing (∼66%) and decreasing (∼50%) relative to resting values during resisted expirations and unresisted inspirations, respectively. In conclusion, fatiguing expiratory muscle work did not affect group mean LVR or [Formula: see text] in otherwise resting humans. We speculate that any sympathetically mediated peripheral vasoconstriction was counteracted by transient mechanical effects of high intra-abdominal pressures during ERL.NEW & NOTEWORTHY Fatiguing expiratory muscle work in otherwise resting humans elicits an increase in sympathetic motor outflow; whether limb blood flow ([Formula: see text]) and leg vascular resistance (LVR) are affected remains unknown. We found that fatiguing expiratory resistive loaded breathing (ERL) did not affect group mean [Formula: see text] or LVR. However, within-breath oscillations in [Formula: see text] may reflect a sympathetically mediated vasoconstriction that was counteracted by transient increases in [Formula: see text] due to the mechanical effects of high intra-abdominal pressure during ERL.
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Affiliation(s)
- Tim A Hardy
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Marcelle Paula-Ribeiro
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Department of Physiology, Federal University of São Paulo, São Paulo, Brazil
| | - Bruno M Silva
- Department of Physiology, Federal University of São Paulo, São Paulo, Brazil
| | - Gemma K Lyall
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Karen M Birch
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Carrie Ferguson
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Bryan J Taylor
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom.,Department of Cardiovascular Diseases, Mayo Clinic, Jacksonville, Florida
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10
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Hardy TA, How SC, Taylor BJ. The Effect of Preexercise Expiratory Muscle Loading on Exercise Tolerance in Healthy Men. Med Sci Sports Exerc 2021; 53:421-430. [PMID: 32735113 DOI: 10.1249/mss.0000000000002468] [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: 11/21/2022]
Abstract
PURPOSE Acute nonfatiguing inspiratory muscle loading transiently increases diaphragm excitability and global inspiratory muscle strength and may improve subsequent exercise performance. We investigated the effect of acute expiratory muscle loading on expiratory muscle function and exercise tolerance in healthy men. METHODS Ten males cycled at 90% of peak power output to the limit of tolerance (TLIM) after 1) 2 × 30 expiratory efforts against a pressure-threshold load of 40% maximal expiratory gastric pressure (PgaMAX) (EML-EX) and 2) 2 × 30 expiratory efforts against a pressure-threshold load of 10% PgaMAX (SHAM-EX). Changes in expiratory muscle function were assessed by measuring the mouth pressure (PEMAX) and PgaMAX responses to maximal expulsive efforts and magnetically evoked (1 Hz) gastric twitch pressure (Pgatw). RESULTS Expiratory loading at 40% of PgaMAX increased PEMAX (10% ± 5%, P = 0.001) and PgaMAX (9% ± 5%, P = 0.004). Conversely, there was no change in PEMAX (166 ± 40 vs 165 ± 35 cm H2O, P = 1.000) or PgaMAX (196 ± 38 vs 192 ± 39 cm H2O, P = 0.215) from before to after expiratory loading at 10% of PgaMAX. Exercise time was not different in EML-EX versus SHAM-EX (7.91 ± 1.96 vs 8.09 ± 1.77 min, 95% CI = -1.02 to 0.67, P = 0.651). Similarly, exercise-induced expiratory muscle fatigue was not different in EML-EX versus SHAM-EX (-28% ± 12% vs -26% ± 7% reduction in Pgatw amplitude, P = 0.280). Perceptual ratings of dyspnea and leg discomfort were not different during EML-EX versus SHAM-EX. CONCLUSION Acute expiratory muscle loading enhances expiratory muscle function but does not improve subsequent severe-intensity exercise tolerance in healthy men.
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Affiliation(s)
- Tim A Hardy
- Faculty of Biological Sciences, School of Biomedical Sciences, University of Leeds, Leeds, UNITED KINGDOM
| | - Stephen C How
- School of Sport and Exercise, University of Gloucestershire, Gloucester, UNITED KINGDOM
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11
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Do Sex Differences in Physiology Confer a Female Advantage in Ultra-Endurance Sport? Sports Med 2021; 51:895-915. [PMID: 33502701 DOI: 10.1007/s40279-020-01417-2] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/20/2020] [Indexed: 01/09/2023]
Abstract
Ultra-endurance has been defined as any exercise bout that exceeds 6 h. A number of exceptional, record-breaking performances by female athletes in ultra-endurance sport have roused speculation that they might be predisposed to success in such events. Indeed, while the male-to-female performance gap in traditional endurance sport (e.g., marathon) remains at ~ 10%, the disparity in ultra-endurance competition has been reported as low as 4% despite the markedly lower number of female participants. Moreover, females generally outperform males in extreme-distance swimming. The issue is complex, however, with many sports-specific considerations and caveats. This review summarizes the sex-based differences in physiological functions and draws attention to those which likely determine success in extreme exercise endeavors. The aim is to provide a balanced discussion of the female versus male predisposition to ultra-endurance sport. Herein, we discuss sex-based differences in muscle morphology and fatigability, respiratory-neuromechanical function, substrate utilization, oxygen utilization, gastrointestinal structure and function, and hormonal control. The literature indicates that while females exhibit numerous phenotypes that would be expected to confer an advantage in ultra-endurance competition (e.g., greater fatigue resistance, greater substrate efficiency, and lower energetic demands), they also exhibit several characteristics that unequivocally impinge on performance (e.g., lower O2-carrying capacity, increased prevalence of GI distress, and sex-hormone effects on cellular function/injury risk). Crucially, the advantageous traits may only manifest as ergogenic in the extreme endurance events which, paradoxically, are those that females less often contest. The title question should be revisited in the coming years, when/if the number of female participants increases.
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Tiller NB. Pulmonary and Respiratory Muscle Function in Response to Marathon and Ultra-Marathon Running: A Review. Sports Med 2020; 49:1031-1041. [PMID: 31030408 PMCID: PMC6548745 DOI: 10.1007/s40279-019-01105-w] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The physiological demands of marathon and ultra-marathon running are substantial, affecting multiple body systems. There have been several reviews on the physiological contraindications of participation; nevertheless, the respiratory implications have received relatively little attention. This paper provides an up-to-date review of the literature pertaining to acute pulmonary and respiratory muscle responses to marathon and ultra-marathon running. Pulmonary function was most commonly assessed using spirometry, with infrequent use of techniques including single-breath rebreathe and whole-body plethysmography. All studies observed statistically significant post-race reductions in one-or-more metrics of pulmonary function, with or without evidence of airway obstruction. Nevertheless, an independent analysis revealed that post-race values rarely fell below the lower-limit of normal and are unlikely, therefore, to be clinically significant. This highlights the virtue of healthy baseline parameters prior to competition and, although speculative, there may be more potent clinical manifestations in individuals with below-average baseline function, or those with pre-existing respiratory disorders (e.g., asthma). Respiratory muscle fatigue was most commonly assessed indirectly using maximal static mouth-pressure manoeuvres, and respiratory muscle endurance via maximum voluntary ventilation (MVV12). Objective nerve-stimulation data from one study, and others documenting the time-course of recovery, implicate peripheral neuromuscular factors as the mechanism underpinning such fatigue. Evidence of respiratory muscle fatigue was more prevalent following marathon compared to ultra-marathon, and might be a factor of work rate, and thus exercise ventilation, which is tempered during longer races. Potential implications of respiratory muscle fatigue on health and marathon/ultra-marathon performance have been discussed, and include a diminished postural stability that may increase the risk of injury when running on challenging terrain, and possible respiratory muscle fatigue-induced effects on locomotor limb blood flow. This review provides novel insights that might influence marathon/ultra-marathon preparation strategies, as well as inform medical best-practice of personnel supporting such events.
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Affiliation(s)
- Nicholas B Tiller
- Academy of Sport and Physical Activity, Sheffield Hallam University, Collegiate Crescent, Sheffield, S10 2BP, UK.
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Sheel AW, Taylor JL, Katayama K. The hyperpnoea of exercise in health: Respiratory influences on neurovascular control. Exp Physiol 2020; 105:1984-1989. [PMID: 32034952 DOI: 10.1113/ep088103] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2019] [Accepted: 02/03/2020] [Indexed: 12/29/2022]
Abstract
NEW FINDINGS What is the topic of this review? Elevated demand is placed on the respiratory muscles during whole-body exercise-induced hyperpnoea. What is the role of elevated demand in neural modulation of cardiovascular control in respiratory and locomotor skeletal muscle, and what are the mechanisms involved? What advances does it highlight? There is a sympathetic restraint of blood flow to locomotor muscles during near-maximal exercise, which might function to maintain blood pressure. During submaximal exercise, respiratory muscle blood flow might be also be reduced if ventilatory load is sufficiently high. Methodological advances (near-infrared spectroscopy with indocyanine green) confirm that blood flow is diverted away from respiratory muscles when the work of breathing is alleviated. ABSTRACT It is known that the respiratory muscles have a significant increasing oxygen demand in line with hyperpnoea during whole-body endurance exercise and are susceptible to fatigue, in much the same way as locomotor muscles. The act of ventilation can itself be considered a form of exercise. The manipulation of respiratory load at near-maximal exercise alters leg blood flow significantly, demonstrating a competitive relationship between different skeletal muscle vascular beds to perfuse both sets of muscles adequately with a finite cardiac output. In recent years, the question has moved towards whether this effect exists during submaximal exercise, and the use of more direct measurements of respiratory muscle blood flow itself to confirm assumptions that uphold the concept. Evidence thus far has shown that there is a reciprocal effect on blood flow redistribution during ventilatory load manipulation observed at the respiratory muscles themselves and that the effect is observable during submaximal exercise, where active limb blood flow was reduced in conditions that simulated a high work of breathing. This has clinical applications for populations with respiratory disease and heart failure, where the work of breathing is remarkably high, even during submaximal efforts.
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Affiliation(s)
- A William Sheel
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, BC, Canada
| | - Joshua Landen Taylor
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, BC, Canada
| | - Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan.,Graduate School of Medicine, Nagoya University, Nagoya, Japan
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Effects of Inspiratory Muscle Training With Progressive Loading on Respiratory Muscle Function and Sports Performance in High-Performance Wheelchair Basketball Athletes: A Randomized Clinical Trial. Int J Sports Physiol Perform 2019; 15:238-242. [PMID: 31172823 DOI: 10.1123/ijspp.2018-0979] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Revised: 04/07/2019] [Accepted: 05/08/2019] [Indexed: 11/18/2022]
Abstract
PURPOSE To evaluate the effects of inspiratory muscle training associated with interval training on respiratory muscle strength and fatigue and aerobic physical performance (PP) in high-performance wheelchair basketball athletes. METHODS Blinded, randomized clinical trial with 17 male wheelchair basketball players, randomized into control group (CG; n = 8) and training group (TG; n = 9). Respiratory muscle strength was evaluated by measuring maximal inspiratory and expiratory pressures (MIP and MEP), aerobic PP by the Yo-Yo test for wheelchair, and recovery of inspiratory muscle fatigue was assessed at 1, 5, 10, and 15 minutes after exercise test. TG performed inspiratory muscle training protocol with incremental loading for 12 weeks with 50%, 60%, and 70% of MIP, while CG performed with load 15% of MIP. RESULTS After training period, CG presented a significant increase in MIP and MEP (P ≤ .05), with no change in aerobic PP (P ≥ .05). TG showed a significant increase for all variables (≤.05). MIP showed a large effect size for CG (1.00) and TG (1.35), while MEP showed a moderate effect for CG (0.61) and TG (0.73); distance covered had a moderate effect size for TG (0.70). For recovery of inspiratory muscle strength, CG did not present differences, while TG recovered in 10 minutes (≤.05), representing 87% of the pretest value. Positive and significant correlation between MIP and distance (.54; P ≤ .05) was observed. CONCLUSION Inspiratory muscle training protocol with progressive loading was more effective for increasing aerobic PP and maximal inspiratory strength recovery.
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Welch JF, Kipp S, Sheel AW. Respiratory muscles during exercise: mechanics, energetics, and fatigue. CURRENT OPINION IN PHYSIOLOGY 2019. [DOI: 10.1016/j.cophys.2019.04.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Abstract
This short review offers a general summary of the consequences of whole body exercise on neuromuscular fatigue pertaining to the locomotor musculature. Research from the past two decades have shown that whole body exercise causes considerable peripheral and central fatigue. Three determinants characteristic for locomotor exercise are discussed, namely, pulmonary system limitations, neural feedback mechanisms, and mental/psychological influences. We also discuss existing data suggesting that the impact of whole body exercise is not limited to locomotor muscles, but can also impair non-locomotor muscles, such as respiratory and cardiac muscles, and other limb muscles not directly contributing to the task.
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Affiliation(s)
- Joshua C Weavil
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT
| | - Markus Amann
- Geriatric Research, Education, and Clinical Center, Salt Lake City VAMC, Salt Lake City, UT.,Department of Anesthesiology, University of Utah, Salt Lake City, UT
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Katayama K, Goto K, Ohya T, Iwamoto E, Takao K, Kasai N, Sumi D, Mori H, Ishida K, Shimizu K, Shiozawa K, Suzuki Y. Effects of Respiratory Muscle Endurance Training in Hypoxia on Running Performance. Med Sci Sports Exerc 2019; 51:1477-1486. [PMID: 30789438 DOI: 10.1249/mss.0000000000001929] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE We hypothesized that respiratory muscle endurance training (RMET) in hypoxia induces greater improvements in respiratory muscle endurance with attenuated respiratory muscle metaboreflex and consequent whole-body performance. We evaluated respiratory muscle endurance and cardiovascular response during hyperpnoea and whole-body running performance before and after RMET in normoxia and hypoxia. METHODS Twenty-one collegiate endurance runners were assigned to control (n = 7), normoxic (n = 7), and hypoxic (n = 7) groups. Before and after the 6 wk of RMET, incremental respiratory endurance test and constant exercise tests were performed. The constant exercise test was performed on a treadmill at 95% of the individual's peak oxygen uptake (V˙O2peak). The RMET was isocapnic hyperpnoea under normoxic and hypoxic conditions (30 min·d). The initial target of minute ventilation during RMET was set to 50% of the individual maximal voluntary ventilation, and the target increased progressively during the 6 wk. Target arterial oxygen saturation in the hypoxic group was set to 90% in the first 2 wk, and thereafter it was set to 80%. RESULTS Respiratory muscle endurance was increased after RMET in the normoxic and hypoxic groups. The time to exhaustion at 95% V˙O2peak exercise also increased after RMET in the normoxic (10.2 ± 2.4 to 11.2 ± 2.6 min) and hypoxic (11.5 ± 2.6 to 12.6 ± 3.0 min) groups, but not in the control group (9.6 ± 3.2 to 9.4 ± 4.0 min). The magnitude of these changes did not differ between the normoxic and the hypoxic groups (P = 0.84). CONCLUSION These results suggest that the improvement of respiratory muscle endurance and blunted respiratory muscle metaboreflex could, in part, contribute to improved endurance performance in endurance-trained athletes. However, it is also suggested that there are no additional effects when the RMET is performed in hypoxia.
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Affiliation(s)
- Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, JAPAN.,Graduate School of Medicine, Nagoya University, Nagoya, JAPAN
| | - Kazushige Goto
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, JAPAN
| | - Toshiyuki Ohya
- School of Health and Sport Sciences, Chukyo University, Toyota, JAPAN
| | - Erika Iwamoto
- School of Health Sciences, Sapporo Medical University, Sapporo, JAPAN
| | - Kenji Takao
- Graduate School of Sport and Health Sciences, Ritsumeikan University, Kusatsu, JAPAN
| | - Nobukazu Kasai
- Graduate School of Sport and Health Sciences, Ritsumeikan University, Kusatsu, JAPAN.,Japan Society for the Promotion of Science, Chiyoda, JAPAN
| | - Daichi Sumi
- Graduate School of Sport and Health Sciences, Ritsumeikan University, Kusatsu, JAPAN.,Japan Society for the Promotion of Science, Chiyoda, JAPAN
| | - Hisashi Mori
- Faculty of Sport and Health Science, Ritsumeikan University, Kusatsu, JAPAN.,Japan Society for the Promotion of Science, Chiyoda, JAPAN
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, JAPAN.,Graduate School of Medicine, Nagoya University, Nagoya, JAPAN
| | - Kaori Shimizu
- Graduate School of Education and Human Development, Nagoya University, Nagoya, JAPAN
| | - Kana Shiozawa
- Graduate School of Medicine, Nagoya University, Nagoya, JAPAN
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Tiller NB, Turner LA, Taylor BJ. Pulmonary and respiratory muscle function in response to 10 marathons in 10 days. Eur J Appl Physiol 2018; 119:509-518. [PMID: 30467593 DOI: 10.1007/s00421-018-4037-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 11/15/2018] [Indexed: 10/27/2022]
Abstract
PURPOSE Marathon and ultramarathon provoke respiratory muscle fatigue and pulmonary dysfunction; nevertheless, it is unknown how the respiratory system responds to multiple, consecutive days of endurance exercise. METHODS Nine trained individuals (six male) contested 10 marathons in 10 consecutive days. Respiratory muscle strength (maximum static inspiratory and expiratory mouth-pressures), pulmonary function (spirometry), perceptual ratings of respiratory muscle soreness (Visual Analogue Scale), breathlessness (dyspnea, modified Borg CR10 scale), and symptoms of Upper Respiratory Tract Infection (URTI), were assessed before and after marathons on days 1, 4, 7, and 10. RESULTS Group mean time for 10 marathons was 276 ± 35 min. Relative to pre-challenge baseline (159 ± 32 cmH2O), MEP was reduced after day 1 (136 ± 31 cmH2O, p = 0.017), day 7 (138 ± 42 cmH2O, p = 0.035), and day 10 (130 ± 41 cmH2O, p = 0.008). There was no change in pre-marathon MEP across days 1, 4, 7, or 10 (p > 0.05). Pre-marathon forced vital capacity was significantly diminished at day 4 (4.74 ± 1.09 versus 4.56 ± 1.09 L, p = 0.035), remaining below baseline at day 7 (p = 0.045) and day 10 (p = 0.015). There were no changes in FEV1, FEV1/FVC, PEF, MIP, or respiratory perceptions during the course of the challenge (p > 0.05). In the 15-day post-challenge period, 5/9 (56%) runners reported symptoms of URTI, relative to 1/9 (11%) pre-challenge. CONCLUSIONS Single-stage marathon provokes acute expiratory muscle fatigue which may have implications for health and/or performance, but 10 consecutive days of marathon running does not elicit cumulative (chronic) changes in respiratory function or perceptions of dyspnea. These data allude to the robustness of the healthy respiratory system.
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Affiliation(s)
- Nicholas B Tiller
- Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, UK.
| | - Louise A Turner
- Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, UK
| | - Bryan J Taylor
- School of Biomedical Sciences, University of Leeds, Leeds, UK
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19
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Exercise-induced trunk fatigue decreases double poling performance in well-trained cross-country skiers. Eur J Appl Physiol 2018; 118:2077-2087. [DOI: 10.1007/s00421-018-3938-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 07/06/2018] [Indexed: 10/28/2022]
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20
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Sheel AW, Boushel R, Dempsey JA. Competition for blood flow distribution between respiratory and locomotor muscles: implications for muscle fatigue. J Appl Physiol (1985) 2018; 125:820-831. [PMID: 29878876 DOI: 10.1152/japplphysiol.00189.2018] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Sympathetically induced vasoconstrictor modulation of local vasodilation occurs in contracting skeletal muscle during exercise to ensure appropriate perfusion of a large active muscle mass and to maintain also arterial blood pressure. In this synthesis, we discuss the contribution of group III-IV muscle afferents to the sympathetic modulation of blood flow distribution to locomotor and respiratory muscles during exercise. This is followed by an examination of the conditions under which diaphragm and locomotor muscle fatigue occur. Emphasis is given to those studies in humans and animal models that experimentally changed respiratory muscle work to evaluate blood flow redistribution and its effects on locomotor muscle fatigue, and conversely, those that evaluated the influence of coincident limb muscle contraction on respiratory muscle blood flow and fatigue. We propose the concept of a "two-way street of sympathetic vasoconstrictor activity" emanating from both limb and respiratory muscle metaboreceptors during exercise, which constrains blood flow and O2 transport thereby promoting fatigue of both sets of muscles. We end with considerations of a hierarchy of blood flow distribution during exercise between respiratory versus locomotor musculatures and the clinical implications of muscle afferent feedback influences on muscle perfusion, fatigue, and exercise tolerance.
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Affiliation(s)
- A William Sheel
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Robert Boushel
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Jerome A Dempsey
- Department of Population Health Sciences, John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin , Madison, Wisconsin
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21
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Tiller NB, Campbell IG, Romer LM. Influence of Upper-Body Exercise on the Fatigability of Human Respiratory Muscles. Med Sci Sports Exerc 2017; 49:1461-1472. [PMID: 28288012 PMCID: PMC5473371 DOI: 10.1249/mss.0000000000001251] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Purpose Diaphragm and abdominal muscles are susceptible to contractile fatigue in response to high-intensity, whole-body exercise. This study assessed whether the ventilatory and mechanical loads imposed by high-intensity, upper-body exercise would be sufficient to elicit respiratory muscle fatigue. Methods Seven healthy men (mean ± SD; age = 24 ± 4 yr, peak O2 uptake [V˙O2peak] = 31.9 ± 5.3 mL·kg−1·min−1) performed asynchronous arm-crank exercise to exhaustion at work rates equivalent to 30% (heavy) and 60% (severe) of the difference between gas exchange threshold and V˙O2peak. Contractile fatigue of the diaphragm and abdominal muscles was assessed by measuring pre- to postexercise changes in potentiated transdiaphragmatic and gastric twitch pressures (Pdi,tw and Pga,tw) evoked by supramaximal magnetic stimulation of the cervical and thoracic nerves, respectively. Results Exercise time was 24.5 ± 5.8 min for heavy exercise and 9.8 ± 1.8 min for severe exercise. Ventilation over the final minute of heavy exercise was 73 ± 20 L·min−1 (39% ± 11% maximum voluntary ventilation) and 99 ± 19 L·min−1 (53% ± 11% maximum voluntary ventilation) for severe exercise. Mean Pdi,tw did not differ pre- to postexercise at either intensity (P > 0.05). Immediately (5–15 min) after severe exercise, mean Pga,tw was significantly lower than pre-exercise values (41 ± 13 vs 53 ± 15 cm H2O, P < 0.05), with the difference no longer significant after 25–35 min. Abdominal muscle fatigue (defined as ≥15% reduction in Pga,tw) occurred in 1/7 subjects after heavy exercise and 5/7 subjects after severe exercise. Conclusions High-intensity, upper-body exercise elicits significant abdominal, but not diaphragm, muscle fatigue in healthy men. The increased magnitude and prevalence of fatigue during severe-intensity exercise is likely due to additional (nonrespiratory) loading of the thorax.
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Affiliation(s)
- Nicholas B Tiller
- 1Academy of Sport and Physical Activity, Sheffield Hallam University, Sheffield, UNITED KINGDOM; 2Division of Sport, Health and Exercise Sciences, Brunel University London, London, UNITED KINGDOM; and 3School of Life and Medical Sciences, University of Hertfordshire, Hertfordshire, UNITED KINGDOM
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Peters CM, Welch JF, Dominelli PB, Molgat-Seon Y, Romer LM, McKenzie DC, Sheel AW. Influence of inspiratory resistive loading on expiratory muscle fatigue in healthy humans. Exp Physiol 2017. [PMID: 28646592 DOI: 10.1113/ep086346] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
NEW FINDINGS What is the central question of this study? This study is the first to measure objectively both inspiratory and expiratory muscle fatigue after inspiratory resistive loading to determine whether the expiratory muscles are activated to the point of fatigue when specifically loading the inspiratory muscles. What is the main finding and its importance? The absence of abdominal muscle fatigue suggests that future studies attempting to understand the neural and circulatory consequences of diaphragm fatigue can use inspiratory resistive loading without considering the confounding effects of abdominal muscle fatigue. Expiratory resistive loading elicits inspiratory as well as expiratory muscle fatigue, suggesting parallel coactivation of the inspiratory muscles during expiration. It is unknown whether the expiratory muscles are likewise coactivated to the point of fatigue during inspiratory resistive loading (IRL). The purpose of this study was to determine whether IRL elicits expiratory as well as inspiratory muscle fatigue. Healthy male subjects (n = 9) underwent isocapnic IRL (60% maximal inspiratory pressure, 15 breaths min-1 , 0.7 inspiratory duty cycle) to task failure. Abdominal and diaphragm contractile function was assessed at baseline and at 3, 15 and 30 min post-IRL by measuring gastric twitch pressure (Pga,tw ) and transdiaphragmatic twitch pressure (Pdi,tw ) in response to potentiated magnetic stimulation of the thoracic and phrenic nerves, respectively. Fatigue was defined as a significant reduction from baseline in Pga,tw or Pdi,tw . Throughout IRL, there was a time-dependent increase in cardiac frequency and mean arterial blood pressure, suggesting activation of the respiratory muscle metaboreflex. The Pdi,tw was significantly lower than baseline (34.3 ± 9.6 cmH2 O) at 3 (23.2 ± 5.7 cmH2 O, P < 0.001), 15 (24.2 ± 5.1 cmH2 O, P < 0.001) and 30 min post-IRL (26.3 ± 6.0 cmH2 O, P < 0.001). The Pga,tw was not significantly different from baseline (37.6 ± 17.1 cmH2 O) at 3 (36.5 ± 14.6 cmH2 O), 15 (33.7 ± 12.4 cmH2 O) and 30 min post-IRL (32.9 ± 11.3 cmH2 O). Inspiratory resistive loading elicits objective evidence of diaphragm, but not abdominal, muscle fatigue. Agonist-antagonist interactions for the respiratory muscles appear to be more important during expiratory versus inspiratory loading.
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Affiliation(s)
- Carli M Peters
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Joseph F Welch
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Yannick Molgat-Seon
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
| | - Lee M Romer
- Centre for Human Performance, Exercise and Rehabilitation, College of Health and Life Sciences, Brunel University London, Uxbridge, UK.,Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, UK
| | - Donald C McKenzie
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.,Faculty of Medicine, Division of Sports Medicine, University of British Columbia, Vancouver, BC, Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
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Pietro KM, Ricardo G, Rui GPND, Marcelo BG, Fernando FG, Bruno H, Samuel V, Danilo CB. Relationship of pectoralis muscle area and skeletal muscle strength with exercise tolerance and dyspnea in interstitial lung disease. SARCOIDOSIS VASCULITIS AND DIFFUSE LUNG DISEASES 2017; 34:200-208. [PMID: 32476847 PMCID: PMC7170103 DOI: 10.36141/svdld.v34i3.5384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 03/20/2017] [Indexed: 11/16/2022]
Abstract
Background: Pectoralis muscle area (PMA) is an easily derived computed tomography-based assessment that can provide insight into clinical features of other skeletal muscles. Respiratory and locomotor muscle dysfunction has been increasingly recognized in patients with interstitial lung disease (ILD). Its contribution to exercise performance has been controversial. Objective: We aimed to investigate if PMA is related with respiratory and locomotor skeletal muscle strength in ILD patients, and if skeletal muscle function is compromised and independently related with exercise capacity and dyspnea. Methods: Cross-sectional study where subjects performed incremental cycling cardiopulmonary exercise testing with maximal inspiratory (MIP) and expiratory (MEP) pressure measurements, and quadriceps maximal voluntary contraction (MVC) before and after exercise. Results: Thirty ILD patients (forced vital capacity [FVC] and lung diffusing capacity [DLCO] of 60±15% and 38±10% of predicted, respectively) and 15 healthy control subjects were studied. Patients presented significantly lower MIP and qMVC compared to controls. PMA was significantly associated with qMVC only (r=0.506; p<0.01). Only expiratory muscles showed a significant strength decline after exercise, both in patients and controls. In multivariate regression analysis, only FVC remained as independent predictor of peak aerobic capacity and MEP post exercise remained as independent predictor of peak exercise dyspnea even adjusting for FVC. Conclusion: ILD patients exhibited reduced inspiratory and quadriceps strength, but PMA was associated with the later only. Muscle strength was not associated with exercise capacity while expiratory muscle fatigue might underlie exertional dyspnea. (Sarcoidosis Vasc Diffuse Lung Dis 2017; 34: 200-208)
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Affiliation(s)
- Krauspenhar Merola Pietro
- Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Gass Ricardo
- Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Gustavo Paulus Nenê Dorneles Rui
- Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Respiratory Division, Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | - Basso Gazzana Marcelo
- Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Respiratory Division, Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
| | | | - Hochhegger Bruno
- Medical Imaging Research Lab, Santa Casa de Porto Alegre/Federal University of Health Sciences of Porto Alegre (UFCSPA), Porto Alegre, Brazil
| | - Verges Samuel
- Université Grenoble Alpes, HP2 laboratory, Grenoble, France.,INSERM, U1042, Grenoble, France
| | - C Berton Danilo
- Graduation Program in Pulmonology, School of Medicine, Federal University of Rio Grande do Sul (UFRGS), Porto Alegre, Brazil.,Respiratory Division, Hospital de Clínicas de Porto Alegre (HCPA), Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, Brazil
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Hureau TJ, Romer LM, Amann M. The 'sensory tolerance limit': A hypothetical construct determining exercise performance? Eur J Sport Sci 2016; 18:13-24. [PMID: 27821022 DOI: 10.1080/17461391.2016.1252428] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Neuromuscular fatigue compromises exercise performance and is determined by central and peripheral mechanisms. Interactions between the two components of fatigue can occur via neural pathways, including feedback and feedforward processes. This brief review discusses the influence of feedback and feedforward mechanisms on exercise limitation. In terms of feedback mechanisms, particular attention is given to group III/IV sensory neurons which link limb muscle with the central nervous system. Central corollary discharge, a copy of the neural drive from the brain to the working muscles, provides a signal from the motor system to sensory systems and is considered a feedforward mechanism that might influence fatigue and consequently exercise performance. We highlight findings from studies supporting the existence of a 'critical threshold of peripheral fatigue', a previously proposed hypothesis based on the idea that a negative feedback loop operates to protect the exercising limb muscle from severe threats to homeostasis during whole-body exercise. While the threshold theory remains to be disproven within a given task, it is not generalisable across different exercise modalities. The 'sensory tolerance limit', a more theoretical concept, may address this issue and explain exercise tolerance in more global terms and across exercise modalities. The 'sensory tolerance limit' can be viewed as a negative feedback loop which accounts for the sum of all feedback (locomotor muscles, respiratory muscles, organs, and muscles not directly involved in exercise) and feedforward signals processed within the central nervous system with the purpose of regulating the intensity of exercise to ensure that voluntary activity remains tolerable.
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Affiliation(s)
- Thomas J Hureau
- a Department of Medicine , University of Utah , Salt Lake City , UT , USA
| | - Lee M Romer
- b Centre for Human Performance, Exercise and Rehabilitation, Department of Life Sciences , Brunel University London , UK
| | - Markus Amann
- a Department of Medicine , University of Utah , Salt Lake City , UT , USA
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Kurti SP, Smith JR, Emerson SR, Castinado KM, Harms CA. Absence of Respiratory Muscle Fatigue in High-Intensity Continuous or Interval Cycling Exercise. J Strength Cond Res 2015; 29:3171-6. [DOI: 10.1519/jsc.0000000000000974] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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WÜTHRICH THOMASU, MARTY JULIA, BENAGLIA PASCAL, EICHENBERGER PHILIPPA, SPENGLER CHRISTINAM. Acute Effects of a Respiratory Sprint-Interval Session on Muscle Contractility. Med Sci Sports Exerc 2015; 47:1979-87. [DOI: 10.1249/mss.0000000000000627] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Katayama K, Itoh Y, Saito M, Koike T, Ishida K. Sympathetic vasomotor outflow and blood pressure increase during exercise with expiratory resistance. Physiol Rep 2015; 3:3/5/e12421. [PMID: 26019293 PMCID: PMC4463841 DOI: 10.14814/phy2.12421] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The purpose of the present study was to elucidate the effect of increasing expiratory muscle work on sympathetic vasoconstrictor outflow and arterial blood pressure (BP) during dynamic exercise. We hypothesized that expiratory muscle fatigue would elicit increases in sympathetic vasomotor outflow and BP during submaximal exercise. The subjects performed four submaximal exercise tests; two were maximal expiratory pressure (PEmax) tests and two were muscle sympathetic nerve activity (MSNA) tests. In each test, the subjects performed two 10-min exercises at 40% peak oxygen uptake using a cycle ergometer in a semirecumbent position [spontaneous breathing for 5 min and voluntary hyperpnoea with and without expiratory resistive breathing for 5 min (breathing frequency: 60 breaths/min, inspiratory and expiratory times were set at 0.5 sec)]. PEmax was estimated before and immediately after exercises. MSNA was recorded via microneurography of the right median nerve at the elbow. PEmax decreased following exercise with expiratory resistive breathing, while no change was found without resistance. A progressive increase in MSNA burst frequency (BF) appeared during exercise with expiratory resistance (MSNA BF, without resistance: +22 ± 5%, with resistance: +44 ± 8%, P < 0.05), accompanied by an augmentation of BP (mean BP, without resistance: +5 ± 2%, with resistance: +29 ± 5%, P < 0.05). These results suggest that an enhancement of expiratory muscle activity leads to increases in sympathetic vasomotor outflow and BP during dynamic leg exercise.
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Affiliation(s)
- Keisho Katayama
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Yuka Itoh
- Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Mitsuru Saito
- Faculty of Psychological and Physical Science, Aichigakuin University, Nisshin, Japan
| | - Teruhiko Koike
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Koji Ishida
- Research Center of Health, Physical Fitness and Sports, Nagoya University, Nagoya, Japan Graduate School of Medicine, Nagoya University, Nagoya, Japan
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Dominelli PB, Render JN, Molgat-Seon Y, Foster GE, Romer LM, Sheel AW. Oxygen cost of exercise hyperpnoea is greater in women compared with men. J Physiol 2015; 593:1965-79. [PMID: 25652549 DOI: 10.1113/jphysiol.2014.285965] [Citation(s) in RCA: 97] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Accepted: 01/20/2015] [Indexed: 12/15/2022] Open
Abstract
KEY POINTS The oxygen cost of breathing represents a significant fraction of total oxygen uptake during intense exercise. At a given ventilation, women have a greater work of breathing compared with men, and because work is linearly related to oxygen uptake we hypothesized that their oxygen cost of breathing would also be greater. For a given ventilation, women had a greater absolute oxygen cost of breathing, and this represented a greater fraction of total oxygen uptake. Regardless of sex, those who developed expiratory flow limitation had a greater oxygen cost of breathing at maximal exercise. The greater oxygen cost of breathing in women indicates that a greater fraction of total oxygen uptake (and possibly cardiac output) is directed to the respiratory muscles, which may influence blood flow distribution during exercise. ABSTRACT We compared the oxygen cost of breathing (V̇O2 RM ) in healthy men and women over a wide range of exercise ventilations (V̇E). Eighteen subjects (nine women) completed 4 days of testing. First, a step-wise maximal cycle exercise test was completed for the assessment of spontaneous breathing patterns. Next, subjects were familiarized with the voluntary hyperpnoea protocol used to estimate V̇O2 RM . During the final two visits, subjects mimicked multiple times (four to six) the breathing patterns associated with five or six different exercise stages. Each trial lasted 5 min, and on-line pressure-volume and flow-volume loops were superimposed on target loops obtained during exercise to replicate the work of breathing accurately. At ∼55 l min(-1) V̇E, V̇O2 RM was significantly greater in women. At maximal ventilation, the absolute V̇O2 RM was not different (P > 0.05) between the sexes, but represented a significantly greater fraction of whole-body V̇O2 in women (13.8 ± 1.5 vs. 9.4 ± 1.1% V̇O2). During heavy exercise at 92 and 100% V̇O2max, the unit cost of V̇E was +0.7 and +1.1 ml O2 l(-1) greater in women (P < 0.05). At V̇O2max, men and women who developed expiratory flow limitation had a significantly greater V̇O2 RM than those who did not (435 ± 44 vs. 331 ± 30 ml O2 min(-1) ). In conclusion, women have a greater V̇O2 RM for a given V̇E, and this represents a greater fraction of whole-body V̇O2. The greater V̇O2 RM in women may have implications for the integrated physiological response to exercise.
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Affiliation(s)
- Paolo B Dominelli
- School of Kinesiology, University of British Columbia, Vancouver, BC, Canada
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Wüthrich TU, Eberle EC, Spengler CM. Locomotor and diaphragm muscle fatigue in endurance athletes performing time-trials of different durations. Eur J Appl Physiol 2014; 114:1619-33. [DOI: 10.1007/s00421-014-2889-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Accepted: 04/06/2014] [Indexed: 01/19/2023]
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Abstract
During dynamic exercise, the healthy pulmonary system faces several major challenges, including decreases in mixed venous oxygen content and increases in mixed venous carbon dioxide. As such, the ventilatory demand is increased, while the rising cardiac output means that blood will have considerably less time in the pulmonary capillaries to accomplish gas exchange. Blood gas homeostasis must be accomplished by precise regulation of alveolar ventilation via medullary neural networks and sensory reflex mechanisms. It is equally important that cardiovascular and pulmonary system responses to exercise be precisely matched to the increase in metabolic requirements, and that the substantial gas transport needs of both respiratory and locomotor muscles be considered. Our article addresses each of these topics with emphasis on the healthy, young adult exercising in normoxia. We review recent evidence concerning how exercise hyperpnea influences sympathetic vasoconstrictor outflow and the effect this might have on the ability to perform muscular work. We also review sex-based differences in lung mechanics.
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Affiliation(s)
- Andrew William Sheel
- The School of Kinesiology, The University of British Columbia, Vancouver, Canada.
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Taylor BJ, How SC, Romer LM. Expiratory muscle fatigue does not regulate operating lung volumes during high-intensity exercise in healthy humans. J Appl Physiol (1985) 2013; 114:1569-76. [DOI: 10.1152/japplphysiol.00066.2013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
To determine whether expiratory muscle fatigue (EMF) is involved in regulating operating lung volumes during exercise, nine recreationally active subjects cycled at 90% of peak work rate to the limit of tolerance with prior induction of EMF (EMF-ex) and for a time equal to that achieved in EMF-ex without prior induction of EMF (ISO-ex). EMF was assessed by measuring changes in magnetically evoked gastric twitch pressure. Changes in end-expiratory and end-inspiratory lung volume (EELV and EILV) and the degree of expiratory flow limitation (EFL) were quantified using maximal expiratory flow-volume curves and inspiratory capacity maneuvers. Resistive breathing reduced gastric twitch pressure (−24 ± 14%, P = 0.004). During EMF-ex, EELV decreased from rest to the 3rd min of exercise [39 ± 8 vs. 27 ± 7% of forced vital capacity (FVC), P = 0.001] before increasing toward baseline (34 ± 8% of FVC end exercise, P = 0.073 vs. rest). EILV increased from rest to the 3rd min of exercise (54 ± 8 vs. 84 ± 9% of FVC, P = 0.006) and remained elevated to end exercise (88 ± 9% of FVC). Neither EELV ( P = 0.18) nor EILV ( P = 0.26) was different at any time point during EMF-ex vs. ISO-ex. Four subjects became expiratory flow limited during the final minute of EMF-ex and ISO-ex; the degree of EFL was not different between trials (37 ± 18 vs. 35 ± 16% of tidal volume, P = 0.38). At end exercise in both trials, EELV was greater in subjects without vs. subjects with EFL. These findings suggest that 1) contractile fatigue of the expiratory muscles in healthy humans does not regulate operating lung volumes during high-intensity sustained cycle exercise; and 2) factors other than “frank” EFL cause the terminal increase in EELV.
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Affiliation(s)
- Bryan J. Taylor
- Centre for Sports Medicine and Human Performance, Brunel University, London, United Kingdom
- Division of Cardiovascular Diseases, Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, New York; and
| | - Stephen C. How
- Exercise and Sport Research Centre, University of Gloucestershire, Gloucester, United Kingdom
| | - Lee M. Romer
- Centre for Sports Medicine and Human Performance, Brunel University, London, United Kingdom
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Illi SK, Hostettler S, Aliverti A, Spengler CM. Compartmental chest wall volume changes during volitional hyperpnoea with constant tidal volume in healthy individuals. Respir Physiol Neurobiol 2013; 185:410-5. [DOI: 10.1016/j.resp.2012.08.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/30/2012] [Accepted: 08/23/2012] [Indexed: 11/30/2022]
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Illi SK, Held U, Frank I, Spengler CM. Effect of Respiratory Muscle Training on Exercise Performance in Healthy Individuals. Sports Med 2012; 42:707-24. [DOI: 10.1007/bf03262290] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Illi SK, Held U, Frank I, Spengler CM. Effect of Respiratory Muscle Training on Exercise Performance in Healthy Individuals. Sports Med 2012. [DOI: 10.2165/11631670-000000000-00000] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Brown TM. A case of Shoshin Beriberi: lessons old and new for the psychiatrist. PSYCHOSOMATICS 2012; 54:175-80. [PMID: 22658327 DOI: 10.1016/j.psym.2012.01.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2012] [Revised: 01/25/2012] [Accepted: 01/27/2012] [Indexed: 10/28/2022]
Affiliation(s)
- Thomas M Brown
- Dept. of Psychiatry, Audie L. Murphy Memorial VAMC, San Antonio, TX 78229, USA.
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Reilly CC, Ward K, Jolley CJ, Frank LA, Elston C, Moxham J, Rafferty GF. Effect of endurance exercise on respiratory muscle function in patients with cystic fibrosis. Respir Physiol Neurobiol 2012; 180:316-22. [DOI: 10.1016/j.resp.2011.12.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2011] [Revised: 12/15/2011] [Accepted: 12/20/2011] [Indexed: 11/17/2022]
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Leatherman JW, Bastin-Dejong C, Shapiro RS, Saavedra-Romero R. Use of expiratory change in bladder pressure to assess expiratory muscle activity in patients with large respiratory excursions in central venous pressure. Intensive Care Med 2012; 38:453-7. [PMID: 22231173 DOI: 10.1007/s00134-011-2450-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2010] [Accepted: 12/16/2011] [Indexed: 01/20/2023]
Abstract
BACKGROUND Expiratory muscle activity may cause the end-expiratory central venous pressure (CVP) to greatly overestimate right atrial transmural pressure. METHODS We recorded CVP and expiratory change in intra-abdominal pressure (ΔIAP) in 39 patients who had a respiratory excursion in CVP from end-expiration to end-inspiration (CVP(ee)-CVP(ei)) ≥ 8 mmHg. Uncorrected CVP was measured at end-expiration, and corrected CVP was calculated as uncorrected CVP-ΔIAP. In 13 patients measurements were repeated during relaxed breathing. RESULTS The CVP(ee)-CVP(ei) was 15.2 ± 6.3 mmHg (range 8-34 mmHg), and ΔIAP was 7.4 ± 6.0 mmHg (range 0-30 mmHg). Uncorrected CVP was 18.3 ± 6.1 mmHg, and corrected CVP was 10.9 ± 3.9 mmHg. There was a significant positive correlation between CVP(ee)-CVP(ei) and ΔIAP (r = 0.814). However, some patients with a large CVP(ee)-CVP(ei) had negligible ΔIAP. In a subset of 13 patients with active expiration who had a relaxed CVP tracing available for comparison, the difference between uncorrected CVP and relaxed CVP was much greater than the difference between corrected CVP and relaxed CVP (7.3 ± 3.0 vs. 1.1 ± 0.7 mmHg, p < 0.001). CONCLUSION Patients with large respiratory excursions in CVP often have significant expiratory muscle activity that will cause their CVP to overestimate transmural right atrial pressure. The magnitude of expiratory muscle activity can be assessed by measuring ΔIAP. Subtracting ΔIAP from the end-expiratory CVP usually provides a reasonable estimate of the CVP that would be obtained if exhalation were passive.
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Affiliation(s)
- James W Leatherman
- Division of Pulmonary and Critical Care Medicine, Hennepin County Medical Center, Minneapolis, USA.
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A Comparison of 2 Assessment Protocols to Specifically Target Abdominal Muscle Endurance. J Manipulative Physiol Ther 2011; 34:188-94. [DOI: 10.1016/j.jmpt.2011.02.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 12/31/2010] [Accepted: 01/14/2011] [Indexed: 11/21/2022]
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Verges S, Bachasson D, Wuyam B. Effect of acute hypoxia on respiratory muscle fatigue in healthy humans. Respir Res 2010; 11:109. [PMID: 20701769 PMCID: PMC2929221 DOI: 10.1186/1465-9921-11-109] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Accepted: 08/11/2010] [Indexed: 11/14/2022] Open
Abstract
Background Greater diaphragm fatigue has been reported after hypoxic versus normoxic exercise, but whether this is due to increased ventilation and therefore work of breathing or reduced blood oxygenation per se remains unclear. Hence, we assessed the effect of different blood oxygenation level on isolated hyperpnoea-induced inspiratory and expiratory muscle fatigue. Methods Twelve healthy males performed three 15-min isocapnic hyperpnoea tests (85% of maximum voluntary ventilation with controlled breathing pattern) in normoxic, hypoxic (SpO2 = 80%) and hyperoxic (FiO2 = 0.60) conditions, in a random order. Before, immediately after and 30 min after hyperpnoea, transdiaphragmatic pressure (Pdi,tw ) was measured during cervical magnetic stimulation to assess diaphragm contractility, and gastric pressure (Pga,tw ) was measured during thoracic magnetic stimulation to assess abdominal muscle contractility. Two-way analysis of variance (time x condition) was used to compare hyperpnoea-induced respiratory muscle fatigue between conditions. Results Hypoxia enhanced hyperpnoea-induced Pdi,tw and Pga,tw reductions both immediately after hyperpnoea (Pdi,tw : normoxia -22 ± 7% vs hypoxia -34 ± 8% vs hyperoxia -21 ± 8%; Pga,tw : normoxia -17 ± 7% vs hypoxia -26 ± 10% vs hyperoxia -16 ± 11%; all P < 0.05) and after 30 min of recovery (Pdi,tw : normoxia -10 ± 7% vs hypoxia -16 ± 8% vs hyperoxia -8 ± 7%; Pga,tw : normoxia -13 ± 6% vs hypoxia -21 ± 9% vs hyperoxia -12 ± 12%; all P < 0.05). No significant difference in Pdi,tw or Pga,tw reductions was observed between normoxic and hyperoxic conditions. Also, heart rate and blood lactate concentration during hyperpnoea were higher in hypoxia compared to normoxia and hyperoxia. Conclusions These results demonstrate that hypoxia exacerbates both diaphragm and abdominal muscle fatigability. These results emphasize the potential role of respiratory muscle fatigue in exercise performance limitation under conditions coupling increased work of breathing and reduced O2 transport as during exercise in altitude or in hypoxemic patients.
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Affiliation(s)
- Samuel Verges
- HP2 laboratory (INSERM ERI17), Joseph Fourier University, Grenoble University Hospital, Grenoble, France.
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Athanasopoulos D, Louvaris Z, Cherouveim E, Andrianopoulos V, Roussos C, Zakynthinos S, Vogiatzis I. Expiratory muscle loading increases intercostal muscle blood flow during leg exercise in healthy humans. J Appl Physiol (1985) 2010; 109:388-95. [PMID: 20507965 DOI: 10.1152/japplphysiol.01290.2009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated whether expiratory muscle loading induced by the application of expiratory flow limitation (EFL) during exercise in healthy subjects causes a reduction in quadriceps muscle blood flow in favor of the blood flow to the intercostal muscles. We hypothesized that, during exercise with EFL quadriceps muscle blood flow would be reduced, whereas intercostal muscle blood flow would be increased compared with exercise without EFL. We initially performed an incremental exercise test on eight healthy male subjects with a Starling resistor in the expiratory line limiting expiratory flow to approximately 1 l/s to determine peak EFL exercise workload. On a different day, two constant-load exercise trials were performed in a balanced ordering sequence, during which subjects exercised with or without EFL at peak EFL exercise workload for 6 min. Intercostal (probe over the 7th intercostal space) and vastus lateralis muscle blood flow index (BFI) was calculated by near-infrared spectroscopy using indocyanine green, whereas cardiac output (CO) was measured by an impedance cardiography technique. At exercise termination, CO and stroke volume were not significantly different during exercise, with or without EFL (CO: 16.5 vs. 15.2 l/min, stroke volume: 104 vs. 107 ml/beat). Quadriceps muscle BFI during exercise with EFL (5.4 nM/s) was significantly (P = 0.043) lower compared with exercise without EFL (7.6 nM/s), whereas intercostal muscle BFI during exercise with EFL (3.5 nM/s) was significantly (P = 0.021) greater compared with that recorded during control exercise (0.4 nM/s). In conclusion, increased respiratory muscle loading during exercise in healthy humans causes an increase in blood flow to the intercostal muscles and a concomitant decrease in quadriceps muscle blood flow.
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Affiliation(s)
- Dimitris Athanasopoulos
- Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, M. Simou, and G. P. Livanos Laboratories, Athens, Greece
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Hopkinson NS, Dayer MJ, Moxham J, Polkey MI. Abdominal muscle fatigue following exercise in chronic obstructive pulmonary disease. Respir Res 2010; 11:15. [PMID: 20132549 PMCID: PMC2824704 DOI: 10.1186/1465-9921-11-15] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 02/04/2010] [Indexed: 11/16/2022] Open
Abstract
Background In patients with chronic obstructive pulmonary disease, a restriction on maximum ventilatory capacity contributes to exercise limitation. It has been demonstrated that the diaphragm in COPD is relatively protected from fatigue during exercise. Because of expiratory flow limitation the abdominal muscles are activated early during exercise in COPD. This adds significantly to the work of breathing and may therefore contribute to exercise limitation. In healthy subjects, prior expiratory muscle fatigue has been shown itself to contribute to the development of quadriceps fatigue. It is not known whether fatigue of the abdominal muscles occurs during exercise in COPD. Methods Twitch gastric pressure (TwT10Pga), elicited by magnetic stimulation over the 10th thoracic vertebra and twitch transdiaphragmatic pressure (TwPdi), elicited by bilateral anterolateral magnetic phrenic nerve stimulation were measured before and after symptom-limited, incremental cycle ergometry in patients with COPD. Results Twenty-three COPD patients, with a mean (SD) FEV1 40.8(23.1)% predicted, achieved a mean peak workload of 53.5(15.9) W. Following exercise, TwT10Pga fell from 51.3(27.1) cmH2O to 47.4(25.2) cmH2O (p = 0.011). TwPdi did not change significantly; pre 17.0(6.4) cmH2O post 17.5(5.9) cmH2O (p = 0.7). Fatiguers, defined as having a fall TwT10Pga ≥ 10% had significantly worse lung gas transfer, but did not differ in other exercise parameters. Conclusions In patients with COPD, abdominal muscle but not diaphragm fatigue develops following symptom limited incremental cycle ergometry. Further work is needed to establish whether abdominal muscle fatigue is relevant to exercise limitation in COPD, perhaps indirectly through an effect on quadriceps fatigability.
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Affiliation(s)
- Nicholas S Hopkinson
- National Heart and Lung Institute, Imperial College, Royal Brompton Hospital, Fulham Rd, London SW3 6NP, UK.
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Behm DG, Cappa D, Power GA. Trunk muscle activation during moderate- and high-intensity running. Appl Physiol Nutr Metab 2009; 34:1008-16. [DOI: 10.1139/h09-102] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Time constraints are cited as a barrier to regular exercise. If particular exercises can achieve multiple training functions, the number of exercises and the time needed to achieve a training goal may be decreased. It was the objective of this study to compare the extent of trunk muscle electromyographic (EMG) activity during running and callisthenic activities. EMG activity of the external obliques, lower abdominals (LA), upper lumbar erector spinae (ULES), and lumbosacral erector spinae (LSES) was monitored while triathletes and active nonrunners ran on a treadmill for 30 min at 60% and 80% of their maximum heart rate (HR) reserve, as well as during 30 repetitions of a partial curl-up and 3 min of a modified Biering-Sørensen back extension exercise. The mean root mean square (RMS) amplitude of the EMG signal was monitored over 10-s periods with measures normalized to a maximum voluntary contraction rotating curl-up (external obliques), hollowing exercise (LA), or back extension (ULES and LSES). A main effect for group was that triathletes had greater overall activation of the external obliques (p < 0.05), LA (p = 0.01), and LSES (p < 0.05) than did nonrunners. Main effects for exercise type showed that the external obliques had less EMG activity during 60% and 80% runs, respectively, than with the curl-ups (p = 0.001). The back extension exercise provided less ULES (p = 0.009) and LSES (p = 0.0001) EMG activity than the 60% and 80% runs, respectively. In conclusion, triathletes had greater trunk activation than nonrunners did while running, which could have contributed to their better performance. Back-stabilizing muscles can be activated more effectively with running than with a prolonged back extension activity. Running can be considered as an efficient, multifunctional exercise combining cardiovascular and trunk endurance benefits.
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Affiliation(s)
- David G. Behm
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Dr. Jorge E. Coll Institute of Physical Education, Mendoza, Argentina
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London ON N6A 5B8, Canada
| | - Dario Cappa
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Dr. Jorge E. Coll Institute of Physical Education, Mendoza, Argentina
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London ON N6A 5B8, Canada
| | - Geoffrey A. Power
- School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
- Dr. Jorge E. Coll Institute of Physical Education, Mendoza, Argentina
- School of Kinesiology, Faculty of Health Sciences, The University of Western Ontario, London ON N6A 5B8, Canada
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Vogiatzis I, Athanasopoulos D, Habazettl H, Kuebler WM, Wagner H, Roussos C, Wagner PD, Zakynthinos S. Intercostal muscle blood flow limitation in athletes during maximal exercise. J Physiol 2009; 587:3665-77. [PMID: 19451206 PMCID: PMC2742289 DOI: 10.1113/jphysiol.2009.171694] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Accepted: 05/13/2009] [Indexed: 11/08/2022] Open
Abstract
We investigated whether, during maximal exercise, intercostal muscle blood flow is as high as during resting hyperpnoea at the same work of breathing. We hypothesized that during exercise, intercostal muscle blood flow would be limited by competition from the locomotor muscles. Intercostal (probe over the 7th intercostal space) and vastus lateralis muscle perfusion were measured simultaneously in ten trained cyclists by near-infrared spectroscopy using indocyanine green dye. Measurements were made at several exercise intensities up to maximal (WRmax) and subsequently during resting isocapnic hyperpnoea at minute ventilation levels up to those at WRmax. During resting hyperpnoea, intercostal muscle blood flow increased linearly with the work of breathing (R2 = 0.94) to 73.0 +/- 8.8 ml min-1 (100 g)-1 at the ventilation seen at WRmax (work of breathing approximately 550-600 J min-1), but during exercise it peaked at 80% WRmax (53.4 +/- 10.3 ml min-1 (100 g)-1), significantly falling to 24.7 +/- 5.3 ml min-1 (100 g)-1 at WRmax. At maximal ventilation intercostal muscle vascular conductance was significantly lower during exercise (0.22 +/- 0.05 ml min-1 (100 g)-1 mmHg-1) compared to isocapnic hyperpnoea (0.77 +/- 0.13 ml min-1 (100 g)-1 mmHg-1). During exercise, both cardiac output and vastus lateralis muscle blood flow also plateaued at about 80% WRmax (the latter at 95.4 +/- 11.8 ml min-1 (100 g)-1). In conclusion, during exercise above 80% WRmax in trained subjects, intercostal muscle blood flow and vascular conductance are less than during resting hyperpnoea at the same minute ventilation. This suggests that the circulatory system is unable to meet the demands of both locomotor and intercostal muscles during heavy exercise, requiring greater O2 extraction and likely contributing to respiratory muscle fatigue.
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Affiliation(s)
- Ioannis Vogiatzis
- Department of Critical Care Medicine and Pulmonary Services, Evangelismos Hospital, M. Simou, G. P. Livanos Laboratories, National and Kapodistrian University of Athens, Athens, Greece.
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Effect of expiratory resistive loading on inspiratory and expiratory muscle fatigue. Respir Physiol Neurobiol 2009; 166:164-74. [DOI: 10.1016/j.resp.2009.03.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2008] [Revised: 03/02/2009] [Accepted: 03/05/2009] [Indexed: 11/20/2022]
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Aliverti A. Lung and chest wall mechanics during exercise: Effects of expiratory flow limitation. Respir Physiol Neurobiol 2008; 163:90-9. [PMID: 18721912 DOI: 10.1016/j.resp.2008.07.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 07/23/2008] [Accepted: 07/24/2008] [Indexed: 11/17/2022]
Affiliation(s)
- Andrea Aliverti
- TBM Lab, Dipartimento di Bioingegneria, Politecnico di Milano, P. zza L. da Vinci 32, 20133 Milano, Italy.
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Ross E, Middleton N, Shave R, George K, McConnell A. Changes in respiratory muscle and lung function following marathon running in man. J Sports Sci 2008; 26:1295-301. [DOI: 10.1080/02640410802104904] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Dempsey JA, McKenzie DC, Haverkamp HC, Eldridge MW. Update in the Understanding of Respiratory Limitations to Exercise Performance in Fit, Active Adults. Chest 2008; 134:613-622. [DOI: 10.1378/chest.07-2730] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
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Mechanics of breathing during exercise in men and women: sex versus body size differences? Exerc Sport Sci Rev 2008; 36:128-34. [PMID: 18580293 DOI: 10.1097/jes.0b013e31817be7f0] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Women have smaller airways and lung volumes and lower resting maximal expiratory flow rates relative to men. Female athletes develop expiratory flow limitation more frequently than male athletes, and they have greater increases in end-expiratory and end-inspiratory lung volume at maximal exercise. Women use a greater fraction of their ventilatory reserve and have a higher metabolic cost of breathing.
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Dempsey JA, Amann M, Romer LM, Miller JD. Respiratory system determinants of peripheral fatigue and endurance performance. Med Sci Sports Exerc 2008; 40:457-61. [PMID: 18379207 DOI: 10.1249/mss.0b013e31815f8957] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We briefly summarize recent evidence pertaining to how mechanisms primarily under the control of the respiratory system-namely, arterial oxyhemoglobin desaturation, respiratory muscle work and fatigue, and cyclical fluctuations in intrathoracic pressure-may contribute to exercise limitation. Respiratory influences on cardiac output and on sympathetic vasoconstrictor activity and blood flow distribution are shown to be important determinants of performance. We also address how a compromised O2 transport exacerbates the rate of development of peripheral muscle fatigue and, in turn, precipitates central fatigue and exercise limitation.
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Affiliation(s)
- Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, University of Wisconsin-Madison, Madison, WI 53706, USA.
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