1
|
Huang PH, Hsiao TC. Use of Intrinsic Entropy to Assess the Instantaneous Complexity of Thoracoabdominal Movement Patterns to Indicate the Effect of the Iso-Volume Maneuver Trial on the Performance of the Step Test. ENTROPY (BASEL, SWITZERLAND) 2023; 26:27. [PMID: 38248153 PMCID: PMC10814788 DOI: 10.3390/e26010027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/21/2023] [Accepted: 12/23/2023] [Indexed: 01/23/2024]
Abstract
The recent surge in interest surrounds the analysis of physiological signals with a non-linear dynamic approach. The measurement of entropy serves as a renowned method for indicating the complexity of a signal. However, there is a dearth of research concerning the non-linear dynamic analysis of respiratory signals. Therefore, this study employs a novel method known as intrinsic entropy (IE) to assess the short-term dynamic changes in thoracoabdominal movement patterns, as measured by respiratory inductance plethysmography (RIP), during various states such as resting, step test, recovery, and iso-volume maneuver (IVM) trials. The findings reveal a decrease in IE of thoracic wall movement (TWM) and an increase in IE of abdominal wall movement (AWM) following the IVM trial. This suggests that AWM may dominate the breathing exercise after the IVM trial. Moreover, due to the high temporal resolution of IE, it proves to be a suitable measure for assessing the complexity of thoracoabdominal movement patterns under non-stationary states such as the step test and recovery. The results also demonstrate that the instantaneous complexity of TWM and AWM can effectively capture instantaneous changes during non-stationary states, which may prove valuable in understanding the respiratory mechanism for healthcare purposes in daily life.
Collapse
Affiliation(s)
- Po-Hsun Huang
- Institute of Computer Science and Engineering, College of Computer Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan;
| | - Tzu-Chien Hsiao
- Institute of Computer Science and Engineering, College of Computer Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan;
- Department of Computer Science, College of Computer Science, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
- Institute of Biomedical Engineering, College of Electrical and Computer Engineering, National Yang Ming Chiao Tung University, Hsinchu 30010, Taiwan
| |
Collapse
|
2
|
Piotrowska M, Okrzymowska P, Kucharski W, Rożek-Piechura K. Application of Inspiratory Muscle Training to Improve Physical Tolerance in Older Patients with Ischemic Heart Failure. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph182312441. [PMID: 34886168 PMCID: PMC8657106 DOI: 10.3390/ijerph182312441] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/20/2021] [Accepted: 11/24/2021] [Indexed: 11/23/2022]
Abstract
Regardless of the management regime for heart failure (HF), there is strong evidence supporting the early implementation of exercise-based cardiac rehabilitation (CR). Respiratory therapy is considered to be an integral part of such secondary prevention protocols. The aim of the study was to evaluate the effect of inspiratory muscle training (IMT) on exercise tolerance and the functional parameters of the respiratory system in patients with heart failure involved in cardiac rehabilitation. The study included 90 patients with HF who took part in the second-stage 8-week cycle of cardiac rehabilitation (CR). They were randomly divided into three groups: Group I underwent CR and IMT; Group II only CR; and patients in Group III underwent only the IMT. Before and after the 8-week cycle, participants were assessed for exercise tolerance and the functional parameters of respiratory muscle strength. Significant statistical improvement concerned the majority of the hemodynamic parameters, lung function parameters, and respiratory muscle strength in the first group. Moreover, the enhancement in the exercise tolerance in the CR + IMT group was accompanied by a negligible change in the HRpeak. The results confirm that the addition of IMT to the standard rehabilitation process of patients with heart failure can increase the therapeutic effect while influencing some of the parameters measured by exercise electrocardiography and respiratory function.
Collapse
Affiliation(s)
- Monika Piotrowska
- Department of Physiotherapy in Internal Disease, Wroclaw University of Health and Sport, Al. I.J. Paderewskiego 35, Building P4, 51-612 Wrocław, Poland; (M.P.); (K.R.-P.)
| | - Paulina Okrzymowska
- Department of Physiotherapy in Internal Disease, Wroclaw University of Health and Sport, Al. I.J. Paderewskiego 35, Building P4, 51-612 Wrocław, Poland; (M.P.); (K.R.-P.)
- Correspondence:
| | - Wojciech Kucharski
- Department of Human Biology, Wroclaw University of Health and Sport Sciences, Al. I.J. Paderewskiego 35, Building P4, 51-612 Wrocław, Poland;
- Cardiac Rehabilitation Unit, Hospital of Vratislavia Medica, Saint John Paul II, ul. Lekarska 1, 51-134 Wrocław, Poland
| | - Krystyna Rożek-Piechura
- Department of Physiotherapy in Internal Disease, Wroclaw University of Health and Sport, Al. I.J. Paderewskiego 35, Building P4, 51-612 Wrocław, Poland; (M.P.); (K.R.-P.)
| |
Collapse
|
3
|
Welch JF, Archiza B, Guenette JA, West CR, Sheel AW. Effect of diaphragm fatigue on subsequent exercise tolerance in healthy men and women. J Appl Physiol (1985) 2018; 125:1987-1996. [PMID: 30307818 DOI: 10.1152/japplphysiol.00630.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Women are more resistant to diaphragmatic fatigue (DF) and experience an attenuated inspiratory muscle metaboreflex relative to men. The effects of such sex-based differences on whole body exercise tolerance are yet to be examined. It was hypothesized that DF induced prior to exercise would cause less of a reduction in subsequent exercise time in women compared to men. Healthy men ( n = 9, age = 24 ± 3 yr) and women ( n = 9, age = 24 ± 3 yr) completed a maximal incremental cycle test on day 1. On day 2, subjects performed isocapnic inspiratory pressure-threshold loading (PTL) to task failure followed by a constant load submaximal time-to-exhaustion (TTE) exercise test at 85% of the predetermined peak work rate. On day 3, subjects performed the same exercise test without prior induced DF. Days 2 and 3 were randomized and counterbalanced. Magnetic stimulation of the phrenic nerve roots was used to nonvolitionally assess DF by measurement of transdiaphragmatic twitch pressure ( Pdi,tw). A similar degree of DF was produced in both sexes following PTL [ Pdi,tw (% change from baseline): M = -24.6 ± 7.8%, W = -23.1 ± 5.4%; P = 0.54)]. There was a significant reduction in TTE with prior induced DF compared with the control condition in both men (10.9 ± 3.5 min vs. 13.0 ± 3.2 min, P = 0.05) and women (10.1 ± 2.4 min vs. 12.2 ± 3.3 min, P = 0.03) that did not differ in magnitude between the sexes (M = -15.8 ± 19.5%, W = -14.5 ± 19.2%, P = 0.89). In conclusion, DF negatively and equally impairs exercise tolerance independent of sex. NEW & NOTEWORTHY Women are more resistant to diaphragmatic fatigue (DF) relative to men. The effect of DF on exercise tolerance is currently being debated. Our findings show that DF negatively and equally affects exercise tolerance in healthy men and women. Mechanisms beyond the inspiratory muscle metaboreflex (e.g., dyspnea, central fatigue, breathing pattern) may explain the absence of a sex-based difference.
Collapse
Affiliation(s)
- Joseph F Welch
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada
| | - Bruno Archiza
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada.,Department of Physical Therapy, Federal University of Sao Carlos , Sao Carlos , Brazil
| | - Jordan A Guenette
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada.,Department of Physical Therapy, University of British Columbia , Vancouver, British Columbia , Canada.,Centre for Heart Lung Innovation, Providence Health Care Research Institute, University of British Columbia and St. Paul's Hospital , Vancouver, British Columbia , Canada
| | - Christopher R West
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada.,International Collaboration on Repair Discoveries, University of British Columbia , Vancouver, British Columbia , Canada
| | - A William Sheel
- School of Kinesiology, University of British Columbia , Vancouver, British Columbia , Canada
| |
Collapse
|
4
|
Shembel AC, Hartnick CJ, Bunting G, Ballif C, Vanswearingen J, Shaiman S, Johnson A, de Guzman V, Verdolini Abbott K. The Study of Laryngoscopic and Autonomic Patterns in Exercise-Induced Laryngeal Obstruction. Ann Otol Rhinol Laryngol 2018; 127:754-762. [PMID: 30187760 DOI: 10.1177/0003489418796524] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES (1) Identify laryngeal patterns axiomatic to exercise-induced laryngeal obstruction (EILO) and (2) investigate the role of autonomic function in EILO. METHODS Twenty-seven athletic adolescents (13 EILO, 14 control) underwent laryngoscopy at rest and exercise. Glottal configurations, supraglottic dynamics, systolic blood pressure responses, and heart rate recovery were compared between conditions and groups. RESULTS Inspiratory glottal angles were smaller in the EILO group than the control group with exercise. However, group differences were not statistically significant ( P > .05), likely due to high variability of laryngeal responses in the EILO group. Expiratory glottal patterns showed statistically greater abductory responses to exercise in the control group ( P = .001) but not the EILO group ( P > .05). Arytenoid prolapse occurred variably in both groups. Systolic blood pressure responses to exercise were higher in the control group, and heart rate recovery was faster in the EILO group. However, no significant differences were seen between the 2 groups on either autonomic parameter ( P > .05). CONCLUSIONS "Paradoxical" inspiratory and blunted expiratory vocal fold pattern responses to exercise best characterize EILO. Group differences were only seen with exercise challenge, thus highlighting the utility of provocation and control groups to identify EILO.
Collapse
Affiliation(s)
- Adrianna C Shembel
- 1 Department of Otolaryngology, NYU Langone Medical Center, Voice Center, New York, New York, USA.,2 Massachusetts Eye and Ear, Pediatric Airway, Voice, and Swallowing Center, Division of Pediatric Otolaryngology, Boston, Massachusetts, USA.,3 School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Christopher J Hartnick
- 2 Massachusetts Eye and Ear, Pediatric Airway, Voice, and Swallowing Center, Division of Pediatric Otolaryngology, Boston, Massachusetts, USA
| | - Glenn Bunting
- 4 Massachusetts Eye and Ear, Voice and Speech Laboratory, Boston, Massachusetts, USA
| | - Catherine Ballif
- 4 Massachusetts Eye and Ear, Voice and Speech Laboratory, Boston, Massachusetts, USA
| | - Jessie Vanswearingen
- 3 School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Susan Shaiman
- 3 School of Health and Rehabilitation Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Aaron Johnson
- 1 Department of Otolaryngology, NYU Langone Medical Center, Voice Center, New York, New York, USA
| | - Vanessa de Guzman
- 2 Massachusetts Eye and Ear, Pediatric Airway, Voice, and Swallowing Center, Division of Pediatric Otolaryngology, Boston, Massachusetts, USA
| | | |
Collapse
|
5
|
Özdal M. Influence of an eight-week core strength training program on respiratory muscle fatigue following incremental exercise. ISOKINET EXERC SCI 2016. [DOI: 10.3233/ies-160621] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
6
|
Abstract
The study and management of episodic laryngeal breathing disorders (ELBD)—characterized by paradoxical laryngeal movement patterns and dyspnea—has traditionally focused on clinical presentation of these conditions. However, the underlying mechanisms driving these entities are largely unknown. This article provides a review of potential underlying mechanisms driving clinical expression in ELBD and suggests approaches to the future study of ELBD etiology.
Collapse
Affiliation(s)
- Adrianna C. Shembel
- School of Health and Rehabilitation Sciences, University of Pittsburgh
Pittsburgh, PA
| |
Collapse
|
7
|
Pendergast DR, Moon RE, Krasney JJ, Held HE, Zamparo P. Human Physiology in an Aquatic Environment. Compr Physiol 2015; 5:1705-50. [PMID: 26426465 DOI: 10.1002/cphy.c140018] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Water covers over 70% of the earth, has varying depths and temperatures and contains much of the earth's resources. Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses. The translocation of blood into the thorax and elevation of plasma volume by autotransfusion of fluid from cells to the vascular compartment lead to increased cardiac stroke volume and output and there is a hyperperfusion of some tissues. Pulmonary artery and capillary hydrostatic pressures increase causing a decline in vital capacity with the potential for pulmonary edema. Atrial stretch and increased arterial pressure cause reflex autonomic responses which result in endocrine changes that return plasma volume and arterial pressure to preimmersion levels. Plasma volume is regulated via a reflex diuresis and natriuresis. Hydrostatic pressure also leads to elastic loading of the chest, increasing work of breathing, energy cost, and thus blood flow to respiratory muscles. Decreases in water temperature in HOWI do not affect the cardiac output compared to TN; however, they influence heart rate and the distribution of muscle and fat blood flow. The reduced muscle blood flow results in a reduced maximal oxygen consumption. The properties of water determine the mechanical load and the physiological responses during exercise in water (e.g. swimming and water based activities). Increased hydrostatic pressure caused by submersion does not affect stroke volume; however, progressive bradycardia decreases cardiac output. During submersion, compressed gas must be breathed which introduces the potential for oxygen toxicity, narcosis due to nitrogen, and tissue and vascular gas bubbles during decompression and after may cause pain in joints and the nervous system.
Collapse
Affiliation(s)
- David R Pendergast
- Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York, USA
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York, USA
| | - Richard E Moon
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University, Durham, North Carolina, USA
| | - John J Krasney
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York, USA
| | - Heather E Held
- Biomedical Hyperbarics Research Laboratory, Molecular Pharmacology and Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Paola Zamparo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
| |
Collapse
|
8
|
Stickford ASL, Stickford JL, Tanner DA, Stager JM, Chapman RF. Runners maintain locomotor-respiratory coupling following isocapnic voluntary hyperpnea to task failure. Eur J Appl Physiol 2015. [PMID: 26194932 DOI: 10.1007/s00421-015-3220-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Evidence has long suggested that mammalian ventilatory and locomotor rhythms are linked, yet determinants and implications of locomotor-respiratory coupling (LRC) continue to be investigated. Anecdotally, respiratory muscle fatigue seen at the end of heavy exercise may result in an uncoupling of movement-ventilation rhythms; however, there is no scientific evidence to substantiate this claim. PURPOSE We sought to determine whether or not fatigue of the respiratory muscles alters locomotor-respiratory coupling patterns typically observed in highly trained individuals while running. A related query was to examine the relationship between the potential changes in LRC and measures of running economy. METHOD Twelve male distance runners ran at four submaximal workloads (68-89 % VO2peak) on two separate days while LRC was quantified. One LRC trial served as a control (CON), while the other was performed following an isocapnic voluntary hyperpnea to task failure to induce respiratory muscle fatigue (FT+). LRC was assessed as stride-to-breathing frequency ratios (SF/fB) and degree of LRC (percentage of breaths occurring during the same decile of the step cycle). RESULT Hyperpnea resulted in significant declines in maximal voluntary inspiratory (MIP) and expiratory (MEP) mouth pressures (ΔMIP = -10 ± 12 cm H2O; ΔMEP = -6 ± 9 cm H2O). There were no differences in minute ventilation between CON and FT+ (CON, all speeds pooled = 104 ± 25 L min(-1); FT+ pooled = 106 ± 23 L min(-1)). Stride frequency was not different between trials; however, breathing frequency was significantly greater during FT+ compared to CON at all speeds (CON pooled = 47 ± 10 br min(-1); FT+ pooled = 52 ± 9 br min(-1)), resulting in smaller corresponding SF/fB. Yet, the degree of LRC was the same during CON and FT+ (CON pooled = 63 ± 15 %; FT+ pooled = 64 ± 18 %). CONCLUSION The results indicate that trained runners are able to continue entraining breath and step cycles, despite marked changes in exercise breathing frequency, after a fatiguing hyperpnea challenge.
Collapse
Affiliation(s)
- Abigail S L Stickford
- Human Performance Laboratories, Department of Kinesiology, Indiana University, Bloomington, IN, USA.
| | - Jonathon L Stickford
- Human Performance Laboratories, Department of Kinesiology, Indiana University, Bloomington, IN, USA
| | - David A Tanner
- Human Performance Laboratories, Department of Kinesiology, Indiana University, Bloomington, IN, USA
| | - Joel M Stager
- Human Performance Laboratories, Department of Kinesiology, Indiana University, Bloomington, IN, USA
| | - Robert F Chapman
- Human Performance Laboratories, Department of Kinesiology, Indiana University, Bloomington, IN, USA
| |
Collapse
|
9
|
Ventilation and Locomotion in Humans: Mechanisms, Implications, and Perturbations to the Coupling of These Two Rhythms. ACTA ACUST UNITED AC 2014. [DOI: 10.1007/s40362-014-0020-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
10
|
Sugiura H, Sako S, Oshida Y. Effect of Expiratory Muscle Fatigue on the Respiratory Response during Exercise. J Phys Ther Sci 2013; 25:1491-5. [PMID: 24396218 PMCID: PMC3881485 DOI: 10.1589/jpts.25.1491] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 06/24/2013] [Indexed: 11/24/2022] Open
Abstract
[Purpose] The aim of this study was to reveal the effect of expiratory muscle fatigue
(EMF) on respiratory response under two different exercise conditions: exercise (EX) with
EMF (EMF-EX) and control EX without EMF (CON-EX). [Methods] Nine healthy adult men
performed cycle exercise with a ramp load, and a spirometer was used to measure forced
vital capacity (FVC), forced expiratory volume in one second, percent of forced expiratory
volume, maximal expiratory mouth pressure, and maximal inspiratory mouth pressure
(PImax) to evaluate respiratory functions immediately and at 15 and 30 min
after exercise. To assess the respiratory response during exercise, an exhaled gas
analyzer was used to measure minute ventilation (VE), respiratory frequency
(f), tidal volume (VT), oxygen uptake, and carbon dioxide output. In addition,
the Borg Scale was used to evaluate dyspnea, while electrocardiography was used to measure
heart rate. [Results] The results showed that compared with the CON-EX condition, no
change in VE, an increase in f, or a decrease in VT was observed
under the medium-intensity EMF-EX condition, while high-intensity exercise reduced
VE and f without changing VT. [Conclusion] These results suggest
that during medium-intensity exercise, EMF modulates the respiratory response by inducing
shallow and fast breathing to increase ventilation volume.
Collapse
Affiliation(s)
- Hiromichi Sugiura
- Department of Physical Therapy, Nagoya Isen, Japan ; Graduate School of Medicine, Nagoya University, Japan
| | - Shunji Sako
- Department of Physical Therapy, Nagoya Isen, Japan
| | | |
Collapse
|
11
|
Bachasson D, Wuyam B, Pepin JL, Tamisier R, Levy P, Verges S. Quadriceps and respiratory muscle fatigue following high-intensity cycling in COPD patients. PLoS One 2013; 8:e83432. [PMID: 24324843 PMCID: PMC3855800 DOI: 10.1371/journal.pone.0083432] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 11/05/2013] [Indexed: 11/24/2022] Open
Abstract
Exercise intolerance in COPD seems to combine abnormal ventilatory mechanics, impaired O2 transport and skeletal muscle dysfunction. However their relative contribution and their influence on symptoms reported by patients remain to be clarified. In order to clarify the complex interaction between ventilatory and neuromuscular exercise limiting factors and symptoms, we evaluated respiratory muscles and quadriceps contractile fatigue, dynamic hyperinflation and symptoms induced by exhaustive high-intensity cycling in COPD patients. Fifteen gold II-III COPD patients (age = 67 ± 6 yr; BMI = 26.6 ± 4.2 kg.m(-2)) performed constant-load cycling test at 80% of their peak workload until exhaustion (9.3 ± 2.4 min). Before exercise and at exhaustion, potentiated twitch quadriceps strength (Q(tw)), transdiaphragmatic (P(di,tw)) and gastric (P(ga,tw)) pressures were evoked by femoral nerve, cervical and thoracic magnetic stimulation, respectively. Changes in operational lung volumes during exercise were assessed via repetitive inspiratory capacity (IC) measurements. Dyspnoea and leg discomfort were measured on visual analog scale. At exhaustion, Q(tw) (-33 ± 15%, >15% reduction observed in all patients but two) and Pdi,tw (-20 ± 15%, >15% reduction in 6 patients) were significantly reduced (P<0.05) but not Pga,tw (-6 ± 10%, >15% reduction in 3 patients). Percentage reduction in Q(tw) correlated with the percentage reduction in P(di,tw) (r = 0.66; P<0.05). Percentage reductions in P(di,tw) and P(ga,tw) negatively correlated with the reduction in IC at exhaustion (r = -0.56 and r = -0.62, respectively; P<0.05). Neither dyspnea nor leg discomfort correlated with the amount of muscle fatigue. In conclusion, high-intensity exercise induces quadriceps, diaphragm and less frequently abdominal contractile fatigue in this group of COPD patients. In addition, the rise in end-expiratory lung volume and diaphragm flattening associated with dynamic hyperinflation in COPD might limit the development of abdominal and diaphragm muscle fatigue. This study underlines that both respiratory and quadriceps fatigue should be considered to understand the complex interplay of factors leading to exercise intolerance in COPD patients.
Collapse
Affiliation(s)
- Damien Bachasson
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Bernard Wuyam
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Jean-Louis Pepin
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Renaud Tamisier
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Patrick Levy
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
- CHU, Grenoble Locomotor Unit, Reeducation & Physiology, Clinical Physiology, Sleep and Exercise, Grenoble, France
| | - Samuel Verges
- Grenoble Alpes University, HP2 Laboratory, Grenoble, France
- INSERM, U1042, Grenoble, France
| |
Collapse
|
12
|
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.
Collapse
Affiliation(s)
- Andrew William Sheel
- The School of Kinesiology, The University of British Columbia, Vancouver, Canada.
| | | |
Collapse
|
13
|
Wüthrich TU, Notter DA, Spengler CM. Effect of inspiratory muscle fatigue on exercise performance taking into account the fatigue-induced excess respiratory drive. Exp Physiol 2013; 98:1705-17. [DOI: 10.1113/expphysiol.2013.073635] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
|
14
|
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.
Collapse
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
| |
Collapse
|
15
|
Dempsey JA, Adams L, Ainsworth DM, Fregosi RF, Gallagher CG, Guz A, Johnson BD, Powers SK. Airway, Lung, and Respiratory Muscle Function During Exercise. Compr Physiol 2011. [DOI: 10.1002/cphy.cp120111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
16
|
|
17
|
Wells GD, Norris SR. Assessment of physiological capacities of elite athletes & respiratory limitations to exercise performance. Paediatr Respir Rev 2009; 10:91-8. [PMID: 19651378 DOI: 10.1016/j.prrv.2009.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Physiological assessment of athletes is an important process for the characterization of the athlete, monitoring progress and the trained state or 'level of preparedness' of an athlete, as well as aiding the process of training program design. Interestingly, the majority of physiological assessments performed on athletes can also be performed on children with disease, and therefore clinicians can learn a great deal about physiology and assessment of patient populations through the examination of the physiological responses of elite athletes. This review describes typical physiological responses of elite athletes to tests of aerobic and anaerobic metabolism and provides a specific focus upon respiratory limitations to exercise performance. Typical responses of elite athletes are described to provide the scientist and clinician with a perspective of the upper range of physiological capacities of elite athletes.
Collapse
Affiliation(s)
- Greg D Wells
- Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada M5G 1X8.
| | | |
Collapse
|
18
|
Taylor BJ, Romer LM. Effect of expiratory muscle fatigue on exercise tolerance and locomotor muscle fatigue in healthy humans. J Appl Physiol (1985) 2008; 104:1442-51. [DOI: 10.1152/japplphysiol.00428.2007] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
High-intensity exercise (≥90% of maximal O2 uptake) sustained to the limit of tolerance elicits expiratory muscle fatigue (EMF). We asked whether prior EMF affects subsequent exercise tolerance. Eight male subjects (means ± SD; maximal O2 uptake = 53.5 ± 5.2 ml·kg−1·min−1) cycled at 90% of peak power output to the limit of tolerance with (EMF-EX) and without (CON-EX) prior induction of EMF and for a time equal to that achieved in EMF-EX but without prior induction of EMF (ISO-EX). To induce EMF, subjects breathed against an expiratory flow resistor until task failure (15 breaths/min, 0.7 expiratory duty cycle, 40% of maximal expiratory gastric pressure). Fatigue of abdominal and quadriceps muscles was assessed by measuring the reduction relative to prior baseline values in magnetically evoked gastric twitch pressure (Pgatw) and quadriceps twitch force (Qtw), respectively. The reduction in Pgatw was not different after resistive breathing vs. after CON-EX (−27 ± 5 vs. −26 ± 6%; P = 0.127). Exercise time was reduced by 33 ± 10% in EMF-EX vs. CON-EX (6.85 ± 2.88 vs. 9.90 ± 2.94 min; P < 0.001). Exercise-induced abdominal and quadriceps muscle fatigue was greater after EMF-EX than after ISO-EX (−28 ± 9 vs. −12 ± 5% for Pgatw, P = 0.001; −28 ± 7 vs. −14 ± 6% for Qtw, P = 0.015). Perceptual ratings of dyspnea and leg discomfort (Borg CR10) were higher at 1 and 3 min and at end exercise during EMF-EX vs. during ISO-EX ( P < 0.05). Percent changes in limb fatigue and leg discomfort (EMF-EX vs. ISO-EX) correlated significantly with the change in exercise time. We propose that EMF impaired subsequent exercise tolerance primarily through an increased severity of limb locomotor muscle fatigue and a heightened perception of leg discomfort.
Collapse
|
19
|
Romer LM, Polkey MI. Exercise-induced respiratory muscle fatigue: implications for performance. J Appl Physiol (1985) 2008; 104:879-88. [DOI: 10.1152/japplphysiol.01157.2007] [Citation(s) in RCA: 173] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
It is commonly held that the respiratory system has ample capacity relative to the demand for maximal O2and CO2transport in healthy humans exercising near sea level. However, this situation may not apply during heavy-intensity, sustained exercise where exercise may encroach on the capacity of the respiratory system. Nerve stimulation techniques have provided objective evidence that the diaphragm and abdominal muscles are susceptible to fatigue with heavy, sustained exercise. The fatigue appears to be due to elevated levels of respiratory muscle work combined with an increased competition for blood flow with limb locomotor muscles. When respiratory muscles are prefatigued using voluntary respiratory maneuvers, time to exhaustion during subsequent exercise is decreased. Partially unloading the respiratory muscles during heavy exercise using low-density gas mixtures or mechanical ventilation can prevent exercise-induced diaphragm fatigue and increase exercise time to exhaustion. Collectively, these findings suggest that respiratory muscle fatigue may be involved in limiting exercise tolerance or that other factors, including alterations in the sensation of dyspnea or mechanical load, may be important. The major consequence of respiratory muscle fatigue is an increased sympathetic vasoconstrictor outflow to working skeletal muscle through a respiratory muscle metaboreflex, thereby reducing limb blood flow and increasing the severity of exercise-induced locomotor muscle fatigue. An increase in limb locomotor muscle fatigue may play a pivotal role in determining exercise tolerance through a direct effect on muscle force output and a feedback effect on effort perception, causing reduced motor output to the working limb muscles.
Collapse
|
20
|
Verges S, Notter D, Spengler CM. Influence of diaphragm and rib cage muscle fatigue on breathing during endurance exercise. Respir Physiol Neurobiol 2006; 154:431-42. [PMID: 16423567 DOI: 10.1016/j.resp.2005.12.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 12/14/2005] [Accepted: 12/14/2005] [Indexed: 11/26/2022]
Abstract
Inspiratory muscle fatigue (IMF) can develop during exhaustive exercise and cause tachypnea or rapid shallow breathing. We assessed the effects of rib cage muscle (RCM-F) and diaphragm fatigue (DIA-F) on breathing pattern and respiratory mechanics during high-intensity endurance exercise. Twelve healthy subjects performed a constant-load (85% maximal power) cycling test to exhaustion with prior IMF and a cycling test of similar intensity and duration without prior IMF (control). IMF was induced by resistive breathing and assessed by oesophageal and gastric twitch pressure measurements during cervical magnetic stimulation. Both RCM-F and DIA-F increased RCM and abdominal muscle force production during exercise compared to control. With RCM-F, tidal volume decreased while it increased with DIA-F. RCM-F was associated with a smaller increase in end-expiratory oesophageal pressure (i.e. decrease in lung volume) than DIA-F. These results suggest that RCM-F and not DIA-F is associated with rapid shallow breathing and that lowering the operating lung volume with DIA-F may help to preserve diaphragmatic function.
Collapse
Affiliation(s)
- Samuel Verges
- Exercise Physiology, Institute for Human Movement Sciences, ETH Zurich and Institute of Physiology and Center for Integrative Human Physiology (CIHP), University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Switzerland
| | | | | |
Collapse
|
21
|
McConnell AK, Romer LM. Dyspnoea in health and obstructive pulmonary disease : the role of respiratory muscle function and training. Sports Med 2004; 34:117-32. [PMID: 14965190 DOI: 10.2165/00007256-200434020-00005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A consistent finding of recent research on respiratory muscle training (RMT) in healthy humans has been an attenuation of respiratory discomfort (dyspnoea) during exercise. We argue that the neurophysiology of dyspnoea can be explained in terms of Cambell's paradigm of length-tension inappropriateness. In the context of this paradigm, changes in the contractile properties of the respiratory muscles modify the intensity of dyspnoea predominantly by changing the required level of motor outflow to these respiratory muscles. Thus, factors that impair the contractile properties of the respiratory muscles (e.g. the pattern of tension development, functional weakening and fatigue) have the potential to increase the intensity of dyspnoea, while factors that improve the contractile properties of these respiratory muscles (e.g. RMT) have the potential to reduce the intensity of dyspnoea. In patients with obstructive pulmonary disease, functional weakening of the inspiratory muscles in response to dynamic lung hyperinflation appears to be a central component of dyspnoea. A decrease in the intensity of respiratory effort sensation (during exercise and loaded breathing) has been observed in both healthy individuals and patients with obstructive pulmonary disease after RMT. We conclude that RMT has the potential to reduce the severity of dyspnoea in healthy individuals and in patients with obstructive pulmonary disease, and that this probably occurs via a reduction in the level of motor outflow. Further work is required to clarify the role of RMT in the management of other disease conditions in which the function of the respiratory muscles is impaired, or the loads that they must overcome are elevated (e.g. cardiorespiratory and neuromuscular disorders).
Collapse
Affiliation(s)
- Alison K McConnell
- Department of Sport Sciences, Brunel University, Uxbridge, Middlesex, UK.
| | | |
Collapse
|
22
|
Hue O, Le Gallais D, Boussana A, Chollet D, Prefaut C. Ventilatory responses during experimental cycle-run transition in triathletes. Med Sci Sports Exerc 1999; 31:1422-8. [PMID: 10527314 DOI: 10.1097/00005768-199910000-00010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
PURPOSE AND METHODS To determine the effects of cycling on a subsequent triathlon run, nine male triathletes underwent four successive laboratory trials: 1) an incremental treadmill test, 2) an incremental cycle test, 3) 30 min of cycling followed by 5 km of running (C-R), and 4) 30 min of running followed by 5 km of running (R-R). Before and 10 min after the third and fourth trials, the triathletes underwent pulmonary function testing including spirometry and diffusing capacity testing for carbon monoxide (DL(CO)). During the C-R and R-R trials, arterialized blood samples were obtained to measure arterial oxygen pressure (PaO2). During all trials, ventilatory data were collected every minute using an automated breath-by-breath system. RESULTS The results showed that 1) the oxygen uptake (VO2) observed during subsequent running was similar for the C-R and R-R trials; 2) the ventilatory response (VE) during the first 8 min of subsequent running was significantly greater in the C-R than in R-R trial (P < 0.05); 3) only the C-R trial induced a significant increase (P < 0.05) in residual volume (RV), functional residual capacity (FRC), and the ratio of residual volume to total lung capacity (RV/TLC); and 4) although a significant decrease (P < 0.05) in DL(CO) was noted after C-R, no difference between the two exercise trials was found for the maximal drop in PaO2. CONCLUSIONS We concluded that 1) the C-R trial induced specific alterations in pulmonary function that may be associated with respiratory muscle fatigue and/or exercise-induced hypoxemia, and 2) the greater VE observed during the first minute of running after cycling was due to the specificity of cycling. This reinforces the necessity for triathletes to practice multi-trial training to stimulate the physiological responses experienced during the swim-cycle and the cycle-run transitions.
Collapse
Affiliation(s)
- O Hue
- Centre d'Optimisation de la Performance Motrice, Laboratoire Sport, Santé, Développement, UFR-STAPS, Montpellier, France.
| | | | | | | | | |
Collapse
|
23
|
Capdevila X, Perrigault PF, Ramonatxo M, Roustan JP, Peray P, d'Athis F, Prefaut C. Changes in breathing pattern and respiratory muscle performance parameters during difficult weaning. Crit Care Med 1998; 26:79-87. [PMID: 9428547 DOI: 10.1097/00003246-199801000-00020] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study examined, using noninvasive means, the changes in breathing pattern and inspiratory muscle pressure-time indices during difficult progressive withdrawal of pressure-support ventilation. DESIGN A prospective analysis of the temporal evolution of several respiratory variables in difficult-to-wean patients. SETTING A university hospital intensive care unit. PATIENTS A heterogeneous group of 17 patients receiving prolonged mechanical ventilation. INTERVENTIONS Daily measurements of breathing pattern and respiratory muscle performance parameters in difficult-to-wean patients. MEASUREMENTS AND MAIN RESULTS We examined breathing pattern variables, rapid shallow breathing (respiratory rate/tidal volume), tracheal occlusion pressure, maximal inspiratory pressure (P(I)max), and the tension-time index of the inspiratory muscles (TTmus = P(I)/P(I)max x Ti/Ttot) (where Ti/Ttot is inspiratory fraction of the cycle). All measurements were repeated at 24-hr intervals throughout the difficult weaning period. The patients were extubated on satisfying ten of 12 classical weaning criteria. Eleven patients were successfully weaned from mechanical ventilation while six patients were not. Weaning failure was associated with the following: a) longer periods of mechanical ventilation before weaning; b) high values of tracheal occlusion pressure, respiratory rate, minute ventilation, and effective impedance maintained throughout the difficult weaning period; and c) persistent high PaCO2 and intrinsic positive end-expiratory pressure values. As the weaning failure patients' inspiratory muscles confronted an increasing inspiratory load, values of the tension-time index of the inspiratory muscles entered or remained in the fatigue zone. In contrast, weaning success patients normalized their breathing pattern and decreased their tracheal occlusion pressure, effective impedance, and tension-time index values. CONCLUSIONS Breathing pattern alterations and respiratory muscle performance impairments lead to ventilator dependency after prolonged mechanical ventilation. The measurement of variables such as the noninvasive tracheal occlusion pressure, inspiratory power of breathing, and tension-time index of the inspiratory muscles facilitate the management of difficult-to-wean patients.
Collapse
Affiliation(s)
- X Capdevila
- Département d'Anesthésie Réanimation A, C.H.U. Montpellier, France
| | | | | | | | | | | | | |
Collapse
|
24
|
Johnson BD, Aaron EA, Babcock MA, Dempsey JA. Respiratory muscle fatigue during exercise: implications for performance. Med Sci Sports Exerc 1996; 28:1129-37. [PMID: 8883000 DOI: 10.1097/00005768-199609000-00008] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Heavy whole-body exercise, requiring a 10- to 15-fold increase in minute ventilation, encroaches on the capacities of the respiratory muscle system to respond. Recently, using the technique of bilateral phrenic nerve stimulation, it has been shown that heavy endurance exercise (> 85% of VO2max) lasting > 8-10 min causes diaphragmatic fatigue (15-30% reduction in transdiaphragmatic pressures when electrically stimulated at low frequencies [1-20 Hz] supramaximally). The fatigue appears to be due to an interaction of diaphragmatic work (i.e., pressure production) combined with effects related to exercise intensity (i.e., increased blood flow competition with the locomotor muscles and increased production of metabolic by-products) and requires > 60 min for recovery. Fitness (i.e., as implied from VO2max) appears to allow greater diaphragmatic work for a similar degree of fatigue. Unloading the respiratory muscles (with helium/oxygen gas or using a pressure-assist device) during heavy exercise < 90-95% of VO2max does not appear to alter exercise time, VO2max, or minute ventilation, implying that respiratory muscle fatigue plays little role in altering human performance at these work intensities. However, unloading the respiratory system with helium at work intensities > 90-95% of VO2max has been shown to improve exercise time. This would imply that respiratory muscle fatigue may play a role in limiting human performance at the extremes of human performance or that other factors related to the respiratory system (i.e., alterations in the sensation of dyspnea or mechanical load) may play an important role.
Collapse
Affiliation(s)
- B D Johnson
- Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN 55905, USA
| | | | | | | |
Collapse
|
25
|
Güell R, Casan P, Giménez M. [Peripheral muscle fatigue and ventilatory response to effort in chronic airflow limitation]. Arch Bronconeumol 1996; 32:79-84. [PMID: 8948871 DOI: 10.1016/s0300-2896(15)30815-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
We aimed to analyze peripheral muscle fatigue and ventilatory pattern in a group of 28 individuals (12 health and 16 with chronic air flow limitation) performing incremental exercise. The level of exercise reached was significantly less for patients than for healthy subjects (107 +/- 30 W vs. 234 +/- 44 W). Minute ventilation (VE) was 54 +/- 15 l/min evolving linearly with no breaking pint, and the respiration pattern was tachypneic with high frequency (f) and low circulating volumen (VT) in patients. The ration Ti/Ttot did not change during exercise in either of the groups. Occlusion pressure (P0.1) was always higher in the patient group (p < 0.001) while mean inspiratory flow was higher at rest and at moderate levels of exercise (P < 0.05) but significantly lower at high levels (1.95 +/- 0.6 vs. 3.98 +/- 1 l.s-1). Muscle fatigue, defined as the fall in the H/L index in the electromyogram, appeared in 11/12 healthy subjects (H/L: 71 +/- 11%) and in 9/16 patients (H/L: 67 +/- 17%). There were no physical differences between the 2 groups of patients (those with and without fatigue). Patients with fatigue showed a more moderate degree of obstruction (FEV1 68 +/- 12% vs. 42 +/- 13% v. ref) with less airways impedance (p < 0.001) and hypoxia (SaO2 91.3% vs. 87%), and a better ventilatory response to exercise (VE 61 +/- 14 vs. 45 +/- 10 l/min) with a higher mean inspiratory flow (2.25 +/- 0.54 vs. 1.57 +/- 0.54 l.s-1) in spite of there being no differences in P0.1. The restricting factor was ventilatory limitation, although muscle fatigue appeared in 53% of the patients. Patients who experienced muscle fatigue had less obstruction and better ventilatory response to exercise.
Collapse
Affiliation(s)
- R Güell
- Departamento de Neumología, Hospital de la Santa Creu i de Sant Pau, Barcelona
| | | | | |
Collapse
|
26
|
Spengler CM, von Ow D, Boutellier U. The role of central command in ventilatory control during static exercise. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1994; 68:162-9. [PMID: 8194546 DOI: 10.1007/bf00244030] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The role of central command in the respiratory response to 15 min of rhythmic-static (isometric) exercise was studied in humans. Voluntary exercise (VE) was compared with electrically induced exercise (EE) at three different work intensities, i.e. 5%, 15% and 25% of maximal voluntary contraction. A group of 12 volunteers participated in the study and each of them performed six sessions. A session consisted of at least 5 min rest, 15 min rhythmic-static single leg exercise (4 s contraction/12 s relaxation) and at least 5 min recovery. Force, minute ventilation (VE) and oxygen uptake (VO2) were measured. In EE, both VE and VO2 increased continuously during the entire exercise period after an initial rapid increase at all three work intensities. Correlation between VE and VO2 was highly significant during EE. During all three work intensities of VE, VE and VO2 achieved a steady-state after the initial increase. During VE, VE did not correlate as closely with VO2 as during EE. All these findings indicate that central command was not imperative for an adequate ventilatory response to exercise within all three work intensities investigated. Without the influence of central command, correlation between VE and VO2 was even better than during VE.
Collapse
Affiliation(s)
- C M Spengler
- Department of Physiology, University of Zurich, Switzerland
| | | | | |
Collapse
|
27
|
Mador MJ, Magalang UJ, Rodis A, Kufel TJ. Diaphragmatic fatigue after exercise in healthy human subjects. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1993; 148:1571-5. [PMID: 8256903 DOI: 10.1164/ajrccm/148.6_pt_1.1571] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The purpose of this study was to determine whether diaphragmatic fatigue occurs after high-intensity constant-load whole-body exercise to volitional exhaustion. Ten sedentary subjects with a maximal oxygen uptake of 2.52 +/- 0.47 L/min were studied. Subjects exercised on a bicycle ergometer at 80% of their maximal working capacity until volitional exhaustion. Minute ventilation during the last minute of exercise was 89.9 +/- 13.6 L/min, which represented 50 +/- 6% of the subjects' 12-s maximal voluntary ventilation. During the last minute of exercise, mean inspiratory esophageal pressure was 18.1 +/- 5.3 cm H2O, which represented only 15 +/- 4% of the subjects' maximal static inspiratory pressure. Bilateral transcutaneous supramaximal phrenic nerve stimulation was performed before and 10, 30, 45 and 60 min after exercise. Twitch diaphragmatic pressure (twitch Pdi) was significantly decreased after exercise in seven of the 10 subjects. For the group as a whole, twitch Pdi fell from 28.9 +/- 3.7 cm H2O during control to 23.9 +/- 5.1 cm H2O at 10 min after exercise (p < 0.005). The fall in twitch Pdi was due to a significant decrease in twitch esophageal pressure from 19.6 +/- 4.3 cm H2O during control to 15.5 +/- 4.9 cm H2O (p < 0.001). Twitch gastric pressure was not significantly different: 8.7 +/- 4.0 cm H2O, compared with 9.2 +/- 3.8 cm H2O during control. Twitch Pdi recovered to 93 +/- 7% of control values at 60 min after exercise. The fall in twitch Pdi after exercise indicates that diaphragmatic fatigue can occur following heavy endurance exercise in sedentary healthy persons.
Collapse
Affiliation(s)
- M J Mador
- Division of Pulmonary Medicine, State University of New York at Buffalo
| | | | | | | |
Collapse
|
28
|
Caillaud C, Anselme F, Mercier J, Préfaut C. Pulmonary gas exchange and breathing pattern during and after exercise in highly trained athletes. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1993; 67:431-7. [PMID: 8299615 DOI: 10.1007/bf00376460] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Highly trained athletes (HT) have been found to show arterial hypoxaemia during strenuous exercise. A lack of compensatory hyperpnoea and/or a limitation of pulmonary diffusion by pulmonary interstitial oedema have been suggested as causes, but the exact role of each is not clear. It is known, however, that interstitial pulmonary oedema may result in rapid shallow breathing (RSB). The purpose of this study was therefore twofold: firstly, to determine the exact role of a lack of compensatory hyperpnoea versus a widened in ideal alveolar minus arterial oxygen partial pressure difference [PA(i)-aO2] in the decrease in partial pressure of oxygen in arterial blood (PaO2) and, secondly, to detect RSB during recovery in HT. Untrained subjects (UT) and HT performed exhausting incremental exercise. During rest, exercise testing, and recovery, breathing pattern, respiratory gas exchange, and arterial blood gases were measured. The PA(i)-aO2 and the difference in tidal volume (VT) between exercise and recovery for the same level of ventilation, normalized to vital capacity of the subject [delta VT(%VC)], were then calculated. A large positive delta VT(%VC) was considered to be the sign of RSB. HT showed a marked hypoxaemia (F = 11.6, P < 0.0001), higher partial pressure of carbon dioxide in arterial blood (F = 3.51, P < 0.05), and lower ideal partial pressure of oxygen in alveolar gas (P < 0.001). The relationship between PA(i)-aO2 and oxygen consumption was the same for the two groups. The widening PA(i)-aO2 persisted throughout recovery for both HT and UT. The RSB was observed in HT during recovery.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- C Caillaud
- Service d'Exploration de la Fonction Respiratoire, Hôpital Arnaud de Villeneuve, Montpellier, France
| | | | | | | |
Collapse
|
29
|
Yang KL. Inspiratory pressure/maximal inspiratory pressure ratio: a predictive index of weaning outcome. Intensive Care Med 1993; 19:204-8. [PMID: 8366228 DOI: 10.1007/bf01694771] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To compare the accuracy of PI/PImax ratio and other commonly used indices in predicting weaning outcome. DESIGN A prospective study. SETTING Intensive care unit. PATIENTS 31 stable intubated patients ready to undergo weaning trial. METHODS A simple method was developed to measure the PI and PImax in intubated patients. The accuracy of PI/PImax ratio and other commonly used indices in predicting outcome were compared. All indices were measured prior to weaning trial using standardized methods. MEASUREMENTS AND RESULTS Minute ventilation of the successful patients (13.00 +/- 0.67 (SE) l/min) was not significantly different from the failure patients (10.64 +/- 1.26 l/min, p = 0.10). The PI and PImax for the successful patients (11.48 +/- 1.25 cmH2O and 47.77 +/- 4.48 cmH2O, respectively) and the unsuccessful patients (14.32 +/- 2.31 cmH2O and 40.16 +/- 4.55 cmH2O, respectively) were also not significantly different (p = 0.28 and 0.24, respectively). The PI/PImax ratio was lower for the weaning successes (0.26 +/- 0.03) than for the weaning failures (0.36 +/- 0.04, p < 0.05). The threshold value of 0.3 for PI/PImax provided the best separation between weaning success and failure patients. The combined usage of rapid shallow breathing index and PI/PImax ratio provided the highest accuracy with sensitivity of 0.81 and specificity of 0.93. CONCLUSION The PI/PImax ratio provided a good separation between the patients who were successfully weaned and those who failed. It provides additional discriminative power to f/VT.
Collapse
Affiliation(s)
- K L Yang
- Division of Pulmonary and Critical Care Medicine, University of Texas Health Science Center, Houston
| |
Collapse
|
30
|
Abstract
Although weaning parameters can accurately predict weaning outcome, variability of the measurements of these parameters has not been closely examined. In the current study, we examined the reproducibility of these parameters using a standardized technique. Before the weaning trial, maximal inspiratory pressure (PImax), minute ventilation (VE), respiratory frequency (f), tidal volume (VT), rapid shallow breathing index (f/VT), and vital capacity (VC) were obtained on three trials over a period of 15 min. The results of these parameters over three measurements were compared. There were no statistical differences in the values of PImax, VE, f, VT, and f/VT over three trials (p = 0.45, p = 0.37, p = 0.69, p = 0.64, p = 0.1, respectively). The VC was the only parameter that showed statistical differences among three trials (p < 0.05). For the group, respiratory frequency had the lowest coefficient of variation (COV = SD/mean x 100 percent) at 6.7 percent while the VC had the highest COV at 19.6 percent. We concluded that most weaning parameters of breathing pattern can be measured reliably with bedside instruments using a standard technique.
Collapse
Affiliation(s)
- K L Yang
- Division of Pulmonary and Critical Care Medicine, University of Texas Health Science Center, Houston
| |
Collapse
|
31
|
Mador MJ, Kufel TJ. Effect of inspiratory muscle fatigue on inspiratory muscle relaxation rates in healthy subjects. Chest 1992; 102:1767-73. [PMID: 1446487 DOI: 10.1378/chest.102.6.1767] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Simple methods to diagnose inspiratory muscle fatigue in the clinical setting would be of considerable benefit. Inspiratory muscle relaxation rates are known to slow following induction of fatigue. Inspiratory muscle relaxation rates have been measured following a short sharp inspiratory effort against an occluded airway (sniffmouth) or through the unoccluded nostrils (sniffnostrils). Relaxation rates in the absence of fatigue are faster when sniffs are performed through the unoccluded nostrils. While both methods have been shown to be capable of detecting inspiratory muscle fatigue, there may be quantitative or qualitative differences between the two techniques in their ability to detect fatigue similar to the differences observed in the fresh state. Accordingly, we measured relaxation rates with the two sniff techniques in five healthy naive male subjects before and after induction of fatigue. Inspiratory muscle fatigue was induced by threshold loading at 80 percent of Pesmax until the subjects were unable to generate the target pressure. For those trials in which sniffnostrils were performed, the maximum relaxation rate from the esophageal pressure curve (MRRes) was significantly decreased following induction of fatigue in nine of ten trials, while the exponential time constant (taues) was significantly increased in all ten trials. In contrast, for those trials in which sniffmouth were performed, the MRRes was significantly decreased following induction of fatigue in only six of ten trials. Similarly, taues was significantly increased following induction of fatigue in only six of ten trials. In addition, the magnitude of change in the MRR or tau following induction of fatigue was quantitatively greater with sniffnostrils compared with sniffmouth. Similar findings were obtained when relaxation rates were measured from the diaphragmatic pressure tracing. In conclusion, changes in relaxation rate following induction of fatigue were quantitatively greater and more consistently observed when sniffs were performed through the unoccluded nostrils rather than against an occluded airway.
Collapse
Affiliation(s)
- M J Mador
- Division of Pulmonary Medicine, State University of New York, Buffalo
| | | |
Collapse
|
32
|
Mador MJ, Tobin MJ. The effect of inspiratory muscle fatigue on breathing pattern and ventilatory response to CO2. J Physiol 1992; 455:17-32. [PMID: 1484352 PMCID: PMC1175631 DOI: 10.1113/jphysiol.1992.sp019288] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
1. The effects of inducing inspiratory muscle fatigue on the subsequent breathing pattern were examined during resting unstimulated breathing and during CO2 rebreathing. In addition, we examined whether induction of inspiratory muscle fatigue alters CO2 responsiveness. 2. Global inspiratory muscle fatigue and diaphragmatic fatigue were achieved by having subjects breathe against an inspiratory resistive load while generating a predetermined fraction of either their maximal mouth pressure or maximal transdiaphragmatic pressure until they were unable to generate the target pressure. 3. Induction of inspiratory muscle fatigue had no effect on the subsequent breathing pattern during either unstimulated breathing or during CO2 rebreathing. 4. Following induction of inspiratory muscle fatigue, the slope of the ventilatory response to CO2 was significantly decreased from 18.8 +/- 3.3 during control to 13.8 +/- 2.1 l min-1 (% end-tidal CO2 concentration)-1 with fatigue (P < 0.02).
Collapse
Affiliation(s)
- M J Mador
- Division of Pulmonary Medicine, State University of New York, Buffalo
| | | |
Collapse
|
33
|
Affiliation(s)
- M J Tobin
- Loyola University, Chicago Stritch School of Medicine, IL
| |
Collapse
|
34
|
Boutellier U, Büchel R, Kundert A, Spengler C. The respiratory system as an exercise limiting factor in normal trained subjects. EUROPEAN JOURNAL OF APPLIED PHYSIOLOGY AND OCCUPATIONAL PHYSIOLOGY 1992; 65:347-53. [PMID: 1425635 DOI: 10.1007/bf00868139] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Recently, we have shown that an untrained respiratory system does limit the endurance of submaximal exercise (64% peak oxygen consumption) in normal sedentary subjects. These subjects were able to increase breathing endurance by almost 300% and cycle endurance by 50% after isolated respiratory training. The aim of the present study was to find out if normal, endurance trained subjects would also benefit from respiratory training. Breathing and cycle endurance as well as maximal oxygen consumption (VO2max) and anaerobic threshold were measured in eight subjects. Subsequently, the subjects trained their respiratory muscles for 4 weeks by breathing 85-160 l.min-1 for 30 min daily. Otherwise they continued their habitual endurance training. After respiratory training, the performance tests made at the beginning of the study were repeated. Respiratory training increased breathing endurance from 6.1 (SD 1.8) min to about 40 min. Cycle endurance at the anaerobic threshold [77 (SD 6) %VO2max] was improved from 22.8 (SD 8.3) min to 31.5 (SD 12.6) min while VO2max and the anaerobic threshold remained essentially the same. Therefore, the endurance of respiratory muscles can be improved remarkably even in trained subjects. Respiratory muscle fatigue induced hyperventilation which limited cycle performance at the anaerobic threshold. After respiratory training, minute ventilation for a given exercise intensity was reduced and cycle performance at the anaerobic threshold was prolonged. These results would indicate the respiratory system to be an exercise limiting factor in normal, endurance trained subjects.
Collapse
Affiliation(s)
- U Boutellier
- Department of Physiology, University of Zürich, Switzerland
| | | | | | | |
Collapse
|
35
|
Abstract
The major determinants of VO2 resp and, thus, diaphragmatic endurance are the tension-time index, work rate and lung volume. Changes in breathing pattern that adversely affect any of these factors can impair diaphragmatic endurance. A TTdi above 0.15-0.18 indicates a potentially fatiguing pattern of contraction. However, fatigue may occur at a TTdi below 0.15 if the work rate is sufficiently high or the Pdimax is not measured at the prevailing lung volume. Inspiratory muscle fatigue usually elicits an increase in minute ventilation and respiratory rate and to a lesser degree a reduction in tidal volume. However, fatigue may not always be accompanied by changes in breathing pattern. Furthermore, fatigue may sometimes result in a reduction rather than an increase in motor outflow to the respiratory muscles. Finally, abdominal paradox initially considered to be characteristic clinical sign of inspiratory muscle fatigue appears to be due to increases in respiratory load rather than to muscle fatigue.
Collapse
Affiliation(s)
- M J Mador
- Division of Pulmonary Medicine, State University of New York, Buffalo
| |
Collapse
|