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Neder JA, Santyr G, Zanette B, Kirby M, Pourafkari M, James MD, Vincent SG, Ferguson C, Wang CY, Domnik NJ, Phillips DB, Porszasz J, Stringer WW, O'Donnell DE. Beyond Spirometry: Linking Wasted Ventilation to Exertional Dyspnea in the Initial Stages of COPD. COPD 2024; 21:2301549. [PMID: 38348843 DOI: 10.1080/15412555.2023.2301549] [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: 10/15/2023] [Accepted: 12/29/2023] [Indexed: 02/15/2024]
Abstract
Exertional dyspnea, a key complaint of patients with chronic obstructive pulmonary disease (COPD), ultimately reflects an increased inspiratory neural drive to breathe. In non-hypoxemic patients with largely preserved lung mechanics - as those in the initial stages of the disease - the heightened inspiratory neural drive is strongly associated with an exaggerated ventilatory response to metabolic demand. Several lines of evidence indicate that the so-called excess ventilation (high ventilation-CO2 output relationship) primarily reflects poor gas exchange efficiency, namely increased physiological dead space. Pulmonary function tests estimating the extension of the wasted ventilation and selected cardiopulmonary exercise testing variables can, therefore, shed unique light on the genesis of patients' out-of-proportion dyspnea. After a succinct overview of the basis of gas exchange efficiency in health and inefficiency in COPD, we discuss how wasted ventilation translates into exertional dyspnea in individual patients. We then outline what is currently known about the structural basis of wasted ventilation in "minor/trivial" COPD vis-à-vis the contribution of emphysema versus a potential impairment in lung perfusion across non-emphysematous lung. After summarizing some unanswered questions on the field, we propose that functional imaging be amalgamated with pulmonary function tests beyond spirometry to improve our understanding of this deeply neglected cause of exertional dyspnea. Advances in the field will depend on our ability to develop robust platforms for deeply phenotyping (structurally and functionally), the dyspneic patients showing unordinary high wasted ventilation despite relatively preserved FEV1.
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Affiliation(s)
- J Alberto Neder
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, Canada
| | - Giles Santyr
- Translational Medicine Department, Faculty of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Canada
| | - Brandon Zanette
- Translational Medicine Department, Faculty of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Canada
| | - Miranda Kirby
- Department of Physics, Faculty of Science, Toronto Metropolitan University, Toronto, Canada
| | - Marina Pourafkari
- Department of Radiology and Diagnostic Imaging, Kingston Health Sciences Centre, Kingston, Canada
| | - Matthew D James
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, Canada
| | - Sandra G Vincent
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, Canada
| | - Carrie Ferguson
- The Lundquist Institute for Biomedical Innovation, Harbor U.C.L.A Medical Centre, Torrance, CA, USA
| | - Chu-Yi Wang
- The Lundquist Institute for Biomedical Innovation, Harbor U.C.L.A Medical Centre, Torrance, CA, USA
| | - Nicolle J Domnik
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, Canada
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Canada
| | - Devin B Phillips
- School of Kinesiology and Health Science, York University, Toronto, Canada
| | - Janos Porszasz
- The Lundquist Institute for Biomedical Innovation, Harbor U.C.L.A Medical Centre, Torrance, CA, USA
| | - William W Stringer
- The Lundquist Institute for Biomedical Innovation, Harbor U.C.L.A Medical Centre, Torrance, CA, USA
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston, Canada
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Lopes TR, de Oliveira DM, Amoroso de Lima LA, Silva BM. Breathing variability during running in athletes: The role of sex, exercise intensity and breathing reserve. Respir Physiol Neurobiol 2024; 331:104350. [PMID: 39270950 DOI: 10.1016/j.resp.2024.104350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2024] [Revised: 09/10/2024] [Accepted: 09/10/2024] [Indexed: 09/15/2024]
Abstract
Highly trained aerobic athletes progressively use most of their breathing reserve with increased exercise intensity during whole-body exercise. Additionally, females typically present proportionally smaller lungs than males. Therefore, sex, exercise intensity, and breathing reserve use likely influence the volume and time in which respiratory parameters vary between consecutive breaths during whole-body exercise. However, breath-by-breath variability has been scarcely investigated during exercise. Accordingly, we sought to investigate breath-by-breath pulmonary ventilation (V̇E), tidal volume (VT), and respiratory frequency (fR) variability during a maximal treadmill incremental exercise test in 17 females and 18 males highly trained professional endurance runners. The breath-by-breath variability was analyzed by root mean square of successive differences (RMSSD) within 1-minute windows. Females had lower absolute and percent predicted forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) than males, as well as lower height-adjusted absolute FVC than males. V̇E and VT reserve use were similar between the sexes at peak exercise. While RMSSDV̇E and RMSSDfR did not change over exercise (P > 0.05), RMSSDVT progressively decreased (P < 0.001). RMSSDVT was negatively correlated with VT reserve use only in males. Females showed lower RMSSDV̇E than males during the entire exercise test (P < 0.001). At iso-V̇E reserve use, between-sex differences in RMSSDV̇E persisted (P = 0.003). Our findings indicate that exercise intensity decreases VT variability in professional runners, which is linked to VT reserve use in males but not females. Additionally, the female sex lowers V̇E variability regardless of exercise intensity and V̇E reserve use.
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Affiliation(s)
- Thiago Ribeiro Lopes
- Laboratory of Exercise Physiology at Olympic Center of Training and Research, Department of Physiology, Federal University of São Paulo, São Paulo, SP, Brazil; São Paulo Association for Medicine Development, São Paulo, Sp, Brazil; Post-graduate Program in Translational Medicine, Department of Medicine, Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Diogo Machado de Oliveira
- Laboratory of Exercise Physiology at Olympic Center of Training and Research, Department of Physiology, Federal University of São Paulo, São Paulo, SP, Brazil; Post-graduate Program in Translational Medicine, Department of Medicine, Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Luís Adriano Amoroso de Lima
- Laboratory of Exercise Physiology at Olympic Center of Training and Research, Department of Physiology, Federal University of São Paulo, São Paulo, SP, Brazil; Post-graduate Program in Translational Medicine, Department of Medicine, Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Bruno Moreira Silva
- Laboratory of Exercise Physiology at Olympic Center of Training and Research, Department of Physiology, Federal University of São Paulo, São Paulo, SP, Brazil; Post-graduate Program in Translational Medicine, Department of Medicine, Paulista School of Medicine, Federal University of São Paulo, São Paulo, SP, Brazil.
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Hijleh AA, Berton DC, Neder-Serafini I, James M, Vincent S, Domnik N, Phillips D, O'Donnell DE, Neder JA. Sex- and age-adjusted reference values for dynamic inspiratory constraints during incremental cycle ergometry. Respir Physiol Neurobiol 2024; 327:104297. [PMID: 38871042 DOI: 10.1016/j.resp.2024.104297] [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: 04/08/2024] [Revised: 06/04/2024] [Accepted: 06/09/2024] [Indexed: 06/15/2024]
Abstract
Activity-related dyspnea in chronic lung disease is centrally related to dynamic (dyn) inspiratory constraints to tidal volume expansion. Lack of reference values for exertional inspiratory reserve (IR) has limited the yield of cardiopulmonary exercise testing in exposing the underpinnings of this disabling symptom. One hundred fifty apparently healthy subjects (82 males) aged 40-85 underwent incremental cycle ergometry. Based on exercise inspiratory capacity (ICdyn), we generated centile-based reference values for the following metrics of IR as a function of absolute ventilation: IRdyn1 ([1-(tidal volume/ICdyn)] x 100) and IRdyn2 ([1-(end-inspiratory lung volume/total lung capacity] x 100). IRdyn1 and IRdyn2 standards were typically lower in females and older subjects (p<0.05 for sex and age versus ventilation interactions). Low IRdyn1 and IRdyn2 significantly predicted the burden of exertional dyspnea in both sexes (p<0.01). Using these sex and age-adjusted limits of reference, the clinician can adequately judge the presence and severity of abnormally low inspiratory reserves in dyspneic subjects undergoing cardiopulmonary exercise testing.
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Affiliation(s)
- Abed A Hijleh
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston General Hospital, Connell 2-200. 102 Stuart St., Kingston, ON K7L 2V7, Canada
| | - Danilo C Berton
- Pulmonary Function Tests Laboratory, Federal University of Rio Grande to Sul, Rua Ramiro Barcelos, 2350 Bloco A, Av. Protásio Alves, 211 - Bloco B e C - Santa Cecília, Porto Alegre, RS 90035-903, Brazil
| | - Igor Neder-Serafini
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston General Hospital, Connell 2-200. 102 Stuart St., Kingston, ON K7L 2V7, Canada
| | - Matthew James
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston General Hospital, Connell 2-200. 102 Stuart St., Kingston, ON K7L 2V7, Canada
| | - Sandra Vincent
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston General Hospital, Connell 2-200. 102 Stuart St., Kingston, ON K7L 2V7, Canada
| | - Nicolle Domnik
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston General Hospital, Connell 2-200. 102 Stuart St., Kingston, ON K7L 2V7, Canada
| | - Devin Phillips
- School of Kinesiology and Health Science, Faculty of Health, York University, Norman Bethune College, 170 Campus Walk Room 341, Toronto, ON M3J 1P3, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston General Hospital, Connell 2-200. 102 Stuart St., Kingston, ON K7L 2V7, Canada
| | - J Alberto Neder
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston General Hospital, Connell 2-200. 102 Stuart St., Kingston, ON K7L 2V7, Canada.
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Hijleh AA, Wang S, Berton DC, Neder-Serafini I, Vincent S, James M, Domnik N, Phillips D, Nery LE, O'Donnell DE, Neder JA. Reference values for leg effort during incremental cycle ergometry in non-trained healthy men and women, aged 19-85. Scand J Med Sci Sports 2024; 34:e14625. [PMID: 38597357 DOI: 10.1111/sms.14625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 03/19/2024] [Accepted: 03/24/2024] [Indexed: 04/11/2024]
Abstract
Heightened sensation of leg effort contributes importantly to poor exercise tolerance in patient populations. We aim to provide a sex- and age-adjusted frame of reference to judge symptom's normalcy across progressively higher exercise intensities during incremental exercise. Two-hundred and seventy-five non-trained subjects (130 men) aged 19-85 prospectively underwent incremental cycle ergometry. After establishing centiles-based norms for Borg leg effort scores (0-10 category-ratio scale) versus work rate, exponential loss function identified the centile that best quantified the symptom's severity individually. Peak O2 uptake and work rate (% predicted) were used to threshold gradually higher symptom intensity categories. Leg effort-work rate increased as a function of age; women typically reported higher scores at a given age, particularly in the younger groups (p < 0.05). For instance, "heavy" (5) scores at the 95th centile were reported at ~200 W (<40 years) and ~90 W (≥70 years) in men versus ~130 W and ~70 W in women, respectively. The following categories of leg effort severity were associated with progressively lower exercise capacity: ≤50th ("mild"), >50th to <75th ("moderate"), ≥75th to <95th ("severe"), and ≥ 95th ("very severe") (p < 0.05). Although most subjects reporting peak scores <5 were in "mild" range, higher scores were not predictive of the other categories (p > 0.05). This novel frame of reference for 0-10 Borg leg effort, which considers its cumulative burden across increasingly higher exercise intensities, might prove valuable to judging symptom's normalcy, quantifying its severity, and assessing the effects of interventions in clinical populations.
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Affiliation(s)
- Abed A Hijleh
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Sophia Wang
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Danilo C Berton
- Pulmonary Function Tests Laboratory, Federal University of Rio Grande to Sul, Porto Alegre, RS, Brazil
| | - Igor Neder-Serafini
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Sandra Vincent
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Matthew James
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Nicolle Domnik
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - Devin Phillips
- School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, Canada
| | - Luiz E Nery
- Clinical Exercise Physiology Unit, Division of Pulmonology, Department o Medicine, Federal University of Sao Paulo, São Paulo, Brazil
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
| | - J Alberto Neder
- Respiratory Investigation Unit, Division of Respirology, Department of Medicine, Queen's University, Kingston, Ontario, Canada
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Haverkamp HC, Balmain BN. Ventilatory Responses to Exercise by Age, Sex, and Health Status. Curr Sports Med Rep 2024; 23:79-85. [PMID: 38437493 DOI: 10.1249/jsr.0000000000001149] [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: 03/06/2024]
Abstract
ABSTRACT An understanding of the normal pulmonary responses to incremental exercise is requisite for appropriate interpretation of findings from clinical exercise testing. The purpose of this review is to provide concrete information to aid the interpretation of the exercise ventilatory response in both healthy and diseased populations. We begin with an overview of the normal exercise ventilatory response to incremental exercise in the healthy, normally trained young-to-middle aged adult male. The exercise ventilatory responses in two nonpatient populations (females, elderly) are then juxtaposed with the responses in healthy males. The review concludes with overviews of the exercise ventilatory responses in four patient populations (obesity, chronic obstructive pulmonary disease, asthma, congestive heart failure). Again, we use the normal response in healthy adults as the framework for interpreting the responses in the clinical groups. For each healthy and clinical population, recent, impactful research findings will be presented.
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Affiliation(s)
- Hans Christian Haverkamp
- Department of Nutrition and Exercise Physiology, Elson S. Floyd College of Medicine, Washington State University-Spokane Health Sciences, Spokane, WA
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