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Kowalski T, Rebis K, Wilk A, Klusiewicz A, Wiecha S, Paleczny B. Body Oxygen Level Test (BOLT) is not associated with exercise performance in highly-trained individuals. Front Physiol 2024; 15:1430837. [PMID: 39290618 PMCID: PMC11406178 DOI: 10.3389/fphys.2024.1430837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2024] [Accepted: 08/16/2024] [Indexed: 09/19/2024] Open
Abstract
Introduction The analysis of chemoreflex and baroreflex sensitivity may contribute to optimizing patient care and athletic performance. Breath-holding tests, such as the Body Oxygen Level Test (BOLT), have gained popularity as a feasible way to evaluate the reflex control over the cardiorespiratory system. According to its proponents, the BOLT score reflects the body's sensitivity to carbon dioxide and homeostasis disturbances, providing feedback on exercise tolerance. However, it has not yet been scientifically validated or linked with exercise performance in highly-trained individuals. Therefore, we investigated the association of BOLT scores with the results of standard performance tests in elite athletes. Methods A group of 49 speedskaters performed BOLT, Wingate Anaerobic Test (WAnT), and cardiopulmonary exercise test (CPET) on a cycle ergometer. Peak power, total work, and power drop were measured during WAnT. Time to exhaustion and maximum oxygen uptake were measured during CPET. Spearman's rank correlation and multiple linear regression were performed to analyze the association of BOLT scores with parameters obtained during the tests, age, somatic indices, and training experience. Results No significant correlations between BOLT scores and parameters obtained during WAnT and CPET were found, r(47) = -0.172-0.013, p = 0.248-0.984. The parameters obtained during the tests, age, somatic indices, and training experience were not significant in multiple linear regression (p = 0.38-0.85). The preliminary regression model showed an R 2 of 0.08 and RMSE of 9.78 sec. Conclusions Our findings did not demonstrate a significant relationship between BOLT scores and exercise performance. Age, somatic indices, and training experience were not significant in our analysis. It is recommended to interpret BOLT concerning exercise performance in highly-trained populations with a great degree of caution.
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Affiliation(s)
- Tomasz Kowalski
- Department of Physiology, Institute of Sport - National Research Institute, Warsaw, Poland
| | - Kinga Rebis
- Department of Physiology, Institute of Sport - National Research Institute, Warsaw, Poland
| | - Adrian Wilk
- Department of Physiology, Institute of Sport - National Research Institute, Warsaw, Poland
| | - Andrzej Klusiewicz
- Department of Physical Education and Health in Biala Podlaska, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland
| | - Szczepan Wiecha
- Department of Physical Education and Health in Biala Podlaska, Józef Piłsudski University of Physical Education in Warsaw, Warsaw, Poland
| | - Bartłomiej Paleczny
- Department of Physiology and Pathophysiology, Wroclaw Medical University, Wrocław, Poland
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Brotto AR, Phillips DB, Rowland SD, Moore LE, Wong E, Stickland MK. Reduced tidal volume-inflection point and elevated operating lung volumes during exercise in females with well-controlled asthma. BMJ Open Respir Res 2023; 10:e001791. [PMID: 38135461 DOI: 10.1136/bmjresp-2023-001791] [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: 04/24/2023] [Accepted: 12/01/2023] [Indexed: 12/24/2023] Open
Abstract
INTRODUCTION Individuals with asthma breathe at higher operating lung volumes during exercise compared with healthy individuals, which contributes to increased exertional dyspnoea. In health, females are more likely to develop exertional dyspnoea than males at a given workload or ventilation, and therefore, it is possible that females with asthma may develop disproportional dyspnoea on exertion. The purpose of this study was to compare operating lung volume and dyspnoea responses during exercise in females with and without asthma. METHODS Sixteen female controls and 16 females with asthma were recruited for the study along with 16 male controls and 16 males with asthma as a comparison group. Asthma was confirmed using American Thoracic Society criteria. Participants completed a cycle ergometry cardiopulmonary exercise test to volitional exhaustion. Inspiratory capacity manoeuvres were performed to estimate inspiratory reserve volume (IRV) and dyspnoea was evaluated using the Modified Borg Scale. RESULTS Females with asthma exhibited elevated dyspnoea during submaximal exercise compared with female controls (p<0.05). Females with asthma obtained a similar IRV and dyspnoea at peak exercise compared with healthy females despite lower ventilatory demand, suggesting mechanical constraint to tidal volume (VT) expansion. VT-inflection point was observed at significantly lower ventilation and V̇O2 in females with asthma compared with female controls. Forced expired volume in 1 s was significantly associated with VT-inflection point in females with asthma (R2=0.401; p<0.01) but not female controls (R2=0.002; p=0.88). CONCLUSION These results suggest that females with asthma are more prone to experience exertional dyspnoea, secondary to dynamic mechanical constraints during submaximal exercise when compared with females without asthma.
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Affiliation(s)
- Andrew R Brotto
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Devin B Phillips
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
- School of Kinesiology and Health Science, Faculty of Health, York University, Toronto, Ontario, Canada
| | - Samira D Rowland
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Linn E Moore
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Eric Wong
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michael K Stickland
- Pulmonary Division, Department of Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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3
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Phillips DB, James MD, O'Donnell CJD, Vincent SG, Webb KA, de-Torres JP, Neder JA, O'Donnell DE. Physiological Predictors of Morbidity and Mortality in COPD: The Relative Importance of Reduced Inspiratory Capacity and Inspiratory Muscle Strength. J Appl Physiol (1985) 2022; 133:679-688. [PMID: 35952349 DOI: 10.1152/japplphysiol.00352.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Low resting inspiratory capacity (IC) and low maximal inspiratory pressure (MIP) have previously been linked to exertional dyspnea, exercise limitation and poor survival in chronic obstructive pulmonary disease (COPD). The interaction and relative contributions of these two related variables to important clinical outcomes are unknown. The objective of the current study was to examine the interaction between resting IC and MIP (both % predicted), exertional dyspnea, exercise capacity and long-term survival in patients with COPD. Two hundred and eighty-five patients with mild to advanced COPD completed standard lung function testing and a cycle cardiopulmonary exercise test. Multiple regression determined predictors of the exertional dyspnea-ventilation slope and peak oxygen uptake (V̇O2peak). Cox regression determined predictors of 10-year mortality. IC was associated with the dyspnea-ventilation slope (standardized β=-0.44, p<0.001), while MIP was excluded from the regression model (p=0.713). IC and MIP were included in the final model to predict V̇O2peak. However, the standardized β was greater for IC (0.49) than MIP (0.22). After adjusting for age, sex, body mass index, cardiovascular risk, airflow obstruction and diffusing capacity, resting IC was independently associated with 10-year all-cause mortality (hazard ratio=1.25, confidence interval5-95%=1.16-1.34, p<0.001), while MIP was excluded from the final model (all p=0.829). Low resting IC was consistently linked to heightened dyspnea intensity, low V̇O2peak and worse survival in COPD even after accounting for airway obstruction, inspiratory muscle strength, and diffusing capacity. These results support the use of resting IC as an important physiological biomarker closely linked to key clinical outcomes in COPD.
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Affiliation(s)
- Devin B Phillips
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Matthew D James
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Conor J D O'Donnell
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Sandra G Vincent
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Katherine A Webb
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Juan Pablo de-Torres
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - J Alberto Neder
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Department of Medicine and Queen's University and Kingston Health Sciences Centre, Kingston, Ontario, Canada
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Dempsey JA, Neder JA, Phillips DB, O'Donnell DE. The physiology and pathophysiology of exercise hyperpnea. HANDBOOK OF CLINICAL NEUROLOGY 2022; 188:201-232. [PMID: 35965027 DOI: 10.1016/b978-0-323-91534-2.00001-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In health, the near-eucapnic, highly efficient hyperpnea during mild-to-moderate intensity exercise is driven by three obligatory contributions, namely, feedforward central command from supra-medullary locomotor centers, feedback from limb muscle afferents, and respiratory CO2 exchange (V̇CO2). Inhibiting each of these stimuli during exercise elicits a reduction in hyperpnea even in the continuing presence of the other major stimuli. However, the relative contribution of each stimulus to the hyperpnea remains unknown as does the means by which V̇CO2 is sensed. Mediation of the hyperventilatory response to exercise in health is attributed to the multiple feedback and feedforward stimuli resulting from muscle fatigue. In patients with COPD, diaphragm EMG amplitude and its relation to ventilatory output are used to decipher mechanisms underlying the patients' abnormal ventilatory responses, dynamic lung hyperinflation and dyspnea during exercise. Key contributions to these exercise-limiting responses across the spectrum of COPD severity include high dead space ventilation, an excessive neural drive to breathe and highly fatigable limb muscles, together with mechanical constraints on ventilation. Major controversies concerning control of exercise hyperpnea are discussed along with the need for innovative research to uncover the link of metabolism to breathing in health and disease.
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Affiliation(s)
- Jerome A Dempsey
- John Rankin Laboratory of Pulmonary Medicine, Department of Population Health Sciences, University of Wisconsin-Madison, Madison, WI, United States.
| | - J Alberto Neder
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
| | - Devin B Phillips
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre Kingston General Hospital Campus, Kingston, ON, Canada
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Phillips DB, Neder JA, Elbehairy AF, Milne KM, James MD, Vincent SG, Day AG, DE-Torres JP, Webb KA, O'Donnell DE. Qualitative Components of Dyspnea during Incremental Exercise across the COPD Continuum. Med Sci Sports Exerc 2021; 53:2467-2476. [PMID: 34649264 DOI: 10.1249/mss.0000000000002741] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Evaluation of the intensity and quality of activity-related dyspnea is potentially useful in people with chronic obstructive pulmonary disease (COPD). The present study sought to examine associations between qualitative dyspnea descriptors, dyspnea intensity ratings, dynamic respiratory mechanics, and exercise capacity during cardiopulmonary exercise testing (CPET) in COPD and healthy controls. METHODS In this cross-sectional study, 261 patients with mild-to-very severe COPD (forced expiratory volume in 1 s, 62 ± 25%pred) and 94 age-matched controls (forced expiratory volume in 1 s, 114 ± 14%pred) completed an incremental cycle CPET to determine peak oxygen uptake (V˙O2peak). Throughout exercise, expired gases, operating lung volumes, and dyspnea intensity were assessed. At peak exercise, dyspnea quality was assessed using a modified 15-item questionnaire. RESULTS Logistic regression analysis revealed that among 15 dyspnea descriptors, only those alluding to the cluster "unsatisfied inspiration" were consistently associated with an increased likelihood for both critical inspiratory mechanical constraint (end-inspiratory lung volume/total lung capacity ratio ≥0.9) during exercise and reduced exercise capacity (V˙O2peak < lower limit of normal) in COPD (odds ratio (95% confidence interval), 3.26 (1.40-7.60) and 3.04 (1.24-7.45), respectively; both, P < 0.05). Thus, patients reporting "unsatisfied inspiration" (n = 177 (68%)) had an increased relative frequency of critical inspiratory mechanical constraint and low exercise capacity compared with those who did not select this descriptor, regardless of COPD severity or peak dyspnea intensity scores. CONCLUSIONS In patients with COPD, regardless of disease severity, reporting descriptors in the unsatisfied inspiration cluster complemented traditional assessments of dyspnea during CPET and helped identify patients with critical mechanical abnormalities germane to exercise intolerance.
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Affiliation(s)
- Devin B Phillips
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, CANADA
| | - J Alberto Neder
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, CANADA
| | | | | | - Matthew D James
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, CANADA
| | - Sandra G Vincent
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, CANADA
| | - Andrew G Day
- Kingston General Hospital Health Research Institute, Kingston, Ontario, CANADA
| | - Juan P DE-Torres
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, CANADA
| | - Katherine A Webb
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, CANADA
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, CANADA
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James MD, Phillips DB, Elbehairy AF, Milne KM, Vincent SG, Domnik NJ, de Torres JP, Neder JA, O'Donnell DE. Mechanisms of Exertional Dyspnea in Patients with Mild COPD and a Low Resting DL CO. COPD 2021; 18:501-510. [PMID: 34496691 DOI: 10.1080/15412555.2021.1932782] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Patients with mild chronic obstructive pulmonary disease (COPD) and lower resting diffusing capacity for carbon monoxide (DLCO) often report troublesome dyspnea during exercise although the mechanisms are not clear. We postulated that in such individuals, exertional dyspnea is linked to relatively high inspiratory neural drive (IND) due, in part, to the effects of reduced ventilatory efficiency. This cross-sectional study included 28 patients with GOLD I COPD stratified into two groups with (n = 15) and without (n = 13) DLCO less than the lower limit of normal (<LLN; Global Lung Function Initiative criteria) and 16 healthy controls. We compared dyspnea (Borg scale), IND (by diaphragm electromyography), ventilatory equivalent for CO2 (V̇E/V̇CO2), and respiratory mechanics during incremental cycle exercise in the three groups. Spirometry and resting lung volumes were similar between COPD groups. During exercise, dyspnea, IND and V̇E/V̇CO2 were higher at equivalent work rates (WR) in the DLCO<LLN group compared with the other two groups (all p < 0.05). In patients with DLCO<LLN, severe respiratory mechanical constraints, indicated by end-inspiratory lung volume of approximately 90% of total lung capacity, occurred at a lower WR than the other two groups (p < 0.05). The dyspnea/IND relationship was similar across groups; therefore, the increased dyspnea at a standardized WR in the low DLCO<LLN group reflected the higher corresponding IND. Higher dyspnea ratings in patients with mild COPD and DLCO<LLN were associated with higher IND and V̇E/V̇CO2 at a given work rate. Higher ventilatory requirements in the DLCO<LLN group accelerated dynamic mechanical abnormalities earlier in exercise, further increasing IND and dyspnea.
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Affiliation(s)
- Matthew D James
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Devin B Phillips
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Amany F Elbehairy
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada.,Department of Chest Diseases, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Kathryn M Milne
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada.,Centre for Heart Lung Innovation, Providence Health Care Research Institute, University of British Colombia, St. Paul's Hospital, Vancouver, British Columbia, Canada.,Division of Respiratory Medicine, Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sandra G Vincent
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Nicolle J Domnik
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada.,Department of Physiology and Pharmacology, Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Juan P de Torres
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - J Alberto Neder
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Department of Medicine, Queen's University, and Kingston Health Sciences Centre, Kingston, Ontario, Canada
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7
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Gonzalez-Garcia M, Barrero M, Maldonado D. Exercise Capacity, Ventilatory Response, and Gas Exchange in COPD Patients With Mild to Severe Obstruction Residing at High Altitude. Front Physiol 2021; 12:668144. [PMID: 34220533 PMCID: PMC8249805 DOI: 10.3389/fphys.2021.668144] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/28/2021] [Indexed: 01/04/2023] Open
Abstract
Background Exercise intolerance, desaturation, and dyspnea are common features in patients with chronic obstructive pulmonary disease (COPD). At altitude, the barometric pressure (BP) decreases, and therefore the inspired oxygen pressure and the partial pressure of arterial oxygen (PaO2) also decrease in healthy subjects and even more in patients with COPD. Most of the studies evaluating ventilation and arterial blood gas (ABG) during exercise in COPD patients have been conducted at sea level and in small populations of people ascending to high altitudes. Our objective was to compare exercise capacity, gas exchange, ventilatory alterations, and symptoms in COPD patients at the altitude of Bogotá (2,640 m), of all degrees of severity. Methods Measurement during a cardiopulmonary exercise test of oxygen consumption (VO2), minute ventilation (VE), tidal volume (VT), heart rate (HR), ventilatory equivalents of CO2 (VE/VCO2), inspiratory capacity (IC), end-tidal carbon dioxide tension (PETCO2), and ABG. For the comparison of the variables between the control subjects and the patients according to the GOLD stages, the non-parametric Kruskal–Wallis test or the one-way analysis of variance test was used. Results Eighty-one controls and 525 patients with COPD aged 67.5 ± 9.1 years were included. Compared with controls, COPD patients had lower VO2 and VE (p < 0.001) and higher VE/VCO2 (p = 0.001), A-aPO2, and VD/VT (p < 0.001). In COPD patients, PaO2 and saturation decreased, and delta IC (p = 0.004) and VT/IC increased (p = 0.002). These alterations were also seen in mild COPD and progressed with increasing severity of the obstruction. Conclusion The main findings of this study in COPD patients residing at high altitude were a progressive decrease in exercise capacity, increased dyspnea, dynamic hyperinflation, restrictive mechanical constraints, and gas exchange abnormalities during exercise, across GOLD stages 1–4. In patients with mild COPD, there were also lower exercise capacity and gas exchange alterations, with significant differences from controls. Compared with studies at sea level, because of the lower inspired oxygen pressure and the compensatory increase in ventilation, hypoxemia at rest and during exercise was more severe; PaCO2 and PETCO2 were lower; and VE/VO2 was higher.
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Affiliation(s)
- Mauricio Gonzalez-Garcia
- Pulmonary Function Testing Laboratory, Fundación Neumologica Colombiana, Bogotá, Colombia.,Faculty of Medicine, Universidad de La Sabana, Bogotá, Colombia
| | - Margarita Barrero
- Pulmonary Function Testing Laboratory, Fundación Neumologica Colombiana, Bogotá, Colombia
| | - Dario Maldonado
- Pulmonary Function Testing Laboratory, Fundación Neumologica Colombiana, Bogotá, Colombia
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8
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Phillips DB, James MD, Elbehairy AF, Milne KM, Vincent SG, Domnik NJ, de-Torres JP, Neder JA, O'Donnell DE. Reduced exercise tolerance in mild chronic obstructive pulmonary disease: The contribution of combined abnormalities of diffusing capacity for carbon monoxide and ventilatory efficiency. Respirology 2021; 26:786-795. [PMID: 33829588 DOI: 10.1111/resp.14045] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/26/2021] [Accepted: 03/08/2021] [Indexed: 01/15/2023]
Abstract
BACKGROUND AND OBJECTIVE The combination of both reduced resting diffusing capacity of the lung for carbon monoxide (DLCO ) and ventilatory efficiency (increased ventilatory requirement for CO2 clearance [V˙E /V˙CO2 ]) has been linked to exertional dyspnoea and exercise intolerance in chronic obstructive pulmonary disease (COPD) but the underlying mechanisms are poorly understood. The current study examined if low resting DLCO and higher exercise ventilatory requirements were associated with earlier critical dynamic mechanical constraints, dyspnoea and exercise limitation in patients with mild COPD. METHODS In this retrospective analysis, we compared V˙E /V˙CO2 , dynamic inspiratory reserve volume (IRV), dyspnoea and exercise capacity in groups of patients with Global Initiative for Chronic Obstructive Lung Disease stage 1 COPD with (1) a resting DLCO at or greater than the lower limit of normal (≥LLN; Global Lung Function Initiative reference equations [n = 44]) or (2) below the <LLN (n = 33), and age- and sex-matched healthy controls (n = 81). RESULTS Spirometry and resting lung volumes were similar in the two COPD groups. During exercise, V˙E /V˙CO2 (nadir and slope) was consistently higher in the DLCO < LLN compared with the other groups (all p < 0.05). The DLCO < LLN group had lower IRV and greater dyspnoea intensity at standardized submaximal work rates and lower peak work rate and oxygen uptake than the other two groups (all p < 0.05). CONCLUSION Reduced exercise capacity in patients with DLCO < LLN was related to higher ventilatory requirements, a faster rate of decline in dynamic IRV and greater dyspnoea during exercise. These simple measurements should be considered for the clinical evaluation of unexplained exercise intolerance in individuals with ostensibly mild COPD.
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Affiliation(s)
- Devin B Phillips
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada
| | - Matthew D James
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada
| | - Amany F Elbehairy
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada.,Department of Chest Diseases, Faculty of Medicine, Alexandria University, Alexandria, Egypt
| | - Kathryn M Milne
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada.,Department of Medicine Clinician Investigator Program, University of British Columbia, Vancouver, British Columbia, Canada
| | - Sandra G Vincent
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada
| | - Nicolle J Domnik
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada
| | - Juan P de-Torres
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada
| | - J Alberto Neder
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada
| | - Denis E O'Donnell
- Respiratory Investigation Unit, Department of Medicine, Queen's University and Kingston Health Sciences Centre, Kingston General Hospital Campus, Kingston, Ontario, Canada
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9
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Phillips DB, Domnik NJ, Elbehairy AF, Preston ME, Milne KM, James MD, Vincent SG, Ibrahim-Masthan M, Neder JA, O’Donnell DE. Elevated exercise ventilation in mild COPD is not linked to enhanced central chemosensitivity. Respir Physiol Neurobiol 2021; 284:103571. [DOI: 10.1016/j.resp.2020.103571] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Revised: 10/27/2020] [Accepted: 11/01/2020] [Indexed: 11/25/2022]
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10
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Phillips DB, Brotto AR, Ross BA, Bryan TL, Wong EYL, Meah VL, Fuhr DP, van Diepen S, Stickland MK. Inhaled nitric oxide improves ventilatory efficiency and exercise capacity in patients with mild COPD: A randomized-control cross-over trial. J Physiol 2021; 599:1665-1683. [PMID: 33428233 DOI: 10.1113/jp280913] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2020] [Accepted: 12/22/2020] [Indexed: 01/01/2023] Open
Abstract
KEY POINTS Patients with mild chronic obstructive pulmonary disease (COPD) have an elevated ventilatory equivalent to CO2 production ( V ̇ E / V ̇ C O 2 ) during exercise, secondary to increased dead space ventilation. The reason for the increased dead space is unclear, although pulmonary microvascular dysfunction and the corresponding capillary hypoperfusion is a potential mechanism. Despite emerging evidence that mild COPD is associated with pulmonary microvascular dysfunction, limited research has focused on experimentally modulating the pulmonary microvasculature during exercise in mild COPD. The present study sought to examine the effect of inhaled nitric oxide (iNO), a selective pulmonary vasodilator, on V ̇ E / V ̇ C O 2 , dyspnoea and exercise capacity in patients with mild COPD. Experimental iNO increased peak oxygen uptake in mild COPD, secondary to reduced V ̇ E / V ̇ C O 2 and dyspnoea. This is the first study to demonstrate that experimental manipulation of the pulmonary circulation alone, can positively impact dyspnoea and exercise capacity in mild COPD. ABSTRACT Patients with mild chronic obstructive pulmonary disease (COPD) have an exaggerated ventilatory response to exercise, contributing to dyspnoea and exercise intolerance. Previous research in mild COPD has demonstrated an elevated ventilatory equivalent to CO2 production ( V ̇ E / V ̇ C O 2 ) during exercise, secondary to increased dead space ventilation. The reason for the increased dead space is unclear, although pulmonary microvascular dysfunction and the corresponding capillary hypoperfusion is a potential mechanism. The present study tested the hypothesis that inhaled nitric oxide (iNO), a selective pulmonary vasodilator, would lower V ̇ E / V ̇ C O 2 and dyspnoea, and improve exercise capacity in patients with mild COPD. In this multigroup randomized-control cross-over study, 15 patients with mild COPD (FEV1 = 89 ± 11% predicted) and 15 healthy controls completed symptom-limited cardiopulmonary exercise tests while breathing normoxic gas or 40 ppm iNO. Compared with placebo, iNO significantly increased peak oxygen uptake (1.80 ± 0.14 vs. 1.53 ± 0.10 L·min-1 , P < 0.001) in COPD, whereas no effect was observed in controls. At an equivalent work rate of 60 W, iNO reduced V ̇ E / V ̇ C O 2 by 3.8 ± 4.2 units (P = 0.002) and dyspnoea by 1.1 ± 1.2 Borg units (P < 0.001) in COPD, whereas no effect was observed in controls. Operating lung volumes and oxygen saturation were unaffected by iNO in both groups. iNO increased peak oxygen uptake in COPD, secondary to reduced V ̇ E / V ̇ C O 2 and dyspnoea. These data suggest that mild COPD patients demonstrate pulmonary microvascular dysfunction that contributes to increased V ̇ E / V ̇ C O 2 , dyspnoea and exercise intolerance. This is the first study to demonstrate that experimental manipulation of the pulmonary circulation alone, can positively impact dyspnoea and exercise capacity in mild COPD.
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Affiliation(s)
- Devin B Phillips
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Andrew R Brotto
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Bryan A Ross
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Tracey L Bryan
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Eric Y L Wong
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Victoria L Meah
- Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, Alberta, Canada
| | - Desi P Fuhr
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Sean van Diepen
- Department of Critical Care and Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Michael K Stickland
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada.,G.F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, Alberta, Canada
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Phillips DB, Collins SÉ, Stickland MK. Measurement and Interpretation of Exercise Ventilatory Efficiency. Front Physiol 2020; 11:659. [PMID: 32714201 PMCID: PMC7344219 DOI: 10.3389/fphys.2020.00659] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/25/2020] [Indexed: 12/19/2022] Open
Abstract
Cardiopulmonary exercise testing (CPET) is a method for evaluating pulmonary and cardiocirculatory abnormalities, dyspnea, and exercise tolerance in healthy individuals and patients with chronic conditions. During exercise, ventilation (V˙E) increases in proportion to metabolic demand [i.e., carbon dioxide production (V˙CO2)] to maintain arterial blood gas and acid-base balance. The response of V˙E relative to V˙CO2 (V˙E/V˙CO2) is commonly termed ventilatory efficiency and is becoming a common physiological tool, in conjunction with other key variables such as operating lung volumes, to evaluate exercise responses in patients with chronic conditions. A growing body of research has shown that the V˙E/V˙CO2 response to exercise is elevated in conditions such as chronic heart failure (CHF), pulmonary hypertension (PH), interstitial lung disease (ILD), and chronic obstructive pulmonary disease (COPD). Importantly, this potentiated V˙E/V˙CO2 response contributes to dyspnea and exercise intolerance. The clinical significance of ventilatory inefficiency is demonstrated by findings showing that the elevated V˙E/V˙CO2 response to exercise is an independent predictor of mortality in patients with CHF, PH, and COPD. In this article, the underlying physiology, measurement, and interpretation of exercise ventilatory efficiency during CPET are reviewed. Additionally, exercise ventilatory efficiency in varying disease states is briefly discussed.
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Affiliation(s)
- Devin B Phillips
- Clinical Physiology Laboratory, Division of Pulmonary Medicine, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - Sophie É Collins
- Clinical Physiology Laboratory, Division of Pulmonary Medicine, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada.,Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michael K Stickland
- Clinical Physiology Laboratory, Division of Pulmonary Medicine, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada.,G.F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, AB, Canada
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Collins SÉ, Phillips DB, McMurtry MS, Bryan TL, Paterson DI, Wong E, Ezekowitz JA, Forhan MA, Stickland MK. The Effect of Carotid Chemoreceptor Inhibition on Exercise Tolerance in Chronic Heart Failure. Front Physiol 2020; 11:195. [PMID: 32226392 PMCID: PMC7080702 DOI: 10.3389/fphys.2020.00195] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 02/20/2020] [Indexed: 12/14/2022] Open
Abstract
Purpose Chronic heart failure (CHF) is characterized by heightened sympathetic nervous activity, carotid chemoreceptor (CC) sensitivity, marked exercise intolerance and an exaggerated ventilatory response to exercise. The purpose of this study was to determine the effect of CC inhibition on exercise cardiovascular and ventilatory function, and exercise tolerance in health and CHF. Methods Twelve clinically stable, optimally treated patients with CHF (mean ejection fraction: 43 ± 2.5%) and 12 age- and sex-matched healthy controls were recruited. Participants completed two time-to-symptom-limitation (TLIM) constant load cycling exercise tests at 75% peak power output with either intravenous saline or low-dose dopamine (2 μg⋅kg–1⋅min–1; order randomized). Ventilation was measured using expired gas data and operating lung volume data were determined during exercise by inspiratory capacity maneuvers. Cardiac output was estimated using impedance cardiography, and vascular conductance was calculated as cardiac output/mean arterial pressure. Results There was no change in TLIM in either group with dopamine (CHF: saline 13.1 ± 2.4 vs. dopamine 13.5 ± 1.6 min, p = 0.78; Control: saline 10.3 ± 1.2 vs. dopamine 11.5 ± 1.3 min, p = 0.16). In CHF patients, dopamine increased cardiac output (p = 0.03), vascular conductance (p = 0.01) and oxygen delivery (p = 0.04) at TLIM, while ventilatory parameters were unaffected (p = 0.76). In controls, dopamine improved vascular conductance at TLIM (p = 0.03), but no other effects were observed. Conclusion Our findings suggest that the CC contributes to cardiovascular regulation during full-body exercise in patients with CHF, however, CC inhibition does not improve exercise tolerance.
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Affiliation(s)
- Sophie É Collins
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Devin B Phillips
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,Faculty of Kinesiology, Sport, and Recreation, University of Alberta, Edmonton, AB, Canada
| | - M Sean McMurtry
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Tracey L Bryan
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - D Ian Paterson
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Eric Wong
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Justin A Ezekowitz
- Division of Cardiology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Mary A Forhan
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Michael K Stickland
- Division of Pulmonary Medicine, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada.,G.F. MacDonald Centre for Lung Health, Covenant Health, Edmonton, AB, Canada
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