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Wang L, Wu S, He B, Liu S, Liang S, Luo Y. Exercise-induced bronchoconstriction assessed by a ratio of surface diaphragm EMG to tidal volume. Physiol Rep 2023; 11:e15860. [PMID: 37960999 PMCID: PMC10643992 DOI: 10.14814/phy2.15860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Revised: 10/30/2023] [Accepted: 10/30/2023] [Indexed: 11/15/2023] Open
Abstract
Exercise-induced bronchoconstriction (EIB) is usually assessed by changes in forced expiratory volume in 1 s (FEV1 ) which is effort dependent. The purpose of this study was to determine whether the diaphragm electromyogram (EMGdi ) recorded from chest wall surface electrodes could be used to reflect changes in airway resistance during an exercise challenge test and to distinguish patients with EIB from those without EIB. Ninety participants with or without asthma history were included in the study. FEV1 was recorded before and 5, 10, 15, and 20 min after exercise. EIB was defined as an FEV1 decline greater than 10% after exercise. A ratio of root mean square of EMGdi to tidal volume (EMGdi /VT ) was used to assess changes in airway resistance. Based on changes in FEV1 , 25 of 90 participants exhibited EIB; the remainder were defined as non-EIB participants. EMGdi /VT in EIB increased by 124% (19%-478%) which was significantly higher than that of 21% (-39% to 134%) in non-EIB participants (p < 0.001). At the optimal cutoff point (54% in EMGdi /VT ), the area under the ROC curve (AUC) for detection of a positive test was 0.92 (p < 0.001) with sensitivity 92% and specificity 88%. EMGdi /VT can be used to assess changes in airway resistance after exercise and could be used to distinguish participants with EIB from those without EIB.
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Affiliation(s)
- Lishuang Wang
- State Key Laboratory of Respiratory DiseaseGuangzhou Medical UniversityGuangzhouChina
| | - Senrui Wu
- State Key Laboratory of Respiratory DiseaseGuangzhou Medical UniversityGuangzhouChina
| | - Baiting He
- State Key Laboratory of Respiratory DiseaseGuangzhou Medical UniversityGuangzhouChina
| | - Simin Liu
- State Key Laboratory of Respiratory DiseaseGuangzhou Medical UniversityGuangzhouChina
| | - Shanfeng Liang
- State Key Laboratory of Respiratory DiseaseGuangzhou Medical UniversityGuangzhouChina
| | - Yuanming Luo
- State Key Laboratory of Respiratory DiseaseGuangzhou Medical UniversityGuangzhouChina
- Division of Sleep and Circadian DisordersBrigham and Women's Hospital and Harvard Medical SchoolBostonMassachusettsUSA
- College of Medicine and Public Health, Adelaide Institute for Sleep HealthFlinders UniversityAdelaideSouth AustraliaAustralia
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Molgat-Seon Y, Ramsook AH, Peters CM, Schaeffer MR, Dominelli PB, Romer LM, Road JD, Guenette JA, Sheel AW. Manipulation of mechanical ventilatory constraint during moderate intensity exercise does not influence dyspnoea in healthy older men and women. J Physiol 2019; 597:1383-1399. [PMID: 30578651 DOI: 10.1113/jp277476] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 12/17/2018] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The perceived intensity of exertional breathlessness (i.e. dyspnoea) is higher in older women than in older men, possibly as a result of sex-differences in respiratory system morphology. During exercise at a given absolute intensity or minute ventilation, older women have a greater degree of mechanical ventilatory constraint (i.e. work of breathing and expiratory flow limitation) than their male counterparts, which may lead to a greater perceived intensity of dyspnoea. Using a single-blind randomized study design, we experimentally manipulated the magnitude of mechanical ventilatory constraint during moderate-intensity exercise at ventilatory threshold in healthy older men and women. We found that changes in the magnitude of mechanical ventilatory constraint within the physiological range had no effect on dyspnoea in healthy older adults. When older men and women perform moderate intensity exercise, mechanical ventilatory constraint does not contribute significantly to the sensation of dyspnoea. ABSTRACT We aimed to determine the effect of manipulating mechanical ventilatory constraint during submaximal exercise on dyspnoea in older men and women. Eighteen healthy subjects (aged 60-80 years; nine men and nine women) completed two days of testing. On day 1, subjects were assessed for pulmonary function and performed a maximal incremental cycle exercise test. On day 2, subjects performed three 6-min bouts of cycling at ventilatory threshold, in a single-blind randomized manner, while breathing: (i) normoxic helium-oxygen (HEL) to reduce the work of breathing (Wb ) and alleviate expiratory flow limitation (EFL); (ii) through an inspiratory resistance (RES) of ∼5 cmH2 O L-1 s-1 to increase Wb ; and (iii) ambient air as a control (CON). Oesophageal pressure, diaphragm electromyography, and sensory responses (category-ratio 10 Borg scale) were monitored throughout exercise. During the HEL condition, there was a significant decrease in Wb (men: -21 ± 6%, women: -17 ± 10%) relative to CON (both P < 0.01). Moreover, if EFL was present during CON (four men and five women), it was alleviated during HEL. Conversely, during the RES condition, Wb (men: 42 ± 19%, women: 50 ± 16%) significantly increased relative to CON (both P < 0.01). There was no main effect of sex on Wb (P = 0.59). Across conditions, women reported significantly higher dyspnoea intensity than men (2.9 ± 0.9 vs. 1.9 ± 0.8 Borg scale units, P < 0.05). Despite significant differences in the degree of mechanical ventilatory constraint between conditions, the intensity of dyspnoea was unaffected, independent of sex (P = 0.46). When older men and women perform moderate intensity exercise, mechanical ventilatory constraint does not contribute significantly to the sensation of dyspnoea.
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Affiliation(s)
- Yannick Molgat-Seon
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, Canada.,Centre for Heart Lung Innovation, St Paul's Hospital, Vancouver, Canada
| | - Andrew H Ramsook
- Centre for Heart Lung Innovation, St Paul's Hospital, Vancouver, Canada.,Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Carli M Peters
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, Canada
| | - Michele R Schaeffer
- Centre for Heart Lung Innovation, St Paul's Hospital, Vancouver, Canada.,Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Paolo B Dominelli
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, Canada.,Mayo Clinic, Rochester, MN, USA
| | - Lee M Romer
- Centre for Human Performance, Exercise and Rehabilitation, College of Health and Life Sciences, Brunel University London, Uxbridge, UK.,Division of Sport, Health and Exercise Sciences, Department of Life Sciences, Brunel University London, Uxbridge, UK
| | - Jeremy D Road
- Division of Respiratory Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Jordan A Guenette
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, Canada.,Centre for Heart Lung Innovation, St Paul's Hospital, Vancouver, Canada.,Department of Physical Therapy, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - A William Sheel
- School of Kinesiology, Faculty of Education, University of British Columbia, Vancouver, Canada
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