Please use this identifier to cite or link to this item: http://bura.brunel.ac.uk/handle/2438/15645
Title: The effects of age and sex on mechanical ventilatory constraint and dyspnea during exercise in healthy humans
Authors: Dominelli, PB
Ramsook, AH
Schaeffer, MR
Sereacki, SM
Foster, GE
Romer, LM
Road, JD
Guenette, JA
Sheel, AW
Keywords: aging;dyspnea;exercise,;expiratory flow limitation;operating lung volumes;respiratory mechanics;sex-differences;work of breathing.
Issue Date: 2017
Citation: Journal of Applied Physiology
Abstract: We examined the effects of age, sex, and their interaction on mechanical ventilatory constraint 30 and dyspnea during exercise in 22 older (age=68±1y, n=12 women) and 22 younger (age=25±1y, 31 n=11 women) subjects. During submaximal exercise, older subjects had higher end-inspiratory 32 (EILV) and end-expiratory (EELV) lung volumes than younger subjects (both p<0.05). During 33 maximal exercise, older subjects had similar EILV (p>0.05), but higher EELV than younger 34 subjects (p<0.05). No sex-differences in EILV or EELV were observed. We observed that women had a higher work of breathing (Wb) for a given minute ventilation (V̇ 35 E) ≥65 l·min-1 than men (p<0.05), and older subjects had a higher Wb for a given V̇ 36 E≥60 l·min-1 (p<0.05). No sex- or age-differences in Wb were present at any submaximal relative V̇ 37 E. At absolute exercise 38 intensities, older women experienced expiratory flow limitation (EFL) more frequently than 39 older men (p<0.05), and older subjects were more likely to experience EFL than younger 40 subjects (p<0.05). At relative exercise intensities, women and older individuals experienced EFL 41 more frequently than men and younger individuals, respectively (both p<0.05). There were 42 significant effects of age, sex, and their interaction on dyspnea intensity during exercise at 43 absolute, but not relative, intensities (all p<0.05). Across subjects, dyspnea at 80W was 44 significantly correlated with indices of mechanical ventilatory constraint (all p<0.05). 45 Collectively, our findings suggest age and sex have significant impacts on Wb, operating lung 46 volumes, EFL, and dyspnea during exercise. Moreover, it appears that mechanical ventilatory 47 constraint may partially explain sex-differences in exertional dyspnea in older individuals.
Description: This study was supported by the Natural Science and Engineering Research Council of Canada 590 (NSERC) and the British Columbia Lung Association (BCLA). YMS, PBD, and AHR were 591 supported by graduate scholarships from NSERC. PBD and MRS were supported by fellowships 592 from the University of British Columbia and BCLA. JAG was supported by a Scholar Award 593 from the Michael Smith Foundation for Health Research, a New Investigator Award from the 594 Providence Health Care Research Institute and St. Paul’s Hospital Foundation, and a Canadian 595 Institutes of Health Research Clinical Rehabilitation New Investigator Award.
URI: http://bura.brunel.ac.uk/handle/2438/15645
ISSN: 1522-1601
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