title: Dysanapsis and the resistive work of breathing during exercise in healthy men and women.
abstract: We asked if the higher work of breathing (Wb) during exercise in women compared with men is explained by biological sex. We created a statistical model that accounts for both the viscoelastic and the resistive components of the total Wb and independently compares the effects of biological sex. We applied the model to esophageal pressure-derived Wb values obtained during an incremental cycle test to exhaustion. Subjects were healthy men (n = 17) and women (n = 18) with a range of maximal aerobic capacities (V̇o2 max range: men = 40-68 and women = 39-60 ml·kg(-1)·min(-1)). We also calculated the dysanapsis ratio using measures of lung recoil and forced expiratory flow as index of airway caliber. By applying the model we found that the differences in the total Wb during exercise in women are due to a higher resistive Wb rather than viscoelastic Wb. We also found that the higher resistive Wb is independently explained by biological sex. To account for the known effect of lung volumes on the dysanapsis ratio we compared the sexes with an analysis of covariance procedures and found that when vital capacity was accounted for the adjusted mean dysanapsis ratio is statistically lower in women (0.17 vs. 0.25 arbitrary units; P < 0.05). Our collective findings suggest that innate sex-based differences may exist in human airways, which result in significant male-female differences in the Wb during exercise in healthy subjects.
authors.affiliation: School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada; p.dominelli@alumni.ubc.ca.
authors.forename: Paolo B
authors.initials: PB
authors.lastname: Dominelli
authors.affiliation: School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada;
authors.forename: Yannick
authors.initials: Y
authors.lastname: Molgat-Seon
authors.affiliation: Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, British Columbia, Canada;
authors.forename: Derek
authors.initials: D
authors.lastname: Bingham
authors.affiliation: Department of Statistics and Actuarial Science, Simon Fraser University, Burnaby, British Columbia, Canada;
authors.forename: Philippa M
authors.initials: PM
authors.lastname: Swartz
authors.affiliation: Faculty of Medicine, Division of Respiratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada; and.
authors.forename: Jeremy D
authors.initials: JD
authors.lastname: Road
authors.affiliation: Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia Okanagan, Kelowna, British Columbia, Canada.
authors.forename: Glen E
authors.identifier: http://orcid.org/0000-0003-4110-9574
authors.initials: GE
authors.lastname: Foster
authors.affiliation: School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada;
authors.forename: A William
authors.initials: AW
authors.lastname: Sheel
mesh_terms: D000328:Adult; D015444:Exercise / Q000502:physiology*; D005105:Expiratory Reserve Volume / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009929:Organ Size / Q000502:physiology; D012123:Pulmonary Ventilation / Q000502:physiology*; D015656:Respiratory Mechanics / Q000502:physiology*; D012727:Sex Characteristics; D014939:Work of Breathing / Q000502:physiology*; D055815:Young Adult
keywords: airways; expiratory flow limitation; mechanical ventilatory constraints; sex differences