title: Precise mimicking of exercise hyperpnea to investigate the oxygen cost of breathing.
abstract: The oxygen cost of exercise hyperpnea (V˙(O2 RM)) has been quantified using a variety of techniques with inconsistent findings. Between-study variation relates to poor control of breathing patterns and lung mechanics. We developed a methodology allowing precise matching of exercising WOB in order to estimate V˙(O2 RM). Thirteen healthy young subjects (7 male) completed an incremental cycle exercise test, familiarization and experimental days where exercise hyperpnea was mimicked. On experimental days, feedback of exercise flow, volume and the respiratory pressures were provided while end-tidal CO2 was kept at exercise levels during each 5-min trial. Minute ventilation levels between 50 and 100% maximum were mimicked 3-5 times. The r(2) between exercise and mimic trails was 0.99 for frequency, tidal volume and minute ventilation; 0.86 for esophageal pressure swings and 0.93 for WOB. The coefficient of variation for (V˙(O2) averaged 4.3, 4.4 and 5.7% for 50, 75 and 100% ventilation trials. When WOB and other respiratory parameters are tightly controlled, the V˙(O2 RM) can be consistently estimated.
authors: School of Kinesiology, University of British Columbia, Vancouver, BC, Canada. Electronic address: p.dominelli@alumni.ubc.ca.
authors: P B
authors: PB
authors: Dominelli
authors: School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
authors: J N
authors: JN
authors: Render
authors: School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
authors: Y
authors: Y
authors: Molgat-Seon
authors: School of Kinesiology, University of British Columbia, Vancouver, BC, Canada; Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, University of British Columbia, Kelowna, BC, Canada.
authors: G E
authors: GE
authors: Foster
authors: School of Kinesiology, University of British Columbia, Vancouver, BC, Canada.
authors: A W
authors: AW
authors: Sheel
mesh_terms: D000328:Adult; D001049:Apnea / Q000503:physiopathology; D015444:Exercise / Q000502:physiology*; D025461:Feedback, Physiological; D005260:Female; D006801:Humans; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology*; D012119:Respiration; D015656:Respiratory Mechanics / Q000502:physiology*; D012132:Respiratory Muscles / Q000378:metabolism*; D013997:Time Factors; D012122:Ventilators, Mechanical; D014939:Work of Breathing; D055815:Young Adult
keywords: Oxygen consumption of respiratory muscles; Respiratory mechanics; Respiratory muscles; Ventilation; Work of breathing