title: Effect of inspired CO₂ on the ventilatory response to high intensity exercise.
abstract: We tested the hypothesis that preventing the poikilocapnic response to high intensity exercise would increase the ventilatory response to exercise. We measured ventilatory variables in 10 healthy men during incremental cycling with and without inspired CO(2) (randomised order). Inspired CO(2) elevated resting ventilation (V(E)), tidal volume (V(T)), PETCO₂ and PETO₂ by 5 ± 5 L/min, 0.3 ± 0.2 L, 6 ± 3 mm Hg and 11 ± 7 mm Hg, respectively (P<0.05); resting breathing frequency (f), expired CO(2) (VCO₂) and O(2) consumption (VO₂) remained similar (P>0.05). During high intensity exercise, inspired CO(2) elevated PETCO₂ by 7 ± 2, 10 ± 4 and 11 ± 4 mm Hg at 80%, 90% and 100% VO₂ max, respectively (P<0.01), while PETCO₂ remained unchanged (P>0.05). During high intensity exercise, inspired CO(2) elevated VT by 0.2 ± 0.3 L at 80%, 90% and 100% VO₂ max, respectively (P<0.05), while no differences were observed in V(E), f, VO₂, or power output (P>0.05). These data suggest a progressively diminishing role of CO(2) chemoreception in the control of ventilation during maximal incremental exercise.
authors.affiliation: Institute of Movement Sciences and Sports Medicine, Faculty of Medicine, University of Geneva, Geneva, Switzerland.
authors.forename: Jui-Lin
authors.initials: JL
authors.lastname: Fan
authors.forename: Christian
authors.initials: C
authors.lastname: Leiggener
authors.forename: Florian
authors.initials: F
authors.lastname: Rey
authors.forename: Bengt
authors.initials: B
authors.lastname: Kayser
mesh_terms: D000280:Administration, Inhalation; D000328:Adult; D015308:Anaerobic Threshold / Q000502:physiology; D001642:Bicycling / Q000502:physiology; D002245:Carbon Dioxide / Q000008:administration & dosage / Q000494:pharmacology*; D003627:Data Interpretation, Statistical; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D016857:Hypocapnia / Q000503:physiopathology; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010465:Perception / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology; D011659:Pulmonary Gas Exchange / Q000502:physiology; D012123:Pulmonary Ventilation / Q000187:drug effects*; D013990:Tidal Volume / Q000502:physiology; D055815:Young Adult
chemical_list: D002245:Carbon Dioxide