title: Bicarbonate infusion and pH clamp moderately reduce hyperventilation during ramp exercise in humans.
abstract: To test the hypothesis that the decrease in plasma pH contributes to the hyperventilation observed in humans in response to exercise at high workloads, five healthy male subjects performed a ramp exercise [maximal workload: 352 W (SD 35)] in a control situation and when arterialized plasma pH was maintained at the resting level (pH clamp) by intravenous infusion of sodium bicarbonate [129 mmol (SD 23), beginning at 59% maximal workload (SD 5)]. Bicarbonate infusion did not modify O(2) consumption (Vo(2)) but significantly (P < 0.05) increased arterial Pco(2), plasma bicarbonate concentration, and respiratory exchange ratio (P < 0.05). At the three highest workloads, pulmonary ventilation (Ve) and Ve/Vo(2) were approximately 5-10% lower (P < 0.05) when bicarbonate was infused than in the control situation, and hyperventilation was reduced by 15-30%. These data suggest that the decrease in plasma pH is one of the factors that contribute to the hyperventilation observed at high workloads.
authors.affiliation: Département de Kinésiologie, Université de Montréal, CP 6128, Centre Ville, Montréal, QC, Canada H3C3J7. francois.peronnet@umontreal.ca
authors.forename: François
authors.initials: F
authors.lastname: Péronnet
authors.forename: Tim
authors.initials: T
authors.lastname: Meyer
authors.forename: Bernard
authors.initials: B
authors.lastname: Aguilaniu
authors.forename: Carl-Etienne
authors.initials: CE
authors.lastname: Juneau
authors.forename: Oliver
authors.initials: O
authors.lastname: Faude
authors.forename: Wilfried
authors.initials: W
authors.lastname: Kindermann
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology; D000328:Adult; D001639:Bicarbonates / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000097:blood; D015444:Exercise / Q000502:physiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006985:Hyperventilation / Q000503:physiopathology*; D007262:Infusions, Intravenous; D008297:Male; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D012123:Pulmonary Ventilation / Q000187:drug effects / Q000502:physiology; D012146:Rest / Q000502:physiology
chemical_list: D001639:Bicarbonates; D002245:Carbon Dioxide