title: Modulation of the ventilatory increase at the onset of exercise in humans.
abstract: The fast initial increase in ventilation at the start of exercise is generally assumed to be of reflex origin (exercising limbs) and/or caused by a 'feedforward' mechanism increasing breathing via brainstem respiratory centres or cortical areas controlling respiratory muscles. We wanted to test whether this ventilatory increase is in part a learned response which can be modified. Eleven subjects did two 20 min low-intensity arm-cranking exercise bouts on eight different days. Seven subjects were assigned to the experimental group which performed exercise paired with an 1.5 L external dead space. Before and after their eight exercise 'training'-days, these subjects did the same exercise without dead space. At the beginning of the first post-training exercise test (without dead space), the ventilatory increase at the start of exercise (sum of the first four breaths) was significantly increased (31.1 +/- 4.1 L . min-1) compared to the pre-training test session (24.4 +/- 3.9 L . min-1). No significant change was observed in the control group. We conclude that part of the ventilatory increase at the start of exercise can be modulated and might possibly be a learned response.
authors.affiliation: Swiss Federal Institute of Technology Zurich, Switzerland.
authors.forename: D
authors.initials: D
authors.lastname: Helbling
authors.forename: U
authors.initials: U
authors.lastname: Boutellier
authors.forename: C M
authors.initials: CM
authors.lastname: Spengler
mesh_terms: D000328:Adult; D002245:Carbon Dioxide / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D010100:Oxygen / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D012119:Respiration / Q000502:physiology*; D012126:Respiratory Dead Space; D012129:Respiratory Function Tests; D013147:Spirometry; D013990:Tidal Volume / Q000502:physiology
chemical_list: D002245:Carbon Dioxide; D010100:Oxygen