title: Inter-individual differences in breathing pattern at high levels of incremental cycling exercise in healthy subjects.
abstract: Interindividual differences in the rate of changes in tidal volume (V(T)) and respiratory frequency (f(R)) were examined during a maximal incremental cycling exercise. The gain of the inspiratory off-switch reflex was inferred from the V(T) vs. inspiratory duration (T(i)) relationship. Some subjects also executed a static handgrip exercise, used as a "non-dynamic" exercise trial to study patterning of breathing. Above the ventilatory threshold (V(Th)), two patterns of response were identified: in group 1, the rate of change in V(T) significantly increased, while in group 2 the breakpoint of ventilation solely resulted from f(R) increase. After the respiratory compensation point, a tachypnoeic response always occurred. A leftward shift of the V(T) vs. Ti relationship, i.e., an inspiratory off-switch reflex, was measured during the handgrip in group 2 subjects as well as marked f(R) variations. Our study identifies two different patterns of breathing after the V(Th). The subjects who present a tachypnoeic response to exercise above the V(Th) have a higher sensitivity to pulmonary inflation and their tachypnoeic response was ubiquitous during a maximal handgrip test.
authors.affiliation: UMR MD2 "Dysoxia/Hyperactivity", Faculty of Medicine, Aix-Marseille University, Marseille, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Gravier
authors.forename: Stephane
authors.initials: S
authors.lastname: Delliaux
authors.forename: Stephane
authors.initials: S
authors.lastname: Delpierre
authors.forename: Regis
authors.initials: R
authors.lastname: Guieu
authors.forename: Yves
authors.initials: Y
authors.lastname: Jammes
mesh_terms: D000328:Adult; D000368:Aged; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D012123:Pulmonary Ventilation / Q000502:physiology*; D012119:Respiration; D059246:Tachypnea / Q000503:physiopathology; D013990:Tidal Volume / Q000502:physiology; D055815:Young Adult
keywords: Maximal exercise, Break points, Breathing pattern