title: Cardio-ventilatory responses to poikilocapnic hypoxia and hypercapnia in trained breath-hold divers.
abstract: Trained breath-hold divers (BHDs) are exposed to repeated bouts of intermittent hypoxia and hypercapnia during prolonged breath-holding. It has thus been hypothesized that their specific training may develop enhanced chemo-responsiveness to hypoxia associated with reduced ventilatory response to hypercapnia. Hypercapnic ventilatory responses (HCVR) and hypoxic ventilatory responses at rest (HVRr) and exercise (HVRe) were assessed in BHDs (n=7) and a control group of non-divers (NDs=7). Cardiac output (CO), stroke volume (SV) and heart rate (HR) were also recorded. BHDs presented carbon dioxide sensitivity similar to that of NDs (2.85±1.41 vs. 1.85±0.93Lmin(-1)mmHg(-1), p>0.05, respectively). However, both HVRr (+68%) and HVRe (+31%) were increased in BHDs. CO and HR reached lower values in BHDs than NDs during the hypoxic exercise test. These results suggest that the exposure to repeated bouts of hypoxia/hypercapnia frequently experienced by trained breath-hold divers only enhances their chemo-responsiveness to poikilocapnic hypoxia, without altering HCVR.
authors.affiliation: Faculté des sciences du sport, CETAPS, EA n°3832, Université de Rouen, France. Electronic address: guillaume.costalat1@univ-rouen.fr.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Costalat
authors.affiliation: Université Paris 13 Nord, Sorbonne Paris Cité, Laboratoire "Réponses cellulaires et fonctionnelles à l'hypoxie", EA n°2363 Bobigny, France.
authors.forename: Aurélien
authors.initials: A
authors.lastname: Pichon
authors.affiliation: Faculté des sciences du sport, CETAPS, EA n°3832, Université de Rouen, France.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Coquart
authors.affiliation: Département de cardiologie, Centre Hospitalier Universitaire, Unité INSERM n°U1096, Rouen, France.
authors.forename: Fabrice
authors.initials: F
authors.lastname: Bauer
authors.affiliation: Faculté des sciences du sport, CETAPS, EA n°3832, Université de Rouen, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Lemaître
mesh_terms: D000328:Adult; D062485:Breath Holding; D002245:Carbon Dioxide; D004242:Diving / Q000502:physiology*; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology*; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D012119:Respiration; D014655:Vascular Resistance
chemical_list: D002245:Carbon Dioxide
keywords: Breath-holding; Hypercapnic ventilatory response; Hypoxic ventilatory response; Poikilocapnic hypoxia