Arterial oxygen saturation and heart rate variation during breath-holding: comparison between breath-hold divers and controls.
Breath-holding induces cardiovascular responses, notably bradycardia and peripheral vasoconstriction, which are known collectively as the diving response. This response is oxygen-conserving, i.e. an augmented response attenuates arterial oxygen desaturation, and is enhanced by apnoea training. To test this hypothesis, we compared heart rate (HR) and arterial oxygen saturation (SaO (2)) in breath-hold divers (BHD) and non-divers (ND). Nine BHD and nine healthy ND performed two static apnoeas (for 30 s and 45 s) and two dynamic apnoeas (for 30 s and 45 s) while swimming underwater at 0.7 m . s (-1). The pool temperature was 26 degrees C. The apnoeas were performed at 60 % of forced vital capacity. Heart rate (HR) and SaO (2) were recorded before breath-holding and at its end and are expressed in % change from rest values (DeltaHR and DeltaSaO (2)). Comparisons between BHD and ND showed that DeltaSaO (2) were lower in divers after both static apnoeas for 30 s and 45 s (- 2.8 % vs. - 5.5 %; - 3.2 % vs. 6.3 %; p < 0.05, respectively) and dynamic apnoeas (- 6 % vs. - 10.1 %; - 7.2 % vs. - 12.3 %; p < 0.05, respectively). The change in HR did not differ between the two groups and negative linear relations were found between DeltaHR and DeltaSaO (2) in both divers and ND (r = 0.66 and 0.61, respectively; p < 0.001). Moreover, the slope was lower for the divers (- 0.785 vs. - 0.1429; p < 0.001). Our results suggest that apnoea training explained the greater oxygen conservation seen in the divers in both static and dynamic conditions.
Delahoche
J
J
Centre d'Etudes des Transformations des Activités Physiques et Sportives (CETAPS), Jeune Equipe UPRES no. 2318, Faculté des Sciences du Sport et de l'Education Physique de Rouen, Université de Rouen, 34 rue de l'Hôpital, 76000 Rouen, France.
Delapille
P
P
Lemaître
F
F
Verin
E
E
Tourny-Chollet
C
C
D000328:Adult; D001158:Arteries; D001919:Bradycardia / Q000209:etiology; D016022:Case-Control Studies; D004242:Diving / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000097:blood*; D012119:Respiration; D018709:Statistics, Nonparametric; D013997:Time Factors
D010100:Oxygen