Ventilatory responses to hypercapnia and hypoxia in elite breath-hold divers

Grassi, Bruno; Ferretti, Guido; Costa, M.; Ferrigno, Massimo; Panzacchi, A.; Lundgren, Ceg; Marconi, C.; Cerretelli, Paolo

doi:10.1016/0034-5687(94)90068-x

Cited by 41 publications

(13 citation statements)

References 17 publications

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“…This phenomenon has previously been described in commercial female South-Korean BHD (Song et al 1963) and was explained by an adaptation to the repeated exposure to high CO 2 tensions during the repeated short (up to 90 s) breathhold dives. Grassi et al (1994) subsequently conWrmed a blunted ventilatory response to CO 2 in three elite BHD who 1 Mean (SD) static lung compliance in the time course before and following a GI maneuver. Cstat rest static compliance measured from total lung capacity at rest; Cstat GI static compliance during the glossopharyngeal insuZation (GI); Cstat 1 min static compliance measured from total lung capacity 1 min after the GI maneuver; Cstat 3 min static compliance measured from total lung capacity 3 min after the GI maneuver; min minutes were all members of the same family.…”

Section: Discussionmentioning

confidence: 89%

Characteristics of the respiratory mechanical and muscle function of competitive breath-hold divers

et al. 2008

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Competitive breath-hold divers (BHD) employ glossopharyngeal insufflation (GI) to increase intrapulmonary oxygen stores and prevent the lungs from dangerous compressions at great depths. Glossopharyngeal insufflation is associated with inflation of the lungs beyond total lung capacity (TLC). It is currently unknown whether GI transiently over-distends the lungs or adversely affects lung elastic properties in the long-term. Resting lung function, ventilatory drive, muscle strength, and lung compliance were measured in eight BHD who performed GI since 5.5 (range 2-6) years on average, eight scuba divers, and eight control subjects. In five BHD subsequent measures of static lung compliance (Cstat) were obtained after 1 and 3 min following GI. Breath-hold divers had higher than predicted ventilatory flows and volumes and did not differ from control groups with regard to gas transfer, inspiratory muscle strength, and lung compliance. A blunted response to CO2 was obtained in BHD as compared to control groups. Upon GI there was an increase in mean vital capacity (VCGI) by 1.75 +/- 0.85 (SD) L compared to baseline (p < 0.001). In five BHD Cstat raised from 3.7 (range 2.9-6.8) L/kPa at baseline to 8.1 (range 3.4-21.2) L/kPa after maximal GI and thereafter gradually decreased to 5.6 (range 3.3-8.1) L/kPa after 1 min and 4.2 (range 2.7-6.6) L/kPa after 3 min (p < 0.01). We conclude that in experienced BHD there is a transient alteration in lung elastic recoil. Resting lung function did not reveal a pattern indicative of altered lung ventilatory or muscle function.

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Section: Discussionmentioning

confidence: 89%

Characteristics of the respiratory mechanical and muscle function of competitive breath-hold divers

et al. 2008

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“…Indeed, this response is not only lower than that of the non-divers, but also than that of individuals whom Lambertsen (1960) de®ned as having a low carbon dioxide sensitivity. In addition, the ventilatory response to oxygen was analysed by Grassi et al (1994), who determined the time course of the changes in _ V E following four breaths of pure oxygen administered from a baseline of steady-state ventilation in normoxia and in hypoxia. The peak _ V E change following pure oxygen breathing was equal in divers and non-divers, indicating that the two groups had the same ventilatory responses to oxygen.…”

Section: Studymentioning

confidence: 99%

“…The ventilatory response to breathing oxygen and carbon dioxide was determined by Grassi et al (1994) for three extreme divers. Steady-state expired ventilation ( _ V E ), normalised per unit surface area, is plotted as a function of P A CO 2 in Fig.…”

Section: Studymentioning

confidence: 99%

Extreme human breath-hold diving

Ferretti¹

2001

Eur J Appl Physiol

148

155

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In this paper, the respiratory, circulatory and metabolic adjustments to human extreme breath-hold diving are reviewed. A survey of the literature reveals that in extreme divers, adaptive mechanisms take place that allow prolongation of apnoea beyond the limits attained by non-diving subjects, and preservation of oxygen stores during the dives. The occurrence of a diving response, including peripheral vasoconstriction, increased arterial blood pressure, bradycardia and lowered cardiac output, is strongly implicated. Some peripheral regions may be excluded from perfusion, with consequent reliance on anaerobic metabolism. In addition, extreme breath-hold divers show a blunted ventilatory response to carbon dioxide breathing, possibly as a consequence of frequent exposure to high carbon dioxide partial pressures during the dives. These mechanisms allow the attainment of particularly low alveolar oxygen (< 30 mmHg) and high alveolar carbon dioxide (> 50 mmHg) partial pressures at the end of maximal dry breath-holds, and reduce oxygen consumption during the dive at the expense of increased anaerobic glycolysis (rate of blood lactate accumulation > 0.04 mM.s-1). The current absolute world record for depth in breath-hold diving is 150 m. Its further improvement depends upon how far the equilibrium between starting oxygen stores, the overall rate of energy expenditure, the fraction of energy provided by anaerobic metabolism and the diving speed can be pushed, with consciousness upon emersion. The ultimate limit to breath-hold diving records may indeed be imposed by an energetic constraint.

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“…Several authors have also reported a blunted hypercapnic ventilatory response in various groups of breath-hold divers, such as submarine escape training instructors (Schaefer 1965), Ama divers (Song et al 1963;Masuda et al 1982), underwater hockey players (Davis et al 1987;Lemaître et al 2007), and trained breath-hold divers (Grassi et al 1994;Delapille et al 2001). Contradictory results regarding the hypoxic ventilatory response have been reported (Ferretti and Costa 2003).…”

Section: Introductionmentioning

confidence: 84%

Repeated apneas do not affect the hypercapnic ventilatory response in the short term

Andersson

Schagatay

2008

Eur J Appl Physiol

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Long-term training of breath-hold diving reduces the hypercapnic ventilatory response (HCVR), an index of the CO(2) sensitivity. The aim of the present study was to elucidate whether also short-term apnea training (repeating apneas with short intervals) reduces the HCVR, thereby being one contributing factor explaining the progressively increasing breath-holding time (BHT) with repetition of apneas. Fourteen healthy volunteers performed a series of five maximal-duration apneas with face immersion and two measurements of the HCVR, using the Read rebreathing method. The BHT increased by 43% during the series of apneas (P < 0.001). However, the slope of the HCVR test was not affected by the series of apneas, being 2.52 (SD 1.27) and 2.24 (SD 1.14) l min(-1) mmHg(-1) in the control test and in the test performed within 2 min after the last apnea of the series, respectively (NS). Thus, a change in the HCVR cannot explain the observed short-term training effect on BHT.

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Ventilatory responses to hypercapnia and hypoxia in elite breath-hold divers

Cited by 41 publications

References 17 publications

Characteristics of the respiratory mechanical and muscle function of competitive breath-hold divers

Characteristics of the respiratory mechanical and muscle function of competitive breath-hold divers

Extreme human breath-hold diving

Repeated apneas do not affect the hypercapnic ventilatory response in the short term

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