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dc.contributor.authorStewart, B.en_US
dc.contributor.authorC. Bulmer, Andrewen_US
dc.contributor.authorSharman, E.en_US
dc.contributor.authorRidgeway, Lynneen_US
dc.description.abstractPurpose: To quantify the rate of arterial oxygen desaturation during apnea in freedivers. Methods: Ten freedivers and ten controls undertook five maximal face immersion apneas in 10àwater separated by 2 min of recovery. Electrocardiogram (ECG), blood pressure, and pulse oximetry were recorded continuously. Peripheral blood flow was measured by calf plethysmography every 30 s, and venous blood samples were collected at rest and after apneas 1, 3, and 5. The blood was analyzed for hematocrit (Hct), lactate, and hemoglobin (Hb) concentration. The arterial oxygen saturation (SaO2) data were curve fitted with both a sigmoid and two-slope continuous function. Results: Apnea duration increased with successive attempts, with freedivers achieving significantly longer maximal apneas (trained 246 ᠴ4 s, untrained 129 ᠳ9 s, P < 0.001). Compared with controls, freedivers displayed a significant change from baseline in heart rate (trained -27.2 ᠹ.5 bpm, untrained -19.7 ᠹ.3 bpm, P < 0.001) and mean arterial pressure (MAP) (trained 48 ᠲ0.7 mm Hg, untrained 37 ᠱ0.0 mm Hg, P = 0.002), but no difference existed in peripheral blood flow, Hct, lactate, or Hb. The maximal slope of the SaO2 sigmoid curve was not significantly different between the groups (trained -0.16 ᠰ.05%糭1, untrained -0.15 ᠰ.06%糭1, P = 0.26), but the [DELTA]SaO2/[DELTA]t obtained from the two-slope continuous model indicated that 85% of the variance in the freedivers [DELTA]SaO2/[DELTA]t could be explained by the apnea-induced bradycardia, preapnea vital capacity, and Hb concentration. Conclusions: The sigmoidal function provided no quantifiable difference in the rate of oxygen desaturation. The two-slope continuous method, however, indicated that freedivers who had larger oxygen stores and produced the largest bradycardia were able to slow the [DELTA]SaO2/[DELTA]t to two to three times that of the least marked response.en_US
dc.publisherLippincott Williams & Wilkinsen_US
dc.publisher.placeUnited Statesen_US
dc.relation.ispartofjournalMedicine and Science in Sports and Exerciseen_US
dc.subject.fieldofresearchMedical and Health Sciences not elsewhere classifieden_US
dc.titleArterial Oxygen Desaturation Kinetics during Apneaen_US
dc.typeJournal articleen_US
dc.type.descriptionC1 - Peer Reviewed (HERDC)en_US
dc.type.codeC - Journal Articlesen_US
gro.hasfulltextNo Full Text

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