Arterial oxygen desaturation kinetics during apnea

Stewart, Ian B., Bulmer, Andrew .C, Sharman, James E. and Ridgway, Lynne (2005) Arterial oxygen desaturation kinetics during apnea. Medicine And Science In Sports And Exercise, 37 11: 1871-1876. doi:10.1249/01.mss.0000176305.51360.7e

Author Stewart, Ian B.
Bulmer, Andrew .C
Sharman, James E.
Ridgway, Lynne
Title Arterial oxygen desaturation kinetics during apnea
Journal name Medicine And Science In Sports And Exercise   Check publisher's open access policy
ISSN 0195-9131
Publication date 2005-01-01
Sub-type Article (original research)
DOI 10.1249/01.mss.0000176305.51360.7e
Volume 37
Issue 11
Start page 1871
End page 1876
Total pages 6
Editor Kent Pandolf
Kenneth Wilson
Place of publication USA
Publisher Lippincott Williams & Wilkins
Language eng
Subject CX
321405 Sports Medicine
730399 Health and support services not elsewhere classified
Formatted abstract
To quantify the rate of arterial oxygen desaturation during apnea in freedivers.


Ten freedivers and ten controls undertook five maximal face immersion apneas in 10 degrees C water 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 apineas 1, 3, and 5. The blood was analyzed for hematocrit (Hct), lactate, and hemoglobin (Hb) concentration. The arterial oxygen saturation (SaO(2)) data were curve fitted with both a sigmoid and two-slope continuous function.

Apnea duration increased with successive attempts, with freedivers achieving significantly longer maximal apneas (trained 246 +/- 44 s, untrained 129 +/- 39 s, P < 0.001). Compared with controls, freedivers displayed a significant change from baseline in heart rate (trained -27.2 +/- 9.5 bpm, untrained -19.7 +/- 9.3 bpm, P < 0.001) and mean arterial pressure (MAP) (trained 48 +/- 20.7 mm Hg, untrained 37 +/- 10.0 mm Hg, P = 0.002), but no difference existed in peripheral blood flow, Hct, lactate, or Hb. The maximal slope of the SaO(2) sigmoid curve was not significantly different between the groups (trained -0.16 +/- 0.05%center dot s(-1), untrained -0.15 +/- 0.06%center dot s(-1), P = 0.26), but the Delta SaO(2)/Delta t obtained from the two-slope continuous model indicated that 85% of the variance in the freedivers Delta SaO(2)/Delta t could be explained by the apnea-induced bradycardia, preapnea vital capacity, and Hb concentration.

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 SaO(2)/Delta t to two to three times that of the least marked response.
Keyword Sport Sciences
Diving Response
Breath Hold
Arterial Oxygen Saturation
Sigmoid Logistic Function
Breath-hold Divers
Oxidative Stress
Face Immersion
Exercising Men
Spleen Volume
Q-Index Code CX

Document type: Journal Article
Sub-type: Article (original research)
Collections: Excellence in Research Australia (ERA) - Collection
School of Medicine Publications
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Citation counts: TR Web of Science Citation Count  Cited 16 times in Thomson Reuters Web of Science Article | Citations
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Created: Wed, 15 Aug 2007, 20:07:59 EST