Hematological response and diving response during apnea and apnea with face immersion

This study addressed the effects of apnea in air and apnea with face immersion in cold water (10°C) on the diving response and arterial oxygen saturation during dynamic exercise. Eight trained breath-hold divers performed steady-state exercise on a cycle ergometer at 100 W. During exercise, each subject performed 30-s apneas in air and 30-s apneas with face immersion. The heart rate and arterial oxygen saturation decreased and blood pressure increased during the apneas. Compared with apneas in air, apneas with face immersion augmented the heart rate reduction from 21 to 33% ( P < 0.001) and the blood pressure increase from 34 to 42% ( P < 0.05). The reduction in arterial oxygen saturation from eupneic control was 6.8% during apneas in air and 5.2% during apneas with face immersion ( P < 0.05). The results indicate that augmentation of the diving response slows down the depletion of the lung oxygen store, possibly associated with a larger reduction in peripheral venous oxygen stores and increased anaerobiosis. This mechanism delays the fall in alveolar and arterial Po 2 and, thereby, the development of hypoxia in vital organs. Accordingly, we conclude that the human diving response has an oxygen-conserving effect during exercise.

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Effect of lung volume on the diving response in man

Journal of Applied Physiology ◽

10.1152/jappl.1978.45.5.783 ◽

1978 ◽

Vol 45 (5) ◽

pp. 783-785 ◽

Cited By ~ 5

Author(s):

P. J. Openshaw ◽

G. M. Woodroof

Keyword(s):

Lung Volume ◽

Pulse Interval ◽

Diving Response ◽

Face Immersion ◽

The Face ◽

Cardiac Component

In an attempt to clarify the influence of lung volume on the cardiac component of the diving response in man, 10 subjects were studied while holding their breath for 20 s after inspiration or expiration, with or without immersion of the face in water. The electrocardiogram was recorded before and during each maneuver. After expiration, an increase in pulse interval was seen only on face immersion. After inspiration, an equal change in pulse interval was seen whether or not the face was immersed. Therefore the early bradycardia of face immersion is not apparent after inspiration.

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Cardiovascular and respiratory responses to apneas with and without face immersion in exercising humans

Journal of Applied Physiology ◽

10.1152/japplphysiol.01057.2002 ◽

2004 ◽

Vol 96 (3) ◽

pp. 1005-1010 ◽

Cited By ~ 67

Author(s):

Johan P. A. Andersson ◽

Mats H. Linér ◽

Anne Fredsted ◽

Erika K. A. Schagatay

Keyword(s):

Oxygen Uptake ◽

Anaerobic Metabolism ◽

Lactate Concentration ◽

Cardiovascular Responses ◽

Cycle Ergometer ◽

Diving Response ◽

Face Immersion ◽

Oxygen Stores ◽

Plasma Lactate Concentration ◽

Alveolar Gas Exchange

The effect of the diving response on alveolar gas exchange was investigated in 15 subjects. During steady-state exercise (80 W) on a cycle ergometer, the subjects performed 40-s apneas in air and 40-s apneas with face immersion in cold (10°C) water. Heart rate decreased and blood pressure increased during apneas, and the responses were augmented by face immersion. Oxygen uptake from the lungs decreased during apnea in air (-22% compared with eupneic control) and was further reduced during apnea with face immersion (-25% compared with eupneic control). The plasma lactate concentration increased from control (11%) after apnea in air and even more after apnea with face immersion (20%), suggesting an increased anaerobic metabolism during apneas. The lung oxygen store was depleted more slowly during apnea with face immersion because of the augmented diving response, probably including a decrease in cardiac output. Venous oxygen stores were probably reduced by the cardiovascular responses. The turnover times of these gas stores would have been prolonged, reducing their effect on the oxygen uptake in the lungs. Thus the human diving response has an oxygen-conserving effect.

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Selected Contribution: Role of spleen emptying in prolonging apneas in humans

Journal of Applied Physiology ◽

10.1152/jappl.2001.90.4.1623 ◽

2001 ◽

Vol 90 (4) ◽

pp. 1623-1629 ◽

Cited By ~ 75

Author(s):

Erika Schagatay ◽

Johan P. A. Andersson ◽

Magnus Hallén ◽

Birger Pålsson

Keyword(s):

Protein Concentration ◽

Venous Blood ◽

Hemoglobin Concentration ◽

Diving Response ◽

Short Term ◽

Plasma Protein Concentration ◽

Face Immersion ◽

Short Term Adaptation ◽

Hematological Changes

This study addressed the interaction between short-term adaptation to apneas with face immersion and erythrocyte release from the spleen. Twenty healthy volunteers, including ten splenectomized subjects, participated. After prone rest, they performed five maximal-duration apneas with face immersion in 10°C water, with 2-min intervals. Cardiorespiratory parameters and venous blood samples were collected. In subjects with spleens, hematocrit and hemoglobin concentration increased by 6.4% and 3.3%, respectively, over the serial apneas and returned to baseline 10 min after the series. A delay of the physiological breaking point of apnea, by 30.5% (17 s), was seen only in this group. These parameters did not change in the splenectomized group. Plasma protein concentration, preapneic alveolar Pco 2, inspired lung volume, and diving bradycardia remained unchanged throughout the series in both groups. Serial apneas thus triggered the hematological changes that have been previously observed after long apneic diving shifts; they were rapidly reversed and did not occur in splenectomized subjects. This suggests that splenic contraction occurs in humans as a part of the diving response and may prolong repeated apneas.

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