Physiological and Genomic Consequences of Intermittent Hypoxia: Selected Contribution: Role of spleen emptying in prolonging apneas in humans

• Published in: Journal of applied physiology (1985) 2001-04, Vol.90 (4), p.1623
• Main Authors: Schagatay, Erika, Andersson, Johan P. A, Hallen, Magnus, Palsson, Birger
• Format: Article
• Language: English
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/jappl.2001.90.4.1623

1  Department of Animal Physiology, Lund University, S-223 62 Lund; 2  Department of Natural Science, Mid Sweden University, S-871 88 Härnösand; and 3  Department of Surgery, Lund University Hospital, S-221 85 Lund, Sweden 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 P CO 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. diving response; breath-hold; bradycardia; vasoconstriction; blood pressure