| The hematocrit paradox - how does blood doping really work? | |
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MedLine Citation:
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PMID: 20617487 Owner: NLM Status: In-Data-Review |
Abstract/OtherAbstract:
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The wide-spread assumption that doping with erythropoietin or blood transfusion is only effective by increasing arterial blood O2 content because of rising hematocrit is not self-evident. "Natural blood dopers" (horses, dogs) increase both hematocrit and circulating blood volume during exercise by releasing stored erythrocytes from the spleen. Improvement of aerobic performance by augmenting hemoglobin concentration may be expected until the optimal hematocrit is reached; above this value maximal cardiac output declines due to the steep increase of blood viscosity. Therefore an enlarged blood oxygen content might only be useful if the normal hematocrit of man during exercise is suboptimal. However, recent studies suggest that cardiac power rises after erythropoietin allowing an unchanged cardiac output in spite of increased viscosity. Other factors underlying improved performance after blood doping might be: augmented diffusion capacity for oxygen in lungs and tissues, increased percentage of young red cells with good functional properties (after erythropoietin), increased buffer capacity, increase of blood volume, vasoconstriction, reduced damage by radicals, mood improvement by cerebral effects of erythropoietin. Also the importance of placebo is unknown since double-blind studies are rare. It is suggested that blood doping has multifactorial effects not restricted to the increase in arterial oxygen content. |
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Authors:
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D Böning; N Maassen; A Pries |
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Publication Detail:
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Type: Journal Article Date: 2010-07-08 |
Journal Detail:
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Title: International journal of sports medicine Volume: 32 ISSN: 1439-3964 ISO Abbreviation: Int J Sports Med Publication Date: 2011 Apr |
Date Detail:
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Created Date: 2011-04-07 Completed Date: - Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8008349 Medline TA: Int J Sports Med Country: Germany |
Other Details:
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Languages: eng Pagination: 242-6 Citation Subset: IM |
Copyright Information:
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© Georg Thieme Verlag KG Stuttgart · New York. |
Affiliation:
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Sportmedizin, Charité-Universitätsmedizin Berlin, Germany. |
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From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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