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The utility of immature reticulocyte fraction as an indicator of erythropoietic response to altitude training in elite cyclists
Author(s) -
NADARAJAN V. S.,
OOI C. H.,
STHANESHWAR P.,
THOMPSON M. W.
Publication year - 2010
Publication title -
international journal of laboratory hematology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.705
H-Index - 55
eISSN - 1751-553X
pISSN - 1751-5521
DOI - 10.1111/j.1751-553x.2008.01132.x
Subject(s) - erythropoietin , reticulocyte , altitude training , erythropoiesis , soluble transferrin receptor , altitude (triangle) , medicine , red cell , effects of high altitude on humans , endocrinology , biology , athletes , anemia , iron deficiency , physical therapy , iron status , biochemistry , anatomy , geometry , mathematics , messenger rna , gene
Summary Altitude training is sometimes employed by elite endurance athletes to improve their sea level performance. This improvement results from the increased red cell mass consequent upon the boost in erythropoietin (EPO) level that occurs as a response to the relatively hypoxic environment at high altitudes. We measured serum EPO levels together with various red cell and reticulocyte parameters including immature reticulocyte fraction (IRF) in eight national track‐endurance cyclists, resident at sea‐level, prior to and upon return from an altitude of approximately 1905 m. Reticulocytes and soluble transferrin receptor (sTfR) were significantly increased with reduction in ferritin levels immediately on return from high altitude indicating increased erythropoietic activity. IRF in particular showed a significant peak immediately on return but decline to sub‐baseline levels by day 9, and recovery to baseline by day 16. Our results indicate that IRF is a sensitive marker of erythropoietic status in athletes undergoing altitude training and subsequent loss of EPO stimuli on return to sea level.