title: Magnetic resonance imaging of the lumbar spine and blood volume in professional cyclists.
abstract: Stimulated hematopoiesis is observed in the bone marrow of endurance-trained athletes by magnetic resonance imaging (MRI) independent of the hemoglobin concentration (hematocrit or erythrocyte count) or circulating reticulocytes, but may be related to blood volume (BV). This study determined whether hyperplasia of hematopoietic bone marrow of professional cyclists correlates with their red cell volume (RCV). Twelve male professional cyclists (mean +/- SD; 20.2 +/- 1.4 years, 69.0 +/- 4.5 kg, VO2max 64.4 +/- 4.6 ml/min/kg, BV 7257 +/- 884 ml, RCV 2990 +/- 299 g) completed an MRI of the lumbar spine, a total BV determination using a CO-rebreathing method and a graded exercise testing within two consecutive days. Significant correlations were found between performance and BV data. A significant correlation existed also between the signal intensity of the Turbo inversion-recovery sequence with short inversion time (Turbo-STIR) and BV (r (2) = 0.47, P < 0.05), RCV (r (2) = 0.56, P < 0.05) and plasma volume (r (2) = 0.39, P < 0.05) per kilogram body mass. The present study provides evidence of stimulated erythropoiesis with hyperplasia of the hematopoietic bone marrow of endurance athletes explaining their large RCV.
authors.affiliation: Department of Preventive and Rehabilitative Sports Medicine, University of Freiburg, Hugstetterstr. 55, 79106, Freiburg, Germany. stefan.vogt@uniklinik-freiburg.de
authors.forename: Stefan
authors.initials: S
authors.lastname: Vogt
authors.forename: Carsten
authors.initials: C
authors.lastname: Altehoefer
authors.forename: Dirk
authors.initials: D
authors.lastname: Bueltermann
authors.forename: Torben
authors.initials: T
authors.lastname: Pottgiesser
authors.forename: Stephan
authors.initials: S
authors.lastname: Prettin
authors.forename: Andreas
authors.initials: A
authors.lastname: Schmid
authors.forename: Kai
authors.initials: K
authors.lastname: Roecker
authors.forename: Walter
authors.initials: W
authors.lastname: Schmidt
authors.forename: Katja
authors.initials: K
authors.lastname: Heinicke
authors.forename: Lothar
authors.initials: L
authors.lastname: Heinrich
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D001810:Blood Volume / Q000502:physiology*; D001853:Bone Marrow / Q000033:anatomy & histology / Q000502:physiology; D004909:Erythrocyte Indices; D004920:Erythropoiesis / Q000502:physiology*; D006801:Humans; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D010807:Physical Endurance / Q000502:physiology