title: Exercise-induced hemolysis is caused by protein modification and most evident during the early phase of an ultraendurance race.
abstract: Whether structural changes of the erythrocyte membrane increase the susceptibility to hemolysis particularly of the relatively older cell population during the early phase of a 216-km ultrarace was tested in six male runners (age 53.6 +/- 10.4 yr, height 175.8 +/- 11.1 cm, body mass 75.9 +/- 8.4 kg). Erythrocyte membrane spectrins were lowest (P < 0.001) after 42 km (75.59 +/- 5.25% of prerace) and increased (P < 0.001) toward 216 km (88.27 +/- 3.37%). Susceptibility to osmotic hemolysis was highest (P < 0.01) after 42 km (107.34 +/- 3.02 mOsm sodium phosphate buffer) with almost identical (P > 0.05) values prerace (97.98 +/- 3.41 mOsm) and postrace (98.61 +/- 3.26 mOsm). Haptoglobin indicated intravascular hemolysis of 9.27 x 10(9) cells/l (P < 0.05) during the initial 84 km. Changes in hematocrit and plasma proteins indicated an estimated total net erythrocyte loss of 3.47 x 10(11) cells/l (P < 0.05) after 21 km. This was compensated by a gain in erythrocytes (P < 0.05) of 3.31 x 10(11) cells/l during the final 132 km. A main effect (P < 0.05) on erythropoietin suggests increased erythropoiesis throughout the race. Exercise-induced hemolysis reflects alterations in erythrocyte membrane spectrins and occurs particularly in the early phase of an ultraendurance race because of a relative older cell population.
authors.affiliation: Centre for Sports and Exercise Science, Dept. of Biological Sciences, Univ. of Essex, Wivenhoe Park, Colchester CO4 3SQ, United Kingdom. ashril@um.edu.my
authors.forename: Ashril
authors.initials: A
authors.lastname: Yusof
authors.forename: Renate M
authors.initials: RM
authors.lastname: Leithauser
authors.forename: Heinz J
authors.initials: HJ
authors.lastname: Roth
authors.forename: Holger
authors.initials: H
authors.lastname: Finkernagel
authors.forename: Michael T
authors.initials: MT
authors.lastname: Wilson
authors.forename: Ralph
authors.initials: R
authors.lastname: Beneke
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology; D004910:Erythrocyte Membrane / Q000378:metabolism; D004920:Erythropoiesis; D004921:Erythropoietin / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D006242:Haptoglobins / Q000378:metabolism; D006461:Hemolysis / Q000502:physiology*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D008875:Middle Aged; D010807:Physical Endurance / Q000502:physiology*; D012420:Running / Q000502:physiology; D013049:Spectrin / Q000378:metabolism
chemical_list: D006242:Haptoglobins; D008565:Membrane Proteins; D004921:Erythropoietin; D013049:Spectrin