Effect of Body Iron Stores on Indices of Biosynthesis and Destruction of Red Blood Cells after a Single Session of Cycling Exercise / 体力科学

ABSTRACT

Objectives: The present study investigates the effects of body iron stores upon indices of biosynthesis and destruction of red blood cells (RBC) induced by a single session of cycling exercise.<BR>Design: Eight sedentary female students were divided into groups depending on their body iron stores normal (C group, n=5) and iron deficient (D group, n=3) . Blood samples were collected at five time points of before (pre), immediately after (0 hours), then 1, 3 and 6 hours after exercise (248±31 kcal, 70% V0<SUB>2</SUB> peak level) . Osmotic fragility and serum haptoglobin (hp) concentration served as of for degradation, and &delta;-aminolevulinate dehydratase (ALAD) activity, erythropoietin concentration and number of reticulocytes served as indices of RBC biosynthesis.<BR>Results: A single session of cycling exercise did not affect the level of RBC, hemoglobin, hematocrit, serum iron, ferritin, transferrin saturation, hp and osmotic fragility in either groups. The &delta;-ALAD activity increased at 3 (p<0.05) and 6 hours (p<0.01) after exercise compared with that at 0 hours in the C group. In contrast, &delta; -ALAD activity in the D group was significantly lower at 3 hours after exercise than that of C group (p<0.001) . Reticulocytes and erythropoietin concentration increased gradually in the C group after exercise, but not in the D group.<BR>Conclusions: A single session of cycling exercise under our experimental conditions enhanced RBC biosynthesis indicated by &delta; -ALAD activity, whereas exercise-induced hemolysis was not evident. Body iron stores affect the &delta; -ALAD activity induced by a single bout of cycling exercise.