[335] Changes in RBC indexes of long distance runners during endurance training and the significance

The purpose of this study was to investigate changes in the RBC indexes of student long distance runners during endurance training and the significance. The subjects were student long distance runners(n=41), who had the same training program and participated in this study for four years(1995 to 1999). Blood collection was performed in the early morning and analysed by the SRL company to measure RBC indexes and plasma (HDL). Plasma lipids were extracted and the plasma phosphatidylcholine (PC) was determined by thin layer and gas-chromatography. The RBCs of the subjects decreased with endurance training and a compensative increase of MCV and MCH occurred. The decrease of RBC was linealy related to blood viscosity. There was a significant relationship between MCV and plasma HDL, but in low and high HDL(below 60mg/dl, upper 100mg/dl), this relationship disappeared. One of the factors of this relationship was plasma PC, which was found in high HDL plasma. These results suggest that an increase of MCV in long distance runners is not only related to the amount of endurance training, but also the individual plasma HDL level.