Reticulocytes as a Marker of Oxygen Transport System Adaptation to Physical Activity in Endurance Sports

Abstract

Backgraund. Peripheral blood reticulocytes and aging of the activity of these cells are markers of erythropoiesis
activity. The purpose of this study was to examine changes of reticulocytes in blood formation of elite athletes in
endurance sports during the preparation and the competitive periods.
Methods. Reticulocytes and IRF content was examined in blood of 305 elite athletes aged 20-26 years that
specialized in swimming, biathlon, cross-country skiing, kayaking and canoeing, rowing and cycling. At various
stages  of  preparation  459  blood  tests  were  performed  and  processed.  Capillary  blood  was  analysed  using  a
haematology analyser SYSMEX XT 2000i.
Results. Differences in reticulocytes depending on sport, gender and qualification were not found. Increase in
reticulocytes was marked for male athletes in the age aspect, for females, reduction was observed. A tendency of
average reticulocytes group data in peripheral blood at various stages of the annual preparation cycle was found:
reduction of the amount of reticulocytes in competition period. This pattern was found regardless of gender. Similar
evidence was found concerning the dynamics of IRF at the stages of the annual training.
Conclusion. The effect of training activity on reticulocyte indices in the annual training cycle is related to the
direction, duration and intensity of physical activity in different periods of training. Changes in reticulocytic indices
may be due to effects such as hemoconcentration and hemodilution appearing after exercise in the corresponding
areas of energy supply.

Keywords:  reticulocytes, erythropoiesis, elite athletes, training loads