Abstract des Autors

A suboptimal hematological status has often been recorded in athletes involved in intensive physical activity. There have even been reports of ,,sports anemia" associated with intensive physical exercise. The studies, however, on the effect of different types of exercise practiced over a long period of time on the red blood cell parameters in pubescent athletes are very few. The aim of this study was to assess the basic red blood cell parameters in highly trained pubescent athletes in different sports and to compare the results with those of a control, non-trained group. Sex-related differences of the values of these parameters were also assessed. Subjects: 876 highly trained athletes (559 boys and 317 girls) were included in the study. Their mean age, weight, and sports practice were (X+/-SEM): 14.01+/-0.06 years, 56.24+/-0.52 kg. and 3.52+/-0.07 years, respectively. The control group consisted of 357 nontrained subjects (171 boys and 186 girls) with mean age and weight of 14.58+/-0.09 years and 57.75+/-0.67 kg. The group of athletes was divided into 7 subgroups according to the practiced sport: athletics (105), swimming (107), rowing (230), wrestling (225), weight lifting (47), games (92), and other sports (67). Red blood cell parameters: Venous blood samples were drawn from the cubital vein and the red blood cell count (RBC), hematocrit (Hct), hemoglobin (HB), and mean corpuscular volume (MCV) were measured. Statistics: Statistical indices were computed for each group and for each parameter, and ANOVA-factorial analysis was performed to evaluate the statistical significance of the detected differences. Results: The highly trained group was found to have lower RBC, Hct, and HB (P<0.001) than the control, non-trained group (4.61+/-0.01 x 10**12/l vs 4.75+/-0.02 x 10**12/l, 0.389+/-0.001 l/l vs 0.404+/-0.002 l/l, and 133.01+/-0.38 g/l vs 139.9+/-0.62 g/l, respectively). These parameters were lower for the boys of the trained group than they were for the boys of the control group (P<0.001), and were also lower for the girls of the trained group in comparison with the control girls (P<0.001). The lowest RBC, Hct, and HB were measured in the blood samples obtained from the boys of the swimming subgroup (4.54+/-0.06 x 10**12/l, 0.386+/-0.06 l/l, and 129.38+/-1.80 g/l, respectively), and of the rowing subgroup (4.66+/-0.03 x 10**12/l, 0.400+/-0.003 l/l, and 136.21+/-0.94 g/l, respectively). The same distribution for these parameters was found in girls - they were the lowest in the rowing subgroup (4.32+/-0.04 x 10**12/l, 0.314+/-0.003 l/l, and 124.27+/-0.93 g/l), and in the swimming subgroup (4.40+/-0.05 x 10**12/l, 0.375+/-0.005 l/l, and 125.90+/-1.30 g/l). No differences were found in the MCV measurements. Conclusions: The results of this study suggest that a continuous (more than 1 year) high-intensity sports training (twice a day/5 days a week) reduces the basic red blood cell parameters in pubescent boys and girls, this being most pronounced in the submaximal sports. Verf.-Referat