RESUMO
The aim of this study was to analyse the effectiveness of new haematology parameters related to reticulocytes and mature red blood cells to differentiate pre latent and latent iron deficiency. The study included 219 female athletes (aged 15-20 years) representing volleyball, handball, cycling, canoeing, cross-country skiing, swimming and judo. To assess iron status the concentration of ferritin, soluble transferrin receptor (sTfR), iron and total iron binding capacity (TIBC) were determined in serum. In addition to blood morphology, the mean cellular haemoglobin content in erythrocytes (CH) and reticulocytes (CHr), mean cellular haemoglobin concentration in reticulocytes (CHCMr), the percentage of erythrocytes (HYPOm) and reticulocytes (HYPOr) with decreased cellular haemoglobin concentration, the percentage of erythrocytes (LowCHm) and reticulocytes (LowCHr) with decreased cellular haemoglobin content, and percentage of erythrocytes with decreased volume (MICROm) were determined. Subjects with ferritin <30 ng/ml were classified as having stage I (pre-latent) iron deficiency (ID). The second stage (latent ID) was diagnosed when low ferritin was accompanied by elevated sTfR and/or elevated TIBC values. The frequency of ID (without anaemia symptoms) was high, amounting to 60% (stage I in 45%, stage II in 15% of subjects). In subjects with stage I ID significant changes in haematological variables concerned mainly reticulocytes: CHCMr (p<.001), CHr (p<.05), LowCHr (p<.05), HYPOr (p<.001) in comparison to normal iron stores. In athletes with latent ID, there were also significant changes (p<.001) in many indices of mature red blood cells, i.e. haemoglobin concentration (Hb), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC), CH, %LowCHm, as well as %MICROm (p<.01) in relation to the group without iron deficiency. The main finding of this study was that the diminished or exhausted iron stores had already caused changes in reticulocytes, and intensified iron deficiency (stage II) increased changes in both reticulocytes' and erythrocytes' hypochromia indices, while microcythaemia symptoms appeared later. This suggests that the markers of hypochromia relating especially to reticulocytes are useful for diagnosis of early ID in athletes with absence of an acute phase reaction.
RESUMO
The aim of this study was to determine the relationship between the degree of cardiorespiratory fitness and the function of the right ventricle (RV). 117 rowers, age 17.5±1.5 years. All subjects underwent cardiopulmonary exercise. Standard echocardiography and 2D speckle tracking echocardiography with evaluation of longitudinal strain in each segment of the RV (basal - RVLS-B; mid - RVLS-M, apical - RVLS-A) and global RV free-wall strain (RVLS-G) were performed. RVLS-B values were lower compared to the RVLS-M (-25.8±4.4 vs -29.3±3.5; p<0.001) and RVLS-A values (-25.8±4.4 vs -26.2±3.4; p=0.85). Correlations between VO2max and RVLS were observed in men: RVLS-G strain (r = 0.43; p <0.001); RVLS-B (r = 0.30; p = 0.02); RVLS-M (r = 0.38; p = 0.02). A similar relationship was not observed in the group of women. The strongest predictors corresponding to a change in global and basal strain were VO2max and training time: RVLS-G (VO2max: ß = 0.18, p = 0.003; training time: ß = -0.39; p = 0.02) and RVLS-B (VO2max: ß = 0.23; p = 0.0001 training time: ß = -1.16; p = 0.0001). The global and regional reduction of RV systolic function positively correlates with the level of fitness, and this relationship is observed already in young athletes. The character of the relationship between RV deformation parameters and the variables that determine the physical performance depend on gender. The dependencies apply to the proximal fragment of the RV inflow tract, which may be a response to the type of flow during exercise in endurance athletes.
RESUMO
Twelve girls who trained in rowing were examined twice a year for 4 years. Their initial age was 11.7 +/- (SD) 0.2 yrs. Control groups consisted of 13 girls age 11.5 +/- 0.3 yrs and 18 girls age 14.4 +/- 0.3 yrs examined simultaneously with trained girls in the first and last year of the study, respectively. The examination involved basic anthropometry, estimation of sexual maturation (Tanner scale), 2-day food records, measurements of resting metabolic rate, energy expenditure following glucose ingestion (50 g), and determinations of blood glucose and plasma insulin concentrations prior to and 2 hrs after glucose load. Body mass, height, and fat content were slightly greater in trained girls. None of the subjects reported disturbances in menstrual function, and the age of menarche was similar for all. Both trained and untrained girls reported similar daily energy intake closer to the lower limit or slightly below the estimates of energy requirements for adolescents. Resting metabolic rate calculated per kg of total body mass or lean body mass was lower in trained girls, while the thermogenic effect of glucose was greater. Plasma insulin concentrations measured 2 hrs after glucose ingestion were lower in trained girls. The results suggest that in circumpubertal girls, increased physical activity leads to energy conservation at rest in postabsorptive state and a tendency toward enhancement of food-induced thermogenesis.