The presumption that physical activity, i.e. exercise, as an independent and separated factor influences different aspects of cognitive mechanisms is substantially supported by the literature. The investigations of the influence of physical activity on cognitive functioning have offered several mechanisms which could explain this relationship. Physiological mechanisms including increased cerebral blood flow, changes in neurotransmitter release, structural changes in central nervous system and altered arousal levels are based on physical changes that occur in the body as a consequence of the physical activity. There is evidence that physical training selectively increases angiogenesis, synaptogenesis and neurogenesis. The role of central (BDNF) and peripheral (estrogens, corticosteroids, growth hormone, IGF-1) factors in mediation of the effects of physical exercise on brain functions, has been promoted. Also, there is convergent data on molecular and cellular level, as well as on behavioral and systemic level which support the presumption that physical activity is beneficial to cognition. These data emphasizes the importance of promotion of physical activity during the life span for the prevention of contemporary (obesity, diabetes and cardiovascular) diseases and cognitive decline in humans.

Background: This study aimed to assess the basic red blood cell variables and hematological indices in children and adolescents and analyze the differences regarding age and sex. Methods: Overall, 320 young participants, age 8 to 18 yr, were enrolled at Laboratory of Sport’s Medicine, Medical Faculty, Skopje, Macedonia in 2016. Capillary blood samples were drawn and following hematologic parameters were measured: the red blood cell count (RBC), hemoglobin concentration (Hb), hematocrit level (Hct) and hematological indexes: mean corpuscular volume (MCV), mean hemoglobin concentration (MCH), mean corpuscular hemoglobin concentration (MCHC) and red cell distribution width (RDW). Results: RBC variables in male group showed high statistical level of significance between age different groups (P=0.001) for all studied parameters except MCHC (P=0.423) and RDW (P=0.174). ANOVA test and multivariate tests in female group showed that there was no significant difference for all hematological parameters between age different groups. Regarding the sex differences, male participants had significantly higher red blood count (P<0.001), hemoglobin content (P<0.001) and hematocrit (P<0.001). Conclusion: Hematological parameters in adolescent as inhomogeneous population are not quantified sufficiently, especially hematological indices. RBC variables, regardless of the age, differ very much between male and female examinees, in favor of the male examinees. Hematological indices were insignificantly higher in males. Regarding the age of examinees, RBC variables showed significant inter-groups differences only within male adolescents. While with girls, ages span 8 to 18 yr, we did not find significant differences for most of the hematological variables.

AbstractAim: The aim of this study was to determine and analyse the relations between anthropometric parameters, red blood cells’ (RBC) variables and cardio-physiological parameters in healthy and physically active children and adolescents.Material and Methods: In this study 625 subjects, (410 males and 215 females; age span 8 to 18 years) underwent body composition analysis (Matiegka method), blood analysis and ergometry testing (Bruce protocol).Results: In both groups, body height and weight were positively correlated with RBC variables. In female group almost all correlations between RBC variables and body components were insignificant. In boys all absolute body mass components showed positive correlations with RBC variables with notice that body fat mass had lowest correlation coefficient. Body fat percent (BF %) did not show any correlation with RBC variables in both gender groups. In boys BF % had moderate negative correlation with aerobic performance: exercise time (ET) and VO2max (rs = -0.41 and rs = -0.39). Lean body components showed weak positive correlations with ET and VO2max. RBC count did not show significant correlation with any cardio-physiological parameter in both groups. Haematocrit and haemoglobin showed weak positive correlations with VO2 max and general endurance (exercise time). In girls all correlations between cardio-physiological and RBC variables were insignificant. The relationship between all body components and all cardio-physiological variables in girls were statistically insignificant.Conclusions: Our findings revealed that there are some expected positive correlations between lean body mass components, aerobic performance and RBC variables in boys, while in girls such relations were not noticed.

The objective of this study was to analyze the hematologic parameters and their correlation with body composition components in healthy boys at pubertal age. One hundred and ninety physically active male subjects, aged 10 to 17 years, mean age 13.87 ±4.5 years, were included in the study. Capillary blood was drawn from all subjects and the following hematologic parameters were measured: RBC, Hct, Hb, MCV, MCH, MCHC. The following body components derived from Matiegka anthropometric method were assessed: muscle mass (MM), bone mass (BM), and body fat mass (BF). The mean values (±SD) of hematologic parameters were: RBC= 4.87±0.41 x 10 12 /L, Hb=14.24±1.24 g/dL, Hct=43.83±3.8%. Anthropometric characteristics were as follows: body mass index (BMI) = 20.26± 3.27 kg/m 2 , relative muscle mass (MM%) = 53.18± 3.19%, bone mass (BM%) = 18.83± 2.4% and body fat percentage (BF%) = 15.19± 2.64%. Correlation analysis between hematologic parameters and body composition showed a moderate to strong correlation between RBC, Hb and Hct and all body components. The strongest correlations were found between Hb and Hct, and muscle mass (r= 0.60; r= 0.61) and lean body mass (r= 0.59). The body fat mass showed also a positive association with RBC (r=0.47); Hb (r=0.47) and Hct (r=0.48). Our findings showed that the relationship between anthropometric measures and RBC variables in healthy physically active boys were positively correlated, but the level of association was higher with skeletal muscle mass.