Age-Related Erythrocyte Structure and Rheological Blood Properties in Athletes

The relationship between the rheological blood properties and several indices of age-related erythrocyte structure was established in endurance-training athletes (n = 21). Unlike nonathletic subjects, the athletes had a shift in the age-related structure towards younger erythrocyte forms: reticulocytosis, increased erythrocyte resistance, increased percentage of cells with a diameter exceeding 8 m, and decreased percentage of cells with a diameter of less than 7 m. The established correlations between total reticulocyte concentration, mature and immature reticulocyte concentrations, and percentage of cells with a diameter either exceeding 8 m or less than 7 m, on the one hand, and hemorheological parameters (blood viscosity, erythrocyte suspension viscosity, erythrocyte aggregation, and surface/volume ratio) and physical work capacity, on the other hand, revealed a significant effect of younger erythrocyte forms on hemorheological indices in athletes.     

Relationships between hemorheology, erythrocyte metabolism, and von willebrand factor in athletes and patients with peripheral arterial disease

The relationship between hemorheology, erythrocyte ATP and 2,3-diphosphoglycerate (2,3-DPG) concentrations, and von Willebrand factor antigen was studied in athletes and peripheral arterial disease patients. Lower blood viscosity, mainly due to a higher erythrocyte deformability, was found in athletes compared to control subjects. Higher 2,3-DPG/Ht levels in athletes were correlated with blood viscosity, erythrocyte deformability, the rigidity index, and erythrocyte suspension viscosity at low shear stress. It is suggested that these relationships might be determined by the predominance of immature erythrocytes in the blood circulation of the athletes. In the group of patients, a decrease in ATP/Ht was related to increased erythrocyte aggregation and a higher erythrocyte suspension viscosity. Moreover, the concentration of von Willebrand factor was positively correlated with the erythrocyte aggregation index, erythrocyte suspension viscosity, and plasma viscosity. The results show that alterations in erythrocyte and plasma rheology may be involved in the modification of the functional state of the vascular endothelium and the development of atherosclerosis.     

Postural stability during static strain before and after a submaximal aerobic bicycle test in athletes

Control of static balance was studied in wrestlers (n = 31) in the normal state and against the background of physical fatigue, i.e., before and after a bicycle PWC ₁₇₀ test, respectively. The static balance was evaluated using a Ritm force platform (Russia) during normal basic stance (BS) and static strain (half-squatting position (HS) with the eyes open). Before physical exercise, i.e., during BS, the differences in postural control of the center of pressure (CP) between athletes and control subjects (n = 40) were nonsignificant. In the HS position, both linear and angular sway velocities of CP (LSV and ASV, respectively) were significantly lower in wrestlers (p < 0.001), and these parameters were negatively correlated with the PWC ₁₇₀ index (r = −0.454 and r = −455, p < 0.001 for LSV and ASV, respectively), which suggests that up to 20% of the sway velocity variance during static strain is dependent on the working capacity of the subjects. After the PWC ₁₇₀ test, the sway velocities of CP increased in both groups during BS (p < 0.01) and HS (p < 0.001), which testifies to the important role of muscular fatigue in the decrease in postural stability in both groups. During BS, an increase in LSV and ASV was about the same in both groups; however, during HS, an increase in the sway velocities of CP after PWC ₁₇₀ was lower in wrestlers (the intergroup differences at p = 0.037 and p = 0.008 for LSV and ASV, respectively); this parameter was negatively correlated with the recovery of the heart rate (HR) after the bicycle test (r = −0.378, p < 0.001 and r = −0.265, p < 0.05 for LSV and ASV, respectively), which suggests that rapid recovery contributes to a certain extent (about 6.5–14.2%) to the postural stability during static strain of wrestlers against the background of their physical fatigue.     

Postural stability during static strain before and after submaximal aerobic bycycle test in athletes

The aim of study was to investigate static balance control in wrestlers (n = 31) and effects of fatigue on postural regulation in two position: bipedal stance and squat position with open eyes prior to and 2 min after bicycle PWC(170) test. A force platform ("Ritm". Russia) was used to determine static balance control. We found a minimum difference in postural control between wrestlers and controls prior to exercise in bipedal stance. In squat position linear and angular (all p < 0.001) sway velocity of centre of pressure were lower in wrestlers and were negatively correlated to PWC(170) index (r = 0.454 and r = 455, p < 0.001 with linear and angular sway velocities respectively) indicating that 20% dispersion of sway velocities in static strain position may be determined to physical working capacity. After PWC(170) test all parameters of sway were increased in both groups both in bipedal stance (p < 0.01) and squat position (p < 0.001) indicating an important role of muscular fatigue in the decrease of postural stability in both groups. Linear velocity after PWC(170) in bipedal stance increased to an equal extent in both groups but the increases of velocities of sway of centre of pressure in squat position were lower in athletes (ANOVA, p = 0.037 for linear and p = 0.008 for angular sway velocities respectively) and were negatively correlated to an extent of recovery of heart rate after PWC(170) indicating some contribution (6.5-14.2% of dispersion of linear and angular sway velocities) of an recovery rate to maintenance of a high level of postural stability in an static strain position in wrestlers during physical fatigue.     

Autonomic heart rate control and regional vascular reactions

Rheovasographic parameters (the thigh region) were recorded in groups of subjects with high and low heart rate variability (HRV). Correlation between the rheovasographic parameters and the sympathetic-parasympathetic balance value (LF/HF) was found. It was established that vagosympathetic balance in the first group was interrelated with the parameters of the ascending portion of the rheological wave; in the second group, with the parameters characterizing the blood flow in the microcirculatory bed. Thus, predominance of the autonomic loop of regulation mainly ensures an optimal regional arterial blood flow; the predominance of the central loop of regulation of cardiac activity, an optimal blood flow in microvessels.     

Relationships between Thyroid Hormones, Blood Rheology, and Lipid Profile in Athletes

The interrelation of thyroid hormones with blood rheology and lipid profile was studied in athletes (N = 12). A decrease in blood viscosity in the athletes was caused by a lower erythrocyte rigidity index, which correlated with an increased reticulocyte count (P = 0.022), a decreased mean concentration of hemoglobin per cell (MCHC) (P = 0.006), and an increased level of thyrotropin (TTH) (P = 0.040). By multiple regression analysis, MCHC was found to be the primary correlate of the erythrocyte rigidity index (P = 0.044). The interrelation of TTH with the rigidity index was explained by a positive correlation of TTH with the reticulocyte count (P = 0.022). The level of triiodothyronine (T₃) was similar in the athletes and the control subjects and negatively correlated with total cholesterol (Ch) (P = 0.033) and low-density lipoprotein cholesterol (LDL Ch) (P = 0.048), which both correlated positively with blood and plasma viscosity and erythrocyte aggregation (P < 0.05 or 0.01). Thus, the decrease in LDL Ch in the athletes, which was closely related with the higher blood and plasma fluidities and with erythrocyte aggregation, was at least partly due to the effect of T₃.     

Blood Circulation Pattern in Highly Skilled Swimmers

Echocardiography was used to study the parameters of cardiodynamics, systemic hemodynamics, left ventricular morphology and functioning, phase analysis of cardiac activity, and rheological blood properties in highly skilled expert swimmers. The relationship between different levels of blood circulation was established. A close correlation between the blood flow at rest and arterial pressure was found to contribute to the optimization of microvascular pressure and shear stress in accordance with body demands.