In this dissertation the influence of body composition parameters on endothelial function depending on the functional state of the autonomic nervous system, through the determination of heart rate variability, and highlights the impact of body composition changes on the cardiovascular system (CVS) in adult women.
It is well known that obesity is a catalyst for the development of cardiovascular diseases, that’s why many scientific works are devoted to this topic. Defining obesity on the one hand is not a complicated process; on the other hand in the scientific world we also mention the "paradox of obesity". Therefore, the task is to more accurately determine the composition of the body and its impact on human health.
Our sample consisted of women age 40 to 60 years. We used Tanita BC-601 analyzer scales to study body composition, which included the segmental content of adipose and muscle tissue in the body. Determination of endothelial function (EF) was performed using the analysis of post-occlusive vasodilation on the rheographic complex "Reocom".
The study of the autonomic nervous system (ANS) was performed by analyzing the time intervals between the R-R waves of the monitor electrocardiogram of heart rate variability (HRV), using a computer cardiographic complex "CARDIOLAB" (KHAI-Medica). After obtaining the frequency and time methods of HRV the parameters of activity of regulatory systems (PARS) were also determined by automatic computer analysis of the complex "CARDIOLAB", proposed by R.M. Baevsky. Statistical data processing was performed using the computer program "Jamovi 0.8-1.0" (Affero General Public License 3). (STATISTICS)
It was analyzed that the indicators of the distribution of adipose tissue content had a statistically significant effect on the cardiovascular system. Total fat content (F) affected central hemodynamic parameters: (F = 5.600; p = 0.000), namely the total peripheral vascular resistance (TPVR), cardiac output (СО) and stroke blood volume (SV) (F (20, 190) = 4,6396, p = 0.000); indicators of heart rate variability (F = 1.829, p = 0.003), namely the TP, CV, pNN50, RMSSD, SDNN, LF, VLF, CVort. Total body fat (F), visceral fat (VF), total muscle mass (TMM), as well as muscle mass on the trunk (TM) had a statistically significant effect on endothelial function (R = 0.271, R2 = 0.074, Ra2 = 0.042, F = 2.365, p <0.042). The content of visceral fat had a statistically significant effect on vasodilatory function of the endothelium and showed a positive correlation with the tension of regulatory systems and a negative correlation with the index of endothelial function. The content of lean mass (FFM – fat free mass), on the contrary, had a positive correlation with EF.
In women in groups with normal body weight heart rate variability was the highest, which characterizes the healthy state of autonomic regulation of the heart: TP (3850.902 ± 366.599), LF (1036 ± 107.258), VLF (1831.585 ± 207.380), CV (6.707 ± 0.313), SDNN (59.317 ± 2.952), RMSSD (43.463 ± 3.202), pNN50 (21.341 ± 2.589), CVort (6.439 ± 0.317). Low HRV parameters, corresponding to the intensity of regulatory systems and the presence of diseases and dysfunctions were observed in the group of obese women: CV (5 ± 0.334), CVort (5.167 ± 0.338), SDNN (42.083 ± 3.151), RMSSD (30.417 ± 3.417), pNN50 (11,944 ± 2,762), TP (1974,139 ± 391,231), LF (612,778 ± 114,464), VLF (792,139 ± 221,314). Indicators of central hemodynamics, which were influenced by the total fat content in the group with obesity were: the lowest values of TPVR (1402.921 ± 70.161) compared to other groups and the highest rates of CO (5.12 ± 0.2506) and SV (78.19 ± 3.85); and in the group with normal body weight: the highest value of TPVR (1833.743 ± 78.667), the lowest mean values of CO (4.12 ± 0.2810) and SV (63.51 ± 4.31). With increasing body weight, the development of compensatory left ventricular hypertrophy, increased cardiac output, cardiac output, and adaptive decline in total peripheral resistance are likely. However, in all three groups in women, the stroke volume met the generalized norms.
Summarizing the results of the dissertation, overweight women can be recommended to monitor body composition using both BMI and bioimpedance method, in order to further correct body composition for the prevention of 15 cardiovascular diseases. Women at risk for CVD, or women with endothelial dysfunction and ANS dysregulatory activity, may be advised to follow a healthy lifestyle, maintain physical activity, and perform a minimum of 6,000 steps per day to significantly reduce total and visceral fat. This body composition correction program can serve as a prepharmaceutical treatment for endothelial dysfunction.
Key words: endothelial dysfunction, heart rate variability, central hemodynamics, visceral fat, obesity.
