Diferencias en los parámetros lineales del balance autonómico basal entre estudiantes de medicina y atletas juveniles de béisbol / Differences in linear parameters of the basal autonomic balance between medical students and young baseball players

RESUMEN Introducción: La modulación autonómica cardiovascular puede ser considerada como una herramienta útil en la determinación del estado fisiológico de la interacción entre los sistemas nervioso autónomo y cardiovascular. Objetivo: Determinar las diferencias en los parámetros lineales del balance autonómico basal entre estudiantes de medicina y atletas juveniles de béisbol. Método: Se realizó un estudio analítico de tipo transversal en el Laboratorio de Ciencias Básicas Biomédicas de la Facultad Nº. 1 de la Universidad de Ciencias Médicas de Santiago de Cuba. Universo y muestra de 36 individuos (Grupo 1: 18 atletas juveniles de béisbol de alto rendimiento, Grupo 2: 18 estudiantes de medicina). Los datos fueron recolectados mediante de polígrafo PowerLab de 8 canales, y fueron procesados usando el software Kubios® versión 3.0.4 Premium. Resultados: Existieron diferencias significativas en los valores de pNN50 (p=0,009), índice de estrés (stress index [p=0,044]), y en los índices parasimpático (p=0,005) y simpático (p=0,001) entre estudiantes y atletas. La capacidad discriminatoria del índice parasimpático para asociarse con la mejor forma física de los atletas fue buena (área bajo la curva 0,784). El punto de corte óptimo por encima del cual el índice parasimpático se asocia al grupo de los atletas, quedó establecido en 0,57. Conclusiones: El índice parasimpático se asoció con el grupo de atletas, lo que evidencia el predominio vagal en la modulación de la actividad cardíaca en los sujetos de este grupo.

ABSTRACT Introduction: Cardiovascular autonomic modulation can be considered a useful tool in determining the physiological state of the interaction between the autonomic nervous system and the cardiovascular system. Objective: To determine the differences in linear parameters of the basal autonomic balance between medical students and young baseball players. Method: A cross-sectional analytical study was carried out in the Biomedical Basic Sciences Laboratory, Faculty No.1, of the Universidad de Ciencias Médicas in Santiago de Cuba. The population and sample consisted of 36 individuals (Group 1: 18 high-performance young baseball athletes, Group 2: 18 medical students). Data was collected using an 8-channel PowerLab polygraph and it was processed using the Kubios® Software version 3.0.4 Premium. Results: There were significant differences in the values between students and athletes: pNN50 (p=0.009), stress index (p=0.044) and in parasympathetic (p=0.005) and sympathetic (p=0.001) indexes. The discriminatory ability of the parasympathetic index to be associated with the best physical fitness of the athletes was good (area under the curve 0.784). The optimum cut-off point above which the parasympathetic index is associated with the group of athletes was set at 0.57. Conclusions: The parasympathetic index was associated with the group of athletes, showing the vagal predominance in the modulation of cardiac activity in the individuals belonging to this group.

Modifications of the non-linear parameters of the heart rate variability related to the systematic practice of physical exercise

Introduction: In recent years, the relationship between the systematic practice of physical exercise, cardiovascular dynamics and the functioning of the autonomic nervous system has been recognized. Objective: To determine the modifications that non-linear parameters undergo in the autonomic cardiovascular regulation of the heart rate variability with the systematic practice of physical exercise. Methods: A retrospective cohort analytical study was conducted from February 2016 to August 2018. Population and sample: 36 individuals (Group 1: 18 high- performance baseball athletes; Group 2: 18 medical students). The data were collected in the Biomedical Basic Sciences Laboratory at Medical school 1, University of Santiago de Cuba, through the 8-channel PowerLab polygraph, and stored using the Kubios Software version 3.0.4 Premium. Results: Statistically significant differences between means were found in heart rate values (p = 0.000); SD1 (p = 0.025); SD2/SD1 ratio (p = 0.007); sample entropy (p = 0.011); short-term fluctuations α 1 (p = 0.019); mean line length (p = 0.016); max line length (p = 0.001); recurrence rate (p = 0.034); determinism (p = 0.010) and Shannon entropy (p = 0.015). The parameters of SD1 (C = 0.906) and sample entropy (C = 0.712) were significantly associated with a heart rate ≤ 70 beats per minute. Conclusions: With the systematic practice of physical exercise, the non-linear parameters of the autonomic cardiovascular regulation of the heart rate variability undergoes modifications that respond to a better adaptability of the autonomic nervous system, and to a greater capacity to regulate cardiovascular function(AU)