Centro de Fisiología y Medicina de Altura

URI permanente para esta colección

https://repositorioabierto.uantof.cl/handle/uantof/502

Examinar

Examinando Centro de Fisiología y Medicina de Altura por Materia "autonomic nervous system"

Mostrando 1 - 2 de 2
  • Miniatura
    Ítem
    Cardiac Autonomic Modulation in Response to Muscle Fatigue and Sex Differences During Consecutive Competition Periods in Young Swimmers: A Longitudinal Study
    (Frontiers Media SA, 2021) Castillo-Aguilar, Matías; Valdés-Badilla, Pablo; Herrera-Valenzuela, Tomás; Guzmán-Muñoz, Eduardo; Delgado-Floody, Pedro; Andrade, David Cristóbal; Moraes, Michele M.; Arantes, Rosa M. E.; Núñez-Espinosa, Cristian
    Objective: To study the differences in cardiac autonomic modulation in response to muscle fatigue caused by high-intensity exercise during two consecutive competition periods in young swimmers. Methods: Twenty-six competitive swimmers, selected by their training volume, were separated in two groups, females (n = 12 [46%], age: 13.5 ± 1.4 years) and males (n = 14 [54%], age: 13.9 ± 1.7 years), aged between 10 and 16 years, were evaluated five times as follow: (i) 21 days before the first competition (t-0); (ii) two days before (t-1; t-3); and (iii) two days after (t-2; t-4) of the first and second competitions. Morphological measurements (body mass, percentage of total body fat and height), blood pressure, power, and resting heart rate variability (RR with Polar band) were recorded before and after Wingate test at each time. Results: Body fat was higher in females compared to males. However, no differences were found in other morphological parameters. An intra-subject analysis grouped by sex in cardiovascular parameters shows longitudinal variations in systolic pressure and mean pressure among females. Additionally, females depicted higher, very low frequency (VLF, which is intrinsically generated by the heart and strongly associated with emotional stress) after physical fatigue compared to males at t-1. Further, before the competition, the high frequency (HF) component of HRV (parasympathetic drive) was higher in males than females at t-0 and t-4. Conclusion: Our data revealed that males displayed greater parasympathetic reactivity after an anaerobic muscle fatigue test during their competition periods. Contrarily, females had a less cardiac autonomic modulation when comparing the pre-post Wingate test after two consecutive competition periods.
  • Miniatura
    Ítem
    Hypoxic Respiratory Chemoreflex Control in Young Trained Swimmers
    (Frontiers Media SA, 2021) Arce Álvarez, Alexis; Veliz, Carlos; Vazquez-Muñoz, Manuel; von Igel, Magdalena; Alvares, Cristian; Ramirez Campillo, Rodrigo; Izquierdo, Mikel; Millet, Gregoire P.; Del Rio, Rodrigo; Andrade, David C.
    During an apnea, changes in PaO2 activate peripheral chemoreceptors to increase respiratory drive. Athletes with continuous apnea, such as breath-hold divers, have shown a decrease in hypoxic ventilatory response (HVR), which could explain the long apnea times; however, this has not been studied in swimmers. We hypothesize that the long periods of voluntary apnea in swimmers is related to a decreased HVR. Therefore, we sought to determine the HVR and cardiovascular adjustments during a maximum voluntary apnea in young-trained swimmers. In fifteen trained swimmers and twentyseven controls we studied minute ventilation (VE), arterial saturation (SpO2), heart rate (HR), and autonomic response [through heart rate variability (HRV) analysis], during acute chemoreflex activation (five inhalations of pure N2) and maximum voluntary apnea test. In apnea tests, the maximum voluntary apnea time and the end-apnea HR were higher in swimmers than in controls (p < 0.05), as well as a higher low frequency component of HRV (p < 0.05), than controls. Swimmers showed lower HVR than controls (p < 0.01) without differences in cardiac hypoxic response (CHR). We conclude that swimmers had a reduced HVR response and greater maximal voluntary apnea duration, probably due to decreased HVR.