Centro de Fisiología y Medicina de Altura

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Examinando Centro de Fisiología y Medicina de Altura por Autor "Arce Álvarez, Alexis"

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    Ítem
    Hypoxic peripheral chemoreflex stimulation- dependent cardiorespiratory coupling is decreased in swimmer athletes
    (John Wiley & Sons Inc., 2024) Andrade, David C.; Arce Álvarez, Alexis; Salazar Ardiles, Camila; Toledo, Camilo; Guerrero Henriquez, Juan; Alvarez, Cristian; Vasquez Muñoz, Manuel; Izquierdo, Mikel; Millet, Gregoire P.
    Swimmer athletes showed a decreased ventilatory response and reduced sympathetic activation during peripheral hypoxic chemoreflex stimulation. Based on these observations, we hypothesized that swimmers develop a diminished cardiorespiratory coupling due to their decreased hypoxic peripheral response. To resolve this hypothesis, we conducted a study using coherence time- varying analysis to assess the cardiorespiratory coupling in swimmer athletes. We recruited 12 trained swimmers and 12 control subjects for our research. We employed wavelet time- varying spectral coherence analysis to examine the relationship between the respiratory frequency (Rf) and the heart rate (HR) time series during normoxia and acute chemoreflex activation induced by five consecutive inhalations of 100% N2. Comparing swimmers to control subjects, we observed a significant reduction in the hypoxic ventilatory responses to N2 in swimmers (0.012 ± 0.001 vs. 0.015 ± 0.001 ΔVE/ΔVO2, and 0.365 ± 0.266 vs. 1.430 ± 0.961 ΔVE/ΔVCO2/ΔSpO2, both p < 0.001, swimmers vs. control, respectively). Furthermore, the coherence at the LF cutoff during hypoxia was significantly lower in swimmers compared to control subjects (20.118 ± 3.502 vs. 24.935 ± 3.832 area under curve [AUC], p < 0.012, respectively). Our findings strongly indicate that due to their diminished chemoreflex control, swimmers exhibited a substantial decrease in cardiorespiratory coupling during hypoxic stimulation.
  • 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.