Frontiers in Physiology (Feb 2021)

Hypoxic Respiratory Chemoreflex Control in Young Trained Swimmers

  • Alexis Arce-Álvarez,
  • Carlos Veliz,
  • Manuel Vazquez-Muñoz,
  • Manuel Vazquez-Muñoz,
  • Magdalena von Igel,
  • Cristian Alvares,
  • Rodrigo Ramirez-Campillo,
  • Rodrigo Ramirez-Campillo,
  • Mikel Izquierdo,
  • Gregoire P. Millet,
  • Rodrigo Del Rio,
  • Rodrigo Del Rio,
  • Rodrigo Del Rio,
  • David C. Andrade,
  • David C. Andrade,
  • David C. Andrade

DOI
https://doi.org/10.3389/fphys.2021.632603
Journal volume & issue
Vol. 12

Abstract

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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 twenty-seven 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.

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