CO2-dependent components of sinus arrhythmia from the start of breath holding in humans

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Abstract

A substantial portion of sinus arrhythmia in conscious humans appears to be caused by the CO2-dependent central respiratory rhythm. Under some circumstances, therefore, sinus arrhythmia might indicate the presence of the central respiratory rhythm. Humans can voluntarily modify their central respiratory rhythm (e.g., by pacing breathing or by delaying or advancing breaths), but it is not clear what happens to it from the start of breath holding. In this study, we show that sinus arrhythmia persists from the start of breath holds prolonged by preoxygenation. We also show that some of the frequency components of sinus arrhythmia start within each subject's eupneic frequency range and change when end-tidal Pco2 is lowered or raised, as we would expect if the central respiratory rhythm continues from the start of breath holding. We discuss whether sinus arrhythmia can indicate if the central respiratory rhythm continues from the start of breath holding.

Details

Original languageEnglish
Pages (from-to)H841-H848
JournalAmerican Journal of Physiology. Heart and Circulatory Physiology
Volume285
Issue number2
Early online date1 May 2003
Publication statusPublished - 1 Aug 2003

Keywords

  • Adult, Arrhythmia, Sinus, Brain Stem, Carbon Dioxide, Humans, Partial Pressure, Respiratory Mechanics, Volition