Oscillatory Behavior of Respiratory Gas Exchange in Resting Man

This study deals with the dynamics of respiratory gas carbon dioxide concentration are three, ten, twenty, and thirty to forty-five minutes and two hours; in oxygen concentration, three, ten, twenty, and thirty minutes and one and four hours; and in respiratory quotient, one, five, ten, and fifteen minutes and two to four hours. exchange in resting man. Spectral analyses are performed on time series representing four-hour continuous records of ventilation, carbon dioxide release, oxygen takeup, end tidal carbon dioxide concentration, end tidal oxygen concentration, and respiratory quotient. Results imply that the temporal behavior of each of these six variables can be characterized by a superposition of a finite set of self-sustained almost periodic oscillations with periods in the range from one minute to four hours and time dependent stochastic variation. In ventilation, carbon dioxide release, and oxygen takeup, individual components have amplitudes of between five and ten percent of mean values and nominal periods of one, four, ten, and twenty minutes and one and two to four hours. Components in oxygen concentration, carbon dioxide concentration, and respiratory quotient have amplitudes of between two and four percent of mean values.