A study of the complexity of respiratory signals during wake and sleep

In this work we study temporal components of respiratory signals during wake and sleep, searching for some subjacent determinism. A few years ago, it was usual practice to consider a single breathing pattern, obtained by averaging many successive cycles in one register. However, the value of these representative patterns was questioned, as many experiments presented breath-to-breath variability. The behavior appears to be more consistent with a respiratory control system which acts permanently to counteract both metabolic changes and external perturbations in an effective way.