Impeding respiratory venous return fluctuations alters cardiorespiratory autonomic and mechanical interactions

We used an innovative approach to modulate the effects of the respiratory pump on circulation in healthy individuals. By synchronizing lower body negative pressure with either inspiration or expiration, the respiratory pump was inhibited or augmented. The arterial blood pressure declined, and its fluctuations became pronounced when the respiratory pump was impeded, and normal cardiorespiratory interactions were disrupted. Cardiorespiratory interactions seem to supersede the strong baroreceptor stimulus generated by cyclic fluctuations in central blood volume.