RICHAKDSON, DAVID Mr., HERMES A. KONTOS, A. JARRELL RAPER, AND JOHN L. PATTERSON, JR. Systemic circulatory responses to hypocapnia in man. Am. J. Physiol. !223(6): 1308-1312. 1972.Hypocapnic alkalosis, induced by voluntary hyperventilation in normal man, was associated with increases in cardiac output and in heart rate and decreases in mean arterial blood pressure and in systemic vascular resis...

During heavy exercise, hyperventilation-induced hypocapnia leads to cerebral vasoconstriction, resulting in a reduction in cerebral blood flow (CBF). A reduction in CBF would impair cerebral O2 delivery and potentially account for reduced exercise performance in hypoxia. We tested the hypothesis that end-tidal Pco2 (PETCO2) clamping in hypoxic exercise would prevent the hypocapnia-induced reduc...

OBJECTIVES The dynamic interaction between blood pressure (BP) and cerebral blood flow velocity (CBFV) is not fully understood, especially for CBFV changes lasting longer than 50 s. The interaction between BP and CBFV is relatively well characterized for periods <50 s using transfer function (TF) estimations of phase, gain, and coherence. We used TF estimations to compare the phase and gain for...

Emery MJ, Eveland RL, Kim SS, Hildebrandt J, Swenson ER. CO2 relaxes parenchyma in the liquid-filled rat lung. J Appl Physiol 103: 710–716, 2007. First published May 10, 2007; doi:10.1152/japplphysiol.00128.2006.—CO2 regulation of lung compliance is currently explained by pHand CO2-dependent changes in alveolar surface forces and bronchomotor tone. We hypothesized that in addition to, but indep...

We hypothesized that a decreased susceptibility to the development of hypocapnic central apnea during non-rapid eye movement (NREM) sleep in women compared with men could be an explanation for the gender difference in the sleep apnea/hypopnea syndrome. We studied eight men (age 25-35 yr) and eight women in the midluteal phase of the menstrual cycle (age 21-43 yr); we repeated studies in six wom...