Determinants of the hypercapnic and hypoxic response in normal man

Abstract

The purpose of this study was: (1) to identify the determinants of the hypercapnic (HCR) and hypoxic response (HR) in normal man; (2) to find out if they are dependent on the HR model used; and (3) to investigate if the occlusion pressure (P 0.1), in contrast to the V ̇ e HCR and HR, is independent of gender, anthropometrical and lung functional indices. A total of 26 men (42.4±12.4 years) and 25 women (40.1±13.7 years) were studied. We found that men and women have similar P 0.1 respiratory drives, but V ̇ e differs and is higher in men because of their larger vital capacity. For comparisons of the HCR or HR either the P 0.1, or the V ̇ e HCR and HR normalized for VC or FEV 1 should be used. With advanced age the V ̇ e HCR decreases in women. Especially for the HR, the identification of determinants (including age) is dependent on the HR model used.