[Effects of additional breathing resistance on oxygen consumption in healthy subjects]

Decrease of oxygen delivery is common in hypoxia. This is the reason of decrease of consumption (VO2) at Mammalia including human. Previously, we have described a hypoxic hypometabolism at 1/3 health persons breathing 17% O2 oxygen air. This light hypoxic (latent hypoxic) condition didn't issue hypoxia because of SpO2 had dropped from 97-98% to 95-96%. We hypothesized the existence of another reason for VO2 decrease. This is the ability of tissue to decrease oxygen consumption in human organism. Thus the hypometabolism maintains delivery/consumption O2 balance when respiratory center is informed by afferent receptors about potential threat of tissue hypoxia. The aim of this study was to investigate parameters of gas exchange in light mixed resistive load 0.4 cmH2O s L(-1). For compare it was used date obtained at ordinary mouthpiece with resistance less 0.1 cmH2O s L(-1). During the study 14 health subjects (6 men and 8 women) with the age ranging from 23 to 48 years were observed. Date showed a significant decrease in mean (SD) of VO2 at 9% and CO2 release (VCO2) at 10%. Value of SpO2 didn't change and remain 97.5%. The results suggest that hypometabolism may be a reaction prevented by disturbance O2 delivery/consumption for tissue of human organism.