The Effects of Hypoxic Hypoxia on Olfactory Sensitivity in Humans

This study examined the influence of hypoxic hypoxia on olfactory sensitivity in humans. Olfactory detection thresholds for n -butanol were studied when the subjects (male volunteers aged 18–20 years without ear, nose, or throat diseases and with low tolerance to hypoxia) breathed a hypoxic gas mixture. To mimic hypoxic hypoxia, participants were asked to breathe a gas mixture containing 10.5% oxygen. The oxygen level in the blood was controlled by the degree of hemoglobin oxygenation, as measured using a Nonin 9843 digital portable pulse oximeter (United States). The results of our study show that with a low fraction of inspired oxygen the olfactory detection thresholds for n -butanol increased ( p ≤ 0.01). Therefore, a human olfactory receptor becomes less sensitive under hypoxic hypoxia.