Multichannel thermometric study of skin temperature changes in humans while inhaling essential oils

To assess the possible skin temperature changes in humans induced by smelling fragrant compounds, temperature changes were monitored continuously with a multichannel skin thermometer during inhalation of essential oils in a climatic chamber at 20 °C and 60% relative humidity. Sensors were fixed to the tips of the left fingers and left palm of each subject and the obtained data were stored every 15 s using a personal computer connected to the skin thermometers. Skin temperature curves were then plotted from the arithmetic summation of the data from each channel. The essential oils examined in this study were basil, juniper and peppermint, because a sensory test indicated the opposite effects of basil vs peppermint and juniper vs peppermint when undertaking mental work. Using these paired odorants, the results showed that, compared with before and after mental work: (1) inhalation of both basil and juniper, from which a favorable impression was predominant in terms of the sensory evaluation spectrum, was statistically associated with increasing finger-tip skin temperature (p < 0.05), implying an increasing propensity of the aroused state and arousal response; (2) inhalation of peppermint, from which an unfavorable sensory profile was expressed, resulted in decreasing finger-tip skin temperature; although this tendency was found to be statistically negligible (p < 0.05). These attempts should be of importance in human chemoreception science as this paradigm is highly informative about non-verbal responses to odorants. Copyright © 2006 John Wiley & Sons, Ltd.