Physiological effect of olfactory stimuli inhalation in humans: an overview

Abstract

SynopsisThe importance of odorants in human life has long been recognized. Literature contains different approaches of physiological and psychological effects of odorant compounds, fragrances and essential oils. This work discusses odorants inhalation effect, based on an overview of major studies in humans. Beneficial effect of fragrances is mainly related to human behaviour. Studies document odorants influence in sympathetic and parasympathetic nervous systems, and neurophysiological brain activity. Moreover, odours compounds can act on the neuroendocrine system, neurotransmitters and neuromodulators, influencing psychological behaviour as well as body function. Odorant inhalation modulates physiological pathways, and in some cases, results in skin function regulation. The mechanism is incompletely elucidated. These findings suggest that olfactory system plays a role in central nervous system function beyond that of smell. In this overview, it was observed that odour compounds influenced stress biomarkers, dehydroepiandrosterone, oxidative stress, estradiol, dopamine, cutaneous barrier, sebum secretion and cutaneous immune system in humans. Some can be related with skin function. As the skin is associated with an extensive biochemical cascade and has complex mechanisms, studies have far to go, as there are processes not yet investigated related to skin that may be affected through olfaction. Future researches are needed to further understand and describe the mechanisms of action of physiological effects in fragrance compounds.R esum e L'importance des substances odorantes dans la vie humaine est reconnue depuis longtemps. La litt erature contient des approches diverses des effets physiologiques et psychologiques des compos es odorants, des parfums et des huiles essentielles. Ce travail aborde les effets des odorants par inhalation, il est bas e sur une vue d'ensemble des principales etudes chez l'homme. L'effet b en efique des parfums est principalement li e au comportement humain. Les etudes documentent que les odorants influencent les syst emes nerveux sympathique et parasympathique, et l'activit e neurophysiologique du cerveau. En outre, les compos es de mauvaises odeurs peuvent agir sur le syst eme neuroendocrinien, les neurotransmetteurs et neuromodulateurs, influencer le comportement psychologique ainsi que la fonction du corps. L'inhalation odorante module les voies physiologiques, et dans certains cas, peut entraîner la r egulation de la fonction de la peau. Le m ecanisme n'est pas compl etement elucid e. Ces r esultats sugg erent que le syst eme olfactif joue un rôle dans le fonctionnement du syst eme nerveux central au-del a de l'odorat. Dans cet aperc ßu, il a et e observ e que les compos es odorants influencent les biomarqueurs du stress, le d ehydro epiandrost erone, le stress oxydatif, l'estradiol, la dopamine, la barri ere cutan ee, la s ecr etion de s ebum et le syst eme immunitaire cutan e chez l'homme. Certains peuventêtre li es a la fonction de la peau. Comme la peau est associ ee a une large...

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