The Science Behind Breathing in Your Mouth
& Out the Nose, Without Inhaling
MONQ personal aromatherapy diffusers contain only pure essential oils in a vegetable glycerin base. When using MONQ diffusers in a fashion that provides a lot of mist, MONQ users breathe the essential oil blend into the mouth (without touching the device to the mouth) and out the nose using a retronasal breath, without inhaling to the lungs. When using the AirTip method, which method expels just a small number of fragrance molecules, gentle breaths in the nose, still without inhaling into the lungs, may provide for a more pleasant experience.
MONQ has long recommended this method of breathing to maximize the potential therapeutic benefits and perceived smell of MONQ aromatherapy. Terpenes—the aromatic molecules in essential oils and the building blocks of our aromatherapy—activate olfactory receptors, which then use neurotransmission to affect human physiology. When MONQ users hold the mist in their mouths, the important terpene molecules are absorbed by the oral and nasal mucosa in the linings of the mouth and nose, from which they can directly and effectively stimulate olfactory receptors as the therapeutic air directly wafts by the olfactory bulb.
Evolutionary biology suggests that the human oropharyngeal and retronasal pathway has adapted to optimize our sense of taste and smell while protecting the lungs.
- “Retronasal, but not orthonasal, odors share processing circuitry commonly associated with taste “ (Menini, 2010).
- Evidence suggests that humans’ ability to distinguish between specific and delicate food flavors depends primarily on retronasal smell. Using this as the basis for research, scientists found that there are adaptations to the mouth, throat, and nasal passages such that a retronasal breath traps food volatiles (such as fragrant molecules) in a “curtain” at the back of the throat, preventing transportation to the lungs, and optimizing the same volatiles in the retronasal flow to stimulate olfactory receptors (Ni et al., 2015).
- According to Verhagen, there are three routes of odor transport, mouth-lung-nose, nose-lung-nose, and direct mouth-nose. A mouth-to-nose route is typical of retronasal smell during food intake, and it is the only route that does not involve the lungs. This is the breath MONQ recommends.
- When odors are inhaled to the lungs, using either the mouth-lung-nose or nose-lung-nose route, as much as 58% of volatiles (fragrant molecules) are retained in the lungs and do not make a retronasal pass upon exhalation. In other words, the very pathway that MONQ aromatherapy relies on to receive and process the aromatic molecules in a blend is rendered highly ineffective, if not useless, if the blend is inhaled to the lungs (Verhagen, 2015).
In addition to being the most direct and efficient route of absorption, a retronasal breath also minimizes sensory adaptation.
- When researchers investigated the occurrence of sensory adaptation with orthonasal versus retronasal fragrance delivery, they found that adaptation occurred readily with orthonasal but not a retronasal pathway, pointing back to the evolutionary adaptations that have occurred to allow humans to breathe (and taste) without the involvement of the lungs (Pierce & Simons, 2018).
MONQ works best when users breathe retronasally, in their mouth and out their nose, without inhaling to the lungs.
Menini, A. (Ed.). (2010). The Neurobiology of Olfaction. CRC Press/Taylor & Francis.
Ni, R., Michalski, M., Brown, E., Doan, N., Zinter, J., Ouellette, N. T., & Shepherd, G. M. (2015, November 24). Optimal directional volatile transport in retronasal olfaction. Proceedings of the National Academy of Sciences of the United States of America, 112(47), 14700-14704. PMC.
Pierce, A. M., & Simons, C. T. (2018, March). Olfactory Adaptation is Dependent on Route of Delivery. Chemical Senses, 43(3), 197-203.
Verhagen, J. V. (2015, August 1). A role for lung retention in the sense of retronasal smell. Chemosens Percept, 8(2), 78-84. PMC.