If your initial response to this statement is “why?” then the answer is simple - for the same reason that those who work in a sewerage plant no longer smell the poo. In other words, as you become accustomed to a particular scent it has a tendency to lose its effectiveness. It’s for this very reason that intermittent diffusing is a great way to maximize your products.
For those of you who aren’t familiar with the term diffusing, think of it as distributing essential oil molecules into the air, either via a candle, warmer or burner. When you diffuse essential oils into the atmosphere, the constituents that make up each precious essential oil are then absorbed via smell. From here they may enter your bloodstream and even reach your central nervous system, often causing a profound affect on your mood. This takes place without you being consciously aware of it. The reason being is that smell has a direct pathway your limbic system (the part of your brain that deals with emotions) while by-passing the part of the brain that intellectualises stuff.
Diffusing (or as I like to call it, “ambient inhalation”) is one of the most popular methods of use in modern aromatherapy, and fortunately one of the safest. In their book Essential Oil Safety - A Guide for Health Care Professionals (2nd Edition) (https://www.amazon.com/Essential-Oil-Safety-Health-Professionals/dp/0443062412), Robert Tisserand and Rodney Young state: “Even in a relatively small closed room, and assuming 100% evaporation, the concentration of any essential oil or constituent is unlikely to reach a dangerous level, either from aromatherapy massage or from essential oil vaporization.”
Although continuous diffusing is unlikely to be a safety issue, in order get the most out of your oils, Tisserand and Rodney Young recommend intermittent diffusing in order to maximise the efficiency of the product, “If you are diffusing essential oils, it makes more sense to do this intermittently than constantly, all day long. Ideally, diffuse essential oils for 30-60 minutes on, then 30-60 minutes off…it’s also more effective as both our bodies and our nervous system habituate to essential oils after this period of time.”
This point takes us back to the title of this article – specifically “less is more”. In other words, when the smell is constant our bodies and our nervous system become accustomed to it, which makes essential oils less effective. While this mightn’t be a good thing for those of us smelling essential oils, it’s definitely a great thing for those employed in the sewerage industry.