Robert Tisserand wrote some guidelines around diffusion a few years ago, and for some it still causes confusion.
He wrote: “Intermittent diffusion is much more effective, as well as being safer, than continuous diffusion. Intermittent means 30-60 minutes on, then 30-60 minutes off.
This is because our body, especially our nervous system, habituates after this length of time. With continuous diffusion, while benefits do not increase, there is evidence that the body becomes stressed in various ways.
However, very low levels of diffusion – so the essential oil is barely noticeable – are fine anywhere, for any length of time.”
Remember that safety guidelines are just that, guidelines. The standouts to note from his words are that diffusing for too long can stress the body, which is the opposite of what we are generally trying to achieve. Also the other key point is about very low levels of diffusion – if the essential oil is barely noticeable, it is fine anywhere, for any length of time.
If you use it in small spaces, with no ventilation, then intermittent is best practice. But if you are using in an open space or large space with good ventilation then longer is fine.
Does that help clear it up?