Olfactory fatigue, also known as odor fatigue or olfactory adaptation, is the temporary, normal inability to distinguish a particular odor after a prolonged exposure to that airborne compound. For example, when entering a restaurant initially the odor of food is often perceived as being very strong, but after time the awareness of the odor normally fades to the point where the smell is not perceptible or is much weaker. After leaving the area of high odor, the sensitivity is restored with time. Anosmia is the permanent loss of the sense of smell, and is different from olfactory fatigue.
Contents
- Olfactometric method and clinical studies
- Rejuvenation through coffee
- Rejuvenation through other means
- References
It is a term commonly used in wine tasting, where one loses the ability to smell and distinguish wine bouquet after sniffing at wine(s) continuously for an extended period of time. The term is also used in the study of indoor air quality, for example, in the perception of odors from people, tobacco, and cleaning agents.
Olfactory fatigue is an example of neural adaptation or sensory adaptation. The body becomes desensitized to stimuli to prevent the overloading of the nervous system, thus allowing it to respond to new stimuli that are 'out of the ordinary'.
Olfactometric method and clinical studies
Sachs mentions the earliest reference as old as early nineteenth century. The primitive stages in curing the condition in humans were through the clinical experiments. The Ellsberg method was one of the first to determine the threshold value for odorous substances. To date, his olfactometric method is known as one of the best methods to stimulate the threshold of olfactory senses and determine the decaying of the senses once there has been a continuous supply of same smell.
Rejuvenation through coffee
Some perfumers stock coffee beans near their displays as it is commonly believed that smelling coffee between perfume testing can limit or reverse olfactory fatigue.
This view remains controversial, with some researchers citing positive reactions while subsequent research seems to indicate no benefit from sniffing coffee beans compared to lemons scents or plain air:
Rejuvenation through other means
Another commonly believed way to reduce olfactory fatigue is to smell one's own unperfumed skin (typically the crook of the elbow) on the theory this is the "baseline" smell for each individual.