Olfactory fatigue

Olfactory fatigue or 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.

It is a commonly used term 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. Our bodies become desensitised to stimuli in order to prevent the overloading of our nervous system, thus allowing it to respond to new stimuli that are ‘out of the ordinary’.