Whether your sense of smell has been ghosting you since you had Covid or you want to develop a nose for excellence, smell training is here to help. WH sniffs out the science
One morning, Courtney Dunlop was massaging on a face cream she thought was unscented when she detected the aroma of roses. How could that be? Courtney was baffled. The answer wasn’t rooted in magic, but neuroscience. The 41-year-old’s sense of smell had finally made a full recovery, 18 months after she was first infected with Covid.
Loss of smell (anosmia) was one of the virus’s most widely discussed symptoms. But it’s not exclusive to Covid. ‘There are hundreds of reasons why someone can lose their sense of smell,’ says Zara Patel, an associate professor of otolaryngology – a surgical sub-speciality that deals with the neck and head – at Stanford University. Reasons such as endocrine and metabolic issues (eg, hormonal changes), head trauma, medications and the ageing process. Other scent-stealers include the flu, rhinoviruses, sinusitis (inflamed nasal passages), and pregnancy rhinitis (nasal inflammation during pregnancy).
Courtney lost her sense of smell for six weeks, regaining it slowly until, a year and a half later, she could stop and smell the roses in her face cream. For some, this process takes weeks; for others, it takes months. And 20% to 30% of all cases of anosmia have some level of permanent olfactory dysfunction.
To help someone get back their sense of smell (or speed up the process), experts recommend smell retraining, which stimulates your olfactory system. But how does it work? To find out, we inhaled the science to find who it could help. All of us, as it turns out.
OLFACTORY SETTINGS
When you whiff something, you inhale minuscule molecules that attach to cell receptors in your nose. These send signals to nerves in the olfactory bulb, which sits at the bottom of the brain. And because that bulb sits next to the amygdala and the hippocampus areas of the brain, your sense of smell is linked to emotion and memory. (This is why your co-worker’s vanilla-based fragrance reminds you of the cake your gran made every year on your birthday.)
When you’re sniffly or have a virus, mucus and nasal inflammation can block those molecules from getting through. This typically clears when your nostrils do, but in some cases, as with Covid, it lingers. ‘It seems the virus attaches to cells that support the olfactory nerve,’ says Nicholas Rowan, an assistant professor of otolaryngology at Johns Hopkins School of Medicine in Baltimore. ‘Those cells die off and take time to regenerate.’ With a head injury, trauma damages the olfactory nerve, so it stops working properly.
SCENTS AND SENSIBILITY
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