Stress and Smell

Just because you've woken up on the wrong side of the bed doesn't mean the world is out to get you. However, a new study shows your brain may be to blame for the fact that things around you seem a bit more rotten.

Researchers from The University of Wisconsin, Madison found that study participants shown stress-inducing, emotional images perceived neutral, slightly bad, and very bad odors as worse than they actually were. Using functional magnetic resonance imaging (fMRI), researchers observed a physical change in the brains of stressed participants.

Essentially, in response to stress and anxiety, the brain rewires itself and crosses olfactory and emotional pathways so that scents smell worse. So when you’re anxious and stressed, the world actually gets a little stinkier.

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“Anxiety itself has such a huge set of strong biological responses and physiological changes,” says study author Wen Li, Ph.D., an assistant psychology professor at UW-Madison.

Olfactory processing has long been linked to emotions, but this is one of the first studies to look at details in the relationship between smell and feeling. Your sense of smell is an incredibly useful tool to alert you to danger and pleasure. But while smelling smoke or getting to the bacon first is all well and good, a stressful day compounded by bad smells isn’t. Unfortunately, stress and anxiety contribute to a cycle of negative stressors, Li says.

Because anxiety has been shown to produce such strong responses in the brain, it’s a good venue to study changing neurocircuitry phenomenon, Li says. It’s well known that anxiety can make it harder to deal with life's obstacles, and researchers from Ohio State University have recently linked anxiety, stress, and the immune system in mice.

Long term stress also poses health risks, increasing the likelihood of cardiac disease, according to researchers from the University College London in the U.K.

Wired for Stress?

In this study, researchers found that, when stressed, the brain “tricks" itself into perceiving smells as worse than they are by crossing the olfactory pathway—which is comprised of the anterior piriform and orbitofrontal cortices of the brain—and the amygdala, which is the part involved in emotions.

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“Neurocircuitry is very adaptable to the environment we live in, and the internal circuits can rewire themselves when given [new] contextual information,” Li says.

A Smelly Solution

At this point, all you can do to freshen up your olfactory senses when you’re stressed is to take a step back and think through the reasons behind your stress. Ideally, olfactory therapies and mindfulness could be combined to battle anxiety, Li says.

“This opens possibilities for future interventions to focus on sensory aspects of anxiety,” Li says. After all, there’s aromatherapy, which has even been recommend by groups like the American Cancer Society.