Stress may not only make you smell bad, but also the world around you, a new study suggests.
Previous research showed that the sweat our bodies produce in response to anxiety smells worse than other types of sweat -- such as from exposure to high temperatures, for example. Now a new study shows that when we're stressed out, our brains find otherwise neutral odors to be noxious.
Basically, stress just downright stinks all around.
"People experiencing an increase in anxiety show a decrease in the perceived pleasantness of odors," study co-author Dr. Wen Li, a psychology professor at the University of Wisconsin-Madison, said in a written statement. "It becomes more negative as anxiety increases... We encounter anxiety and as a result we experience the world more negatively."
For the study, Li and her research team looked at functional MRI (fMRI) scans of the brains of study participants who were exposed to disturbing images and messages. The team noticed that two distinct and typically independent circuits of the brain — one linked to olfactory processing and the other to emotion — became intertwined under conditions of anxiety.
To explore this relationship, the researchers asked the participants to rate a panel of neutral smells before and after being exposed to disturbing images in the fMRI scanner. It turned out that many of the participants assigned negative responses to smells they actually rated as neutral before being exposed to the stress-inducing images.
"In typical odor processing, it is usually just the olfactory system that gets activated," Li said in the statement. "But when a person becomes anxious, the emotional system becomes part of the olfactory processing stream."
Once the two systems get linked, even more stress can result. "It can become a vicious cycle, making one more susceptible to a clinical state of anxiety as the effects accumulate," Li added. "It can potentially lead to a higher level of emotional disturbances with rising ambient sensory stress."
So then, will de-stressing make things smell better to us?
"Yes, de-stressing will potentially prevent negative emotional information from entering olfactory processing stream, and thus things won't smell as bad," Li told The Huffington Post in an email.
The study was published online in the current issue of the Journal of Neuroscience.