The Surprising Way Stress Can Change Your Sense Of Smell

During your shower, does your shampoo or shaving cream suddenly smell terrible? You can chalk it up to anxiety. A study by a research team at the University of Wisconsin-Madison sheds light on the surprising way stress can actually change the way we interpret different aromas.

Study participants were asked to smell, and then rate, a number of familiar, neutral scents. The individuals were then shown images and text of disturbing, stress-inducing scenes, like car crashes and war, while functional MRI (brain-imaging) technology monitored their brain activity. The participants were then asked to rate the scents again.

Wen Li, the psychology professor at the University of Wisconsin-Madison Waisman Center who led the research team, found some fascinating results. The second time around, most participants rated the same scents as negative, which they had previously rated as neutral.

The distinct parts of the brain that control emotion and scent normally (during low-stress times) work independently, without much interaction or "crosstalk" between them. Add stress, though, and this changes.

Stress actually causes a rewiring of the brain, to where the emotional and olfactory (smell) centers become closely intertwined with activity. As Li explained to Science Daily, "In typical odor processing, it is usually just the olfactory system that gets activated. But when a person becomes anxious, the emotional system becomes part of the olfactory processing stream."

Stress doesn't just change the way scents are interpreted, it changes them for the worse. Amazingly, the negativity that's often a part of anxious, high-stress situations even penetrates our sense of smell. Li adds, "We encounter anxiety and as a result we experience the world more negatively. The environment smells bad in the context of anxiety." Interestingly, this phenomenon can also work in reverse. A Swedish study found that pleasant smells from nature may have a significant, direct role as stress-reducers (via The Scientist).

The takeaway? Don't throw out that bottle of shampoo just yet. Relax, unwind, and try it again tomorrow. It just might smell fine.