I was driving to the post office the other day with the windows down and caught a fresh whiff of freshly cut grass.

I felt the sense of carefree joy rush over me.

I used to mow lawns to make extra money as a teenager, and the smell of grass (and gasoline!) always reminds me of the bright sunshine-filled days of my teenage youth, daydreaming about my high school crush, Aaron.

Our sense of smell is funny like that. Our most prehistoric, guttural sense is also the one we think we use the least. And then it smacks us in the brain right when we least expect it, reminding us, after all, that we are still humans.   

We know scent can transport us to different places in time, but how does that actually work? Does scent have an effect on our brains? Can we use it to intentionally change our moods? Yes, and yes!

One way trip to the limbic (it rhymes!)

A scent is made up of tiny aromatic molecules. When you inhale a scent through the nose, these molecules climb up tiny olfactory nerves in the inner nose and head straight for the brain’s limbic system.

The limbic system is a network of structures that controls some behaviors essential to the life of all mammals, such as finding food, and staying alive.

It has three essential functions: emotions, memories, and arousal (stimulation), which it translates from the information it receives from the outside environment.

Once the message is translated, the limbic system communicates this message to the central nervous system, which directs all of the basic instinctive bodily functions such as heart rate, digestion, respiration, perspiration, and sexual response.

Scent molecules are rare in their ability to quickly cross the blood-brain barrier and interact with the central nervous system. Basically, scent affects mood, and mood affects your basic instinctive bodily functions.

Olfaction goes WAY back

When we were swinging through the ancient jungles of modern-day Africa, our sense of smell was right there with us, helping us identify food, predators, and mates.

Just as it was back then, olfaction is still one of the most important ways the environment communicates with us.

Once humans became a bit more sophisticated, we started using our sense of smell to manipulate the body into healing itself. Many ancient civilizations, including Egypt, China, and India, used aromatherapy (or, healing with aroma) to treat a plethora of disorders like headaches, pain, insomnia, eczema, stress-induced anxiety, depression, and digestive problems.

Today, pharmaceutical companies would have us believe aromatherapy is a “pseudoscience,” but we have real scientific evidence that aromatherapy alters brain wave patterns.

The evidence behind aromatherapy

There have been dozens, if not hundreds of studies on human response to scent. Usually the best tool for the job is a good ol’ electroencephalograph, or EEG. If you haven’t experienced this device firsthand, it’s a non-invasive super sci-fi looking helmet that measures brain wave activity. This machine is used to diagnose epilepsy, brain tumors, brain damage and disfunction, stroke, and sleep disorders. Make no mistake, it’s legit!

Most studies involve a participant inhaling aroma while the EEG monitors reactive brain activity.

The majority of studies on aromatherapy conducted via EEG conclude that fragrances directly affect mood, stress, and cognitive function, in addition to indirectly affecting various physiological conditions.

But that’s old news isn’t it?

In the mood to enhance your mood? Check out this article on 5 fragrances to make you happy!