Science Says Smelling Certain Things While Sleeping Makes You Smarter

By Douglas Helm | Updated

Have you ever smelled a nostalgic scent, like cut grass or pool chlorine, and instantly get transported back to childhood summer days? Well, that’s in part due to the fact that our olfactory sense is one of our strongest links to memories.

Science Alert recently reported that we may be able to take advantage of this fact with sleep smells, which means that smelling certain fragrances while you’re sleeping could boost cognitive performance and strengthen the connection between neurological areas involving memory and decision-making.

Researchers have discovered that certain sleep smells can improve brain function and cognitive performance.

Researchers at the University of California did a study on these sleep smells that involved 43 men and women aged 60 to 85. Spritzing these fragrances throughout the bedroom before bed could possibly help to slow conditions that lead to cognitive decline, such as dementia. It essentially works by stimulating the brain’s gray matter as we sleep, keeping it engaged just like we do with activities that involve sight and sound.

It makes sense, too, because if you can help keep the brain sharp with mental activities like crosswords and sudoku, there’s no reason why sleep smells wouldn’t keep the brain stimulated in a different way.

Humans aren’t the only ones who have shown that these anti-degeneration tactics may work. Studies have shown that animals with symptoms similar to human neurological disorders experienced a boost in neuroplasticity when their environments were enriched with different scents.

In the sleep smells study, the researchers used natural oils like rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender scents to test the theory.

Further making a case for sleep smells is the fact that we often see our sense of smell decline as we age before we see cognitive decline begin to kick in. Furthermore, we also begin to lose brain cells if we lose our sense of smell, which suggests an even stronger link between our olfactory senses and our brain’s ability to function. Unfortunately, there aren’t really measures in place to enhance our smell when it’s lost, unlike glasses with vision impairment and hearing aids with hearing impairment.


In the sleep smells study, the researchers used natural oils like rose, orange, eucalyptus, lemon, peppermint, rosemary, and lavender scents to test the theory. Some members of the group were provided with a ‘sham’ fragrance that only contained trace amounts of an odorant as a control. Each study participant was instructed to use one of the oils with a diffuser to scent their home for two hours every night over a six-month period.

Test subjects exposed to sleep smells saw an improvement of over 200% in cognitive performance.

The group was also asked to rotate through the different sleep smells throughout the study. Tests were then conducted that involved memory, verbal learning, planning, and attention-switching skills. The results were pretty convincing.

According to the study, there was a whopping 226 percent difference between the group provided with the real sleep smells and the control group. The group with the fragrances also saw a significant change in their brain’s links between memory and thinking. The only hitch is that the group in the study were all of sound brain health.

More sleep smells studies will be needed to see how this affects those with cognitive problems. It’ll be interesting to see how these pan out. In the meantime, it may not be a bad idea to use a diffuser at night to keep the nose (and brain) happy.