Scientists have linked scent and long term memory in a study conducted by the American Psychological Review. A simple scent like buttery popcorn can remind us of a movie theatre or passing a woman with a certain fragrance makes us remember a childhood memory of our mother or grandmother. Each whiff provides a link to a memory. A certain combination of smells can become a link to recall the scent of your bedroom at bedtime.
Finding the right mix of scents is what creates better slumber. A study in 2019 found that bad odors and good odors (like the smell of flowers) exist in the olfactory system in our brains. A bad odor (like tobacco smoke) can actually deter a restless sleep while good scents provide more energy when we wake up. The study in the Journal of Post-traumatic Stress even found that good scents provide deeper sleep and healthier dreams.