The effect of the essential oils of lavender and rosemary on the human short-term memory

Essential oils have a long history of traditional use but few clinical trials to evaluate their efficacy. Rosemary essential oil is thought to be energizing, and a study of 20 healthy volunteers found that it increased blood pressure, heart rate, and rate of respiration, leaving participants feeling refreshed. Lavender essential oil is thought to be sedative, and a study of 20 healthy volunteers found that it decreased blood pressure, heart rate, and skin temperature, leaving participants feeling relaxed.

Methods

Because of their opposite effects on the central nervous system, researchers compared the effects of essential oils of rosemary and lavender on short-term memory in secondary-school students in Ukraine. Study participants were 79 students (aged 13-17) in school in a modern Ukrainian city. Participants were divided into 3 groups: the control group was not exposed to any essential oils, the lavender group was exposed to the essential oil of lavender, and the rosemary group was exposed to the essential oil of rosemary.

Participants were not aware that they were being exposed to these airborne essential oils, which were poured into dishes of water inside a closed room before the students entered. Short-term memory was assessed with 2 tests: the memory of images and the memory of numbers. For each of these tests, participants were shown a set of images or numbers and then asked to remember as many as possible for 20 seconds.

Both rosemary and lavender essential oils have cognitive effects.

Results

Both rosemary and lavender significantly increased the image memory compared with the control. Out of 16 images, the control group remembered a median of 7, the lavender group remembered 9, and the rosemary group remembered 9.5.

For numerical memory, there was no significant difference between the experimental groups and the control. There was, however, a statistically significant difference between the rosemary and lavender groups. The rosemary group remembered significantly more numbers (7 out of 12) than the lavender group (5 out of 12).

Conclusions

The results of this study suggest that both rosemary and lavender essential oil improve memory for images but that only rosemary improves memory for numbers. These findings support the traditional notion that both essential oils have cognitive effects with rosemary potentially causing more cognitive activation.

Filiptsova, O.V., Gazzavi-Rogozina, L.V., Timoshyna, I.A., Naboka, O.I., Dyomina, Ye.V., & Ochkur, A.V. (2018). The effect of the essential oils of lavender and rosemary on the human short-term memory. Alexandria Journal of Medicine, 54(1), 41-44.