Relieving psychological stress and improving sleep quality by bergamot essential oil use before bedtime and upon awakening: A randomized crossover trial

The COVID-19 pandemic increased psychological stress and decreased sleep quality, especially among young people. Aromatherapy alleviates psychological stress, and bergamot essential oil helps improve depression. This study aimed to verify whether bergamot essential oil use alleviates psychological stress due to the COVID-19 pandemic and improves sleep quality and morning wakefulness.A placebo-controlled, randomized, open-label, two-arm, two-period crossover trial.Each intervention period was 1 week, with a 1-week washout period between the two periods. Participants used a bergamot or placebo spray before bedtime and upon awakening in each period.The primary outcome measures were sleep quality and morning wakefulness, assessed using the Ogri-Shirakawa-Azumi sleep inventory MA version (OSA-MA). The secondary outcome measures were depression, anxiety, and stress, assessed using the Depression Anxiety Stress Scales-21 (DASS-21).A total of 48 university students participated in the study. A significant improvement was observed in "sleepiness on rising," "refreshing on rising," and "sleep length" in the bergamot group. Additionally, a significant improvement was observed in depression, anxiety, and stress.Using bergamot essential oil before bedtime helps relax the mind and body and provides sound sleep. It also improves mood and wakefulness when used upon awakening. Using aromatic essential oils is expected to relieve psychological stress and improve sleep quality and morning wakefulness.