A few trials have investigated bergamot essential oil (BEO) aromatherapy for job-related stress. However, better-quality studies are needed to be able to draw any conclusions.
A small 2010 randomized controlled trial (RCT) of elementary school teachers in Taiwan compared aromatherapy with BEO to aromatherapy with a synthetic oil with a similar scent. The study found significant pre-post (before-and-after) differences in measures of heart rate variability, a physiological indicator of stress, after natural BEO but not after the synthetic fragrance;[1] however, since the study’s authors didn’t make any comparisons between the changes seen with natural fragrance and with synthetic fragrance, it’s impossible to say whether the difference between the natural BEO and synthetic control is significant. One additional study in school teachers also found decreases in the physiological markers of work-related stress, such as blood pressure and heart rate, after ten minutes of BEO aromatherapy,[2] but we can't be sure that these decreases are attributable to BEO because there was no control group.
One further study deserves mention here. Although this study was noncontrolled, it’s of interest because participants were experiencing exceptionally stressful workplace conditions. A noncontrolled, pre-post study of hospital nurses was carried out during the second COVID-19 outbreak in Taiwan (January–April 2021). This study examined the effects of 4 weeks of BEO aromatherapy on both subjective (standardized questionnaires) and objective (physical) measures of the nurses’ stress. While no significant pre-post differences were seen in the objective measures of stress or on the Nurses’ Stress Checklist, the study did note a significant reduction in the nurses’ scores on a standardized burnout questionnaire.[3] Again, however, this study was not controlled, so it’s impossible to say whether the pre-post differences were due to BEO, especially since it was conducted in the rapidly changing environment of a global emergency.