Effect of Lavender Essential Oil Topical Treatment on the Autonomic Nervous System in Human Subjects Without Olfactory Influence: A Pilot Study

Objective/background As part of a scientific study into the effects of aromatherapy, we investigated the effects of lavender essential oil (LEO) treatment on the autonomic nervous system in subjects for whom the sense of smell had been eliminated.Methods This study used a single-blinded cross-over design for verification. Heart rate variability was measured and effects on the autonomic nervous system were investigated.Results and discussion Although no significant differences were found, aromatherapy treatment with 1% LEO tended to increase parasympathetic nervous system activity. Further, when differences between values before and during aromatherapy treatment were compared, LEO treatment significantly increased parasympathetic nervous system activity. Given these findings, LEO appears to increase parasympathetic nervous system activity, even in the absence of a psychological effect due to an absence of olfactory stimulation.Conclusion The present results provide a scientific method for verifying the effects of aromatherapy and will aid in further elucidation of aromatherapy.