The Effect of Camphor Essential oil That Promotes the Recovery Process From the Psychobiological Stress Responses Induced by Mental Stress Testing
H. Okamura1, A. Tsuda2, J. Yajima3
1Kurume University, Cognitive and Molecular Research Institute of Brain Diseases, Japan
2Kurume University, Department of Psychology, Japan
3Beppu University, Department of Human Studies, Japan
Background: Camphor essential oil can sedate the autonomic nervous system. However, no study has been undertaken in the past to investigate its sedative effects using biological markers. The purpose of this study is to evaluate the sedative effect of camphor essential oil on the recovery process from the psychobiological stress responses induced by mental stress testing. Methods: Twenty healthy participants were recruited, and they were randomly classified into the aroma group and the control group. Salivary MHPG (the major metabolite of noradrenaline) and HF-component (index of parasympathetic activity) were measured at the baseline, immediately after speech & arithmetic tasks and the recovery period. Findings: The level of MHPG in the aroma group returned to the basal level during the recovery period more quickly than the control group, although an increase in MHPG during the task period was equally observed in both groups. HF-component increased in both groups during the recovery period, but these levels were significantly higher in the aroma group than in the control group. Discussion: These results indicate that camphor essential oil could produce sedative effects which promote the recovery process from the psychobiological stress responses.