The Effects of Lavender Oil Inhalation on Emotional States, Autonomic Nervous System, and Brain Electrical Activity
Winai Sayorwan MPham*, Vorasith Siripornpanich MD**, Teerut Piriyapunyaporn BSc***, Tapanee Hongratanaworakit Dr rer nat****, Naiphinich Kotchabhakdi PhD**,***, Nijsiri Ruangrungsi PhD*
Affiliation : * College of Public Health Sciences, Chulalongkorn University, Bangkok, Thailand ** Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhonpathom, Thailand *** Salaya Stem Cell Research and Development Project, Research Center for Neuroscience, Institute of Molecular Biosciences, Mahidol University, Salaya, Nakhonpathom, Thailand **** Faculty of Pharmacy, Srinakharinwirot University, Nakhon-nayok, Thailand
Objective : Investigate the effects of lavender oil on the central nervous system, autonomic nervous system, and mood
responses in humans after inhalation.
Material and Method: Twenty healthy volunteers participated in the experiments. The present study assessed autonomic
parameters such as blood pressure, heart rate, respiratory rate, and skin temperature to determine the arousal level of the
autonomic nervous system. In addition, subjects were asked to estimate their mood responses such as feeling pleasant or
unpleasant, uncomfortable, sensuality, relaxation, or refreshing in order to assess subjective behavioral arousal. Finally,
electroencephalogram (EEG) was recorded from 31 electrodes on the scalp according to the international 10 to 20 system,
and EEG power spectra were calculated by Fast Fourier Transform (FFT). Data was analyzed by comparing the effects of
lavender oil on physiological and mood states with sweet almond oil. These assessments were measured before and after
using paired t-test statistical procedure.
Results : The results revealed that lavender oil caused significant decreases of blood pressure, heart rate, and skin temperature,
which indicated a decrease of autonomic arousal. In terms of mood responses, the subjects in the lavender oil group
categorized themselves as more active, fresher, relaxed than subjects just inhaling base oil. Compared with base oil, lavender
oil increased the power of theta (4-8 Hz) and alpha (8-13 Hz) brain activities. The topographic map showed obviously more
scattering power in alpha range waves particularly in bilateral temporal and central area.
Conclusion : The findings provided evidence the relaxing effect of inhaling lavender oil
Keywords : Lavandula angustifolia Mill, Physiological parameters, EEG, Relaxation
