Influence of the Fragrant Essential Oils’ on
Psychophysiological State of an Individual
KONSTANTIN KOROTKOV, Ph.D.,1 PETER MATRAVERS Ph.D.,2
Objective: Evaluation of the influence of aromas of different essential oils on
the psycho-physiological condition of people. To show by certain methods that
smelling these oils will either have a stimulating, calming/ relaxing, or some other
effect (physiological and/ or psychological) on a given individual. The eventual goal
is to make a correlation between different tests and the clinical tests.
Design: All the participants were volunteers, average age 20. All experiments
were conducted in one and always the same room of the Saint-Petersburg University
ITMO (Russia). We have used essential oils made by Aveda Corporation (USA) and
specially designed box for aroma testing. For the evaluation process we have used
questioners and several types of equipment such as: EPC (Electrophoton capture or
Gas Discharge Visualization – GDV) Camera Compact, Surface Frequency Meter
(SFM), Heart Rate Variation (HRV) tester.
Results: Significant correlation can be observed both among the instrumental
methods (EPC, SFM) and between the instrumental and the subjective evaluations.
High correlation of the data produced by the SFM and EPC methods suggests that
these methods allow independent registration of the influence of the factors under
study, even though the working principles of these methods are absolutely different.
The HRV (cardiorhythmogram) of the individuals under study did not reveal any
dynamics that would unambiguously correlate with the conducting of the
Conclusion: Our experiments showed that perception of different odours depends
strongly on human and his current condition, and no one can say that concrete odour
will always have some definite impact on every individual. EPC method itself is good
enough for registering persons’ reaction on different fragrances, though it is not new
generally, in this field of study it is a novel method.
Natural essential oils are commonly used in perfumery, food, pharmaceutical
production and in aromatherapy. Synthetic essential oils are produced and used like
natural essential oils, but have lower price. Modern chemical technologies allow the
production of synthetic fragrance compounds that can be hardly distinguished by their
odor from natural ones. It is well known that synthetic essential oils doesn’t have any
biological activity as natural ones and also can result in decrease of total immunologic
activity and even toxic effect1
There are two main theories of fragrance influence on human olfactory receptors:
chemical and wave theories1
. It can be shown from the results of research2
and sensitivity of human to different odors depends more from energetic (electron) state
of fragrance compound atoms and less from its chemical nature. That is why EPC
method3,4, as a very fast method of functional state evaluation of biological objects and
some structural properties of materials and liquids3-5, was chosen for research of natural
essential oils influence on human.
By the way we’d like to note that the Nobel prize in physiology or medicine in 2004
was awarded jointly to Richard Axel and Linda B. Buck for their discoveries of
“Odorant receptors and the organization of the olfactory system”. So we can make the
conclusion that this field of research is very important and essential nowadays.
The technique of Electrophotonic (EPC) bioelectrography allows the recording,
from a living subject, of electron and photon emission stimulated by an electromagnetic
field, as well as the acquisition of these data by computer image processing. The electric
impulse on the camera plate stimulates biological subjects (or chemicals evaporated by
this subject) and generates a response in the form of an excited gas plasma (that is why
in physical terms this approach is known as Gas Discharge Visualization – GDV3,4).
This plasma emits both light and other electromagnetic fields over a wide frequency
band because of the short electrical impulse used (10 microsec). The emissions are
directly measured by a charge-coupled device (CCD), the state of the art in measuring
low-level light that is used in astrophysics and other scientific endeavors. The CCD
registers the pattern of photons detected over time. These digital data are transmitted
directly into a computer for data processing, and each image (named a EPC-gram) from
the light emitted is stored as a graphics file. These two-dimensional images of the light
are then used to calculate the area, emission intensity, density, fracticality, and other
parameters. On the basis of the calculated parameters, experimental conclusions are
Reportedly the EPC has overcome the experimental obstacles of older forms of
electrophotography. What were previously considered as confounding parameters (such
as pressure, finger size, sweating, or changes in physical conductivity) in the older
forms of electrophotography have been demonstrated by different researchers to be
overcome by the new EPC method3,4. Researchers report replicability of findings across
different experimenters, different cameras, and different countries6-14.
The EPC technique has been found to be effective in evaluating the state of
individual human health, in monitoring of individual reactions to different kinds of
training, and in studying the energy properties of liquids15-23.
The EPC system is certified by the Ministry of Health of the Russian Federation as a
medical technical device. These devices are being produced in Russia and in Spain.
Scientific researches in the field of fragrance influence on human have started
several years ago. Since that time the obtained results were presented at the international
conferences and published in different journals24-32. In this paper we are going to present
our latest experimental results of investigation the influence of fragrant essential oils on
psychophysiological state on individual.
PARTICIPANTS AND METHODS
All participants were volunteers, they were explained the aims and protocol of the
experiments, and everyone signed a special contract, filled a form for evaluating
psycho-somatic heath state and short Aizenk questioner. Only practically health
mentally stable people having no allergy reactions were selected for the participation in
Conditions of the experiments
Room was well ventilated, temperature was kept at 72±2 о
F, relative humidity not
more than 70%. In a single day only one aroma was tested with different participants.
Every participant tested only one aroma per day. Before the testing a participant was
sitting in a room reading book for accommodation and relaxation. All mobile phones
were switched off. Neither participants nor researches were talking during
measurements. During testing participant was looking to the picture of a mountain
landscape. Before and after the testing participants filled in a special Aveda Essential
Oil Evaluation questionnaire. This is a standard subjective test that gauge an individual’s
perception as to what effect smelling the oil had on him or her. That is, for the
individual was the effect of smelling the oil stimulating, calming/ relaxing, something
else, or was there no effect at all? This questionnaire was administered to the panelists
before (baseline) and immediately after smelling the oils.
Essential oils were kept in hermetically sealed bottles. 10% solutions of each oil in
alcohol (absolute ethanol or specially denatured [SD] alcohol) was prepared in
individual syringes. The mixture was shaken till the homogeneous solution and dropped
to the tester paper immediately before the presentation to the nose of a panelist. After
smelling the tester was placed in a closed jar. All operations with aromas were
conducted inside the smell box.
At any rate, the goal is not to evaluate the aroma strength of the oils, but to evaluate
their stimulating or calming/ relaxing effects.
Aromas are coded as follows: A = cinnamon; B = rose alba; C = Roman chamomile;
D = lavender, E = empty.
Methods of study
Electrocardiography (ECG) – is a standard objective test to monitor the rhythms of
an individual’s heartbeat and/ or Heart Rate Variation (HRV) both before (a baseline
reading) and immediately after smelling the oil. HRV can be calculated by analyzing
the time series of beat-to-beat intervals generated from ECG or the arterial pressure
EPC (Static) – is an objective test measuring the fingertips. The ring (fourth) finger
of the left hand was measured at 15-second intervals during a 5-minute baseline/ before
smell phase, a 2.5-minute during smell phase at which adaptation to smelling the oil
takes place halfway through this phase, and during a 5-minute after smell phase. All 10
fingers were measured with commercial EPC camera before and after smelling.
Surface Frequency Meter (SFM) – is an objective test measuring the dynamical high
frequency signal from the wrists and ankles of a panelist simultaneously with the
dynamical EPC signal. We have designed such an experimental device specially for our
research. The obtained signal is called “dynamical” because it is recorded in time,
during 10 minutes. More information on this method is given later in describing the
realization of it.
The method of subjective estimation of aroma is based on the sensations of the
participants, which are reflected in tests completed right before and right after the
inhalation of the aroma. The test reflecting the self-evaluation of the individual’s mood
(merry, calm, active, etc.) was completed before and after the perception of the aroma,
while the tests that reflect the properties of the aroma were completed right after the
inhalation of the aroma. The tests reflecting the aroma’s properties comprise a numeric
characteristic along with the verbal one, allowing mathematical treatment of the data.
We used the questionnaire developed by the AVEDA Company (USA), which allows
presenting the subjective criteria of the odor estimation (intensity and preference) on a
5-grade scale and the questionnaire developed by the Monell Chemical Senses Center
(MCSC)33, which allows evaluating the odor preference in scores from -10 to 10 and the
intensity in scores from 0 to 100. All tests are brought together in table 1 for better
TABLE 1. ESTIMATION OF AROMA ITSELF, ESTIMATION OF AROMA FORCE AND THE
CRITERION OF IRRITATION AND ASSOCIATIONS
Aroma preference Aroma force
Irritation of nose or
Very unpleasant 0 Very weak 0 No 0 No 0
Unpleasant 1 Weak 1 Yes 1 Yes 1
Neutral 2 Optimum 2
Pleasant 3 Strong 3
Very pleasant 4 Very strong 4
The method of evaluating the health quality. We used the “HELPSY” valeological
program, based on the algorithm of health quality diagnostics34, which was developed in
St. Petersburg Research Institute of Physical Culture. “HELPSY” is a dialogue-based
system that includes necessary and sufficient minimum of hardware-measured parameters
(arterial blood pressure and pulse), which in conjunction with the anamnestic data allow
defining the psychosomatic health quality of the subject, basing on the knowledge that
exists in the expert information system’s database.
The methods of evaluating the psychoemotional status. We used the “POMS” test35
intended for evaluating the psychoemotional status by estimating six indices (factors):
stress-anxiety, depression-despondency, anger-aggressiveness, power-activity, fatiguepassivity,
embarrassment-confusion, and the Eysenk’s personality questionnaire36,
which allows determining the temperament’s constituents, i.e., the extraversion level
and the neurotism level.
Statistical methods of analyzing and processing data: methods of parametric (the ttest)
and nonparametric statistics (Kolmogorov-Smirnov-test, the Spearman correlation
coefficient), implemented in Statistica 6.0 (version 2004, StatSoft, Tulsa, OK)37, the
“GDV Scientific Laboratory”™ (Biotechprogress Co. Ltd.) or SciLab and MS Excel
(Microsoft® Office 2003) programs.
Realization of methods
During the research the data was collected from the 4th finger of right hand of the
participants during 10 minutes, consisting of 2.5 minutes of equipment stabilization,
followed by 2.5 minutes of background state (“Before” stage), 2.5 minutes of aroma’s
inhalation (“Smell” stage) and 2.5 minutes of after-effect (“After” stage). The “GDV
Compact”™ (Biotechprogress Co. Ltd.) device was used in automatic operation mode:
every 15 seconds a voltage impulse was supplied and the glow signal was recorded
from the finger of the participant into the computer. Upon completion of each
experiment all data were processed: the glow parameters were calculated and the data
were statistically processed.
The overall changes in the individual’s psychophysiological state under an aroma’s
influence were also registered by taking the EPC-grams from ten fingers of the
individual’s hands, right before the “Before” stage and right after the “After” stage.
In the course of the research the SFM (Surface Frequency Meter) device was used,
which allows numerically measuring the high frequency current that flows through the
individual’s tissues upon applying 5 microsecond impulse potentials to skin. The
scheme of the electrodes’ connection: two potential electrodes are put on the wrists of
the right and the left hand, respectively, while the two nulling electrodes are put on the
shins. The contacting parts are wiped with alcohol and dried beforehand. The device
outputs the values of the integral sum of current in the right and left channels, and in the
reference channel, which allows taking into account the background disturbances, as
well as performing the detrending when necessary. The registration of the integral sum
of current by means of the SFM method was performed during 10 minutes, in
synchronization with the registration of the EPC-grams.
The HRV (cardiorythmography) method allows registering the electrical activity of
heart and the muscles that participate in the respiratory process. The analysis of the
obtained data provides an opportunity to study certain cardiological and respiratory
peculiarities of the individual under study. The HRV was recorded twice for studying
the influence of each aroma according to the chosen chronology.
Pre-processing of data was handled by software suites that had been especially
developed to interact with the EPC, SFM and HRV equipment. Then the obtained
results were further processed by means of the Statistica 6.0, GDV SciLab and MS
Excel software programs. The homogeneity of data was analysed by means of two main
statistical methods. At the beginning we have taken 4 different methods of data
analysing and compared them, and these two methods have showed the best results:
their sensitivity to the changes was better.
T-test for dependent sample. This criterion is used for checking the hypothesis of
equality of means of two samples having normal distribution. The t-test for dependent
samples is used in those situations (quite common in practice) when an important source
of the intragroup variance (or error) can be easily determined and excluded from the
analysis. Basically, the t-test consists in calculating the difference between groups and
comparing it with the difference. The t-test for dependent samples uses only paired
differences, ignoring the initial numeric values and their variation. Thus, the value of
said difference is not compared with the dispersion of the initial values, but with the
dispersion of the individual differences, which is relatively small.
Kolmogorov-Smirnov-test. This criterion is used for checking the hypothesis stating
that two independent samples were obtained from the same general population, i.e. the
distribution functions of both general populations are identical (in this case the general
populations are said to be homogeneous).
The SciLab program is intended for multi-parameter processing of static and
dynamic GDV-grams and the subsequent statistic comparison of two or more samples
of calculated parameters. Statistical tests implemented in the program were based on
Student criteria, Wilcockson criteria, Mann – Whitney and Valde – Volfovitz criteria as
well as on signs criteria, and ensure the analysis of dependent and independent data
samples possessing various distribution types. SciLab can calculate set of parameters of
acquired from “GDV Compact” images (EPC-gram), we have used in our analysis two
of them: area of EPC-gram and symmetry.
The EPC-grams obtained from the measurements were processed by means of the
SciLab program, including generation of a file with numeric parameters. Then the data
were saved and transferred to the MS Excel program.
Then the homogeneity of the EPC data was analysed for the “Before”, “Smell” and
“After” stages, according to the criteria of the abovementioned statistical methods. The
statistical processing of the data was performed in the Statistica 6.0 program.
The obtained data were transferred to the MS Excel program, where the reaction of
the participant towards the aroma was analysed. The data of the EPC-grams obtained
from 10 fingers allow estimating the changes in the psychophysical state of a participant
under the influence of the aroma.