Aromatherapy Research Article
August 2014
Travelling
The summer is in full swing, bringing the exciting prospect of a fun and relaxing holiday
away to many. However, even just the thought of taking a long journey can be stressful.
In this month’s newsletter, I will be presenting some evidence to support the use of
essential oils for some common complaints while travelling, which will hopefully aid in
easing your travel woes! Please be advised that some of the following information
comes from animal trials, with which Penny Price Aromatherapy is not connected to in
any way.
Travel Sickness
It is estimated that between 7 and 28% of individuals suffer from travel sickness when
travelling by road, air or sea. Despite this being a common, debilitating disorder, much
is still to be learnt about the biological mechanisms that cause travel sickness. However,
there is evidence to suggest that there is a genetic aspect that may lead to inherited
susceptibility. Furthermore, it is linked to a large activation of the sympathetic nervous
system (responsible for the ‘fight or flight’ response to danger) and the glucocorticoid
stress response system (which involves the longer-term stress hormone, cortisol).
Therefore, travel sickness can be regarded as the result of an intense gut-brain
interaction in a physiologically stressful situation (Chouker et al., 2010).
Essential oils could be a convenient alternative to conventional travel sickness tablets. It
is recommended that an essential oil or blend of essential oils in a suitable carrier are
massaged into the chest, stomach and even the relevant pressure points on the hands
and feet a few hours before travelling, and inhaling the oil(s) during travel as needed.
Peppermint (Mentha x piperita)
The use of peppermint in herbal medicine goes back as far as the ancient Greek, Romans
and Egyptian eras, where it was often used in herbal teas for digestive complaints,
including nausea and vomiting (emesis). This use has continued to the present day
around the world (Mckay and Blumberg, 2006), indicating that peppermint may be
useful in the relief of the nausea and vomiting associated with travel sickness. Some
scientific investigations have been carried out to investigate peppermint’s anti-emetic
effects, including a study performed with chickens. Methanolic peppermint extract
given to chickens treated with copper sulphate (a stomach irritant) significantly
reduced the incidence of emesis (Hossein, Masallah and Akbar, 2005). Furthermore, in
humans, a meta-analysis of experiments into the effects of peppermint vapour on
nausea and vomiting concluded that it was an effective anti-emetic, and reduced the
need for conventional anti-emetic drugs, in postoperative and chemotherapy patients
(Lua and Zakaria, 2012). These studies therefore indicate that peppermint oil may aid in
relieving the nausea and vomiting associated with travel sickness.
Ginger (Zingiber officinale)
Like peppermint, ginger has been used for centuries for the relief of nausea amongst
other complaints. Its popularity as an anti-emetic has led to several investigations into
its ability to treat nausea and vomiting. Most of these have focussed on postoperative
and chemotherapy-induced nausea and vomiting. For example, Geiger (2005) studied
the effects of ginger essential oil upon postoperative nausea. A 5% solution of ginger
essential oil in grapeseed oil carrier was applied to the wrist preoperatively alongside a
conventional preventative antiemetic treatment. After surgery, the ginger oil solution
was applied under the nose. It was found that only 20% of patients required further
antiemetic treatment compared to around 50% of patients not treated with ginger. This
suggests that ginger substantially reduced the risk of postoperative nausea and
vomiting and thus may be a useful antiemetic treatment. Research has also been
performed into the effects of ginger upon motion sickness; however this has only been
done on oral intake of powdered ginger root. Administration of powdered ginger root
was found to significantly reduce the incidence of vomiting and cold sweats upon travel
by sea compared to a placebo. Fewer reports of nausea and vertigo were reported in the
group given ginger, however not to a significantly greater level than the placebo group
(Grontved et al., 1988). Another historical study found powdered ginger to significantly
reduce emesis compared to dimenhydrinate, a common over the counter remedy for
travel sickness, when 36 volunteers with a high susceptibility to motion sickness were
placed blindfolded in a rotating chair for up to 6 minutes (Mowrey and Clayson, 1982).
Flight Anxiety
It is reported that between 10 and 40 percent of air travellers suffer from flight anxiety.
This is often due to a disproportionate appreciation of the risks compared to the actual
risks involved, and despite reassurance from others that it is one of the safest ways to
travel, one may need a little help in quelling pre-flight jitters.
Lavender (Lavandula angustifolia)
Probably one of the most commonly used essential oils for stress and anxiety, lavender
is purported to have anti-depressant, anxiolytic and sedative properties, thus may aid in
relaxing while flying. A meta-analysis of 15 randomised controlled trials into the
anxiolytic effect of lavender on humans concluded that the evidence was promising but
more long-term trials may be needed to fully evaluate the significance of its anxiolytic
effect (Perry et al., 2012). However, both acute and chronic inhalation of lavender oil
was found to have a significant anxiolytic effect on Mongolian gerbils and brought about
a similar behavioural profile to treatment with diazepam (Bradley et al., 2007). Linalool
constitutes about 26-49% lavender (Price and Price, 2011). Research has shown linalool
to exert a relaxant effect on the central nervous system in a mouse model (de Fatima et
al., 2012) and an anxiolytic effect in a small trial of 24 human subjects using
physiological parameters of heart rate, blood pressure, electrodermal activity and
salivary cortisol (Hofel, Christ and Buchbauer, 2006), so may be at least in part
responsible for lavender’s anxiolytic effects.
Lemon (Citrus limon)
In agreement with its traditional use, modern studies have shown lemon essential oil
vapour to possess anxiolytic and antidepressant effects in mice (Komiya, Takeuchi, and
Harada, 2006). Knasko (1992) measured several mood and personality parameters in
humans upon inhalation of lemon oil vapour, and found that subjects rated their mood
as more pleasant when a room was scented with lemon essential oil than with a
malodourous or unscented room. Interestingly, the lemon odour also appeared to
influence their personality ratings, as when exposed to the lemon odour, participants
believed more in an internal source of control and the less they believed that their lives
were controlled by chance or powerful others compared to exposure to malodour or no
odour. They were also significantly less likely to report symptoms of existing health
problems when exposed to lemon odour. These results suggest that lemon essential oil
odour lifts the mood and encourages more positive thoughts, which could be beneficial
for anxiousness brought about by flying.
Alertness
If you have a long drive ahead of you, staving off fatigue and remaining alert is essential
to ensure a safe journey. Alongside plenty of breaks, essential oils with central nervous
system stimulating properties may provide a convenient pick-me-up to maintain
alertness and driving performance, as central nervous system stimulants are known to
increase energy levels, concentration and motivation.
Peppermint (Mentha x piperita)
Peppermint essential oil is reportedly a central nervous system stimulant, which is
supported by animal studies showing an increase in activity of mice upon inhalation of
peppermint essential oil as opposed to no odour (Dobetsberger and Buchbauer, 2011).
Peppermint’s central nervous system stimulating effect on humans was also
investigated in a study of 44 healthy volunteers. A concealed essential oil diffuser was
used to deliver the essential oil via inhalation, and several cognitive parameters were
measured in comparison to a control of no aroma. Significant increases in alertness
reported by volunteers using a mood scale were found compared to controls, as well as
a significant increase in memory function (Moss et al., 2008). A small trial also reported
that peppermint odour acted as a CNS stimulant; significantly increasing alertness,
motivation and performance and decrease fatigue and frustration in a simulated driving
test (Raudenbush et al., 2009), which would be ideal for longer journeys. While menthol
alone was shown not to effect cognitive performance (Dobetsberger and Bauchauer,
2011), it is known to interact with cold receptors in the airways when inhaled, which
produces a cool sensation, which may be refreshing in a stuffy car.
Cinnamon Bark (Cinnamomum verum cort.)
Cinnamon bark is used in both traditional Chinese and Aryuvadic medicines for its
central nervous system stimulant effects (Ravindran, Babu and Shylaja, 2005).
Raudenbush et al. (2009) also studied the effects of cinnamon odour on alertness,
motivation and performance and decreased fatigue and frustration in a simulated
driving test, and found that cinnamon odour did indeed significantly improve these
parameters. It was concluded that cinnamon is a central nervous system stimulant. The
major constituent of cinnamon bark, cinnamaldehyde, is reportedly a central nervous
system stimulant in high doses (Douga et al., 2007) so may be responsible for cinnamon
bark’s stimulant effect.
Basil (Ocimum basilicum)
In traditional folk medicine, the dried leaves of European basil (Ocimum basilicum) have
been ground and used as a snuff for achieving mental clarity and focus (Garland, 2004).
Intraperitoneal injection of basil essential oil significantly increased the ambulatory
activity of mice. Ambulatory activity is a type of spontaneous central nervous system
activity, which increases with central nervous system stimulation. Thus, basil may
exhibit central nervous system stimulant effects (Umezu, 2013).
While this is not an exhaustive list of the oils that may be used for the ailments listed, I
hope this has provided an interesting insight and will help you make informed choices
about the oils you select. If you would like any more information or have any queries
relating to scientific research, please do not hesitate to contact me at
lucy@penny-price.com
References
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