Sustainable Futures Wright & Wright - Flipbook - Page 25
Prescribing nature: but what and where?
Kathy Willis
‘The relationship
between biodiversity
and human health
is a relatively
new but rapidly
expanding field
of research’
Opposite:
Research indicates that
walking through forests can
elevate levels of alpha-pinene
and limonene in the bloodstream.
These compounds interact
with biochemical pathways in
the body, helping to reduce
anxiety, promote wakefulness,
or enhance sleep
Increasing evidence suggests that access
to nature is associated with improved
levels of physical and mental wellbeing,
and that such beneficial effects are now
becoming more widely recognised in
policy at both national and international
levels. Interaction with nature can be
linked with many positive mental and
physical health outcomes, triggering
physiological and psychological
calming, enhancing immune functions
and positively influencing biochemical
pathways. These benefits can be gained
by spending at least 20 minutes in
nature, a few times a week.
Nature-based therapy performs
as well as, if not better, than more
conventional cognitive behavioural
therapy (CBT). In a 2018 study of 84
Danish participants, all registered as
clinically stressed and unable to work,
half underwent CBT and half had
sessions three times a week over 10
weeks interacting with nature in gardens.
Both forms of therapy were equally
effective, leading to a significant decrease
in contact with a doctor in the 12-month
period following the intervention.
However, 77% of those who
underwent the nature therapy were
not on sick leave after completing the
treatment, compared to 65% of those
who had CBT. Communing with nature
in an indoor setting, such as green walls
and indoor planting, was also found
to have beneficial effects, lowering
markers in the blood associated with
inflammatory diseases.
The relationship between
biodiversity and human health is a
relatively new but rapidly expanding
field of research, dedicated to examining
the mechanisms of action that occur
when our senses (sight, smell, sound,
touch, and the hidden sense of the
environmental microbiome) interact
with certain aspects of nature, to bring
about positive physical and mental
Prescribing nature: but what and where?
health outcomes. For instance, our sense
of smell might be stimulated by volatile
organic compounds (VOCs) from plants;
sight by the shape, density and colour
of vegetation; touch, through the
textures of wood and vegetative
material, and sound, by bird song,
water and wind in trees.
Experiments with controlled
exposure to VOCs such as the
phytoncides alpha-pinene and
limonene, two of the most common
compounds in nature, found in citrus
oils and the leaves and wood of most
conifer trees, were shown to decrease
the stress hormone adrenaline and
increase the natural killer cell activity
in the blood of trial participants.
Evidence suggests that VOCs can pass
into our bloodstream when the ambient
air which is infused with them – for
example, by simply walking in a
coniferous forest.
The physiological and psychological
benefits of having an outlook onto a
green landscape as opposed to an urban
setting can also be evaluated. Trials
involving monitoring brain activity and
heart rate showed that nature has a
measurably calming effect and that
subjects felt more relaxed when viewing
images of a forest compared to a city.
When assessing how to prescribe
contact with nature for improved
health, the process is similar to that
of prescribing conventional drugs.
Consideration should be given to which
specific interactions with nature lead
to positive physical and mental health
outcomes, what physiological and
psychological changes are triggered by
these interactions and how long these
interactions should be to achieve
tangible health benefits. Finally, the
relative efficacy of interacting with
nature compared to prescription
drugs – in effect, the cost benefit –
should also be carefully evaluated.
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