Health benefits of nature - Aarhus Universitet...•Shinrin-Yoku (‘Forest bathing’, Japan)...
Transcript of Health benefits of nature - Aarhus Universitet...•Shinrin-Yoku (‘Forest bathing’, Japan)...
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Health benefits of nature
Agnes van den Berg
STEEP summerschool, Aarhus, 2012
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Do you believe that a natural environment
has a positive influence on people’s health?
Question
3%
97%
No
Yes
Source: Survey Natuurmonumenten/Menzis, the Netherlands, 2011
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Overview
• Definitions health and nature
• Roots of nature-health research
• Historical examples
• Empirical evidence for nature-
health relationships
• Underlying mechanisms
• Pathogenic approach: health = absence of
disease and illness.
genesis = production; pathos = suffering
• Salutogenic approach (WHO): health = a
condition of (full) physical, mental and social well-
being.
genesis = production; salutas = health
Definition health
• Clinical indicators:
– objective and subjective measures of
patient functioning
Hospital days, medication, patient
satisfaction, symptom severity
• Public health indicators:
– Subjective (self-reports,
questionnaires)
– Objective: morbidity (disease
statistics) and mortality (death
statistics)
Health indicators
• Any place or area where natural elements
(vegetation and water) are dominantly present
• Not only ‘real’ nature, like forests and swamps, but
also agricultural landscapes and urban green
space
• This presentation: focus on green space
Definition nature
1. Restorative environments research
“Access to (natural) environments with relatively
high restorative quality will cumulatively promote
greater health benefits than access to
environments of lesser restorative quality” (Hartig,
2007)2. Medical practices
Long history in the use of the natural environment
for healing purposes
‘Roots’ of nature-health research
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• 300 BC: First healthcare centres of the world
• Temples dedicated to Asclepius, the god of health
and healing
• Spiritual treatment: sleep in temple and tell dreams
to priest
Design Characteristics
• Location in valleys near woods
• Near hot or cold springs (prophetic powers)
Asklepieia of ancient Greece
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• 600-1000 AD
• Charity
• Little knowledge about illness
• Healing in the spirit with prayer, meditation, rest
Design characteristics
• Garden to make connection with God
• Designed as a replica of the Garden of Eden
Monastic infirmaries
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• Mid-19th century
• Many small connected buildings
• Promoted by Florence Nightingale
• 3 design principles:
• Fresh air
• Sunlight
• Natural surroundings
Pavilion-style hospital
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• Green gyms (England)
• Udeskole (Denmark)
• Shinrin-Yoku (‘Forest bathing’, Japan)
Modern practices
Evidence for relationship nature-health
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HealthyEnvironments
Informed decision making
Evidence-based practice
Research
The value of scientific evidence
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• Few controlled evaluations of therapeutic
interventions like Green Gyms
• Study Ulrich (1984) on effects of view from the
window on recovery of patients still stands out as
one of the few clinical studies
Clinical evidence
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0.5
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1.5
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2.5
3D
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tro
ng
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View wall 2.56 2.48 0.22
View trees 2.40 0.96 0.17
Day 0-1 Day 2-5 Day 6-7
Van den Berg, A.E. & Van den Berg, C.G. (2011). A comparison of children
with ADHD in a natural and built setting. Child: Care, Health and
Environment
• Exploratory study among 12
children diagnosed with ADHD
aged 9-17 on an ADHD ‘weekend
farm’
• 2 groups
• Observations and tests during
visits to woods and town (fixed
order)
Field study children with ADHD
• Both groups showed more social and cooperative
behaviour and less aggressive, inattentive, or
impulsive/hyperactive behaviour in the woods than
in the town
Observations
Both groups showed more inhibitory control in the
natural setting
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0.5
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1.5
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4
4.5
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se
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nd
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Group 1 Group 2
Woods
Town
Cognitive functioning (inhibition test)
Experimental study ADHD
16 children with ADHD aged
8-12
No “comorbid” disorders!
No medication!
Cognitive tests in indoor
garden and conference room
2 groups/orders:
• garden office room
• office room garden
Van den Berg, A.E. (2011). Natuur als therapie bij ADHD: Literatuurstudie, interviews
met deskundigen, en empirisch onderzoek. Alterra-rapport 2112. Wageningen: Alterra
Simple memory tests
(e.g., 15-word test)
Complex tests for
executive functioning
(e.g., Trail making test)
Tests
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Results
Both groups are faster in the
garden
Both groups remember more
words in the office
0
2
4
6
8
10
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# w
ord
s
Office-garden Garden-office
15-words test (delayed recall)
Garden
Office
0
20
40
60
80
100
120
seco
nd
s
Office-garden Garden-office
Trail Making Test
A non-distracting, non-natural environment supports
attentional performance on simple cognitive tasks,
while a natural environment supports performance on
complex tasks
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• Vitamin G (Green) program (2004-2010)
• Linking health data to GIS data on green
space in living environment
• Statistical control for confounding variables
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10
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migraine depression asthma diabetes
10% green 1 km 90% green 1 km
Number
complaints
per 1000
inhabitants
Public health epidemiological research
Groenewegen, P.P., Van den Berg, A.E., Maas, J., Verheij, R., De Vries, S. (2012). Is
a green residential environment better for health? If so, why? Annals of the
Association of American Geographers.
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33000 areas, 41 million people, 36000 deaths in 5 years
International replication: UK
Mitchell & Popham (2007, 2008) in the Journal of Epidemiology and Community
Health and the Lancet
• Relationships between mortality rates and green
space exposure
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Van den Berg, A. E., Van Winsum-Westra, M., De Vries, S. & Van Dillen, S. M. E.
(2010). Allotment gardening and health: a comparative survey among allotment
gardeners and their neighbors without an allotment. Environmental Health, 9:74
Comparative study allotment gardeners
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Results: Older gardeners benefit most
Physical activityHealth Well-being
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• Most studies based on quantitative green
space indicators
• Quality of green space (maintenance,
usability) can have an additional positive
impact on health apart from quantity (Vitamin
G study in 80 Dutch neighborhoods)
• Type of green space and aesthetic quality do
not seem to make a big difference
• Bottom line: the more natural, well-maintained
and usable a green area, the healthier it is
Do health benefits differ between types of green space?
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Why is nature healthy?
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• Trees and plants can filter fine particle pollution
from the air
• But filtering capacity of trees is small and trees may
also have a negative influence on air quality; they
can impede airflows in urban areas which can
cause dust to be “trapped’
• In general the effect of trees and plants on air
quality in and around cities appears to be limited
and variable
Air quality
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Physical activity
• Very popular explanation
• However, general physical activity levels do not
differ between more and less green areas
• Some green spaces invite passive reflection rather
than physical activity
• Exception: children tend to be more active when
they have more parks etc. near their home.
Maas, J., Verheij, R. A., Spreeuwenberg, P., & Groenewegen, P. P. (2008).
Physical activity as a possible mechanism behind the relationship between
green space and health: A multilevel analysis. BMC Public Health, 8, 206.
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• People in green neighborhoods less often feel lonely,
and less often experience a lack of social support
than people in ‘barren’ neighbourhoods
• However, people in green neighbourhoods do not
report having more social contacts with their
neighbours.
• Green “place identity” “sense of community”?
Social cohesion
Maas, J., van Dillen, S. M. E., Verheij, R. A., & Groenewegen, P. P. (2009).
Social contacts as a possible mechanism behind the relation between green
space and health. Health & Place, 15(2), 586-595.
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• Theoretically the most plausible explanation
• strongest relationships for stress-related diseases
• health effects also result from mere views of nature
• Supported by large amount of evidence from
experiments on restorative effects of nature
• Few mediational analyses
Stress reduction
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• 30 allotment gardeners
randomly assigned to conditions
of gardening or a passive
reading task
• Stress induction via a Stroop
task with false feedback
• Salivary cortisol measured
before and after the stressful
task, and during and after the
relaxing task
Van den Berg, A.E. & Custers, M.H.G. (2011). Gardening promotes neuroendocrine
and affective restoration from stress. Journal of Health Psychology, 16(1), 3-11
Stress-reducing effects of gardening
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4.5
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T0 T1 T2 T3
Nm
ol/lite
r
Reading
Gardening
Results cortisol
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• subset of 12 699 respondents
• mediational analysis not possible because
relationship between green space and health was not
significant
Stress-buffering effects of green space
Van den Berg, A. E., Maas, J., Verheij, R. A., & Groenewegen, P. P. (2010). Green
space as a buffer between stressful life events and health. Social Science &
Medicine, 70(8), 1203-1210
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Results (green space in 3 km radius)
3.8
4
4.2
4.4
4.6
4.8
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5.2
5.4
Little green Much green
# H
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pla
ints
No life event Life event
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1.4
1.6
1.8
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Little green Much green
Perceiv
ed
Men
tal H
ealt
h
2.7
2.75
2.8
2.85
2.9
Little green Much green
Pe
rce
ive
d G
en
era
l H
ea
lth
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• Growing empirical support for a relationship
between nature and health
• Focus on green space in living environment
• Mostly correlational studies, need for more causal
evidence
• Stress reduction most plausible mechanism
underlying health benefits of nature
• This underlines the importance of considering
psychological factors when promoting healthy green
environments
• Links among nature-stress-health need further study
Conclusions