1

Health benefits of nature

Agnes van den Berg

STEEP summerschool, Aarhus, 2012

2

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

3

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

9

• 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

10

• Mid-19th century

• Many small connected buildings

• Promoted by Florence Nightingale

• 3 design principles:

• Fresh air

• Sunlight

• Natural surroundings

Pavilion-style hospital

11

• Green gyms (England)

• Udeskole (Denmark)

• Shinrin-Yoku (‘Forest bathing’, Japan)

Modern practices

Evidence for relationship nature-health

13

HealthyEnvironments

Informed decision making

Evidence-based practice

Research

The value of scientific evidence

14

• 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

0

0.5

1

1.5

2

2.5

3D

os

e s

tro

ng

pa

ink

ille

r

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

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

se

co

nd

s

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

12

# 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

0

10

20

30

40

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

23

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

24

Results: Older gardeners benefit most

Physical activityHealth Well-being

25

• 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.

29

• 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.

30

• 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

32

4.5

5

5.5

6

6.5

7

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

5

5.2

5.4

Little green Much green

# H

ealt

h C

om

pla

ints

No life event Life event

0.8

1

1.2

1.4

1.6

1.8

2

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

36

Thank you!

a.e.van.den.berg@rug.nl

www.agnesvandenberg.nl