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A Systematic Review and Meta-Analysis of Nature-Based Mindfulness: Effects of Moving Mindfulness Training into an Outdoor Natural Setting

Abstract and Figures

Research has proven that both mindfulness training and exposure to nature have positive health effects. The purpose of this study was to systematically review quantitative studies of mindfulness interventions conducted in nature (nature-based mindfulness), and to analyze the effects through meta-analyses. Electronic searches revealed a total of 25 studies to be included, examining 2990 participants. Three analyses were conducted: Nature-based mindfulness interventions evaluated as open trials (k = 13), nature-based mindfulness compared with groups in non-active control conditions (k = 5), and nature-based mindfulness compared with similar interventions but without contact with nature (k = 7). The overall combined psychological, physiological, and interpersonal effects from pre- to post-intervention were statistically significant and of medium size (g = 0.54, p < 0.001). Moderation analyses showed that natural environments characterized as forests/wild nature obtained larger numerical effects than environments characterized as gardens/parks, as did informal mindfulness compared with formal mindfulness. The small number of studies included, as well as the heterogeneity and generally low quality of the studies, must be taken into consideration when the results are interpreted. PROSPERO registration number: CRD42017065639.
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Int. J. Environ. Res. Public Health 2019, 16, 3202; doi:10.3390/ijerph16173202
A Systematic Review and Meta-Analysis of Nature-
Based Mindfulness: Effects of Moving Mindfulness
Training into an Outdoor Natural Setting
Dorthe Djernis
*, Inger Lerstrup
, Dorthe Poulsen
, Ulrika Stigsdotter
, Jesper Dahlgaard
and Mia O’Toole
Department of Geoscience and Natural Resource Management, University of Copenhagen,
C 1958 Frederiksberg, Denmark
Department of Landscape Architecture and Management, Swedish University of Agricultural Sciences,
230 53 Alnarp, Sweden
Department of Clinical Medicine, Aarhus University; N 8200 Aarhus, Denmark
Research Center for Health and Welfare Technology, VIA University College, N 8200 Aarhus, Denmark
Department of Psychology and Behavioural Sciences, Aarhus University, C 8000 Aarhus, Denmark
* Correspondence:; Tel.: +45-6168-8011
Received: 7 August 2019; Accepted: 28 August 2019; Published: 2 September 2019
Abstract: Research has proven that both mindfulness training and exposure to nature have positive
health effects. The purpose of this study was to systematically review quantitative studies of
mindfulness interventions conducted in nature (nature-based mindfulness), and to analyze the
effects through meta-analyses. Electronic searches revealed a total of 25 studies to be included,
examining 2990 participants. Three analyses were conducted: Nature-based mindfulness
interventions evaluated as open trials (k = 13), nature-based mindfulness compared with groups in
non-active control conditions (k = 5), and nature-based mindfulness compared with similar
interventions but without contact with nature (k = 7). The overall combined psychological,
physiological, and interpersonal effects from pre- to post-intervention were statistically significant
and of medium size (g = 0.54, p < 0.001). Moderation analyses showed that natural environments
characterized as forests/wild nature obtained larger numerical effects than environments
characterized as gardens/parks, as did informal mindfulness compared with formal mindfulness.
The small number of studies included, as well as the heterogeneity and generally low quality of the
studies, must be taken into consideration when the results are interpreted. PROSPERO registration
number: CRD42017065639.
Keywords: nature contact; mindfulness; meditation; nature-based therapy; intervention
1. Introduction
Recent research has paid increasing attention to the healing effects of both mindfulness training
and exposure to nature, and research at the intersection between environmental psychology and
meditation science seems to be a growing field [1], as does the variety of applications available [2].
Possible cumulative or synergistic effects may exist. An example is the correlation between the feeling
of being connected to nature and the capacity to be mindful (i.e., trait mindfulness), which has been
documented by Schutte and Malouff [3]. Another example is the theory-based hypothesis that
meditation training and exposure to nature complement each other when combined [4], and are not
merely the addition of independent effects.
1.1. Mindfulness
Int. J. Environ. Res. Public Health 2019, 16, 3202 2 of 22
Mindfulness is considered to involve the intentional regulation of attention with an attitude of
non-judgment, openness, curiosity, and acceptance of one’s current experience [5]. While state
mindfulness may change rapidly, trait mindfulness can be enhanced through meditation. In programs
such as mindfulness-based stress reduction (MBSR) and mindfulness-based cognitive therapy (MBCT),
most formal meditations can be characterized as “attention training”: Attentional regulation is
cultivated by intentionally bringing the attention back to a chosen object (concentration meditation), by
paying attention to whatever thoughts or sensations unfold by themselves in the mind (open-awareness
meditation), or by being aware of the awareness itself [6,7]. Informal mindfulness is also part of the
MBSR curriculum, and is cultivated while one engages in everyday activities [6]. Short mindfulness
interventions have been documented to enhance state mindfulness [8] but most research on
mindfulness training concerns the effects of programs such as the eight-week MBSR and MBCT. These
have been proven to affect health positively with regard to psychological [9,10], physical [11,12], and
social functioning [13,14]. With regard to the mechanisms that underlie mindfulness interventions
comparable to MBSR, evidence has been found regarding cognitive and emotional reactivity,
mindfulness, and ruminative negative thinking, and preliminary but insufficient evidence has been
found regarding self-compassion and psychological flexibility [15].
1.2. Natural Environments and Exposure to Nature
Nature can be defined as “areas containing elements of living systems that include plants and
nonhuman animals across a range of scales and degrees of human management, from a small urban
park through to relatively ‘pristine wilderness’” [16] (p. 120). For the purposes of data extraction, this
article uses Mausner’s [17] categories of natural environments, which seem appropriate for the task
and compatible with Bratman et al.’s definition.
It has been shown that spending time in nature promotes health, prevents health problems such
as stress, depression, and anxiety [18–20], and improves immune functioning [21] and interpersonal
functioning [22]. The pathways to positive health effects may be via physical and social activity as
well as improved air quality [23]. Improved immune functioning from contact with microbial or other
antigens [21] or exposure to certain natural substances such as phytoncides from trees [24] may also
function as a mechanism for associated health benefits. The most widely investigated psychological
pathways are attention restoration and stress reduction, but other factors, such as emotion regulation
and feelings of awe or mystery, may mediate positive health outcomes [20]. A number of nature-
based interventions have been developed that draw on the healing effects believed to be inherent to
nature, including forest therapy, e.g., [25,26], wilderness therapy e.g., [27], adventure therapy e.g.,
[28], and horticultural therapy e.g., [29].
1.3. Possible Interactions between Mindfulness and Exposure to Nature
Attention is a psychological mechanism suggested to underlie the positive effects of both
mindfulness training as a component of trait mindfulness [30], and exposure to nature [31] as part of
attention restoration. Kaplan’s attention restoration theory (ART) is one of the most widely applied
and empirically supported theories about the benefits of exposure to nature for mental health [31–
33]. According to ART, directed attention is a limited resource, but it may nonetheless be restored.
ART suggests that exposure to nature can support the restorative process [34,35], in part because such
natural settings are often physically distant from one’s stressful everyday life, and also because
nature promotes so-called soft fascination, which is defined as effortless attention drawn to
fascinating objects. Although several environments and settings might potentially foster soft
fascination, it has been suggested that natural environments are particularly well suited, as they
inherently possess patterns that are sufficiently extended, rich, and coherent to engage the mind,
which is believed to enable fascination in an “undramatic fashion” [35] (p. 174). ART is most often
applied in relation to human-nature contact, but Kaplan [4] argues that similar mental processes may
also occur during mindfulness meditation. The meditator is often distanced physically or mentally
from everyday life, and can become softly fascinated as he or she effortlessly observes the stream of
sensations, feelings, and thoughts. In order to be restorative, Kaplan argues that both exposure to
Int. J. Environ. Res. Public Health 2019, 16, 3202 3 of 22
nature and meditation need to fit the individual’s inclinations, motivations, and capabilities [4]. He
suggests in particular that the untrained meditator, who tends to use effort in meditation, will have
easier access to soft fascination in a restorative environment [4]. This may be true whether the
meditation is part of a manual-based mindfulness program or a single guided meditation.
Another possible interaction between attention restoration and mindfulness is that paying
attention to the environment is necessary for soft fascination to occur. This was shown in a study by
Jiang, Schmillen, and Sullivan [36]: Students in a natural environment who were occupied with their
portable electronic devices did not restore their attention in the same way as students in the same
natural environment with no such devices. However, even when one is willing to pay attention to
nature, the mind can easily wander, and the recollection of present-moment awareness may be
challenging. This capacity is cultivated through mindfulness, which would therefore seem to support
the acquisition of the potential health benefits of exposure to nature.
As research including both mindfulness and nature is a growing field, and common mechanisms
and interactions seem to exist, it may be timely to make an initial synthesis in order to assess the
quality and extent of research in the field. To our knowledge, no systematic review or meta-analysis
currently exists that investigates the potential effects of nature-based mindfulness (mindfulness
conducted in nature).
1.4. Aims
The primary aim of this study was to systematically review all existing studies investigating
nature-based mindfulness interventions, and to quantify the results through meta-analyses. The
hypothesis was that, due to the beneficial health-promoting effects of mindfulness and exposure to
nature, combinations of mindfulness and nature evaluated in open trials would be positive, and the
effects of nature-based mindfulness would be superior to passive control conditions, to mindfulness
in non-natural settings, and to interventions in natural settings without mindfulness. Specifically,
manual-based stand-alone mindfulness conducted in nature was to be evaluated, with the hypothesis
that exposure to nature would positively affect the outcomes. To qualify the results, the additional
aims were to explore the potential moderating effect of 1) the type of natural setting and 2) the type
of mindfulness practice.
2. Materials and Methods
The study was preregistered in PROSPERO (registration number CRD42017065639).
2.1. Selection Criteria
The PICOS approach [37] was used to evaluate studies’ eligibility.
2.1.1. Population
Adults and adolescents (>12 years) with or without a formal mental or physical diagnosis were
2.1.2. Intervention
Interventions included both exposure to nature as defined by Mausner [17] and guided
mindfulness, defined as “paying attention on purpose, in the present moment.” We left out one
criterion often employed in the definition of mindfulness—namely, obtaining a non-judgmental
attitude—in order not to exclude studies that did not address this more meta-cognitive component
of the mindfulness construct cf. [38,39]. Studies were excluded if they only examined the effect of
exposure to virtual or indoor nature.
2.1.3. Comparators
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Study groups were compared with (1) interventions without exposure to nature but with guided
mindfulness, or (2) non-active control conditions (e.g., waiting lists or written materials). Studies
were also i nclu ded if they employed other or no comparators, in which ca se the y were then e valuated
as open trials.
2.1.4. Outcomes
These were any psychological (e.g., depression), physiological (e.g., heart rate), or interpersonal
(e.g., prosocial orientation) outcomes based on client-level data for which an effect size could be
2.1.5. Study Design
Both open and controlled studies were evaluated. Only quantitative peer-reviewed studies
reported in the English language were considered for inclusion.
2.2. Search Strategy
Search terms for mindfulness and nature were found in the target research articles. An abstract-
based search was then conducted in electronic databases covering the natural environment and
psychology. The databases searched were PsycINFO, Scopus, Web of Science, and Ovid, covering
Agricola 1970 to August 2018; Ovid MEDLINE(R) Epub ahead of print, in-process, and other non-
indexed citations; Ovid MEDLINE(R) Daily; Ovid MEDLINE(R) 1946 to present; Cab Abstracts 1910–
2018; and Embase 1974 to present. Search terms related to mindfulness (Meditati* or mindfulness or
MBSR or MBCT) were combined with search terms related to therapies used in natural settings—or
“forest bathing”, Ecotherapy, “Eco therapy”, “Eco-therapy”, “Nature-based therapy”, “Nature-based
therapy”, “Wilderness therapy”, “Horticultural therapy”, “Nature therapy”, “Nature involvement”,
“nature-based intervention*”, “cognitive behavior therapy*”, or “Nature-assisted therapy”—and
with search terms related to the natural environment and “Restorative nature”, “nature contact”,
“nature exposure”, “nature-based activities”, “Restorative garden”, “Healing nature”, “Healing
garden”, “Therapeutic nature”, “Therapeutic garden”, “Therapy garden”, “Care garden*”,
Wilderness, Forest*, Woods, Outdoor*, “Open space*”, Park, “Green space*”, greenspace*, “Natural
environment”, “Marine environment”, “Ocean wealth”, or “Blue gym”.
The search terms were defined and the searches were conducted for the period from the earliest
dates available in the databases through August 2018. Additionally, a backward search (snowballing)
and a forward search (citation-tracking) were conducted for the included articles. Abstracts and full
texts were evaluated, and disagreements over the inclusion/exclusion of a study were resolved by
2.3. Data Extraction
Means and standard deviations for all quantitative outcomes were extracted. When these were
not available, other test parameters were used (e.g., F and p). In cases where an effect size could not
be calculated, the study’s authors were contacted. Studies were coded for participant characteristics
(i.e., age, gender, and race/ethnicity), duration of intervention (from first to last intervention session),
time to follow-up, and number of hours with mindfulness practice. All health outcomes were
categorized as measures of physical, psychological, or interpersonal outcomes. The characteristics of
nature were coded as either mixed outdoor environment containing natural elements (often with
predominant built structures), garden/park with settings composed of natural elements intended to
make it “appear natural”, or forest/wild nature with predominantly natural elements unaffected by
human interventions [17]. The types of mindfulness were coded as formal mindfulness i.e., guided
meditation, or informal mindfulness where attention is guided to the present moment during
everyday activities. Formal mindfulness was coded as open-awareness meditation versus
concentration meditation. Mindfulness was also coded as the intention to induce state mindfulness
Int. J. Environ. Res. Public Health 2019, 16, 3202 5 of 22
or build trait mindfulness [6,7]. All the coding was verified by the co-author. Data extraction
protocols are available upon request from the corresponding author.
2.4. Quality Assessment
Studies were evaluated for quality using the quality assessment tool for quantitative studies
from the Effective Public Health Practice Project (EPHPP) [40]. For each of the six components:
Selection bias, study design, confounders, blinding, data collection methods, and withdrawals and
dropouts, the studies were rated as strong, moderate, or weak, following the guidelines from the
EPHPP tool. These ratings were, also in accordance with the EPHPP guidelines summed to create a
global quality score (see Table 1). For studies with no weak ratings for the six components, the global
quality score was set to be 1 = strong. Studies with one weak rating the summed score was set to be
2 = moderate. If two or more of the six components had weak scores, the global quality rating was set
to be 3 = weak. Ratings were made and disagreements were discussed and resolved by consensus.
2.5. Analytical Overview
Meta-analyses were performed for the designs and outcomes combined, as well as separately
for each of the design types and each of the outcome categories. Analyses were conducted for two
time periods: From pre- to immediately post-intervention, and from pre-intervention to the last
follow-up assessment. All analyses were based on random-effects models.
The planned exploratory moderation analyses of categorical variables (e.g., type of nature and
type of mindfulness) were explored with meta-ANOVAs. Analyses were performed when a sufficient
number of studies (k 3) was identified for a given moderator category. Continuous moderator
variables (i.e., age, % women, % Whites, number of sessio ns with mindfulness, duration o f treatment,
and time to last follow-up) were considered in meta-regression analyses, based on random-effects
models and estimated with the maximum likelihood method. In the regression analyses, the
proposed moderators served as independent variables, with effect size serving as the dependent
Effect sizes were expressed as Hedges’ g in order to adjust for potential bias to overestimate the
effect size in small samples [41], with values of 0.2, 0.5, and 0.8 considered small, medium, and large
respectively [42]. A p-value below 0.05 was considered statistically significant. Positive effect sizes
indicate a positive effect of the interventions. Each effect size was weighted by its precision (inverse
variance), so that interventions with larger samples contributed more to the estimate of the overall
effect size. Heterogeneity was explored using Q and I2 statistics. Q-tests concern the probability that
results reflect systematic between-study differences. Due to the generally low statistical power of
heterogeneity tests, a p-value of 0.10 was used to indicate heterogeneity [43]. The I2 statistic is an
estimate of the degree of heterogeneity, and is considered to be unaffected by the number of studies.
An I2 value of 0% indicates no observed heterogeneity. Values of 25%, 50%, and 75% are considered
low, moderate, and high respectively [44].
Positive and negative findings may not be equally likely to get published, introducing the risk
of publication bias. The distribution of effect sizes was therefore visually inspected by means of
funnel plots and tested with Egger’s test [45]. When the analyses indicated possible publication bias,
an adjusted effect size was estimated using Duval and Tweedie’s [46] trim-and-fill method, which
imputes missing results and recalculates the effect size. In addition, the file drawer problem—the
possibility that unidentified or unpublished studies with null findings could alter statistically
significant meta-analysis results—was evaluated by Rosenthal’s fail-safe number [47]. If the fail-safe
number exceeded 5k + 10, with k being the number of studies included in the meta-analysis, the file
drawer problem was considered sufficiently low to allow acceptance of the results as unaffected by
that potential source of bias.
All analyses were conducted using the Comprehensive Meta-Analysis program, version 3.3.070
Eaglewood, NJ, USA: Biostat (“Comprehensive Meta-Analysis,” 2014).
3. Results
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3.1. Search Results
A total of 987 publications were identified: 949 through searches in databases, and 38 from other
sources. After the screening of abstracts, 841 records were excluded, resulting in 146 full-text articles;
of these, 120 were excluded, primarily due to a lack of relevant content on interventions (see Figure
1). Five authors were contacted for the data necessary to calculate an effect size. Three authors
provided the data. In the fourth case, the effect size was set to zero, and the study was included. The
last study was excluded due to a lack of information concerning the relevant outcomes. In total, 26
articles from 25 independent studies were included. Seven interventions with mindfulness in a
natural setting were compared with a similar intervention without exposure to nature (i.e., active
control). Seven studies compared interventions with groups in non-active control conditions (i.e.,
passive control), and 13 studies were evaluated as open trials.
Figure 1. Flow chart of literature search.
3.2. Characteristics of Studies
The characteristics of the 25 included studies are summarized in Table 1. Most studies were from
Western countries (12 North American and five European), while eight were from Southeast Asia.
Included in the meta-analysis were a total of 2990 participants across the studies (mean N per study:
120, range 19–659). The mean age was 30.71 (range 12–89), with 51.8% female (range 0–100) and 66.2%
White/Caucasian participants. In five studies, physical illnesses were targeted (i.e., cancer,
hypertension, coronary diseases, chronic diseases, or pain). In six studies the treatment target was a
psychological diagnosis (e.g., stress, anxiety, and depression), and five studies investigated treatment
for substance abuse. Eight included participants with no diagnoses. Twelve studies reported effects
on psychological measures (e.g., anxiety and depression). Nine studies had physical outcome
measures (e.g., heart rate variability and cortisol level), and eight studies reported effects on
interpersonal measures (e.g., work function).
The EPHPP assessment tool was used to evaluate the studies’ quality [40]. Global ratings were
strong for one study, fair for six, and weak for 18 studies. Most studies obtained a strong score for
data collection methods (k = 22) and for reporting withdrawals and dropouts (k = 14); on the other
hand, most studies obtained a weak score for selection bias (k = 13) and blinding (k = 21).
Int. J. Environ. Res. Public Health 2019, 16, 3202 14 of 22
Table 1. Characteristics of included studies.
Author, Year,
N = Included
up), Age = Range
(Mean), Gender,
Ethnicity, Target
Duration, Content
Measurements, Tools
Timings of Data
Location of
Study Group
Comparator: interventions incl. mindfulness, but without nature contact
Ballew &
(2018) [48]
N = 100
Age = 18–24 (19.3)
% female = 55
% Whites = 21
Study group: Students,
no diagnosis
15 min in natural settings.
Instructions to look at
surrounding features and
pay attention to all details,
colors, and textures, to use all
senses to take everything in.
Same program as
study group,
Absorption, awe,
happiness, joy,
contentment (rating
T1: Survey just
after 15-min.
sitting on a
bench, view of
trees, creek,
bamboo, etc.
Shin et al.
(2012) [49]
N = 69 (68)
Age = 20.4 (±1.5)
% female = 100
% Whites = N/A
Study group: Students,
no diagnosis
35 min. walk, 10 min. rest, 35
min. walk, 10 min. rest.
Mindful walking with focus
on breath and sensations.
Same program as
study group,
indoor setting.
Anxiety (STAI), self-
esteem (RSE), happiness
T1: Before
T2: Just after 90-
rocky area with
evergreen trees
Passmore &
Holder [50]
N = 395 (364)
Age = 20.09
% female = 67
% Whites = N/A
Study group: Students,
no diagnosis
2 weeks. Instructions to be
mindful of emotions evoked
by natural objects/scenes in
everyday life; to describe
strong emotions and take
pictures of the nature that
evoked them.
intervention as
study group,
human built
Passive controls:
Continue regular
Affect (PANAS),
elevation (EES),
meaning (SMS),
connectedness (GSC),
prosocial orientation
(PSO), connectedness to
nature (CNS), engaging
with beauty (EWB)
T1: Just before
(PANAS only)
T2: Just after 2-
intervention (all
environment of
Int. J. Environ. Res. Public Health 2019, 16, 3202 15 of 22
Kim et al.
(2009) [51]
N = 73 (63)
Age = 46.2
% female = 85.7
% Whites = N/A
Study group: Major
depressive disorder
4 weeks, 3 hours weekly, for
CBT, positive psychology
tools, and mindfulness
meditation on breath, wind,
forest, and sounds (insight
Same program as
study group,
indoor setting.
Meditation focus
on breath and
indoor or
window objects.
Passive control:
Depression (BDI,
quality of life (SF-36),
stress (HRV, cortisol)
T1: Just before
treatment, all
T2: T1 + 1 week,
T3: T1 + 2
T4: After 3
weeks of
treatment, all
arboretum, 2035
Willert et al.
(2014) [52]
N = 93 (66/49)
Age = 25–59 (45.0)
% female = 82.8
% Whites = N/A
Study group: Stressed
16 weeks, 5 days a week, 9
a.m. to afternoon. Groups of
max. 12. All-day exercises
from meditation training
programs (MBCT and Five
Tibetans), horticultural
activities, nature walks,
stress management, job
counseling, individual
psychotherapy sessions.
Same program as
study group,
indoor setting.
Stress (PSS-10), sleep
(BNSQ), mindfulness
(FFMQ - 3 dimensions),
self-efficacy (COPSOQ-
II), Outcome Rating
Scale, work ability
T1: Just before
T2: Just after 3
months of
T3: T2 + 3
Garden incl.
near forest and
Vujcic et al.
(2017) [53]
N = 30
Age = 25–65 (45.35)
% female = 70
% Whites = N/A
Study group:
Depressed, anxious
4 weeks, 3 one-hour sessions
per week of horticultural
therapy, art therapy, and
sessions. All main activities
relate to work with living
Parallel indoor
activities with
study group, incl.
occupational, art,
and conventional
Depression and anxiety
T1: Just before
T2: Just after 4
garden incl.
open space,
garden, fountain
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(2018) [54]
Study 1:
N = 89
Age = (23)
% female = 64
% Whites = N/A
Study 2:
N = 51
Age = (23)
% female = 72.5
% Whites = N/A
Study groups: Stressed
5 weeks, 1 weekly 90-min.
session. Manual-based
meditation training program
(REST), each session
beginning and ending with
15–20 min. guided open
monitoring meditation (no
specific tradition). Exercises
and themes. Homework: 15
min. meditation most days.
setting. Same
schedule as study
group. Beginning
and end of
sessions: Focused
meditation (no
specific tradition),
exercises and
Attention (LDST; TMT
study 2), affect (SCAS)
Study 1:
T1: Before/after
session 1
T2: Before/after
session 3
T3: Before/after
session 5
Study 2:
T1: Enrollment
T2: Before/after
initial 20-min.
meditation in
session 1
T3: Before/after
initial 20-min.
meditation in
session 3
T4: Before/after
initial 20-min.
meditation in
session 5
garden incl.
water bodies,
Comparator: Non-active control conditions (see also Kim 2009 and Passmore 2017 above)
(2016) [55]
N = 61
Age = 25–49 (39.75)
% female = 57.4
% Whites = N/A
Study group: Chronic
24-hour residential
intervention (noon to noon).
In forest: Walking,
therapeutic activities,
physical exercises,
mindfulness meditation.
Indoor music therapy,
psycho-education on stress
and pain.
Usual weekend
routines, except
visiting natural
environment or
heavy loads of
Stress (HRV, HR)
natural killer cells (NK),
pain (VAS), depression
(BDI), health-related
quality of life (EQ-VAS)
T1: Just before
T2: T1 + 1 day
just after 24
hours’ treatment
Foot of a
mountain: forest
(2012) [56]
N = 92
Age = 45.26
% female = 8.7
% Whites = N/A
Study group:
Detoxified chronic
9 days: 3 days actively
interacting with nature, 3
days challenging activities in
nature, 3 days activities for
introspection (nature
meditation, counseling in
nature etc.).
Inpatients, no
specific treatment
Depression (BDI)
T1: Just before
T2: T1 + 9 days
just after
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Warber et al.
(2011) [57]
N = 58 (47/41)
Age = 25–75 (59.3)
% female = 40.4
% Whites = 85.1
Study group:
Coronary syndrome
4-day residential program.
Study group 1 (MFTE):
Meditation, guided
imagination, journaling,
drawing, nature activities,
nature imagination.
Study group 2 (LCP):
Nutrition, physical exercise,
stress management based on
mindfulness and whole-
person approach.
Both groups: Telephone
coaching biweekly for 3
No treatment.
Depression (BDI, BSI),
stress (PSS), hope
(SHS), gratitude (SG),
quality of life (SF-36),
spirituality (ISWBS),
personal transformation
(TCQ), physical activity
stress (HR, BP, BMI,
lipid levels, lipid
particle size, high
sensitivity C-reactive
protein, biomarkers IL-6
and IL-10)
T1: Just before
T2: Just after 4
days’ treatment
T3: T2 + 3
T4: T2 + 6
only at T1 and
rural settings 3
Sung et al.
(2012) [58]
N = 56
Age = 66.0
% female = 60.7
% Whites = N/A
Study group:
Hypertension stage 1
3-day forest therapy
program: Relationship-
building, stress and health
management, mindfulness
and gratitude meditation in
Written material
on hypertension
Stress (BP), salivary
cortisol level, quality of
life (QoL, 5 dimensions)
T1: Just before
intervention, all
T2: Just after 3-
intervention, all
Follow-up: Self-
monitoring BP, 8
forest in
mountain region
(2014) [59]
N = 86 (84)
Age = 18–45 (20.96)
% female = 86.9
% Whites = N/A
Study group: Students,
no diagnosis
14 days. Written instructions
to immerse themselves in
nature activities whenever
possible in everyday lives.
Keeping logbook of nature
activities for each day.
Solving anagram
puzzles whenever
possible in their
everyday lives.
Affect (PANAS),
elevation (EES),
meaning (SMS),
motivation (SCM)
T1: Just before
T2: T1 + 14 days
just after
environment of
Studies with no comparators relevant for this review
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(2015) [60]
N = 19
Age = 29.4
% female = 100
% Whites = N/A
Study group: No
2 days, noon day 1 to noon
day 3. Indoors: lectures on
coping with stress,
counseling, cognitive
therapy, music therapy. In
forest: 5 hours’ meditation,
walking, exercises.
Stress (HR, HRV,
cortisol), natural killer
cell activity (NK),
burnout (MBI-GS),
stress (WSRI), recovery
T1: Just before
T2: T1 + 2 days
just after
T3: T2 + 14 days
All measures at
T1 and T2,
except MBI-GS
second measure
at T3
Yu et al.
(2017) [61]
N = 128
Age = 45–86 (60)
% female = 65.6
% Whites = N/A
Study group: 46%
chronic diseases (e.g.,
2 hours, 2.5 km sensory
forest walk incl. guided
stimulation of senses (visual,
auditory, olfactory, tactile).
Groups of 6–12 participants.
Mood (POMS-SF),
anxiety (STAI), stress
(pulse rate, BP, HR,
T1: Just before
T2: Just after 2-
Sensory forest,
in valley
surrounded by
mountains on
three sides (part
of Xitou Nature
Education Area
in Japan)
Korpela et al.
(2017) [62]
N = 283
Age = 13–82 (47.2)
% female = 74
% Whites = N/A
Study group: No
Well-being trails in the 3
countries, 4.4–6.6 km,
containing the same 9
signposts with tasks: Self-
monitoring (first and last),
relaxation, letting oneself be
fascinated, observing nature
and one’s own body and
Restorative change (4
items), mood (1 item),
nature connectedness (3
T1: At first
signpost on the
T2: At last
signpost on the
Hiking tracks
incl. forests,
lakesides, fields,
(2018) [63]
N = 29 (27/26)
Age = 66–89 (73.2)
% female = 83
% Whites = 79
Study group: No
4 weeks, 8 sessions of 30 min.
individual mindful walking.
Before walking, guidance
either to become familiar
with the environment, to
focus on breath or
movement, or to scan
through the body.
Affect (PROMIS),
mindfulness (SMS)
T1: Just before
T2: Just after 30
min. mindful
Flat designated
route in
Int. J. Environ. Res. Public Health 2019, 16, 3202 19 of 22
Corazon et al.
(2018) [64]
(2018) [65]
N = 43 (42/29)
Age = 47.9
% female = 81.6
% Whites = N/A
Study group: Severely
10-week nature-based
therapy, 3 times, 3 hours per
week. Activities individually
and in groups: Exercises in
accordance with
MBSR and related to nature
experiences, such as mindful
walking in natural setting.
Gardening and
relaxation/reflection time.
Individual therapeutic
sessions (CBT) and support
for return to work.
Sick leave and contact
with GP (from national
database), well-being
(PGWBI), burnout
T0-T1: 1-year
time span
T1: Treatment
T2: Just after 10
T3: T2 + 3
T4: T2 + 6
T5: T2 + 12
1.4-ha wild
forest garden
located in larger
Sahlin et al.
(2014) [66]
N = 44 (33)
Age = N/A
% female = 100
% Whites = N/A
Study group: Stressed
12 weeks, 3 hours weekly. 3
intervention groups
Activities: Walks, relaxation,
mindfulness, therapeutic
painting, group therapy,
information about stress and
health, garden and nature
Burnout (SMBQ), work
ability I (WAI,
adjusted), stress (scale
tools created for this
study), sleep (KSQ)
T1: Just after
first session
T2: Just after 12-
week program
T3: T2 + 6
T4: T2 + 12
225-ha wild
nature, incl.
forest, ponds,
moorland, hills;
wooden house,
Nacau et al.
(2013) [67]
N = 22
Age = 58.2
% female = 81.8
% Whites = N/A
Study group: Cancer,
after treatment
12 weeks, once per week, 6
hours. 40 min. walks, 60 min.
horticultural therapy, 90 min.
indoor yoga and meditation
(1 session), 60 min.
supportive group therapy (5
Homework: yoga (video).
Well-being (FACIT)
incl. physical, cancer
fatigue (CFS), quality of
life (SF-36), mood
(POMS-SF), anxiety
(STAI), natural killer
cell activity (NK)
T1: Just before
T2: Just after 12
Park incl. forest,
streams, lawns,
gardens; yoga
and meditation
indoors in the
Int. J. Environ. Res. Public Health 2019, 16, 3202 20 of 22
Combs et al.
(2016) [68]
N = 704 (659)
Age = 16
% female = 32
% Whites = 85
Study group:
behavior/ substance/
mood issues
90-day program. Nomadic
hiking and/or expeditions
and tasks associated with
outdoor living. Therapeutic
tools: The wilderness itself,
CBT, choice therapy, family
systems, mindfulness
techniques, diet, physical
exercise. Individual/ group
therapy sessions twice a
Psychological and
behavioral symptoms
and social functioning
T1: At intake
T2: T1 + 3 weeks
T3: T1 + 5 weeks
T4: At discharge
T5: T4 + 6
T6: T4 + 18
Wilderness in
(2016) [69]
N = 43 (32)
Age = 18–24 (22.9)
% female = 0
% Whites = N/A
Study group:
Substance abuse
90-day, 10-bed outdoor
behavioral healthcare
program (Shunda Creek),
incl. weekly 1–5-day
adventure trips integrating
experience (MBE) with
Subjective discomfort,
interpersonal relations,
social roles (OQ-45.2),
mindfulness (FFMQ)
T1: At intake
T2: At discharge
(average T1 +
93.7 days)
Wild nature,
incl. mountains
Russell et al.
(2017) [70]
N = 168
Age = 21.5
% female = 0
% Whites = 40
Study group:
Substance abuse
90-day outdoor behavioral
healthcare program (Shunda
Creek): Weekly 1–5-day
adventure trips integrating
MBE with psychotherapy.
Helpfulness and
mindfulness (subscales
of OQ-45.2), adventure
therapy experience
T1: At
T2–T13: Every
second week
until discharge
Wild nature,
incl. mountains
(2018) [71]
N = 57 (46)
Age = 12–17 (16.6)
% female = 43.9
% Whites = 57.9
Study group: 74%
ADHD/substance use
8-week, 15-bed program:
family therapy, daily
individual/group therapy,
educational programming.
Base camp model: Adventure
therapy and development of
mindfulness skills.
Emotional and
behavioral symptoms
(Y-OQ SR 2.0),
mindfulness (CAMM)
T1: Just before
T2: Just after 8
Wild nature,
incl. mountains
Chapman et
al. (2018) [72]
N = 177
Age = 18–24 (21.5)
% female = 0
% Whites = 42.1
Study group:
Substance use
90-day outdoor behavioral
healthcare program (Shunda
Creek): Weekly 1–5-day
adventure trips integrating
MBE with psychotherapy.
Subjective discomfort,
interpersonal relations,
social roles (OQ-45.2)
T1: At intake
T2: At discharge
(average T1 +
79.6 days)
Wild nature,
incl. mountains
Int. J. Environ. Res. Public Health 2019, 16, 3202 21 of 22
Unsworth et
(2016) [73]
study 2
N = 39
Age = 21
% female = 64.1
% Whites = N/A
Study group: No
3 days’ Aztec adventure
camp in nature, incl. 15 min.
formal daily morning
meditation, and
encouragement to continue
mindfulness practice
throughout the day.
nature in self (INS),
mindfulness (FMI)
T1: Just before
T2: Just after 3
days’ treatment
Wild nature 3
Outcome measures: Beck Depression Inventory (BDI), Hamilton Rating Scale for Depression (HRSD), Montgomery-Åsberg Depression Rating Scale (MADRS),
Depression Anxiety Stress Scale (DASS21), Workers Stress Response Inventory (WSRI), State-Trait Anxiety Inventory (STAI), Perceived Stress Scale (PSS), Swedish
Core Affect Scale (SCAS), Positive and Negative Affect Scale (PANAS), Psychological General Well-Being Index (PGWBI), Patient Reported Outcomes Measurement
Information System (PROMIS), Profile of Mood States short form (POMS-SF), Rosenberg’s Self-Esteem Scale (RSE), self-efficacy scale from Copenhagen Psychosocial
Questionnaire (COPSOQ-II), Recovery Experience Questionnaire (REQ), Happiness Index for Koreans (HI-K), Elevation Experience Scale (EES), Sense of Meaning
Scale (SMS), State Hope Scale (SHS), Gratitude Scale (GS), Self-Concordant Motivation (SCM), General Sense of Connectedness (GSC), Five-Facet Mindfulness
Questionnaire (FFMQ), Child and Adolescent Mindfulness Measure (CAMM), Freiburg Mindfulness Inventory (FMI), State Mindfulness Scale (SMS), Cancer
Fatigue Scale (CS), Shirom-Melamed Burnout Questionnaire (SMBQ), Malash Burnout Inventory-General Survey (MBI-GS), Visual Analog Scale (VAS), Brief
Symptom Inventory (BSI), Functional Assessment of Chronic Illness Therapy-Spiritual Well-Being Scale (FACIT), Irvine’s Spiritual Well-Being Scale (ISWBS),
Transmutation Change Questionnaire (TCQ), Short Form-36 to measure health-related quality of life (SF-36), Quality of Life (QoL), EuroQol Visual Analog Scale
(EQ-VAS), Basic Nordic Sleep Questionnaire (BNSQ), Karolinska Sleep Questionnaire (KSQ),Work Ability Index (WAI), Paffenbarger Physical Activity
Questionnaire (PPAQ), Prosocial Orientation (PSO), Connectedness to Nature Scale (CNS), Engaging with Beauty Scale (EWB), Inclusion of Nature in Self (INS),
Outcome Rating Scale (everyday functioning), Outcome Rating Scale Youth Outcome Questionnaire Self-Report (Y-OQ_SR), Outcome Questionnaire measuring
psychological and behavioral symptoms (OQ-45.2), Adventure Therapy Experience (ATES), Letter-Digit Substitution Test (LDST), Trail-Making Test (TMT), heart
rate (HR), heart rate variability (HRV), body mass index (BMI), lipid levels, lipid particle size, high sensitivity C-reactive protein, biomarkers IL-6 and IL-10, salivary
cortisol level, pulse rate, systolic and diastolic blood pressure (BP), natural killer cell activity calcein-AM release assay using NK-sensitive K-562 cells as a target
Table 2. Results from overall and subgroup meta-analyses.
Sample Size Heterogeneity Global Effect Aizes Fail-Safe N c Criterion
Q b df p I2 Hedges’
95% CI p
Outcome from pre- to post-treatment
Combined effect across designs and outcomes 25 241.1 24 <0.001 90.0 0.54 0.34-0.75 <0.001 2146 135
Adjusted for publication bias
a 32 0.83 0.55-0.91
Open trials 13 1737 170.4 12 <0.001 93.0 0.66 0.38–0.94 <0.001 1211 75
Adjusted for publication bias 15 0.76 0.50-1.02
Studies with passive control group 6 821 10.3 5 0.068 51.4 0.58 0.34–0.82 <0.001 67 45
Studies with active control group 7 900 12.1 7 0.096 42.3 0.26 0.04–0.49 0.023 11 50
Combined effect across designs for each type of outcome
Int. J. Environ. Res. Public Health 2019, 16, 3202 22 of 22
Psychological 24 2990 215.7 23 <0.001 89.3 0.55 0.36–0.74 <0.001 2169 130
Adjusted for publication bias 30 0.69 0.52–0.87
Physical 7 439 18.6 6 0.005 67.7 0.36 0.08–0.63 0.011 29 45
Adjusted for publication bias 1 0.29 0.02–0.55
Social 4 432 3.9 2 .143 48.6 0.39 0.13–0.65 0.004 13 25
Adjusted for publication bias 5 0.22 –0.03–0.48
Outcome from pre-treatment to follow-up
Combined effect across designs 8 1071 13.5 7 0.060 48.3 0.56 0.34–0.78 <0.001 97 50
Adjusted for publication bias 11 0.73 0.59–0.86
Open trials 4 791 8.9 4 0.064 55.2 0.66 0.39–0.92 <0.001 66 35
Categorical moderators
Type of nature:
Garden/park 8 501 17.3 8 0.027 53.7 0.33 0.09–0.56 0.008 28 55
Wild/forest 15 1578 169.5 13 <0.001 92.3 0.66 0.40–0.93 <0.001 14 80
djusted for publication bias 17 0.80 0.56–1.04
Between-group difference 3.4 1 0.065
Type of mindfulness:
Formal 9 544 18.1 8 0.021 55.7 0.37 0.15–0.59 0.001 53 55
djusted for publication bias 10 0.31 0.08–0.53
Informal 8 1309 127.6 7 <0.001 94.5 0.80 0.38–1.23 <0.001 463 50
Between-group difference 3.1 1 0.078
Trait building 4 276 14.8 3 0.002 79.8 10 –0.49–0.69 0.732
State inducing 21 2624 214.6 20 <0.001 90.7 0.62 0.41–0.83 <0.001 2041 115
Between-group difference 2.6 1 0.107
a The possibility of publication bias was examined with funnel plots and Egger’s tests followed by imputation of missing studies. (k) = k + number of imputed
studies. b For the Q-statistic, p-values of <0.05 are considered indicative of heterogeneity. c The fail-safe N was calculated for statistically significant findings to
examine the robustness of these findings, representing the number of non-significant studies that would bring the p-value to non-significance (i.e., p > 0.05).
Int. J. Environ. Res. Public Health 2019, 16, 3202 16 of 22
3.3. Intervention Characteristics
The interventions were highly heterogeneous concerning length, setup, and content, as well as
the amount and type of mindfulness, and the choice of natural setting. All studies had psychological
endpoints, and the most prevalent outcomes were psychological wellbeing or positive emotions (k =
14), attention (k = 7), depression (k = 5), and anxiety (k = 4). Physiological endpoints were reported in
eight studies, all including cardiovascular system outcomes, e.g., heart rate variability and blood
pressure, and four studies reported outcomes related to the immune system, investigating e.g.,
natural killer cells and inflammation. Of studies including interpersonal outcomes (k = 7), four
reported on interpersonal functioning and three on workability. The length of intervention varied
from 15 minutes to 90 days, with follow-up data available for eight studies. The follow-up time
ranged from two weeks to 18 months post-treatment.
Three main types of intervention emerged:
1. Short single-instruction intervention studies (k = 7) aimed at healthy participants, who were
guided either to be mindful on their own while sitting or walking, or to be more extensively
mindful in their everyday lives.
2. Weekly meetings (once or more per week) targeting stressed, anxious, or depressed people
(k = 6), mostly with gardening activities and psychotherapy. One study stood out in this
format as only containing meditation training.
3. Residential interventions (k = 11), of which five were wilderness therapy of several weeks’
duration. Participants in these studies were young people, mostly males diagnosed with
substance use disorders. The other six residential interventions were shorter and in diverse
Among the interventions reporting on formal meditation (k = 8), three had full meditation
training protocols: MBSR, MBCT [74], and restoration skill training (ReST) [54]. The MBSR and MBCT
were integrated in extended nature-based interventions, with only ReST being a stand-alone
program. Five studies mainly included concentration meditation, while open-awareness meditation
was exclusively practiced in two programs. Among the informal mindfulness interventions (k = 8),
four gave brief guidance toward the present moment, and three investigated a specific program of
mindfulness-based experience [69] that integrated psychotherapy with mindfulness on adventure
trips. The interventions’ natural environments varied widely, from designed small gardens to vast
wild nature areas. The amount of time devoted to guided mindfulness was less than five hours in all
but two studies.
3.4. Pooled Effect Sizes and Between-Study Differences
The overall combined effect size from pre- to post-treatment across outcomes and designs was
significant and of medium size (g = 0.54, p < 0.001; see Table 2). Studies employing an open, non-
controlled design, again across outcomes, revealed a significant effect of medium size (g = 0.66, p <
0.001); the same was true for studies with passive control groups (g = 0.58, p < 0.001). Studies using
active control groups also revealed a significant effect, albeit small in size (g = 0.26, p = 0.023). Only
one intervention was found that had a natural setting but without mindfulness as an active control
group, and only one intervention included manual-based stand-alone mindfulness conducted in
nature. The effects of these types of intervention were therefore not calculated.
When the effects from pre- to post-treatment were evaluated for individual outcomes across
designs, the effect on psychological outcomes was significant and of medium size (g = 0.55, p < 0.001).
The effects on social (g = 0.39, p = 0.004) and physical (g = 0.36, p = 0.011) outcomes were significant
and of small size.
Concerning effects at follow-up, the combined effect across designs and outcomes was
significant and of moderate size (g = 0.56, p < 0.001). Only the studies employing an open trial design
were sufficient in number to perform a separate meta-analysis, which also revealed a significant effect
of medium size (g = 0.66, p < 0.001).
Int. J. Environ. Res. Public Health 2019, 16, 3202 17 of 22
A number of planned moderation analyses were conducted, none of which were statistically
significant. However, type of nature (p = 0.068, Q = 3.4) and trended toward significance. Interventions
in wild/forest environments obtained a numerically larger effect (g = 0.66) than interventions in
garden/park environments (g = 0.33). Moreover, the type of mindfulness (p = 0.078, Q = 0.31) did as well
trend towards significance, and informal mindfulness interventions obtained a numerically larger effect
(g = 0.80) than formal mindfulness interventions (g = 0.37). The effect size for inducing state mindfulness
was larger (g = 0.62) than for building trait mindfulness (g = 0.10). No significance was found for this
moderator (p = 0.107). Only two interventions primarily used open awareness, and the moderating
effect of this type of mindfulness was therefore not calculated (see Table 3).
Table 3. Results from meta-regression-based moderation analyses.
Moderator B SE p
Participant characteristics
Mean sample age <0.01 0.01 0.893
% women <–0.01 <0.01 0.425
% Whites 0.01 0.01 0.506
Intervention characteristics
Intervention duration <0.01 <0.01 0.716
Sessions with mindfulness <–0.01 0.01 0.597
Note: B = Unstandardized beta coefficient; SE = Standard error of B; p = level of significance.
3.5. Publication Bias
For all statistically significant results, publication bias was evaluated. Eight analyses were
adjusted for possible publication bias, which in only one case (i.e., effect on social outcomes) changed
the result from significance to non-significance. Seven out of 13 studies failed to meet the criterion for
the fail-safe N, indicating lack of robustness for approximately half of the results.
4. Discussion
We were able to identify 25 independent studies that met our criteria. Across the designs of these
studies, an initial synthesis showed overall positive effects of mindfulness in natural settings
evaluated in both open trials and controlled trials using non-active control groups. These results
support our hypothesis that context may play a significant role in the benefits of mindfulness-based
interventions. This may be explained by the experience of the natural environment, which is so
fascinating that it calls for soft attention, thereby allowing disengagement [4]. This is comparable to
“letting go” in mindfulness, where the meditator is guided not to mentally hold on to anything, and
not to push anything away [6]. Another explanation could be that natural stimuli occupy the attention
[4] and consequently reduce the tendency for the mind to wander [5], which is another aim in
mindfulness training. While experienced meditators may be able to stay present during meditation,
exposure to nature may support inexperienced or otherwise challenged meditators who would
otherwise be at risk of losing concentration completely or becoming emotionally overwhelmed [4].
A number of moderation analyses were conducted. Forests/wild nature and informal
mindfulness were found to trend-wise increase positive health outcomes based on large differences
in effect size, although these were not significant. The lack of significance may be due to the low
number of studies, and should be interpreted according to the effect sizes. The numerically larger
positive effect of natural settings characterized as wild supports the findings by Grahn and
Stigsdotter [75], suggesting that stressed individuals prefer natural environments that are wild and
untouched and offer a variety of species but are still experienced as safe.
Informal mindfulness tended to moderate positive health outcomes compared with formal
mindfulness, as did inducing state mindfulness compared with building trait-mindfulness. Both may
be explained by the outward focus, which may be more beneficial in a natural setting, as it allows
more contact with nature. Furthermore, the possibility of engaging in activities during informal
mindfulness may explain the more positive outcomes. Corazon, Schilhab, and Stigsdotter [76] argue
Int. J. Environ. Res. Public Health 2019, 16, 3202 18 of 22
that bodily involvement with the environment is important in nature-based therapy, as it strengthens
the memory of experiences in nature, and thereby prolongs and confirms the therapeutic effect.
4.1. Implications for Research and Practice
The field of nature-based mindfulness is in its infancy, and is not yet defined; our study only
suggests some structure. One of the aspects that are still in need of investigation is whether certain
types of mindfulness are more suited than others for training and use in natural settings, and whether
this depends on the characteristics of the natural setting and other components of the intervention.
Informal mindfulness is compatible with ordinary activities [5], such as walking a forest trail e.g.,
[62], and has been shown to be a tool for healthy people to enhance the positive effects of contact with
nature [63,77]. Forest bathing is a research field that addresses this [25], but a systematic approach to
mindfulness is still needed in this context. In nature-based therapy, on the other hand, informal
mindfulness enhances awareness of negative thought patterns, which seem easier to detect in natural
settings, and this is of value in a therapeutic context [66,78,79].
Lymeus et al. [54] argue that the practice of open-monitoring meditation (comparable to open-
awareness meditation) in natural environments is superior to concentration meditation, as it allows
natural stimuli softly and effortlessly to hold the attention to the present moment. Due to the scarcity
of available studies, it was unfortunately not possible to compare open-awareness meditation with
concentration meditation as moderators of positive health outcomes in this review. It is
recommended that future studies should address this gap in knowledge, and should also carefully
define and describe the way the mindfulness is conducted and the characteristics of the natural
setting in which the therapy takes place. In addition, it seems reasonable to not only include nature
in health promoting activities [23], but also to include informal mindfulness (i.e., guided attention to
the senses with an attitude of non-judgment and openness) in nature-based therapy. Formal
meditation in natural settings also seems to be a promising tool, and further research is needed to
provide guidelines for such practice.
4.2. Limitations
The rather low quality of the included studies poses a threat to the validity of the findings, which
need to be confirmed in high-quality studies. In particular, blinding and selection bias were issues,
and only a few trials could be categorized as clinical trials according to the EPHPP assessment criteria.
With only 25 studies included in this review, and in light of the heterogeneity of the participants and
intervention characteristics, the generalizability is limited. Furthermore, a different definition of
mindfulness than that employed in this study might affect the character and number of studies
included. The included studies would preferably define mindfulness as containing an attitude of e.g.,
warmth and non-judgment, but meditation practices are rarely described in detail, and such narrow
inclusion criteria would at present exclude most studies.
5. Conclusions
This systematic review and meta-analysis shows that nature-based mindfulness has had a
positive effect on psychological, physical, and social conditions. Furthermore, nature-based
mindfulness is moderately superior to mindfulness conducted in non-natural settings. However, at
this point we know very little about the effect of different types of mindfulness, and more research is
needed to understand what an optimal mindfulness intervention in a nature-based setting should
consist of. Mindfulness in wild nature seems to be more beneficial than mindfulness in more
cultivated settings, but the importance of the setting needs further investigation.
Author Contributions: Conceptualization, D.D., U.S., J.D. and M.O.T.; Data curation, D.D.; Formal
analysis, D.D. and M.O.T.; Investigation, D.D., I.L. and D.P.; Methodology, D.D. and M.O.T.; Writing
– original draft, D.D. and M.O.T.; Writing – review & editing, D.D., I.L., D.P., U.S., J.D. and M.O.T.
Funding: This research received no external funding.
Int. J. Environ. Res. Public Health 2019, 16, 3202 19 of 22
Acknowledgments: We would like to give thanks to Sus Sola Corazon and Mimi Y. Mehlsen for
inspiration and advice.
Conflicts of Interest: The authors declare no conflict of interest.
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... Multiple reports have suggested that exposure to nature and green environments can have comprehensive health benefits, including mental well-being (Bratman et al. 2012;Hunter et al. 2019). Similar emotional states and accompanying thought patterns confronted during meditation are likely to arise during exposure to nature, which "is so fascinating that it calls for soft attention" and possibly contains a similar level of expectation bias for positive effect (Djernis et al. 2019). Previous research indicates that exposure to nature is associated with a reduced stress response (Mao et al. 2012) and enhanced immune functioning (Kuo 2015). ...
... Previous literature suggests that exposure to nature and mindfulness practices may share common mechanisms (Djernis et al. 2019). Attention is one cognitive process that may be responsible for the positive effects of both mindfulness practice (Shapiro et al. 2006) and exposure to nature (Kaplan 1995). ...
... Mindfulness practice can cultivate present moment awareness that in turn can facilitate immersion in nature. Therefore, mindfulness meditation appears to synergize with the acquisition of naturederived health benefits (Djernis et al. 2019). Altogether, common mechanisms and interactions between mindfulness meditation and nature exposure seem to exist. ...
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Objectives Various active control interventions for Mindfulness-Based Stress Reduction (MBSR) have been developed, though many can fall short in controlling for non-specific or placebo effects. We developed a Nature-Based Stress Reduction (NBSR) program based on previously reported positive results from virtual natural environment exposure on mental health. Methods In the present study, we present the NBSR program with its components that were matched with MBSR to ensure equality in structure, duration, contacts, and intensity, but not in specific active components (i.e., mindfulness meditation). Furthermore, we characterized the nature video component of NBSR (videos consisting of scenes of nature) as an attention-matched activity equivalent to the formal meditation practice components of MBSR. Videos were edited with creator permissions and freely online available content to include ten 3-min clips for scenes of nature from 8 different biomes. All clips were viewed by 3 different staff members and rated based on hedonic valence (pleasant to unpleasant). Each 30-min video set was designed to have a ratio of 4 pleasant, 3 unpleasant, and 3 neutral valence clips consistent with the documented heterogeneity of affective experiences during mindfulness meditation. Amazon Mechanical Turk Workers (n = 127) rated hedonic valence and self-reported arousal for individual video clips. We conducted ANOVA and t-tests to establish how hedonic valence differed by proposed valence category. Results Mean valence ratings significantly differed between the three categories of nature video clips using an ANOVA test (p < .001). Follow-up pairwise t-tests revealed significant differences between valence ratings for pleasant vs. unpleasant (p < .001), neutral vs. unpleasant (p < .001), and pleasant vs. neutral (p < .01). Conclusions The subjective experience of NBSR nature videos was reported as pleasant, with higher variability reported for unpleasant clips. This pattern generally parallels the variability and heterogeneity of subjective experiences during mindfulness meditation. These findings demonstrate that the nature video component of NBSR provides promising attention- and valence-matched placebo activity unrelated to mindfulness meditation. A comparison of NBSR versus MBSR in a randomized controlled trial is needed to validate NBSR; however, the freely available nature videos may be a useful component to match mindfulness meditation practice in studies.
... Contact with nature has a beneficial effect on mental wellbeing, facilitates positive affect, and reduces anxiety and depressive symptoms (18)(19)(20). A recent meta-analytical review suggests that nature-based mindfulness is moderately superior to mindfulness conducted in non-natural settings (21). Moreover, animalassisted therapy has been shown in several meta-analyses to be effective in reducing stress reactions, depressive and anxiety symptoms, and in increasing motivation (22,23). ...
... Our results are in line with a recent meta-analytical review suggesting that nature-based mindfulness shows advantages compared to mindfulness programs in non-natural settings (21). Mindfulness in wild nature-as practiced in our study-seems to be more beneficial than mindfulness in more cultivated settings such as parks or gardens, but the importance of the setting needs further investigation. ...
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Background For relapse prevention in depression, conventional mindfulness programs such as the mindfulness-based cognitive therapy proved to be useful. However, early life trauma is a risk factor for having adverse experiences during meditation. Thus, for this patient group mindfulness skills are often difficult to learn and may be facilitated by using animals and a nature setting. Methods The aim of the study was to evaluate the preventative efficacy of a nature- and animal assisted mindfulness program (NAM) over the course of 1 year in unstable or partially remitted depressed patients with a history of early life trauma. NAM included 8 group sessions of 150 min each over 8 weeks plus one booster session. Sixty-seven participants were randomized to either NAM combined with treatment-as-usual (TAU; guideline oriented treatment) or TAU alone. The primary outcome was depression diagnosis over the course of 12 months after end of treatment. Secondary outcomes included clinician- and self-rated depressive symptoms, quality of life, mindfulness skills, and rumination post, and 12 months after the intervention. In addition, we evaluated the participants' satisfaction with the program. Results Analyses revealed significant differences in relapse rates and number of weeks depressed throughout the course in favor of NAM. Furthermore, global quality of life improved significantly more in the NAM group. There was no significant difference for other secondary outcomes. Satisfaction with the program was high with a low drop-out rate of 6%. The vast majority of the participants felt safe practicing mindfulness in nature and found sheep for assistance helpful and motivating. Conclusions A nature- and animal assisted mindfulness program proved to be feasible, highly acceptable, and more effective than standard treatment in preventing relapses in recurrently depressed patients with childhood maltreatment. Nature and animals can facilitate the engagement in the treatment process for individuals with a history of early trauma. However, further evidence in multicenter trials is necessary.
... A recent systematic review synthesizes results [125]. It includes only studies that examined the effect of real outdoor nature (no virtual and indoor nature). ...
... In all studies included in the previously reported review, mindfulness sessions in nature were only one element of the intervention (i.e., psychotherapy) to cope with stress [125]. However, studies considering only mindfulness intervention showed the same enhanced effect [132][133][134]. ...
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In recent years, work-related stress has grown exponentially and the negative impact that this condition has on people’s health is considerable. The effects of work-related stress can be distinguished in those that affect workers (e.g., depression and anxiety) and those that affect the company (e.g., absenteeism and productivity). It is possible to distinguish two types of prevention interventions. Individual interventions aim at promoting coping and individual resilience strategies with the aim of modifying cognitive assessments of the potential stressor, thus reducing its negative impact on health. Mindfulness techniques have been found to be effective stress management tools that are also useful in dealing with stressful events in the workplace. Organizational interventions modify the risk factors connected to the context and content of the work. It was found that a restorative workplace (i.e., with natural elements) reduces stress and fatigue, improving work performance. Furthermore, practicing mindfulness in nature helps to improve the feeling of wellbeing and to relieve stress. In this paper, we review the role of mindfulness-based practices and of contact with nature in coping with stressful situations at work, and we propose a model of coping with work-related stress by using mindfulness in nature-based practices.
... A mindfulness-based intervention has also been shown to significantly reduce emotional distress and improve quality of life in AYA cancer survivors [54]. Although these reviews did not specifically address mindfulness-based interventions within a nature setting, another systematic review demonstrated that mindfulness practices in combination with exposure to wilderness may have synergistic positive effects on health [55]. In the WAYA programme, the mindfulnessbased exercises included those that were more formal and guided, such as forest bathing, as well as informal exercises that occurred spontaneously, such as silent kayaking. ...
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Detailed descriptions of theory, structure, and activities with causal links to specified outcomes of wilderness programs are lacking. Addressing this gap, the present qualitative study gives a thorough description of the development of the Wilderness programme for Adolescent and Young Adult (AYA) cancer survivors (WAYA). WAYA is adapted to the individual needs of AYA cancer survivors. It was conceived around Næss’s ecosophy and the Positive Health Model, and refined based on findings from a scoping review and patient/public involvement. Programme aims were to increase physical activity, self-confidence, personal growth, joy, safety within nature, meaningful relationships, and self-efficacy. The programme was an eight-day expedition followed three months later by a four-day base-camp. Activities included hiking, backpacking, kayaking, rock climbing, mindfulness and bushcrafting. Evaluation of the programme through focus group and individual interviews with 15 facilitators and 17 participants demonstrated that a diverse group of participants, challenging activities, and mindfulness-based practices were found to positively influence group bonding and the learning process. Furthermore, including an expedition and base-camp component was found to be beneficial in supporting the development of participants’ own personal outdoor practices. In conclusion, this study demonstrated that the WAYA programme is safe and well accepted by AYA cancer survivors.
... For nature-based interventions to gain acceptance in health promotion and treatment, there is a need for studies that compare them to established approaches with known benefits rather than to passive or sham conditions, and with methods suited for evaluating their practical utility (e.g., Annerstedt and Währborg, 2011;Djernis et al., 2019). Such methods include evaluation of both positive and negative change on the individual level (e.g., using a reliable change index) in addition to commonly studied average effects. ...
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Restoration skills training (ReST) is a mindfulness-based course in which participants draw support from a natural practice setting while they learn to meditate. Well-established conventional mindfulness training (CMT) can improve psychological functioning but many perceive it as demanding and fail to sustain practice habits. Applying non-inferiority logic, previous research indicated that ReST overcomes compliance problems without compromising the benefits gained over 5 weeks’ training. This article applies similar logic in a 6-month follow-up. Of 97 contacted ReST and CMT course completers, 68 responded and 29 were included with multiple imputation data. The online survey included questions about their psychological functioning in three domains (dispositional mindfulness, cognitive lapses, and perceived stress) and the forms and frequencies with which they had continued to practice mindfulness after the course. Former ReST participants continued, on average, to show higher dispositional mindfulness and fewer cognitive lapses compared to pre-course ratings. Improved psychological functioning in one or more domains was demonstrated by 35%, as determined by a reliable change index. Again, analyses detected no indications of any substantive disadvantages compared to the more demanding, established CMT approach. Compared to the CMT group, more ReST participants had also continued to practice at least occasionally (92 vs. 67%). Continued practice was linked to sustained improvements for ReST but not clearly so for CMT. ReST participants thus continued to use the skills and sustained the improvements in psychological functioning that they had gained in the course, further supporting the utility of ReST as a health intervention.
... Mindfulness interventions in the context of natural environments have been shown to be effective in improving health and wellbeing. For example, a systematic review including a range of mindfulness NBIs from short single-session interventions to residential forest bathing programmes to a 16-week programme including MBCT found positive changes on psychological, physical and social outcomes [62]. In a randomised experiment, Nisbet and colleagues found that participants in a 20 min outdoors walking condition that included instructions to engage in mindfulness reported less negative affects than those randomised to either walking indoors or walking outdoors without meditation [63]. ...
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Novel approaches for children and young people (CYP) in the prevention and intervention of mental illness are needed and nature-based interventions (NBI) may be clinically useful. This proof-of-principle study tested the effects of a novel brief nature-based meditation on rumination, depressive symptoms and wellbeing in young people. Sixty-eight university students were randomised to one of three conditions: active control (n = 23), indoor meditation (n = 22) or nature-based meditation (n = 23). Participants completed self-report measures on state and trait rumination post intervention and depression and wellbeing at a 2-week follow-up. Depressive rumination significantly decreased post intervention in the nature condition and depressive symptoms improved for both intervention groups. Wellbeing only significantly improved at follow-up in the nature condition. Nature condition participants demonstrated one minimal clinically important difference (MCID) for wellbeing at follow-up. Depressive symptoms for this condition were below the clinically significant threshold for depression. The number needed to treat (NNT) analysis suggested that two to five young people would need to complete the intervention. Preliminary evidence suggests NBIs, such as the one in the present study, can reduce depressive rumination and symptoms and improve wellbeing. Replication with larger clinical samples is required to substantiate findings.
... This is a case where environmentalism can be integrated into solutions to problems already prioritized by the community. In fact, mindfulness therapy utilizing nature has been proven more effective in battling mental illness (Djernis, et al., 2019). Empathy towards the natural world and one's self can be taught through such therapy. ...
This chapter proposes that one mechanism by which positive peace could be achieved is the integration of grassroots environmentalism in academic settings. It is suggested that increasing student involvement in bettering their schools and acknowledging youth as valuable allies in the discussion regarding climate change results in more efficient climate action and an increase in the life satisfaction of students. This mechanism facilitates accessibility to a sustainable lifestyle for all students regardless of socioeconomic background.
... "Mindfulness based interventions had overall positive effect on resting physiological measurements in population" [21,23]. Meta analysis and systematic review shows significantly greater pre-post changes with mindfulness [22] .Exposure to nature and forest views has positive health effects [24]. Interventions through wildflower Smartphone app wildflower has long term benefits for attention control [25] ,virtual reality support the mindfulness and also to understand closer experience issues in general population [26] ,mindfulness helpful during COVID -19 pandemic according to mental health professionals. ...
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Mindfulness meditation is paying attention to the current moment with openness, curiosity and with full acceptance. Mindfulness in every day experiences is best strengthened and supported by a regular meditation practice. This review aimed to identify the impact of Mindfulness meditation on the different sections of the society. A systematic search strategy was conducted with through online databases-Medline , PubMed, SCOPUS,Embase,Goggle Scholar, Cochrane library. The grey literatures from relevant websites were also searched. The keywords were indentified and used to search the literature published from 2007-2020 in English. More than 50 papers published related to this area were reviewed. It was found that people to deal with plenty of psychological problems related to stress, burnout, and fatigue. Mindfulness helps them in having more awareness regarding their inner as compare to their outer and that would captivate their performance in every aspect. Many studies shows evidence – based implementation plan contributes in the psychological well being of students .Conclusion: Mindfulness interventions found very useful for reducing the psychological distress. Further implications include the MBSR (mindfulness based stress reduction) potentially beneficial for oncology nursing intervention as they exposed to more stressful conditions.
... Broadly speaking, the majority of epidemiological studies have been cross-sectional and intervention studies often include only limited follow-up timepoints. For example, in the review of intervention studies by Djernis et al. (2019), the follow-up period in the majority of studies was weeks rather than months or years. Although longer follow-ups are also desirable in depression research, they are typically longer in this area. ...
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There is growing interest in nature-based interventions (NBI) to improve human health and wellbeing. An important nascent area is exploring the potential of outdoor therapies to treat and prevent common mental health problems like depression. In this conceptual analysis on the nature–depression nexus, we distil some of the main issues for consideration when NBIs for depression are being developed. We argue that understanding the mechanisms, or ‘active ingredients’ in NBIs is crucial to understand what works and for whom. Successfully identifying modifiable mediating intervention targets will pave the way for interventions with increased efficacy. We highlight a non-exhaustive list of five clinically relevant putative, candidate mechanisms which may underly the beneficial effects of NBIs on depression: stress, rumination, mindfulness, sleep and exercise. We also make the case that when developing NBIs it is important to not neglect young people, explore personalised approaches and focus on both treatment and prevention approaches. To achieve these aims methodologically rigorous programmes of clinical research are needed that include well-powered and controlled experimental designs including randomised controlled trials, qualitative research, longitudinal studies and large prospective cohorts.
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Evidence on the benefits of virtual nature for individuals is steadily increasing. In this contribution, report a systematic review summarizing studies that examined the implications of virtual nature on psychological and psychophysiological outcomes up to 2021. We used Scopus, Web of Science, and PsycINFO to identify the studies of interest. We found 160 records, of which 38 met the eligibility criteria. Results from quality assessment showed that most studies (thirty) were of medium or high quality and only eight were evaluated as low-quality studies. Studies addressed three main outcomes: mood, stress, and restorativeness. Other outcomes such as environmental preference, nature connectedness, cognitive performance received less attention, whilst others such as creativity, perceived safety, subjective vitality, and behavioral intentions were hardly investigated at all. Findings generally demonstrate a positive effect of virtual nature for its users, often comparable to outdoor nature exposure. Studies adopted experimental or quasi-experimental designs, used heterogeneous measures and often sample sizes of unknown power. Future research directions could consider uninvestigated outcomes using larger studies with adequate power and identified best practices.
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Overuse of portable electronic devices depletes one’s attention capacity, a critical cognitive resource. Although contact with nature promotes attentional functioning, we do not know the extent to which exposure to nature and the use of electronic devices interact to promote or inhibit attentional functioning. In this study, 81 participants performed cognitive tasks and then were randomly assigned to one of four rest treatments: green settings with or without a laptop computer and barren settings with or without a laptop computer. Attention was measured three times. Analysis showed a significant effect for both setting and use of a laptop as well as a significant interaction between setting and laptop use. A further analysis controlling for time spent focused on the laptop screen produced similar results. The findings show that using an electronic device in green settings substantially counteracts the attention enhancement benefits of green spaces.
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Background Stress-related illnesses are a major threat to public health, and there is increasing demand for validated treatments. Aims To test the efficacy of nature-based therapy (NBT) for patients with stress-related illnesses. Method Randomised controlled trial ( ID NCT01849718) comparing Nacadia ® NBT (NNBT) with the cognitive–behavioural therapy known as Specialised Treatment for Severe Bodily Distress Syndromes (STreSS). In total, 84 participants were randomly allocated to one of the two treatments. The primary outcome measure was the mean aggregate score on the Psychological General Well-Being Index (PGWBI). Results Both treatments resulted in a significant increase in the PGWBI (primary outcome) and a decrease in burnout (the Shirom–Melamed Burnout Questionnaire, secondary outcome), which were both sustained 12 months later. No significant difference in efficacy was found between NNBT and STreSS for primary outcome and secondary outcomes. Conclusions The study showed no statistical evidence of a difference between NNBT and STreSS for treating patients with stress-related illnesses. Declaration of interest None.
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Complementary to a quantitative effect study, this paper reports on the factors enabling the effect of a mindful walking retreat following a largely unpaved route along a lowland river and estuary in the Netherlands, on which people make their own choices to find their way. Most participants had a depression background. Interviews, triangulated with diary and questionnaire data, were subjected to iterative coding. Several factors were identified as conducive to positive effect, such as encountering nature, negotiating obstacles, duration of the walk, and walking in silence. The results are helpful for the design of effective walking retreats and also underpin the option to develop mindful walking retreats as a regular element in the mindfulness portfolio. Key Words: Walking - Mindfulness - Depression - Nature - Wilderness experience.
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Research indicates that contact with nature elevates positive emotions; however, relatively less work examines the mechanisms responsible for these effects. The present study experimentally tested whether a brief experience in nature promotes specific positive emotions, such as happiness, joy, and feelings of awe because of feeling absorbed and fully involved in its natural features. Participants (N = 100) were randomly assigned to either sit in a natural environment (i.e., a local arboretum) or a built environment (e.g., an outdoor stadium) for 15 min while focusing their attention on their surroundings, and afterward rated their current feelings. Results from structural equation modeling analyses indicated an excellent fit for a mediation model in which experience in a natural environment, as opposed to a built setting, significantly enhanced feelings of awe and other positive emotions , v 2 (22) = 22.86, p = .41, CFI = 1.00, RMSEA = .02, 90% CI (<.001, .09). Moreover, absorption emerged as a significant mediator of nature's impact on positive emotions. There was a particularly strong effect on feelings of awe (68% of variance explained by the full model). Results indicate that nature fosters awe and other positive emotions when people feel captivated and engrossed in their surroundings. The present study extends research on nature's positive emotional benefits and provides implications for nature-based interventions, specifically on the significance of having absorbing experiences in nature.
Attention Restoration Theory (ART) predicts exposure to natural environments may lead to improved cognitive performance through restoration of a limited cognitive resource, directed attention. A recent review by Ohly and colleagues (2016) uncovered substantial ambiguity surrounding details of directed attention and how cognitive restoration was tested. Therefore, an updated systematic review was conducted to identify relevant cognitive domains from which to describe elements of directed attention sensitive to the restoration effect. Forty-two articles that tested natural environments or stimuli against a suitable control, and included an objective measure of cognitive performance, had been published since July 2013. Articles were subjected to screening procedures and quality appraisal. Random effects meta-analyses were performed to calculate pooled effect sizes across 8 cognitive domains using data from 49 individual outcome measures. Results showed that working memory, cognitive flexibility, and to a less-reliable degree, attentional control, are improved after exposure to natural environments, with low to moderate effect sizes. Moderator analyses revealed that actual exposures to real environments may enhance the restoration effect within these three domains, relative to virtual exposures; however, this may also be due to differences in the typical lengths of exposure. The effect of a participants’ restoration potential, based upon diagnosis or fatigue-induction, was less clear. A new framework is presented to qualify the involvement of directed attention-related processes, using examples of tasks from the three cognitive domains found to be sensitive to the restoration effect. The review clarifies the description of cognitive processes sensitive to natural environments, using current evidence, while exploring aspects of protocol that appear influential to the strength of the restoration effect.
The traits of mindfulness and connectedness to nature may have a reciprocal relationship. Mindfulness, which consists of non-evaluative awareness, may allow individuals to feel more connected to nature, and connection to natural environments may help foster mindfulness. A number of studies have investigated the association between trait mindfulness and connectedness with nature. The current meta-analytic investigation consolidated the findings from these studies. Across 12 samples, which included 2435 individuals, there was a significant relationship between mindfulness and connectedness to nature, with a weighted effect size of r = 0.25. Moderator analyses indicated that studies with older participants and studies with community participants rather than students found significantly stronger associations between mindfulness and connectedness to nature. Associations between mindfulness and connectedness with nature varied significantly depending on measures of mindfulness used. These meta-analytic findings provide a foundation for (1) future intervention programs aimed at drawing on nature exposure to increase mindfulness and (2) intervention programs intended to enhance connectedness to nature through mindfulness.
Mindful walking has emerged as a potential intervention strategy to improve mental health and promote well-being in adult and clinical populations. This strategy has not been implemented specifically with older adults to date. This study evaluated the feasibility, acceptability, sustainability, and preliminary efficacy of a mindful walking program for reducing negative affect in older adults. Community-dwelling older adults (n = 29) completed a one-month, outdoor mindful walking program distributed across eight 30-minute sessions. Responses from the post-program and the follow-up questionnaires revealed that mindful walking was well-accepted, highly-valued, and maintained after the program ended. Analysis from the pre-walk and post-walk surveys also suggested the preliminary efficacy of mindful walking program for reducing negative affect. Positive results identified in the current feasibility study indicate readiness for randomized controlled trials to further examine the efficacy and effectiveness of a mindful walking intervention for promoting health and well-being in older populations.
Mindfulness courses conventionally use effortful, focused meditation to train attention. In contrast, natural settings can effortlessly support state mindfulness and restore depleted attention resources, which could facilitate meditation. We performed two studies that compared conventional training with restoration skills training (ReST) that taught low-effort open monitoring meditation in a garden over five weeks. Assessments before and after meditation on multiple occasions showed that ReST meditation increasingly enhanced attention performance. Conventional meditation enhanced attention initially but increasingly incurred effort, reflected in performance decrements toward the course end. With both courses, attentional improvements generalized in the first weeks of training. Against established accounts, the generalized improvements thus occurred before any effort was incurred by the conventional exercises. We propose that restoration rather than attention training can account for early attentional improvements with meditation. ReST holds promise as an undemanding introduction to mindfulness and as a method to enhance restoration in nature contacts.