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

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.

Nature’s Role in Outdoor Therapies: An Umbrella Review

“…Of the 14 studies in this review, seven were located in the discipline of public health [ 27 , 29 , 30 , 31 , 35 , 36 , 38 ], two in medicine [ 33 , 37 ], two in child, youth, and family studies [ 28 , 32 ], one in mental health and addictions [ 34 ], one in psychology [ 18 ], and one in nursing [ 39 ]. The studies were organized into five categories based on their self-identified approaches: nature-based therapies [ 27 , 29 , 30 , 31 , 36 ], forest therapy [ 34 , 35 , 38 ], horticultural therapy [ 33 , 37 , 39 ], wilderness therapy [ 28 , 32 ], and adventure therapy [ 18 ]. Nature-based therapy is defined as “an intervention with the aim to treat, hasten recovery, and/or rehabilitate patients with a disease or ill health, with the fundamental principle that the therapy involves plants, natural materials, and/or outdoor environment[s]” [ 27 ] (p. 372).…”

“…It is for this reason, they posit the effects of nature-based therapy have relevance and success. Djernis et al [ 31 ] echo the above in stating that nature as context “may play a significant role in the benefits” of these interventions. Playing on the language of ART they suggest the environments may be “so fascinating that it calls for soft attention, thereby allowing disengagement” (n.p.).…”

“…The role and potential need of a trained facilitator was discussed as likely linked to processes [ 33 , 36 ] and subsequently the reported outcomes [ 28 ]. Djernis et al [ 31 ] found explanations of nature increasing the experiences of memory and thereby extending the longevity of benefits gained. Britton et al [ 29 ] pointed to the characteristics and diversity of natural environments and how humans interact with them.…”

“…With scant theory and causal mechanisms identified, there exists a considerable gap in knowledge as to how outcomes in outdoor therapies are achieved. Clinical and practical outcomes reported in each of the 14 papers we reviewed suggest positive benefits from “moderately positive” to “effective.” The reviews of nature-based therapies suggest some improvements in mental health and psycho-social wellbeing [ 29 ], psychological states related to emotions and stress reduction, but that the evidence was weak regarding the links to physiological outcomes [ 31 ]. Forest therapy reviews showed positive outcomes for mental health, particularly anxiety [ 35 ], and physiological improvements such as reducing blood pressure and boosting immunity [ 38 ], again failing to show casual links between physiological change and mental health outcomes.…”

Greenspace Interventions, Stress and Cortisol: A Scoping Review

“…In addition to evidence from public opinion, the physiological and psychological benefits of spending time in nature, or greenspace, have received growing scholarly interest in the past decade [ 1 , 3 , 4 , 5 , 6 , 7 ]. Much of the extant research on greenspace interventions (GSI) focuses on the association between nature and mental health and wellbeing across the lifespan [ 3 , 7 , 8 , 9 , 10 , 11 ]. Several reviews focusing on the physiologic benefits of greenspace have included outcomes related to stress including allostatic load [ 12 ], cardiovascular disease biomarkers [ 13 ] immune function [ 14 ] and cortisol [ 15 ].…”