Nature Exposure and Its Effects on Immune System Functioning: A Systematic Review.

Given the drastic changes in our lifestyles and ecosystems worldwide, the potential health effects of natural environments have grown into a highly pervasive topic. Recent scientific findings suggest beneficial effects from nature exposure on human immune responses. This review aims at providing a comprehensive overview of literature published on immunomodulatory effects of nature exposure by inhalation of natural substances. A systematic database search was performed in SCOPUS and PubMed. The quality and potential bias of included studies (n = 33) were assessed by applying the EPHPP (Effective Public Health Practice Project) tool for human studies and the ARRIVE (Animal Research: Reporting of In Vivo Experiments) and SYRCLE (Systematic Review Centre for Laboratory Animal Experimentation) tools for animal studies. The synthesis of reviewed studies points to positive effects of nature exposure on immunological health parameters; such as anti-inflammatory, anti-allergic, anti-asthmatic effects or increased NK (natural killer) cell activity. Decreased expression of pro-inflammatory molecules, infiltration of leukocytes and release of cytotoxic mediators are outcomes that may serve as a baseline for further studies. However, partially weak study designs evoked uncertainties about outcome reproducibility and key questions remain open concerning effect sizes, duration of exposure and contributions of specific vegetation or ecosystem types.

Psycho-Physiological Stress Recovery in Outdoor Nature-Based Interventions: A Systematic Review of the Past Eight Years of Research.

BACKGROUND: In modern, urban daily life, natural environments are increasingly recognized as an important resource for stress recovery and general well-being. AIM: the present review aims to provide an overview and synthesis of the past eight years' research into the psycho-physiological effects of outdoor nature-based interventions, related to stress recovery. METHOD: a structured search was performed in seven databases, returning 5618 articles. Removal of duplicates and initial screening gave a total of 95 studies. After full text reading, 36 studies were included in the assessment. RESULTS: most of the psychological outcomes were related to different emotional measures. The synthesis of the results points towards outdoor, nature-based exposure having a positive effect on different emotional parameters, related to stress relief. The studies into physiological measures showed more equivocal results. CONCLUSION: the research, conducted over the past eight years, into outdoor, nature-based exposure has now attained a sound evidence base for psychological and especially emotional effects, but the evidence base for physiological effects within this timeframe shows a great degree of heterogeneity. LIMITATIONS: interpretation of the results is limited by the review only covering the past eight years' research on the subject.

The Tree Is My Anchor: A Pilot Study on the Treatment of BED through Nature-Based Therapy.

Binge eating disorder (BED), characterized by recurrent episodes of binge eating with a subjective experience of lack of control, is the world's most common eating disorder. The aim of the present pilot study was to examine the feasibility of implementing nature-based therapy (NBT) in the treatment of BED. The NBT intervention was compared to Support Group Meetings (SGMs), which are the only publicly available form of support for people diagnosed with BED in Denmark. Twenty participants with a BED diagnosis were included in the study, which had a mixed-methods design including Eating Disorder Examination interviews, semi-structured interviews, and questionnaires measuring well-being (The Psychological General Well-Being Index) and self-esteem (Rosenberg's Self-Esteem Scale). Both the NBT and the SGMs showed positive results on all outcome measures (decreases in binge eating episodes and increases in general psychological well-being and self-esteem). The interviews indicated that the NBT context made the psychotherapeutic content more accessible to the participants and further helped them transfer the therapeutic gains to daily life after completing treatment. However, these results should be interpreted with caution due to the small sample size-ideally, they would need to be tested on a larger, randomized sample.

Efficacy of nature-based therapy for individuals with stress-related illnesses: randomised controlled trial.

BACKGROUND: Stress-related illnesses are a major threat to public health, and there is increasing demand for validated treatments.AimsTo test the efficacy of nature-based therapy (NBT) for patients with stress-related illnesses. METHOD: Randomised controlled trial (ClinicalTrials.gov 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 interestNone.

A Long-Term Follow-Up of the Efficacy of Nature-Based Therapy for Adults Suffering from Stress-Related Illnesses on Levels of Healthcare Consumption and Sick-Leave Absence: A Randomized Controlled Trial.

Stress-related illnesses are a growing health problem in the Western world; which also has economic significance for society. As a consequence; there is a growing demand for effective treatments. The study investigates the long-term efficacy of the Nacadia® nature-based therapy (NNBT) by comparing it to the efficacy of a validated cognitive behavioral therapy, called STreSS. The study is designed as a randomized controlled trial in which 84 participants are randomly allocated between the treatments. Long-term efficacy is investigated through data extracts from the national database of Statistics Denmark on the sick leave and the health-care consumption. The results show that both the NNBT and the STreSS lead to a significant decrease in number of contacts with a general practitioner in the period from twelve months prior to treatment to twelve months after treatment; and, a significant decrease in long-term sick leave from the month prior to treatment to twelve months after treatment. The positive long-term effects provide validation for the NNBT as an efficient treatment of stress-related illnesses.

A nationwide Danish survey on the use of green spaces by people with mobility disabilities.

BACKGROUND: There is increasing awareness of the importance and health benefits of living near green spaces. Research usually focuses on the general population's use of green spaces and there has been little focus on the use of green spaces by specific groups, such as people with mobility disabilities. This represents a significant knowledge gap with regard to facilitating access to healthy green environments by all population groups. This study aims to provide knowledge of the use of green spaces by people with mobility disabilities. METHODS: The study was based on data from the Danish Health and Morbidity Survey in 2005. The study participants consisted of 11,238 adult Danes, 383 of whom reported mobility disabilities, meaning that they were dependent on assistive devices for walking or moving around. Multiple logistic regression analysis was used to investigate the association between mobility disability and use of green spaces. RESULTS: The results show that respondents who reported mobility disabilities visited green spaces less often than respondents without mobility disabilities. The severity of the mobility disability was associated with the frequency of visits. Frequency of visits was also related to the respondents' health-related quality of life status. CONCLUSIONS: These results highlight the need for further research into the constraints faced by people with mobility disabilities with regard to visiting green spaces.

It is not all bad for the grey city - A crossover study on physiological and psychological restoration in a forest and an urban environment.

Today, urbanization presents a challenge to urban planning with regard to creating healthy living environments. The aim of this research is to gain further knowledge of the restorativeness of a best case urban and natural environment: that is a historic down town urban environment and forest environment located in an arboretum. The study has a cross-over design where 51 (N) female university students are exposed to the two environments through both seated viewing and walking. A mixed method approach is used with both physiological measurements of blood pressure (BP) and heart rate variability (HRV) and psychological measurements of mood change and perceived restorativeness. The HRV results show no significant differences between the two environments, and both environments are found to be more physiologically restorative than being at the office or on the minibus. The results of the psychological measures indicate that the forest walk has a positive effect on mood, while the walk in the urban environment has no effect. The forest environment is also rated more highly with regard to perceived restorativeness than the urban environment. The results support the current research that shows natural environments as more restorative than urban environments. The study also adds to the ongoing debate on healthy urban planning by indicating that architectural and historical qualities may be associated with the physiological well-being of citizens.