Greenspace Interventions, Stress and Cortisol: A Scoping Review

Abstract

Background: Engaging with nature can profoundly impact psychological and physiological health of persons across the lifespan. Greenspace interventions (GSI) encompass a broad range of strategic, nature-based activities for overall health and wellbeing. Within the past 20 years there has been a growing interest in the access to and management of greenspace to mediate the deleterious impact of acute and chronic stress, particularly, physiologic biomarkers of stress such as cortisol. Objective: This review aims to describe the impact of greenspace interventions on cortisol, to present the current state of the science on GSIs as they impact cortisol, and to uncover any limitations of current research strategies to best inform future research. Methods: A scoping methodology was conducted to systematically study this emerging field and inform future research by mapping the literature based on the GSI category, interventional design, cortisol metrics, and subsequent analysis of cortisol. Conclusion: Considerable heterogeneity in research design, aim(s), interventional strategy, and cortisol metrics were identified from a total of 18 studies on GSIs and cortisol outcomes. While studies demonstrated a potential for the positive association between GSIs and stress relief, more rigorous research is needed to represent GSIs as an intervention to mitigate risks of stress.

Effects of Nature-Based Intervention in Occupational Health Care on Stress – A Finnish Pilot Study Comparing Stress Evaluation Methods

“…The observed decreases in salivary cortisol on the intervention days were aligned with other studies where typically decreases of ~5% in cortisol levels have been observed in a variety of natural settings. 42 A recent study of non-facilitated visits at sensory garden resulted in even greater (16% cf 5%) intervention effect on salivary cortisol. 47 The presence of a statistically significant decrease in cortisol on intervention days versus non-intervention days, despite a low statistical power, does suggest potential contribution of NBI to the moderation of stress.…”

“…The most studies have detected decreasing effect of nature settings on participants’ salivary cortisol levels. 42 Salivary α-amylase is much less studied and depending on the type and physical strenuosity of the intervention, either increase or decrease of α-amylase during the intervention has been detected. 43–45 …”

Shinrin-yoku, yoga and other strategies in the fight against COVID-19

“…It appears that greenspace interventions can also reduce cortisol and stress levels, yet most studies on this topic are limited by data collection methods and heterogeneity of the study design. [ 9 ] Although more research is needed, the current data would suggest that greenspace exposure is associated with numerous health benefits, enough to encourage policymakers and urban planners to create, design and maintain accessible greenspaces in urban centers.…”

Forest-bathing and physical activity as weapons against COVID-19: a review

“…The practice of spending time amongst the trees is known in Japan as Shinrin-yoku or ‘forest-bathing’ and has been shown to be of therapeutic benefit with regards to improving mental and immune system health. In fact, the many documented physiological benefits of forest bathing include among others, a decrease in both pulse rate and cortisol levels which can affect the proper functioning of the immune system (Timko et al 2020 ; Ochiai 2019 ) and which have brought interest for further study (Jones et al 2021 ). In many other parts of the world, the benefits of walking in a wooded area is known but a medical approach that hands out such ‘green prescriptions’ is not common practice.…”