Indicators of psychosocial and physiological effects of forest therapy: A systematic review

Background: Current research on forest therapy and its health outcomes involves various health indicators without unification of measure. Information on the therapeutic elements of forest and forest-therapy programs is insufficient. We investigated forest-therapy programs, therapeutic elements of the forest environment, and health-outcome measures to standardize health indicators of forest therapy. Method: A systematic review was conducted on the health outcomes of forest therapy from 2010 to 2021. We summarized therapeutic elements, forest-therapy sites, characteristics, and health outcomes. Additional cross tabulation was performed by using SAS software Results: Twenty-nine articles were analyzed. Among them, walking and physical activity were conducted most frequently as forest therapy. Also, meditation was used frequently in Pinales environments and viewing sessions in Fagales environments. In Fagales and Pinales environments, stress, psychological status, depression and endocrine function were improved. Apart from the forest therapy environment, stress and depression were most frequently observed psychological outcome. Cardiovascular and endocrine function were most frequently measured physiological outcome which reported positive result. functions were improved. Walking, five-senses stimulation, physical activities, and meditation benefited psychological (stress and depression) and physiological (cardiovascular and endocrine function) outcomes. Viewing sessions benefited both sentiment and cardiovascular function, and meditation benefited both stress and endocrine function. Conclusion: We evaluated therapeutic elements of the forest-environment program and health outcomes. This systematic review can be used as a reference for planning and operation of forest-therapy programs. Keyword: Systematic literature review, forest bathing, Shinrin-yoku, forest elements, health promotion, therapeutic effect, health-related indicators, cross-tabulation