Indicators of the Psychosocial and Physiological Effects of Forest Therapy: A Systematic Review

Abstract

Research on forest therapy and health outcomes is insufficient and involves the limited unification of various health indicators. Information on the natural therapeutic elements of forests and forest-therapy programs is insufficient. We investigated forest-therapy programs, the natural therapeutic elements of the forest environment, and health-outcome measures to standardize the health indicators of forest therapy. A systematic review was conducted on the health outcomes of forest therapy from 2010 to 2021. We summarized natural therapeutic elements and forest-therapy sites, characteristics, and health outcomes. Twenty-nine articles were analyzed. Among them, forest therapies of walking and physical activity were conducted most frequently. Additionally, a positive improvement in general sentiment condition was substantial in all vegetation environments, and a reduction in depression, psychological enhancement, stress alleviation; and an enhancement in the cardiovascular system and the endocrine system occurred in both narrow- and broad-leaved forests. Walking, five-senses stimulation, physical activities, and meditation benefited psychological and physiological outcomes. We evaluated natural therapeutic elements of the forest-environment program and health outcomes. This systematic review can be used as a reference for the planning and operation of forest-therapy programs.

Use of Measurement Tools to Validate the Health Effects of Forest Healing Programs: A Qualitative Analysis

“…We systematically reviewed the literature on the measurement of physical and mental health and formulated a research protocol [7]. We selected five mental health questionnaires that met the following criteria: few questions, completion within 10 min, written in Korean, and appropriate for administration before or after 1-day or 1-night stays.…”

“…The fact that forest healing programs and exposure to green environments promote physical and mental health has been well-established through previous research [7]. However, many commonly used health indicators to confirm such health benefits are known for their non-invasiveness and ease of use in a forest setting without the need for medical professionals [7,31]. Nevertheless, it is essential to investigate whether participants who directly assess their health status through these health indicators find them easy to use and if there are any limitations.…”

“…Research aiming to verify the health-promoting effects of forest healing programs is underway worldwide [7]. Systematic literature reviews [1,7] have shown that a variety of health indicators are used in forest healing research, including ones related to cardiovascular health, the immune system, and the neuroendocrine system. In addition to physiological effects, effects on the emotional state and mental health have also been reported.…”

“…The parameters typically used to evaluate the physical health effects of forest healing are systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate variability (HRV), and blood sugar [1,7]. Prior research on psychosocial effects used the Profile of Mood States (POMS), Positive Affect and Negative Affect Schedule (PANAS), and State-Trait Anxiety Inventory (STAI) [7]. Other surveys have used questionnaires on quality of life (QOL) [16][17][18], stress [19][20][21], and depression [22][23][24].…”

“…The fact that forest healing programs and exposure to green environments promote physical and mental health has been well-established through previous research [7]. However, many commonly used health indicators to confirm such health benefits are known for their non-invasiveness and ease of use in a forest setting without the need for medical professionals [7,31].…”