Table 1.

Interventions by study.

N°	Author/Year	Study Type/ Sample Size	Interventions
1	Lee & Lee, 2014 [32]	RCT 70 participants	Both groups walked 1 h in the park or city and after 30 min had blood drawn. Assessed: arterial stiffness, pulmonary function, blood pressure, plus lifestyle questionnaire including smoking, alcohol consumption, and exercise. Collection pre- and post-intervention.
2	Mao et al., 2012 [18]	RCT 24 participants	Randomized into urban vs. forest. For 7 days, subjects walked a predetermined route at a calm pace for about 1.5 h, with 20 min rest. After lunch, they walked another predetermined route as well. Blood pressure, pathological factors related to cardiovascular diseases, inflammatory cytokines interleukin-6, tumor necrosis factor α, and Profile of Mood States (POMS) were assessed.
3	Szczepańska-Gieracha et al., 2021 [33]	RCT 25 participants	Control received the standard treatment (40 min general physical training and 20 min health promotion education and psychoeducation two times per week). Virtual reality (VR) group received the same treatment + VR therapy. The therapy cycle consisted of eight VR sessions of 20 min, 2× a week, for four weeks. Used Geriatric Depression Scale (GDS-30), Perception of Stress Questionnaire (PSQ), and Anxiety and Depression Scale (HADS).
4	Yeo et al., 2020 [34]	Systematic review 930 participants	Interventions of an “active” nature (intentional, direct, tactile interaction with real forms of nature or VR) vs. interventions of a “passive” nature (observation of forms of real nature, such as indoor plants) or simulated nature (nature videos). Assessment by self-reported scales, researcher observations, participant tests and tasks (e.g., to assess cognition), and direct objective measures (physiological outcomes such as pulse rate).
5	Roe et al., 2020 [35]	RCT 11 participants	Participants were randomly allocated to one of two groups, each of five to six participants. Group 1 walked the “gray” urban route on Day 1, followed by the “green” urban route on Day 2, and Group 2 vice versa, with a one-day break period between walks. Assessed Mood Adjective Check List; subjective well-being; cognitive function—reaction time; cognitive function—memory retrieval; physiological measures; real-time stress, captured with smart watch.
6	Wu et al., 2020 [36]	RCT 31 participants	The intervention group was exposed to forest bathing (C. camphora) vs. control in urban sites. Assessed C-reactive protein, at day 1 and 3, blood pressure measurements, O2 saturation, and heart rate before and after intervention, every day, in addition to mood state assessment.
7	Pedrinolla et al., 2019 [37]	RCT 163 participants	All patients participated in the intervention, lasting 2 h each, 5× per week for six months (120 sessions, 240 h of exposure), either in an indoor therapeutic garden (intervention group) or standard care environment (control group). Assessment by Neuropsychiatric Inventory Scale; Mini Mental State Examination; Actiheart device; Barthel Index; and Salivary cortisol.
8	Fraser et al., 2020 [38]	Systematic review 231 participants	Any form of physical activity performed in an outdoor exercise setting. Psychological assessment for depression, anxiety, quality of life, stress, general well-being.
9	Jia et al., 2016 [39]	RCT 18 participants	One group was sent to the forest (forest bath) vs. urban area (control), with no other details about the intervention. Assessed lung chemokine; surfactant protein D; interleukin-6, -8, and -1β; interferon-γ; tumor necrosis factor α; C-reactive protein; and proportion of T, NK, and POMS lymphocyte subsets.
10	Mao et al., 2018 [40]	RCT 20 participants	Randomized into urban vs. forest. After four weeks, the patients who had experienced the first forest bathing trip were recruited again, and 20 of them were enrolled for the second experiment. These 20 CHF patients were randomly categorized into two groups consisting of 10 patients in each. Collected pre- and post each experiment, fasting. Assessed: brain natriuretic peptide, interleukin-6, and tumor necrosis factor α.
11	Mao et al., 2017 [41]	RCT 33 participants	Preintervention: fasting blood draw + physical examination. Preintervention collection + POMS questionnaire. Allocated into urban vs. forest group. Subjects walked outdoors 2× per day during the experimental period, and each time, they walked along a predetermined flat path in each area at an unhurried pace for about 1.5 h. They were then asked to complete the POMS test for a second time.
12	Yi et al., 2019 [42]	RCT 88 participants	1°: Walking Program (WP) (active walking in the forest). 2°: Breathing Program (BP) (guided breathing meditation). 3°: Control group (no intervention or activities in the forest). The first two groups were conducted in urban forests. The WP consisted of 30 min of preparatory activities, 50 min of walking in the forest, 20 min of muscle training with elastic band, and 20 min of closing activities. Participants taped red Yongquan beans on both feet so that they could be stimulated by acupressure during the walk. The AP consisted of 30 min preparatory session, 30 min guided breathing meditation, 20 min slow forest walk, 20 min muscle training with elastic band, and 20 min closing activities.

RCT—randomised controlled trial.